Low health literacy has a detrimental effect on health outcomes, as well as ability to use online health resources. Good health literacy assessment tools must be brief to be adopted in practice; test development from the perspective of item-response theory requires pretesting on large participant populations. Our objective was to develop a novel classification method for developing brief assessment instruments that does not require pretesting on large numbers of research participants, and that would be suitable for computerized adaptive testing.We present a new algorithm that uses principles of measurement decision theory (MDT) and Shannon's information theory. As a demonstration, we applied it to a secondary analysis of data sets from two assessment tests: a study that measured patients' familiarity with health terms  and a study that assessed health numeracy .In the familiarity data set, the method correctly classified 88.5% of the subjects, and the average length of test was reduced by about 50%. In the numeracy data set, for a two-class classification scheme, 96.9% of the subjects were correctly classified with a more modest reduction in test length of 35.7%; a three-class scheme correctly classified 93.8% with a 17.7% reduction in test length.MDT-based approaches are a promising alternative to approaches based on item-response theory, and are well-suited for computerized adaptive testing in the health domain. More than half of the US adult population has limited health literacy skills . Low heaThe goal of the consumer health informatics initiatives is to improve patients' comprehension of health information. This requires tools that identify deficiencies in disadvantaged patient populations. Several health literacy measures are available, including the Rapid Estimate of Adult Literacy of Medicine (REALM) , the TesEven this partial list suggests that a truly comprehensive health literacy assessment would be prohibitively burdensome for both the patient and the clinician. In order for testing to be useful in clinical practice or for patient-oriented informatics initiatives, it would have to be made as simple and short as possible. Abbreviated versions of REALM-13 and TOur current work is part of a research program with an overall objective of developing a flexible health literacy instrument for older adults. A short and powerful assessment would be particularly useful for older adults, who: (a) are more likely to have low health literacy ,15, (b) The task of health literacy assessment is similar to mastery tests used in educational and professional domains, in which a subject needs to be classified as master or non-master. Huynh and van i, by an examinee of estimated ability θ is calculated as:Under IRT, the probability of a correct response to item i α∈  are item-specific parameters that represent the difficulty, discriminating power and guessing probability of item i respectively [where ectively ,26. IRT ectively .The methods proposed by Kingsbury and Weiss and Reckadapt to the examinees' perceived ability in order to determine the item order and test length, can be suitably administered using computers. Computerized adaptive testing (CAT) provides a way to make assessment more comprehensive while limiting additional burden on the test-taker [These testing methods, which st-taker ,32. CAT st-taker . For insst-taker . CAT hasst-taker , assess st-taker  and to ast-taker . It has st-taker .In this paper we discuss the application of a MDT-based approach to administer variable-length tests in order classify examinees into a limited number of discrete categories. Pilot testing with a relatively small calibration sample is used to estimate the conditional probabilities that subjects of particular literacy levels will answer a particular question correctly. Subsequently, Bayes' Theorem is used to compute the likelihood that an individual test-taker who answers a series of questions correctly is of a specified literacy level. We demonstrate the validity of the proposed method using data from two patient health literacy questionnaires.k literacy classes . One item is presented at a time, and on the basis of the test-taker's previous answers, the next 'best' item is the item that eliminates the most uncertainty about the classification.In the MDT-based CAT process, the goal is to place the examinee in one of Specifically, as described below, the best question is the one that maximally reduces the entropy of the classification. Prior to testing, background or calibration data is needed to calculate:i)P(L- the distribution of different competence levels (iL) in the participant population;1. j = 1/Li) P, then i)Pnext Sresulting from the participant's response to it results in the greatest reduction in entropy i.e. the question that maximizes:After each answered question, the next question is selected such that the new state, Z' = 0Z1...ZnZn+1 Zcan be one of two vectors depending on whether the participant answers n+1 Qcorrectly or incorrectly. If 1 Z'is the vector resulting from a correct response and 0 Z'the vector resulting from an incorrect response, for each of the unanswered questions, new Qthe entropy of the state resulting from presenting the question is calculated as:In (4), new = 1) P  H(S(from 4) was less than a specified threshold for three successive questions. At termination, the participant's predicted class is the class i Lwith maximum i/Z)P determine an optimal question order and (b) to categorize each participant into a literacy or numeracy category. Finally, we also performed ROC analysis to characterize the sensitivity, specificity, and predictive power (area under the curve) of the algorithm.target terms for the questions were manually selected from consumer health terms identified in three frequently visited MedlinePlus articles related to hypertension, back pain and gastroesophageal reflux disease (GERD). For each question  or at the concept level ("biopsy" means "removing sample of a tissue");1. a distractor term that had the same semantic relation to the target term as the key term and of approximately the same difficulty as the key term;2. a distractor term satisfying the same criteria as 2;3. a second 4. a do not know option.Results of the study are reported elsewhere .Cronbach's alpha was found to be 0.93 signifying very high internal consistency. Factor analysis without rotation showed that all questions load heavily on one factor accounting for 26% of the variance. The second and third factors account for 10% and 7% respectively.low literacy (a score of 44 or lower), moderate literacy (a score in the range of 45 and 52) or high literacy (a score of 53 or higher). These score thresholds were selected for demonstration purposes so as to obtain approximately equal-sized groups: 34.6% of participants in the low literacy group and 32.7% in moderate and high literacy groups. However, different thresholds could be selected for other purposes.Different literacy measures use different cut-off points to assign participants to a category. For the current analysis, the participants' scores were used to classify them into one of three categories: numeracy and that the weak second and third factors were probably artifacts of the measurement scale.This on-line questionnaire study was conducted as part of a larger study to evaluate the effect of different visual illustrations of risk on patient decision-making. Two samlow numeracy ) or high numeracy; in the second scheme, they were categorized as low numeracy ), moderate numeracy ), or high numeracy. Classifying patients into 3 categories of competency is typical of other assessments such as the TOFHLA [For the current analysis, two categorization schemes were developed for demonstration purposes. In the first scheme, participants were categorized as i) P(Land j = 1|Li)P described by (4), (5) and (6) by substituting i) P(Lfor i|Z) P.SB: Any question that a participant known to be of moderate literacy has a 40-60% chance of answering correctly.The average number of questions that needed to be presented prior to termination and the number of wrong classifications were calculated and reported.SA and a termination threshold of 0 (i.e. no termination threshold), the algorithm classified 88.5% (n = 46) of the participants correctly. Of the misclassified participants (n = 6), half were of moderate literacy incorrectly classified as low literacy while the others were of high literacy classified as moderate.For data set 1, using the start criterion i = 0|moderate literacy) for this question would be equal to 0, and the participant's incorrect response results in a misclassification.All the misclassified cases appear to result from the same type of outlier question/response pair. For instance, one of the misclassification resulted when a participant with a score of 45 was misclassified to be of low literacy (true category: moderate literacy). An analysis of the response vector and state entropies revealed that this can be attributed to the participant's response to one particular question, for which the participant gave an incorrect response, in contrast to all other participants of moderate literacy. As the algorithm uses a leave-one-out approach, P(QSB) did not result in any discernible difference in the number or type of errors produced by the algorithm.The use of a random moderate-difficulty start question P(Q and i) P(Lwere computed using the subjects recruited online (n = 100) and used to classify subjects recruited at the clinic (n = 62). Table j = 1 | Li)P(Q and i) P calibration with a random half of the population; (b) calibration using the online sample. In both cases, only subjects not used for calibration were used for testing. For example in scheme (b), Using the leave one-out approach, the average number of questions to be answered was 6.6 at 93.8% classification accuracy (accuracy possible if no threshold were used). For calibration scheme (a), 6.8 questions needed to be answered and a higher accuracy of 97.5% was observed. Calibration scheme (b) resulted in a classification accuracy of 91.9% with the subject having had to answer 5.3 items on average. As can be seen in Table Table As illustrated in the ROC curve in Figure Comprehensive, robust and parsimonious diagnostic health literacy measures are needed in consumer health initiatives, as well as clinical practice, to identify low literacy individuals. The need is particularly acute in older adults who are more likely to require frequent health care services and are also more likely to experience fatigue and cognitive burden from a lengthy testing procedure.Our results show that the method discussed in this paper can be useful in reducing the number of questions that need to be answered by a participant without seriously compromising classification accuracy. For the data described in this study, we found that by selecting an appropriate threshold, the number of questions can be reduced by half without making any additional misclassifications. In addition, this high degree of accuracy was achieved with only few calibration cases. By contrast, the number of cases needed for calibrating IRT-based algorithms is estimated to be quite large ,30. For The thresholds used to report the results are values at which the greatest reduction in test length was observed at the same classification accuracy as that achieved had no threshold been used. In a real testing scenario, these values can be estimated by simulating the leave-one out approach on the calibration sample. These simulations can also inform the test administrators on the accuracy/test-length trade-offs and help them choose higher thresholds that further reduce the length of the tests.Results observed with calibration scheme (b) of the second dataset also suggest that the users of the method should be encouraged to have a calibration set that is representative of the overall population and if this is not possible the performance of the classification accuracy can be expected to decrease. Additional analysis, preferably with larger datasets, would be necessary to determine the response of the performance to deviations between calibration and testing samples.Although the results are promising, this study has some limitations. First, it relies on secondary analysis of data from assessments that measure vocabulary familiarity and numeracy, constructs that are related to or contribute to health literacy but do not fully cover the domain of health literacy. Second, the MDT algorithm is predicated on the assumption that the responses to questions are independent of other responses, and this may not be valid. The effect of the violation of this assumption on the performance of this algorithm remains to be investigated. Future work could compare algorithm performance on assessments that have highly correlated questions and assessments with highly independent questions, with independence inferred from Cronbach's alpha or factor analysis. It is relevant to point out however, that IRT makes a similar assumption of question independence.A final limitation is that the assessment would have to be administered on a computer, and many individuals with low literacy also have low computer literacy. We are currently developing a computer interface for this assessment that is expressly designed to be easier to use for our target population of older adults, many of whom are novice computer users. The processing/memory requirements to administer this kind of testing are minimal and a fully equipped computer is not necessary. Touch screen devices such as tablet computers - which are becoming more affordable - hold promise as a more user-friendly medium for administering these tests in healthcare settings.In addition, in future work, we intend to study how to apply this method to scenario-based tests where each scenario is described and is followed by several related questions. In such cases, probability and entropy calculations may need to be performed at the module level rather than at the individual question level. Additionally, we intend to validate the method by applying it to directly test the subjects in contrast to the retrospective process used in this study.The computer-adaptive testing method presented in this paper, which is based on measurement decision theory, can significantly reduce the number of items needed to classify subjects into categories corresponding to levels of competency without significantly compromising the accuracy of the classification. In addition, the measure can be validated with few subjects and test items. This method creates the potential for the development of sensitive diagnostic instruments for measuring health literacy efficiently and without undue burden on subjects.The authors declare that they have no competing interests.QZT, DRK and SK designed and implemented the algorithm. All authors contributed to data analysis and manuscript preparation. All authors have read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6947/11/52/prepub


To compare phase contrast magnetic resonance (PCMR) evaluation of tricuspid inflow against echocardiographic measurements and to assess age-related changes in right ventricular (RV) diastolic function evaluated by both techniques.Several echocardiographic studies demonstrated the age-related changes in RV diastolic function. An MRI study supported these findings using SSFP sequences but to our knowledge, there is no such evaluation using PCMR images. Although blood flow PCMR imaging is less operator-dependant than echocardiography, which is strongly conditioned by the transducer orientation, post-processing of these data remains time-consuming and precludes clinical applications. Accordingly, the primary goal of this study was to develop a reproducible and accurate method to assess RV diastolic function.We studied 55 healthy subjects  who had Doppler echocardiography (GE Vivid7) and PCMR imaging (GE 1.5T) on the same day. The study protocol was approved by the institutional review board and informed consent was obtained from all participants. The previously acquired long axis views were used for positioning a retrospectively ECG-gated PC pulse sequences, in a plane perpendicular to the tricuspid inflow at the level of the tips of the opened tricuspid leaflets. PC images were analyzed using a custom software previously designed to semi-automatically assess transmitral flow. This analysis allowed extracting RV diastolic parameters such as: the peak filling rate  and the peak atrial filling rate  and the Ef/Af ratio. These parameters were compared to the known echocardiographic parameters  and the E/A ratio). Inter-operators variability in PCMR measurements was calculated as the absolute difference of the repeated measurements in the percentage of their mean.Low inter-operators variability in PCMR measurements was found 2.50±2,99%). Comparison between PCMR early to late peak flow rate ratio (Ef/Af) and echocardiographic early to late peak velocity ratio (E/A) resulted in a fair correlation (r=0.58; p=0.0001; Figure .50±2,99%Fast and reproducible evaluation of tricuspid inflow from PCMR images is possible. Although the diastolic parameters obtained from PCMR images are only fairly correlated with echocardiographic measurements, a stronger relation with aging was found while using PCMR than echocardiographic data.


In a wide range of problem-solving settings, the presence of a familiar solution can block the discovery of better solutions . To investigate this effect, we monitored the eye movements of expert and novice chess players while they solved chess problems that contained a familiar move , as well as an optimal move that was located in a different region of the board. When the Einstellung move was an advantageous  move, both the expert and novice chess players who chose the Einstellung move continued to look at this move throughout the trial, whereas the subset of expert players who chose the optimal move were able to gradually disengage their attention from the Einstellung move. However, when the Einstellung move was a blunder, all of the experts and the majority of the novices were able to avoid selecting the Einstellung move, and both the experts and novices gradually disengaged their attention from the Einstellung move. These findings shed light on the boundary conditions of the Einstellung effect, and provide convergent evidence for Bilalić, McLeod, & Gobet (2008)’s conclusion that the Einstellung effect operates by biasing attention towards problem features that are associated with the familiar solution rather than the optimal solution. During creative problem-solving, prior knowledge and experience can enhance performance by efficiently guiding us towards solutions that worked in the past. However, prior knowledge can also harm performance if the problem requires a novel solution. One of the most famous examples of the negative impact of prior experience on problem-solving is the Einstellung  effect e.g., . This efOf relevance to the present study, expertise in a domain has also been shown to induce “Einstellung-like” effects Building on these findings, Extending the investigation of As described in Written informed consent was obtained from each participant (or from a parent/guardian if the participant was a minor). The research programme was approved by the Ethics Review Unit at the University of Toronto.Thirty-four chess players (17 experts and 17 novices) were recruited from online chess forums and from local chess clubs in Toronto and Mississauga (Canada). The mean age was 30 (range = 15 to 56 years) in the expert group, and 26 (range = 17 to 47 years) in the novice group. There was one female player in the expert group, and there were three female players in the novice group. For the expert players, the average CFC (Canadian Chess Federation) rating was 2223 (range = 1876 to 2580). All of the novice players were unrated but active club players. All of the participants had normal or corrected-to-normal vision.The four experimental problems are shown in As shown in In addition to the four experimental problems, the players were shown eight filler trials that were designed to mask the purpose of the experiment. The filler trials incorporated a variety of solutions that ranged from checkmate to material gains to defensive tactics. Thus, every player completed a total of 12 problems  that were always shown in the following trial order: two fillers, Problem 1, three fillers, Problem 2, one filler, Problem 3, two fillers, Problem 4.Eye movements were measured with an SR Research EyeLink 1000 system with high spatial resolution and a sampling rate of 1000 Hz. The experiment was programmed and analyzed using SR Research Experiment Builder and Data Viewer software. Viewing was binocular, but only the right eye was monitored. A chin rest and forehead rest were used to minimize head movements. Following calibration, gaze-position error was less than 0.5°. The chess problems were presented using images (755×755 pixels) that were created using standard chess software (Chessbase 11). These images were displayed on a 21 in. ViewSonic monitor with a refresh rate of 150 Hz and a screen resolution of 1024×768 pixels. Participants were seated 60 cm from the monitor, and the width of one square on the chessboard equaled approximately 3.4 degrees of visual angle.Prior to the experiment, the participants were instructed to choose white’s best move as quickly and as accurately as possible, and they were told that they would be given a maximum of 3 minutes to respond to each problem. At the start of each trial, the participants were required to look at a fixation point in the center of the screen, prior to the presentation of the chessboard. The participants were asked to press a button as soon as they had made their decision, and they then reported their move verbally to the experimenter. If three minutes elapsed prior to the button press , then the chessboard was removed from the screen and the chess player was prompted to immediately provide their best answer. At the end of the experiment, we interviewed both the experts and novices to obtain retrospective subjective responses concerning their problem-solving strategies. Specifically, we provided the chess players with a picture of each of the four experimental problems (with a dotted line surrounding the target region), and we asked them to try to recall their thought processes with regards to the target region of the board.Our main goal was to explore the impact of the level of expertise of the chess players  and the type of Einstellung problem  on the magnitude of the Einstellung effect. Accordingly, in the analyses below, we assessed the magnitude of the Einstellung effect by examining the quality of the chosen moves, and the degree to which looking behavior was biased towards the target region containing the Einstellung move. Following these analyses, we will then discuss the retrospective responses that were provided by the expert and novice chess players during the post-study interview. For all of the analyses reported below, we excluded two of the trials from the novice chess players. Specifically, we excluded one trial from Problem 2 because the chess player selected an illegal move, and we excluded another trial from Problem 3 because the chess player did not fixate on the target region.t(32) = 6.04, p<.001; chess program scores: t(32) = 4.93, p<.001).As summarized in Most strikingly, although the experts showed superior overall performance, an equal proportion of novices and experts selected the suboptimal Einstellung move in Problem 1  instead of the optimal move on the board. Thus, Problem 1 replicates prior findings that the presence of a familiar good solution can prevent chess players from choosing a better solution t test results.To further investigate the Einstellung effect, we next examined the extent to which the expert and novice players’ eye movements were directed towards the target region of the board. As a starting point for this analysis, we used the following measures  to compare the eye movements of the expert and novices players: (1) Time to first fixation ; (2) Average dwell duration ; (3) Total dwell time ; (4) Number of dwells ; (5) Percentage of looking time (the proportion of time that the chess players spent looking at the target region of the board). As shown in Next, we examined the extent to which looking behaviour changed over time, by dividing each of the trials into four time intervals of equal length  = 13.12, p<.01) but not for the novices  = 2.25, p = .138), and by a significant two-way interaction between expertise and time interval  = 3.95, p<.05). In addition, as shown in F = 4.88, p<.01).The pattern of results for the suboptimal move problem  revealed expert/novice differences for both the percentage of looking time and the number of dwells measures. As shown in F <1) and the novices  = 1.76, p = .194), and by the lack of an interaction between expertise and time interval  = 1.08, p = .369). In addition, there were no differences in the pattern of results for the number of dwells when we contrasted the experts and novices who selected the Einstellung move, as shown by a lack of an interaction between expertise and time interval  = 2.34, p = .087).However, the global expert/novice differences shown in F = 43.45, p<.001), as well as by significant two-way interactions between move choice  and time interval when we contrasted the optimal-move experts with the Einstellung-move experts  = 3.65, p<.05) and with the novices  = 9.21, p<.001). Moreover, the experts who selected the optimal move had a higher number of dwells than the Einstellung-move experts  = 12.34, p<.01) and novices  = 13.46, p<.01), and this difference increased over time as shown by significant two-way interactions between move choice and time interval when we contrasted the optimal-move experts with the Einstellung-move experts  = 4.19, p<.05) and with the novices  = 6.60, p<.01). Overall, this pattern of results confirms that the expert/novice differences in In marked contrast, the group of experts that selected the optimal move was better able to disengage their attention from the target region, as shown by a significant linear trend  = 79.88, p<.001) and novices  = 10.84, p<.01), and there were no interactions between level of expertise and time interval  = 1.80, p = .152). Thus, relative to the suboptimal move problem, both the experts and novices were better able to resist the Einstellung effect for the blunder move problems, as shown by their greater ability to disengage their attention from the target region  = 4.03, p<.05). Thus, as shown in Finally, similar to the suboptimal move problem, the number of dwells in the target region increased over time for the experts but not for the novices, as shown by a significant interaction between level of expertise and time interval . For both types of problems, the majority of the chess players stated that they considered the Einstellung move first, which coincides with our findings of rapid times to the first fixation on the target region see . HoweverThe present findings revealed new insights concerning the processes underlying the Einstellung  effect, in which a familiar solution blocks the discovery of a better solution Extending One possible explanation for why the blunder moves reduced the Einstellung effect is that the blunder moves provided feedback that the familiar solution was not viable. This type of feedback may have improved performance on the blunder move Einstellung problems by providing the chess players with increased motivation to search for a new solution. In contrast, such feedback was not available for the suboptimal move Einstellung problem, because the suboptimal move was advantageous for white. Moreover, similar to the suboptimal move, the longer checkmate solution in In addition, another implication of the present findings is that the percentage of looking time measure employed by Finally, future work could investigate the extent to which the mechanisms underlying the Einstellung effect in chess are related to other thinking errors beyond the chess domain. More specifically, as discussed by Appendix S1For each of the four experimental problems ,  See text for further details.(DOCX)Click here for additional data file.


Systematic reviews of healthcare interventions most often focus on randomized controlled trials (RCTs). However, certain circumstances warrant consideration of observational evidence, and such studies are increasingly being included as evidence in systematic reviews.To illustrate the use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies, and how they demonstrate various strength of evidence domains in accordance with current Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) methods guidance.In the presented examples, observational evidence is used when RCTs are infeasible or raise ethical concerns, lack generalizability, or provide insufficient data. Individual study case examples highlight how observational evidence may fulfill required strength of evidence domains, such as study limitations ; directness; consistency; precision; and reporting bias , as well as additional domains of dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect).The cases highlighted in this paper demonstrate how observational studies may provide moderate to (rarely) high strength evidence in systematic reviews. Historically, systematic reviews of healthcare interventions have focused on randomized controlled trials (RCTs), primarily because randomization is intended to control for both known and unknown confounders, resulting in the ability to attribute differences between groups to the intervention under study. Increasingly, systematic reviews of healthcare interventions include observational studies when RCT evidence is considered inadequate; trials may be considered infeasible or unethical, do not report long-term or less common serious outcomes (particularly harms), or do not reflect use in real-world settings in terms of populations included, comparisons made, or how the intervention is applied. We define observational studies according to the definition used in the Agency for Healthcare Research and Quality’s (AHRQ’s) Evidence-based Practice Center (EPC) guidance on using observational studies in systematic reviews: 'Observational studies of interventions are defined herein as those where the investigators did not assign exposure; in other words, these are nonexperimental studies. Observational studies include cohort studies with or without a comparison group, cross-sectional studies, case series, case reports … and case-control studies’ .To support and improve use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies demonstrating various strength of evidence domains. This paper illustrates how the current AHRQ methods guidance can be applied to observational evidence.Methods Guide provide guidance on the role of observational studies [Several chapters of the AHRQ EPC  studies -5: when  studies  in 2012  studies .A systematic review provides evidence to inform decision-making. While some may argue that decisions should only be made on high strength evidence, many acknowledge the necessity of decision-making even in the face of imperfect evidence. With this understanding, the AHRQ EPC guidance recommends that systematic reviews provide the best available evidence to help decision-makers . Due to et al. [Norris et al.  proposedet al. . They hiet al. . While aet al. [a priori inclusion criteria, they highlighted the complexities in making such decisions before other information is known . They described a lack of consensus among authors of systematic reviews as to whether absolute pre-specified criteria should be followed or if a sequential approach to determining and modifying 'best evidence’ throughout the course of the review is preferable in some instances. A decision framework for identifying best evidence was described by Treadwell et al. [While Higgins et al.  providedl et al. , includiet al. [Chou et al.  providedIn some reviews of healthcare interventions, RCTs were considered infeasible or unethical, lacked generalizability, or were poor quality or insufficient in number. In these examples, observational evidence may provide only low strength of evidence, but provide the best available evidence to help decision-makers .A systematic review examining evidence on cesarean delivery on maternal request (CDMR)  sought tAnother review focused on the effectiveness of atypical antipsychotic drugs for schizophrenia, bipolar affective disorder, and other mental health disorders . The revTwo AHRQ reviews ,15 on beCochrane Handbook defines selection bias as 'systematic differences between baseline characteristics of the groups that arise from self-selection of treatments, physician-directed selection of treatments, or association of treatment assignments with demographic, clinical, or social characteristics. It includes Berkson’s bias, nonresponse bias, incidence-prevalence bias, volunteer/self-selection bias, healthy worker bias, and confounding by indication/contraindication ’ [Lack of randomization can bias observational studies. Specifically, potential confounding and selection bias mean treatment and control group differences cannot be assumed to result from the intervention. The tcomes)’ . Additiotcomes)’  and hightcomes)’ ,20).Methods Guide provides guidance for assessing risk of these biases in observational studies [et al. [Potential sources of bias in observational studies are well documented ,21. The  studies . As this studies ,10,22 no studies  ’ [Methods Guide states that 'EPCs may move up the initial grade for strength of evidence based on observational studies to moderate when the body of evidence is scored as low or medium study limitations, based on controls for risk of bias through study conduct or analysis. Similarly, EPCs may initially grade the strength of evidence as moderate for certain outcomes such as harms or certain key questions, when observational study evidence is at less of a risk for study limitations because of a lower risk of bias related to potential confounding. Also, EPCs may well decide that, after assessing the additional domains, the overall strength of evidence of a body of observational studies can be upgraded to moderate ’ [In addition to the inherent biases from lack of randomization, observational studies are subject to the same risks of other biases as RCTs. Thus, observational studies are considered to have greater study limitations than RCTs. Because the study limitations in the body of evidence is considered the starting point for assessing confidence in the findings of a body of evidence , the AHRQ EPC actors)’ , but mayy high)’ , page 20Methods Guide are study limitations ; directness; consistency; precision; and reporting bias . The AHRQ EPC Methods Guide specifically defines three additional domains applicable to observational studies that, if met, would potentially warrant increasing the strength of evidence rating. These three additional domains include dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect). The following studies are provided to demonstrate what these strength of evidence factors look like in real-world examples.The required domains for assessing strength of evidence according to the AHRQ EPC In some cases the observational evidence demonstrates criteria that elevate the strength of evidence. However, because the examples are real-world case examples, not theoretical examples designed to neatly demonstrate all domains, not all included examples would result in increased ratings of strength of evidence. Rather, because we hope to advance training for others conducting systematic reviews, we illustrate how the examples demonstrate specific strength of evidence domains.A Cochrane review  investigThe evidence that helmets reduce brain, head, and facial injuries presented from case-control studies in this review is strengthened by various factors despite the nonexperimental study designs. First, the included studies were classified as having low risk of bias based on criteria specific to case-control studies, because controls were selected from the same population as cases, injuries were verified by medical records, and ascertainment of exposure was equivalent for case and control groups. Additionally, there was a consistent direction of effect for the primary outcome of head injury in all five studies. Finally, a large magnitude of effect and precise estimate was seen across all included studies: the protective effects of helmet use on head, brain, and facial injury ranged from 64% to 88%.An AHRQ systematic review on evaluating and treating cryptorchidism  assessedOf 26 included surgical treatment studies, five were RCTs, one was a prospective cohort, and the rest were retrospective cohort studies rated as having high risk of bias. Decisions about method of surgical repair were made based on clinical presentation  and patient/parent preferences, and not with the intent of comparing the effectiveness of the procedures in comparable groups of patients, making the comparison groups essentially different. Because these studies did not control for initial testicular location, the results can only be interpreted as providing noncomparative data on outcomes in groups with differing clinical presentations treated surgically. The systematic review authors elected to use was based on a historical control group given the known natural history of the condition. Given the low rate of spontaneous testicular descent, the strength of the evidence was considered high because of the large magnitude of effect for an objective outcome when compared with a historical control group. The weighted success rate for all three surgical approaches exceeded 75%, with an overall reported rate of 79% for one-stage Fowler-Stephens (FS) orchiopexy procedure, 86% for two-stage FS orchiopexy procedure, and 96.4% for primary orchiopexy. Due to variation in surgical repair techniques , which are often guided by testicular location, patient/parent preferences, surgeon skill, and recovery time, included studies were not able to provide comparative evidence for the relative effectiveness of these techniques. Although only retrospective cohort studies examined primary orchiopexy for the outcome of testicular decent, the overall effectiveness of this type of surgical treatment was rated as high strength of evidence due to the magnitude of effect when compared with historical controls.et al. [As with many surgical interventions, for treatment of obesity, it is neither feasible nor ethical to randomize bariatric surgery in comparison to conventional nonsurgical obesity interventions. Sjöström et al.  publisheHarms associated with cancer treatments can be difficult to evaluate based on randomized trial results, and evidence of harms is often based on observational study designs. The two studies described here used case-control study designs. Neglia and colleagues  investigThese studies both reported a dose-response relationship between the outcome and the mean dose of radiation therapy Table . In chilMethods Guide, evidence from single studies cannot meet criteria for consistency, and particularly when paired with a small sample size, may warrant an 'insufficient’ strength of evidence rating. Similarly, evidence meeting only some of the strength of evidence criteria should not be upgraded [Although both of these studies were observational designs, the dose-response relationships observed between the intervention and the harm could be considered when rating strength of evidence. When the effect of an intervention increases proportionally to the dose of the intervention, we can be more confident that the observed effect is in response to the intervention and not the result of bias or confounding. As noted in the AHRQ EPC upgraded . HoweverMethods Guide. These cases are meant to inform the decision to include/exclude observational studies and how to evaluate their strength of evidence in systematic reviews.In this paper, we provided cases that highlight: 1) systematic reviews of observational evidence included to fill gaps in RCT evidence; and 2) systematic reviews of observational studies as well as primary observational studies that demonstrate strength of evidence domains as described in the AHRQ EPC Methods Guide, providing support for the comprehensiveness of this and other similar guidance. These strength of evidence domains are often specific to clinical topics and individual study factors warrant careful consideration before upgrading an observational study body of evidence, as noted in the current AHRQ EPC Methods Guide on strength of evidence [In general, we can be more confident in the results of observational studies when design or analyses have minimized the potential for common sources of bias, results are precise and consistent, and when we observe a large strength of association, a dose-response association, or plausible confounding very likely to decrease the observed effect. Importantly, of all the examples of strong observational studies solicited for this project, we did not identify any additional strength of evidence factors not already included in the AHRQ EPC evidence ; howeverAHRQ: Agency for Healthcare Research and Quality; CDMR: Cesarean delivery on maternal request; CI: Confidence interval; EPC: Evidence-based Practice Center; FS: Fowler-Stephens; GRADE: Grading of Recommendations Assessment Development and Evaluation; Gy: Gray; OR: Odds ratio; RCT: Randomized controlled trial.The authors declare that they have no competing interests.MO participated in conception and design of the project, and drafted the manuscript. NB, LH, SC, and JMG helped analyze and interpret project material, and critically revised the manuscript. JA and MM helped analyze project material and helped to draft the manuscript. MSM participated in conception and design of the project, and helped to draft the manuscript. All authors read and approved the final manuscript.


Idiopathic toe walking (ITW) is a condition that commonly presents to podiatrists. This presentation aims to give an overview of the quality of literature focused on the treatment of ITW and determine if common podiatric treatment modalities are evidence based. 24 articles reporting treatment modalities were appraised against the National Health and Medical Research Council Levels of Evidence. There currently is no evidence of any single treatment option having long term effect on ITW gait. The highest level of evidence was in support of serial casting or surgery with some evidence supporting the use of Botulism toxin Type A.Footwear and orthotic intervention with or without stretching programs are reported treatments with no rigorous studies to support these modalities yet anecdotally these are reported effective. This article aims update the knowledge of podiatrists, to enhance how children who present with this gait style can be managed and highlight areas for future research.


The National Comprehensive Cancer Network (NCCN) recently published a task force report on the evaluation of the clinical utility of tumor biomarkers in oncology. In this report, common terminology and the use of levels of evidence scores to aid the evaluation of biomarker tests in oncology were proposed. Furthermore, the task force applied a level of evidence system to selected biomarkers of several cancer types. According to this system, the highest level of evidence, IA, is granted to a biomarker only if it has been evaluated in at least one adequately powered and specifically designed prospective controlled trial. For gliomas, only 1p/19q testing in oligodendroglial tumors was classified as IA by the NCCN task force. For all of the following biomarkers the present evidence level for clinical utility was regarded as lower than that of 1p/19q status: MGMT gene promoter methylation testing (glioblastoma), IDH mutation testing (diffusely growing gliomas), BRAF fusion testing (pilocytic astrocytoma) and CIMP testing (diffusely growing gliomas). The task force acknowledged that the exact application of levels of evidence needs further refinement. To our mind, the implementation of a brain tumor expert panel seems vital to evaluate the evidence levels of neurooncological biomarkers according to generally accepted criteria on a regular basis. Systematic identification of current research needs and widely accepted up-to-date recommendations for efficient biomarker application in everyday practice could be gained.  In clinical medicine, biomarkers are defined as objectively measurable factors that provide information about a disease state, thus providing the possibility for diagnosis, prediction of patient outcome, choice of therapy or follow-up. A myriad of potential biomarkers have been proposed for gliomas, but almost none have translated into actual clinical use so far . For somThe National Comprehensive Cancer Network (NCCN) recently published a task force report on the evaluation of the clinical utility of tumor biomarkers in oncology . In thisBiomarkers have different properties. This complexity necessitates the implementation of a commonly agreed upon terminology . Table 1Several level of evidence systems for assessing tumor biomarkers have been suggested in previous publications. The NCCN Task Force Group created their levels of evidence system from a combination of the revised Tumor Marker Utility Grading System (TMGUS) and the levels of evidence grade for using archived tissue . The higAccording to the NCCN Task Force Report, only 1p/19q testing in oligodendroglial tumors meets the criteria for IA level of evidence among potential glioma biomarkers, because randomized controlled trials support clinical validity and clinical utility of the test, and a practical consensus guideline on performing 1p/19q FISH analysis provides analytic validation , 9, 10. The adoption of biomarkers into everyday practice is challenging. For most potential glioma biomarkers, differences in the study design concerning the evaluation of analytic and clinical validity as well as the clinical utility make it difficult to draw unequivocal conclusions. As a result, only a small proportion of biomarkers have been adopted into everyday practice, whereas on enormous amount of biomarkers is stuck in the research pipeline. The NCCN Task Force Report applies for the first time levels of evidence to evaluate biomarkers in glioma. To our mind, the implementation of a brain tumor expert panel seems vital to evaluate the evidence levels of neurooncological biomarkers according to generally accepted criteria on a regular basis. Systematic identification of current research needs and widely accepted up-to-date recommendations for efficient biomarker application in everyday practice could be gained.


As an integral part of the European Commission (EC) Imaging Referral Guidelines Project a 1.5-day workshop was held in Vienna on 20–21 September, 2012. At this workshop, models and good practices regarding the appropriateness and use of imaging referral guidelines (Guidelines) in Europe and worldwide were presented, together with the results of a survey of Guidelines in Europe. The latter included ideas, innovations and wishes for future Community action.Stronger measures should be taken by the EC and the European competent authorities for making Guidelines available and used in all EU member states.Evidence-based Guidelines with separate guidance for children should be issued or endorsed by a trusted European organisation.Educational initiatives and electronic requesting in connection with clinical decision support (CDS) systems should be used to improve the implementation of Guidelines.Monitoring of Guidelines implementation and use should be by clinical audit, particularly external audit, but also by local/internal audit.Recommendations for future Community action:The online version of this article (doi:10.1007/s13244-013-0299-8) contains supplementary material, which is available to authorised users. Over 60 participants attended the workshop in Vienna , with reThe programme included over 30 talks, divided into five sessions. Each session allowed ample time for discussions, with enthusiastic participation from the floor.The Workshop’s sessions each dealt with a specific subject within the area of Imaging Referral Guidelines in Europe.Scene Setting, served as an introduction to the topic and gave an overview on the current status of Referral Guidelines in Europe. Experts from International Organisations such as the WHO and IAEA presented their perspective and invited speakers from Europe, USA, Canada and Australia shared their views on Referral Guidelines from a national perspective. This session covered the drivers for the effective use of Guidelines, followed by the experience from a number of countries who had developed and used their own referral guidelines. The key messages included the following:Session 1, European and International Legislation related to radiation protection requires effective justification of imaging tests involving radiation based on evidence-based guidance . In addiThere is a similar process for the production and formatting of Guidelines by those countries who presented their experience –5, with There was acknowledgement of duplication of effort, with the same evidence being reviewed in each individual country reaching the same or similar conclusions. The ownership and development of Guidelines by radiologists may well have an impact on the adoption of, and compliance with, Guidelines by the end-user clinician.The evidence base is often related to comparison of differing modalities in terms of accuracy, safety and efficiency, but there are less robust data on the impact of the use of imaging to patient outcomes. Improvements in process are often considered as a proxy for outcome. Evidence in many pathways is not always present and, if present, is not always high level, widely applicable or robust. A key factor should be the overall efficiency gains within the health system by the correct use of Guidelines.The total number of Guidelines was seen as a potential barrier for adoption/adherence—often in excess of 300.It was agreed that there had to be ease of access by the end user at the time of referral, and for this reason paper versions of the Guidelines were the least effective. Web-based or App-based Guidelines should in principle improve this.Ideally Guidelines should be free to recognised referrers but this requires a stable financial model for their production.Guidelines were often regarded as being owned by the radiology department or radiologists, with no real ownership by the referrer. In some instances certain clinical specialties had developed their own guidance as part of clinical pathways which had the potential to conflict with the radiology guidelines.The increasing concern by referrers of the potential for litigation if they miss a diagnosis leads to unnecessary overuse of imaging.Patient expectations are continuing to increase and their insistence on imaging can over-ride clinical judgement.There were common challenges and barriers at the following stages: awareness, agreement, adoption and adherence. Specific barriers that were discussed included:European or International collaboration on reviewing evidence.Focusing on fewer Guidelines which are likely to have the biggest impact on safe, quality and efficient care.Involve referrer groups in the production and promotion of Guidelines.Integrating Guidelines into the electronic referral process—‘decision support’ software.Increasing dose awareness as part of the guideline process.Improved communication/promotion.Focus on improving the evidence base for the Guidelines that are likely to have the most impact.Production of internationally agreed Guidelines with the ability to customise to national/local circumstances.Education/training/audit.Potential solutions to the barriers and challenges were suggested as follows:Specific Issues, addressed the perspectives of stakeholders from paediatrics, interventional radiology and nuclear medicine, as well as representatives from radiographer societies and patient groups.Session 2, Paediatric radiologyInterventional radiologyNuclear medicineRadiological protection, both dose issues and risk as well as implementation issuesRadiography and the radiographerGeneral practitionersThe patient’s perspectiveThis session gave an excellent overview of referral guidelines from the perspectives of varying and diverse stakeholders in respect to Guidelines with input from:Not surprisingly all speakers were strongly in favour of Guidelines although each speaker saw and described their structure, design and use with differing perspectives.The key presentation relating to paediatrics stressed the greater sensitivity of children to radiation-induced effects and the longer period for effects to be manifested. These risks were far greater with CT and fluoroscopy, rather than radiography. Education is essential and the development and provision of specific guidelines for children is essential. Discussion centred on whether these should be stand-alone Guidelines or separate guidelines integrated into a unified publication.Interventional radiology is a rapidly changing field hence the need for frequent updates with practice guidelines for interventional radiology not fully implemented in current diagnostic radiology guidelines.Interventional radiologists act as clinical gatekeepers ensuring that the design of Guidelines involves multidisciplinary practice, collaboration of a large number of diverse stakeholders and robust education, not only across the healthcare community but also to patients, the public and media.It was noted that procedural risks in interventional radiology were often far higher than radiation-related risks.Nuclear medicine benefits from fewer procedures and Guidelines are committee driven and jointly written with clinical specialities. Interestingly technologists prepare parallel Guidelines. All requests are routinely checked and there is a strong culture of audit.The balance between risk and benefit is pivotal, the assessment of dose alone is not helpful and justification requires knowledge of clinical circumstances. The wording of Guidelines must be carefully chosen, especially related to possible risk of misuse, criteria and appropriateness.Key points of implementation are that Guidelines are legally required, but more importantly that they are useful, should be kept up to date, and should be used and audited and their development funded.Radiographers were portrayed as playing a key role at the interface between patient and technology, being the pivot between referrers, patients and radiologists. They are therefore a key player in the implementation of referral guidelines.A presentation from a general practitioner stressed that excellent communication between the patient, general practitioner and radiologist is essential. This will be facilitated by clear referral guidelines.The patient’s perspective stressed the need for dose information, clear communication (no acronyms), the need to be sensitive to the patient’s needs, and that the patient is a member of the team—“No decision about me without me”.The varying and diverse interpretation of “Specific Issues” demonstrates the need for a broad base of knowledge expertise and experience when designing and implementing Guidelines.Survey Feedback, dealt with the formulation and findings from the survey of Guidelines in Europe, conducted as an earlier part of the EC Referral Guidelines Project. Within this session workshop participants were given an opportunity to present examples of good practices from their own countries followed by enthusiastic discussion.Session 3, The survey feedback summarised the survey. It was web-based and involved multiple organisations from 30 countries. These included radiology and nuclear medicine societies and competent authorities. The questions were comprehensive and related to responsibilities, format, circulation and purpose of the referral guidelines. In addition, the survey participants were asked to share their views on barriers to implementation and their potential solutions. In establishing the survey, consideration was given to ease of understanding, completion and subsequent analysis.The analysis provided a wealth of data. More significant information related to awareness of the legal requirement for Guidelines (60 %) and the difference between this requirement and actual availability. There was variation as to the origin of the Guidelines in each of the countries—some were based on practice within the Member State, while others were heavily or entirely based on the publications from organisations external to their country (e.g. translation of RCR guidelines). The survey provided information on a number of key elements and factors of the Guidelines including the evidence base, the grading of procedures and the associated radiation dose.Innovations for improvement in Guideline use. Examples of innovations in use worldwide and potential solutions drawn from other areas of medicine were discussed.Session 4 dealt with The need was identified to improve Guideline development with specific emphasis on the level of Evidence (currently approximately 30 % of Guidelines are not evidence-based). Guidelines should be informed by secondary research and particularly by systematic reviews where available. There was agreement for the need of European Guidelines, either as a synthesis of several National Guidelines or developed by European bodies.An imaging specialist should be the author.Guidelines should be aimed at referrers.Guidelines should also be of use to patients and the public.Guidelines should be included in the curriculum of medical undergraduates and residents.Suggestions made for Guideline development include:The plan for the future should include developments to electronic requesting  in connection with CDS systems.The suggestion was made for developing selected high-impact Guidelines using simple, fast and transparent software, under the leadership of medical practitioners and validated in small integrated patient groups by motivated physicians.Web-based guidance and adequate resources are required. In addition, tablet and smart phone applications (apps) would be useful.Following presentations from over 30 speakers and lengthy discussions at the European Workshop, Work Package 2 of the EC Guidelines Project, a clearer picture of the current situation has emerged with a coherent message as to the way forward.Data to inform the availability of referral guidelines are not as straightforward as hoped. The survey has shown discordance of responses between some national competent authority and professional society representatives, possibly related to issues of awareness of Guideline existence and the legal requirement for Guidelines. In addition, there are issues of access to national guidelines, which may be related to format or media.In the European survey , respondA further, brief, follow-up survey to ascertain the up-to-date status of Guideline availability was planned following the Workshop to enable the current work in progress to be reflected in the final report.Workshop participants agreed that the availability of Guidelines did not equate with their use. As Guidelines cannot encompass all clinical scenarios, adherence can only be expected in up to 90 % of clinical scenarios. Participants at the Workshop reported that even where Guidelines are available, their uptake and use are limited. Reasons for this may include: sub-optimal clinician buy-in, conflicting advice from other  guidelines, and the difficulty associated with monitoring and encouraging Guideline use.Education—at all levels of training and continuing professional development. Web-based, training courses and inclusion in curricula as well as educational reminders [eminders , 9. Theseminders .CDS systems, particularly those with flexible architecture to fit existing requesting systems. Examples of CDS systems were available from many speakers and there was great interest amongst participants, both radiologists and regulators.Management systems, e.g. Radiological benefit management.Governmental incentives, e.g. Payment for performance [formance , Qualityformance .Tools which can encourage Guideline use include:Measures for reinforcement of Guidelines were considered essential to provide encouragement for use and to ensure sustained benefit. The European survey identified models, particularly external clinical audit as the preferred means, with a secondary role for local internal audit. Self-regulation , 14 by hPreference for European Guidelines, which may best be adapted and amalgamated from mature, trusted, nationally developed evidence-based guidelines. This option was considered to be more practical and expeditious than the centralised development of European Guidelines de novo. Later iterations of European Guidelines should encompass a more inclusive methodology with consensus from experts from multiple European countries.Need to include dose information in a form understood by referrers and patients.Separate section for imaging of children.Stakeholders, including referrers and patient representatives, should be involved.Recommendations based on evidence of efficacy, radiation safety and cost.Areas of agreement for Guideline development methodology which were identified from the European survey and consolidated at the Workshop are:Supplementary Material 1Scene Setting (PDF 2840 kb)Workshop proceedings, Session 1 Supplementary Material 2Specific Issues (PDF 989 kb)Workshop proceedings, Session 2 Supplementary Material 3Survey Feedback (PDF 110 kb)Workshop proceedings, Session 3 Supplementary Material 4Innovations (PDF 714 kb)Workshop proceedings, Session 4 Below is the link to the electronic supplementary material.


Chiropractors claim to locate, analyze and diagnose a putative spinal lesion known as subluxation and apply the mode of spinal manipulation (adjustment) for the correction of this lesion.The purpose of this examination is to review the current evidence on the epidemiology of the subluxation construct and to evaluate the subluxation by applying epidemiologic criteria for it's significance as a causal factor.The databases of PubMed, Cinahl, and Mantis were searched for studies using the keywords subluxation, epidemiology, manipulation, dose-response, temporality, odds ratio, relative risk, biological plausibility, coherence, and analogy.The criteria for causation in epidemiology are strength (strength of association), consistency, specificity, temporality , dose response, experimental evidence, biological plausibility, coherence, and analogy. Applied to the subluxation all of these criteria remain for the most part unfulfilled.There is a significant lack of evidence to fulfill the basic criteria of causation. This lack of crucial supportive epidemiologic evidence prohibits the accurate promulgation of the chiropractic subluxation. Historically, generations of chiropractors have contended that a large percentage of all disease is caused by subluxation . In fact disease . The Ass disease  paradigm disease .Epidemiology is the study of the distribution and determinants of health-related conditions or events in defined populations and the application of this study to control health problems . The basIf the chiropractic profession is to embrace the subluxation as a defining factor of health, along with claiming that intervention to correct this lesion is needed for the health of the human body, then there exists an obligation to examine the current status of subluxation against epidemiological methods and criteria. The purpose of this paper is to detail Hill's Criteria and how they may be applied to the concept of subluxation as currently embraced by the chiropractic profession.Hill's Criteria consists of the following: strength (strength of association), consistency, specificity, temporality , dose response, experimental evidence, biological plausibility, coherence, and analogy. These nine criteria form the fundamental prerequisites and assessment of the cause-effect relationship . UltimatThe databases of PubMed, Cinahl, and Mantis were searched for studies using the keywords chiropractic, subluxation, epidemiology, manipulation, dose-response, temporality, odds ratio, relative risk, biological plausibility, coherence, and analogy. Combinations of the aforementioned terms were also utilized as a search strategy in order to isolate studies. Studies identified as pertinent to the purpose of this study were then accessed through the University of South Dakota's  Lomman Health Studies Library. When this search strategy failed to reveal any studies associated with the keywords each of the definitions were then isolated and additional keywords utilized. From this definition-specific method were keywords that could be placed in the search engines. For example, with the consistency criteria a keyword that was used was gender, race, and socio-economic status. Other keywords included morbidity and mortality.Each one of Hill's Criteria was separated as a unique entity. The results of this literature review were separated by strength, consistency, specificity, temporal sequence, dose response, experimental evidence. Overall, there were no studies that demonstrated a satisfactory link of evidence to the chiropractic subluxation construct as per strength, consistency, specificity, temporal sequence, dose response, experimental evidence, biological plausibility, coherence, and analogy Table . SpecifiOpinion on the current state of the epidemiology of the subluxation construct is varied. Historically, chiropractors have claimed that subluxation was directly responsible for 95% of disease. Although this percentage is not currently in evidence, there still appears to be many chiropractors that contend subluxation is still partially responsible and/or involved with disease. The opinion by chiropractors on the connection of subluxation and disease has been substantiated. Biggs et al  found thHowever, opinion from chiropractic scholars on an actual epidemiology of subluxation appears to be mixed. Meeker  suggesteThe strength of the evidence for concluding that there is a cause and an effect association between two entities must be judged by Hill's Criteria . If the Strength is defined as the size of the risk as measured by appropriate statistical tests  and is bConsistency pertains to the association being noted consistently, across many studies in different people, places and circumstances and times . ResultsFor the chiropractic subluxation to meet this criteria it (subluxation) would have to be found repeatedly in different persons, places, times, and circumstances. In the case of a clinical condition, the subluxation would have to be consistently found with the clinical condition. To date there has not been a study that has found the subluxation in any one population . Or that any person of gender, race, ethnicity or age is more prone to subluxation as compared to another group. Furthermore, there were no studies that determined that the subluxation is consistently present in any clinical condition.Specificity reveals that a factor (cause under study) leads to a consistent pattern of consequences . In otheTemporal sequence is the only absolutely essential criterion for a cause-effect association . It asksBiological plausibility refers to the coherence with the current of body of biologic knowledge . The assDose-response is defined as an increasing level of exposure (in amount and/or time) increases the risk . Dose-reThere was no evidence suggestive that there should be more manipulation of subluxation versus no manipulation, or even versus a few manipulations. Studies by Haas et al ,26 on doExperimental evidence is defined as the condition can be altered (prevented or ameliorated) by an appropriate experimental regimen . RothmanCoherence is the association should be compatible with existing theory and knowledge . The criThe analogy criterion looks for a disease or exposure that may have been observed that may be of similarity. It essentially asks the question if there are no other epidemiologic or experimental studies of this exposure-disease relationship, has a causal association been established for a very similar agent?  No studiHill's Criteria do have some limitations. The only criterion of Hill's that is truly a causal criterion is temporality while suggesting that the other criteria were vague . AlthougPhillips and Goodman  have notHill's criteria are the most commonly used epidemiologic model for suggesting a causal link for any diagnostic or treatment approach. There is a significant lack of evidence in the literature to fulfill Hill's criteria of causation with regards to the chiropractic subluxation. No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention. Regardless of popular appeal this leaves the subluxation construct in the realm of unsupported speculation. This lack of supportive evidence suggests the subluxation construct has no valid clinical applicability.The authors declare that they have no competing interests.TM and LM conceived the idea for the original manuscript. TM and LM and LG had initial discussions about this paper. After multiple distributions between all authors TM wrote the initial manuscripts with LM, LW and LG undertaking revisions of the work product. LM, LW, and LG offered editorial support. All authors approved the final manuscript.


The objective of this study was to assess the effect of RB200 combined with TNF blockade in a murine collagen-induced arthritis (CIA) model of RA.Rheumatoid arthritis (RA) is a chronic disease associated with inflammation and destruction of bone and cartilage. Although inhibition of TNFα is widely used to treat RA, a significant number of patients do not respond to TNFα blockade, and therefore there is a compelling need to continue to identify alternative therapeutic strategies for treating chronic inflammatory diseases such as RA. The anti-epidermal growth factor (anti-EGF) receptor antibody trastuzumab has revolutionised the treatment of patients with EGF receptor-positive breast cancer. Expression of EGF ligands and receptors (known as HER) has also been documented in RA. The highly unique compound RB200 is a bispecific ligand trap that is composed of full-length extracellular domains of HER1 and HER3 EGF receptors. Because of its pan-HER specificity, RB200 inhibits responses mediated by HER1, HER2 and HER3 in vivo fluorescent imaging using anti-E-selectin antibody labelled with fluorescent dye to elucidate the effect of RB200 on the vasculature in CIA.Arthritic mice were treated with RB200 alone or in combination with the TNF receptor fusion protein etanercept. We performed immunohistochemistry to assess CD31 and RB200 significantly abrogated CIA by reducing paw swelling and clinical scores. Importantly, low-dose RB200 combined with a suboptimal dose of etanercept led to complete abrogation of arthritis. Moreover, the combination of RB200 with etanercept abrogated the intensity of the E-selectin-targeted signal to the level seen in control animals not immunised to CIA.The human pan-EGF receptor bispecific ligand trap RB200, when combined with low-dose etanercept, abrogates CIA, suggesting that inhibition of events downstream of EGF receptor activation, in combination with TNFα inhibitors, may hold promise as a future therapy for patients with RA. Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterised by severe synovial inflammation that leads to the progressive destruction of bone and cartilage. It is a severe disabling disease that affects approximately 1% of the population worldwide -5. In adThe epidermal growth factor (EGF) ligand/receptor family has been postulated to play a role in RA pathogenesis . The EGFA number of agents targeting EGFRs have been successfully developed for the treatment of cancer. The first approved HER therapeutic drug, trastuzumab, is a monoclonal antibody that targets HER2 and has revolutionised the treatment of HER2-overexpressing, node-positive or node-negative breast cancer . Cetuximin vitro and has shown potency in a variety of cell proliferation assays [in vivo in two human xenograft  nude mouse models [The antagonist RB200 has been developed to target all four members of the EGFR family. RB200 is composed of the ECD of HER1/ErbB1 (amino acids 1 to 621) and HER3/ErbB3 (amino acids 1 to 621), fused with the Fc domain of human immunoglobulin G1 (IgG1) (HER1-HER3/Fc), and acts as a chimeric bispecific ligand trap. The HER3/Fc component of RB200 contains a 6×Histidine tag on the COOH terminal ,19. RB20n assays . In addie models . In parain vivo E-selectin-targeted fluorescence imaging, which is a novel technique that we have shown can detect endothelial activation in CIA and delineate subclinical arthritis [In the present study, we explored the therapeutic effects of RB200 in combination with the TNFα inhibitor etanercept in murine CIA as a model of human RA. Our data demonstrate that RB200 potently reduced all measures of arthritis in CIA. Furthermore, when low-dose RB200 and etanercept were combined, there was complete abrogation of CIA. This was confirmed on the basis of rthritis . These dq) mice  received a single intradermal injection at the base of the tail of 100 μg of bovine type II collagen emulsified in complete Freund's adjuvant and Mycobacterium tuberculosis H37 Ra . The animal work was conducted under Home Office Project Licence PPL 70/5446, 'Pathogenesis and therapy for RA', under the operatives of the Animals (Scientific Procedures) Act 1986.Type II collagen was extracted from bovine articular cartilage as previously described ,20,23. FThe incidence of arthritis in each group of animals reached at least 80%. The earliest signs of disease were observed on day 14 after immunisation, with day 27 postimmunisation being the median day of arthritis onset. The first clinical signs of arthritis were considered to be present when oedema and/or erythema involving any one of the four paws was observed. Human TNF type II receptor fusion protein (etanercept) was obtained from Wyeth Pharmaceuticals, Taplow, UK, and RB200 was a gift from Dr Michael Shepard . Control animals received equivalent volumes of PBS. The mice were treated intraperitoneally on the day of disease onset (day 1) and then on days 4 and 7 of disease with RB200 at the indicated doses. Control mice received intraperitoneal injections of either etanercept or equivalent volumes of PBS. The study involved four comparable experiments to test the efficacy of different doses of RB200. All treatments were administered in a blinded fashion.Paw swelling was measured with 0- to 10-mm callipers . Each limb was further assigned a clinical score as follows: 0 = normal paws and no clinical features of inflammation, 1 = slight oedema or erythema, 2 = pervading oedema or erythema involving the entire paw and 3 = pronounced oedema and erythema leading to incapacitated limb mobility.2O2. Immunostained sections were counterstained with Harris's haematoxylin. As a negative control, rat IgG2a antibody was used . Scores were graded in a blinded fashion, and the criteria assessed were (1) proximity of CD31 staining to the joint, (2) strength of CD31 staining, (3) degree of infiltration of synovial cells into the joint and (4) overall status of joint architecture. Sections were further stained with haematoxylin and eosin as well as with toluidine blue. Each stained section was scored by a blinded observer for changes in the joint architecture using our previously described grading system [Hind paws were removed postmortem and sliced along the sagittal plane prior to fixation with 1% paraformaldehyde. Paws were decalcified for 14 days in 0.3 M ethylenediaminetetraacetic acid, and CD31 expression was examined by immunohistochemistry using anti-mouse CD31 antibody . The sections were then incubated with biotinylated rabbit anti-rat antibody , followed by avidin-biotin-peroxidase complex and diaminobenzidine-Hg system ,24 as foAnti-mouse E-selectin mAb (MES-1) was purified from a hybridoma cell line  and conjugated to DyLight 750 near-infrared (NIR) fluorophore according to the manufacturer's instructions . For imaging studies, mice were anaesthetised with a mixture of isofluorane and oxygen prior to intravenous injection of 5 μg of antibody. Optical imaging was performed using a Kodak FX Pro multispectral fluorescence reflectance imaging device . Filters for excitation and emission were set to 730 nm and 770 nm, respectively. An identical imaging protocol  was maintained for all images as previously described .Images were analysed by a blinded observer using the Kodak Molecular Imaging version 5.0 software program . A region of interest (ROI) created by an automated tool was determined around the inflamed or control paw. Mean ROI signal intensities are expressed as arbitrary fluorescent signal intensity units. Fluorescence greyscale images were artificially coloured for depiction purposes according a colour scale set to the highest and lowest levels of mean fluorescence intensity (MFI) . The fluorescence images were coregistered onto X-ray images taken concurrently.2 test for trends.The data were analysed using GraphPad Prism version 5.01 software  using one-way analysis of variance (ANOVA) or two-way ANOVA as appropriate. Histological data were analysed by ΧP < 0.001 vs PBS for both paw swelling and change in clinical score). On day 10 of established disease, the mean increase in clinical score ± SEM from day 1 of arthritis in mice treated with either PBS or RB200 at 0.1, 1 and 10 mg/kg were 2.17 ± 0.54, 2.00 ± 0.73, 0.88 ± 0.74 and 1.14 ± 0.51, respectively   Figure .P > 0.05 vs PBS-treated mice) and only a modest effect on clinical score (P < 0.01), whereas 10 mg/kg RB200 significantly, albeit not completely, reduced both parameters, in agreement with the experiment illustrated in Figure P < 0.001)  or low-dose RB200 alone . The effectiveness of the combination of 0.5 mg/kg RB200 and 1 mg/kg etanercept was comparable to that seen with the optimal dose of etanercept (5 mg/kg).Importantly, when a low dose of RB200 was combined with a suboptimal dose of the TNFα inhibitor etanercept , a marked beneficial response was observed, with the combination of 0.5 mg/kg RB200 and 1 mg/kg etanercept having a marked effect on both measures of disease activity in CIA Figure . In this) Figure . In contin vivo optical imaging to investigate the effect of RB200. Figure We further applied P < 0.01 by two-way ANOVA) or low-dose RB200 alone (P < 0.001 by two-way ANOVA). In a prior study we have demonstrated that E-selectin-targeted fluorescence imaging is able to detect subclinical levels of fluorescence in animals with a clinical score of 0 [Quantification of MFI over 24 hours in the different treatment groups is shown in Figure ore of 0 . Here coP < 0.001 vs untreated by Chi squared test for trend) compared to 0% in mice that received low-dose RB200 alone (P > 0.05 vs untreated and P < 0.001 vs combination treatment) and 0% in mice treated with low-dose etanercept alone (P < 0.05 vs untreated and P < 0.01 vs combination treatment). Indeed the combination treatment was even more effective than high-dose etanercept alone (P < 0.05 vs combination treatment), highlighting the effectiveness of combined pan-EGFR and TNFα-targeted treatment in promoting joint protection.These data are supported by histological findings. Using serial sections stained with either haematoxylin and eosin or toluidine blue, we evaluated tibiotarsal joints for signs of synovitis and erosive changes to bone and cartilage. There were was a dose-dependent effect of both RB200 alone and etanercept alone on joint architecture, with progressively fewer severely destroyed joints and more joints with mild or moderate destruction Figure . HoweverAnti-HER2 antibody trastuzumab has revolutionised the treatment of patients with EGFR-positive breast cancer, and agents targeting EGFR/HER1 are in use for colorectal cancer therapy as well as for head and neck cancer. Interestingly, researchers in a number of studies have suggested that the family of EGF ligands and receptors may have a role in the development of RA. For example, expression of one of the primary ligands for EGFR/HER1, TGF-α, is increased at both the mRNA and protein levels in RA synovium . High lein vivo models. RB200 inhibited EGF- and NRG1-β1-stimulated tyrosine phosphorylation of HER1, HER2 and HER3 and also showed potency in cell proliferation assays [in vivo in two human tumour xenograft  nude mouse models [in vivo testing of candidate therapeutics for RA, such as TNFα inhibitors [RB200 is a heterodimer of the HER1/ErbB1 and HER3/ErbB3 ECD ,25. Thisn assays . In addie models . Thus, ihibitors ,27 and ihibitors ,28,29. Mhibitors ,31, and The efficacy of combination treatment with low-dose etanercept and RB200 is of potential interest. A significant proportion of patients with RA do not respond to TNFα blockade, and therefore there is a compelling need to continue identification of alternative therapeutic strategies for chronic inflammatory diseases such as RA. Nonetheless, biological therapies, particularly those targeting TNFα, are an undoubted success in RA, and hence an approach combining TNFα inhibition with, for example, an inhibitor of angiogenesis or with an inhibitor of EGFR-induced events might be useful. Moreover, targeting such separate mechanistic pathways could be beneficial, unlike the combination of targeting IL-1 and TNFα, which has been shown to be proinfective . In the in vivo and have found this approach to be a sensitive, specific and quantifiable molecular imaging technique in CIA [P < 0.01) from those in nonarthritic mice (not shown), whereas MFI readings for mice treated with etanercept plus RB200 were not significantly different from nonarthritic mice but lower than those treated with either low-dose etanercept alone (P < 0.01 by two-way ANOVA) or low-dose RB200 alone (P < 0.001 by two-way ANOVA). The in vivo fluorescence imaging data are supported by observations of normalised joint architecture in animals treated with etanercept plus RB200.We have also previously described the use of fluorescently labelled mAb against E-selectin to localise endothelial activation in inflamed tissues e in CIA . The come in CIA . Imagingin vivo mechanism of action of RB200, angiogenesis is a key feature of RA [in vivo models [in vivo mode of action, studies assessing whether synovial cell responses might be affected by RB200 are in progress. However, inhibition of synovial angiogenesis by RB200 could be implicated by the reduction in CD31-positive blood vessels, which we have demonstrated in CIA. Furthermore, EGF, when combined with proinflammatory mediators such as TNFα and IL-1, has been shown to increase expression by fibroblasts of matrix metalloproteinases (MMPs) such as MMP-1, MMP-3 and MMP-13 [in vitro, in particular by assessing MMP expression, as this would provide invaluable insight into how RB200 might affect CIA.Our findings substantiate the hypothesis that combination treatment with low doses of etanercept and RB200 has a significant beneficial effect in CIA, although there are a number of shortcomings of this study, the most notable being the absence of mechanism of action studies to elucidate the mode of action of RB200 in CIA. In terms of a potential re of RA , and indre of RA ,31,33, ire of RA ,30,34,35re of RA -38. Othere of RA , and taro models ,41. Actio models . RB200 hd MMP-13 ,43 and td MMP-13 . MoreoveIt is also unclear which of the many EGFR ligands RB200 inhibits in CIA. In addition to the presence of EGF in RA synovium , expressThe studies described in this report demonstrate that the potent human EGFR HER1/HER3 ECD heterodimer RB200 has a significant abrogating effect in a mouse model of RA, namely, CIA. A recent case report described a patient with long-standing RA who had previously been treated with rituximab and adalimumab. This patient experienced a significant reduction in joint pain during treatment with anti-EGFR/HER1 antibody cetuximab for head and neck cancer . TogetheHowever, cellular heterogeneity, redundancy of molecular pathways and effects of the microenvironment all likely contribute to the disease heterogeneity seen in CIA. This makes it unlikely that therapy directed at one abnormally activated signalling pathway, such as that downstream of EGFR activation, is likely to be sufficient . TherefoANOVA: analysis of variance; AR: amphiregulin; BTC: β-cellulin; CIA: collagen-induced arthritis; EGF: epidermal growth factor; EPG: epigen; EPR: epiregulin; HB-EGF: heparin-binding epidermal growth factor-like growth receptor; HER: human epidermal growth factor receptor; IL: interleukin; mAb: monoclonal antibody; MAPK: mitogen-activated protein kinase; MMP: matrix metalloproteinase; NIR: near-infrared; NRG: neuregulin; PBS: phosphate-buffered saline; RA: rheumatoid arthritis; RTK: receptor tyrosine kinase; TGF-α: transforming growth factor α; TNF: tumour necrosis factor; VEGF: vascular endothelial growth factor.PJ and HMS are former employees of Receptor BioLogix Inc and declare competing financial interests. MF and EMP have acted as consultants for Receptor BioLogix Inc. The other authors declare that they have no competing interests.HMS designed the study. PJ assisted in the study design. LLG, LM and NMM performed all the experiments, data analysis and drafting of the manuscript. EMP and MF assisted in the study design and coordination and oversaw the data analysis and drafting of the manuscript. All authors read and approved the final manuscript for publication.