major depressive disorder ( mdd ) is a common disease in patients with coronary heart disease ( chd ) , with a prevalence of 20% to 30% [ 14 ] and is associated with worse cardiac prognosis .
the american heart association ( aha ) and american academy of family physicians ( aafp ) have recommended routine depression screening for cardiac patients , including those suffering an myocardial infarction ( mi ) .
however , the uk national institute for health care effectiveness does not recommend the routine depression screening in primary care because of limited / conflicting findings on the optimal screening tools .
after screening , further psychosocial assessment of patients who respond positively to the screening tools is considered to effect treatment evaluation .
depression has been categorized by 2 commonly used psychiatric classifications : the diagnostic and statistical manual of mental disorders ( dsm - iv )   and the international classification of diseases ( icd-10 ) .
the criteria for the categorization are based on the severity , sub - types of specific symptoms , duration , course , and whether it is secondary to a physical or other psychiatric condition .
mdd is diagnosed if participants meet at least 1 core criterion ( depressed mood or anhedonia ) and at least 4 additional criteria within the previous 2 weeks .
in addition to these 2 diagnostic criteria , several well - established screening tools have been developed and include self - report questionnaires and observer rating scales for depression .
phq-9 is a self - rating instrument for depression developed in the late 1990s for the primary care evaluation of mental disorders ( prime - md ) .
it consists of 9 items designed to correspond to the dsm - iv for mdd .
the hospital anxiety and depression scale ( hads ) rating scale has 14 items , 7 of which are designed to measure anxiety ( hads - a ) , and 7 for depression ( hads - d ) .
hads - d was developed to assess depression in medically ill patients and its items focus on the loss of interest and pleasure with somatic features excluded from measurement .
phq-9 is mainly used in north american while hads is more frequently used in europe .
furthermore , phq-9 and hads differ in important ways , such as the exclusion of somatic symptoms in the latter .
the beck depression inventory ( bdi ) is 1 of the most commonly used self - rating scales in the evaluation of depression . since the development of this tool in 1961 , it has been employed in numerous empirical studies .
bdi has recently been updated ( the beck depression intervention - ii [ bdi - ii ] ) to better match the current definition of mdd , as it measures symptoms in the preceding 2 weeks , as compared to 1 week in the bdi .
bdi - ii also has fewer items used to assess the somatic symptoms of depression because the somatic symptoms may confound the diagnosis of depression in post - mi patients .
the 90-item symptom check list ( scl-90 ) has been proven to be a useful tool for identifying psychiatric symptoms in primary care and research .
ces - d , a 20-item questionnaire with the total score ranging from 0 to 60 , has been used extensively in chd patients , demonstrating utility , and a cut - off value of 16 has been found to be adequately sensitive and specific in the identification of chd .
the 17-item hamilton depression rating scale ( ham - d-17 ) is an observer rating scale   used to evaluate the severity of depression .
there is currently no consensus on which commonly used screening tool is best for use in identifying mdd in chd .
furthermore , mdd is under - diagnosed in chd patients because healthcare providers rarely use a standardized screening instrument . to the best of our knowledge ,
no systematic review has been published to comparatively evaluate the screening tools against the diagnostic criteria from depression in dsm - iv and icd-10 in chd patients . to investigate the performance of screening tools in identifying mdd in chd patients ,
this systematic review was performed to assess the diagnostic accuracy ( focusing on sensitivity and specificity ) of various screening tools as compared to the diagnostic criteria .
two reviewers independently searched the following electronic databases in english : ovid medline , embase , psycinfo , scopus , cochrane library , cinahl plus , and web of science before 31 dec 2013 .
, following terms were used for searching :  coronary heart disease  ,  ischemic heart disease  or 
heart disease  ; to identify relevant screening tools , a second search was performed using the following terms :  tool  ,  measurement  , or  assessment  ; and to identify studies related to depression ,  depress *  was used as a term for searching .
then , they performed full - text reviewing on each article meeting the inclusion criteria or having some uncertainties for eligibility .
any disagreements in data extraction and/or specific study inclusion were resolved through consensus by discussion .
inclusion criteria were : participants were diagnosed as having chd and randomly recruited from different healthcare settings , including hospitals and communities .
the diagnostic criteria for depression were from dsm - iv of the american psychiatric association   or icd-10 of the world health organization .
the studies included mdd or severe depressive episode ( mde ) diagnosed according to corresponding diagnostic criteria , other than minor depression or depressive syndrome .
exclusion criteria were : participants were diagnosed with other cardiovascular diseases , including cardiomyopathy and heart failure other than chd .
studies did not clearly compare the screening tools with diagnostic criteria in dsm or icd .
studies meeting the inclusion criteria were assessed for methodological quality using the quality assessment of diagnostic accuracy studies ( quadas ) , which is a tool used for quality assessment included in systematic reviews .
each study was independently assessed by 2 authors , and data were extracted from articles according to the collecting data items of quadas   and cochrane - handbook .
the following data were extracted : settings , gender , mean age , stage of depression , screening tools , diagnostic criteria , sensitivity and specificity of screening tools , and numbers of patients with mdd diagnosed by diagnostic criteria .
the sensitivity , specificity , likelihood ratios , and predictive values were determined and the binomial 95% confidence intervals were calculated for the sensitivity and specificity with reference manager ( revman ) version 5.1 from the cochrane collaboration .
two reviewers independently searched the following electronic databases in english : ovid medline , embase , psycinfo , scopus , cochrane library , cinahl plus , and web of science before 31 dec 2013 .
, following terms were used for searching :  coronary heart disease  ,  ischemic heart disease  or 
heart disease  ; to identify relevant screening tools , a second search was performed using the following terms :  tool  ,  measurement  , or  assessment  ; and to identify studies related to depression ,  depress *  was used as a term for searching .
then , they performed full - text reviewing on each article meeting the inclusion criteria or having some uncertainties for eligibility . any disagreements in data extraction and/or specific study inclusion were resolved through consensus by discussion .
inclusion criteria were : participants were diagnosed as having chd and randomly recruited from different healthcare settings , including hospitals and communities .
the diagnostic criteria for depression were from dsm - iv of the american psychiatric association   or icd-10 of the world health organization .
the studies included mdd or severe depressive episode ( mde ) diagnosed according to corresponding diagnostic criteria , other than minor depression or depressive syndrome .
exclusion criteria were : participants were diagnosed with other cardiovascular diseases , including cardiomyopathy and heart failure other than chd .
studies did not clearly compare the screening tools with diagnostic criteria in dsm or icd .
studies meeting the inclusion criteria were assessed for methodological quality using the quality assessment of diagnostic accuracy studies ( quadas ) , which is a tool used for quality assessment included in systematic reviews .
each study was independently assessed by 2 authors , and data were extracted from articles according to the collecting data items of quadas   and cochrane - handbook .
the following data were extracted : settings , gender , mean age , stage of depression , screening tools , diagnostic criteria , sensitivity and specificity of screening tools , and numbers of patients with mdd diagnosed by diagnostic criteria .
the sensitivity , specificity , likelihood ratios , and predictive values were determined and the binomial 95% confidence intervals were calculated for the sensitivity and specificity with reference manager ( revman ) version 5.1 from the cochrane collaboration .
after searching ovid medline , embase , psycinfo , scopus , cochrane library , cinahl plus , and web of science with corresponding terms , a total of 3878 articles were identified by the initial screening and included 769 from ovid medline , 411 from embase , 562 from psycinfo , 887 from scopus , 288 from cochrane library , 229 from cinahl plus , and 662 from web of science .
, there were no diagnostic criteria for depression , 3 studies were conducted from 3 different viewpoints in the same population , and randomization was not performed in 1 study .
finally , 8 studies were included for further meta - analysis in accordance with the prisma flow chart .
we re - analyzed the data of included studies with the methodology , the summary receiver operating characteristic ( sroc ) , and the bivariate approach . in 8 studies
included , there were 10 self - reporting questionnaires ( such as phq-2 , phq-9 , phq categorical algorithm , hads - d , bdi , bdi - ii , bdi - ii - cog , ces - d , scl-90 , 2 simple yes / no items ) and 1 observer rating scale ( ham - d ) . in some self - reporting questionnaires ,
the data were insufficient to calculate the sroc and the pooled statistic sensitivity and specificity of each screening tool and different cut - off values .
thus , the positive lr , negative lr , positive predictive value ( ppv ) , negative predictive value ( npv ) , and prevalence were calculated using revman 5.1 . as shown in table 2 , for mdd alone , the sensitivity and specificity of different screening tools at the validity and optimal cut - off point varied from 0.34 [ 0.19 , 0.52 ] to 0.96 [ 0.78 , 1.00 ] and from 0.69 [ 0.65 , 0.73 ] to 0.97 [ 0.93 , 0.99 ] , respectively .
the quadas was used to assess the quality of included studies , in which the patient spectrum , diagnostic criteria , disease progression bias , verification bias , clinical review bias , incorporation bias , test execution , study withdrawals , and indeterminate results were evaluated .
assessment of the spectrum bias showed that participants in 8 studies were representative of chd patients .
although 5 different diagnostic criteria , such as the revised clinical interview schedule ( cis - r ) , the mini international neuropsychiatric interview ( mini ) , the structure clinical interview for dsm - iv axis disorders ( scid ) , the diagnostic interview schedule ( dis ) and the structure clinical interview ( sci ) , were used in the 8 studies , patients met the criterion standard for mdd according to dsm - iv or icd-10 .
ideally , the results of the index test and the reference standard should be collected from the same patients at the same time .
if this is impossible and a delay occurs , misclassification may be present due to spontaneous recovery or disease progression . assessment of disease progression bias showed 6/8 studies had high quality . in addition
, there was no partial verification bias , differential verification bias , or incorporation bias .
sufficient description of index test and the reference standard were present in all the studies .
assessment of review bias showed 4/8 studies were blinded between index test and reference standard , which can be used in practice when test results are interpreted .
there was explanation of withdrawals and no report of test results that were intermediate or could not be interpreted in any of the studies .
after searching ovid medline , embase , psycinfo , scopus , cochrane library , cinahl plus , and web of science with corresponding terms , a total of 3878 articles were identified by the initial screening and included 769 from ovid medline , 411 from embase , 562 from psycinfo , 887 from scopus , 288 from cochrane library , 229 from cinahl plus , and 662 from web of science .
, there were no diagnostic criteria for depression , 3 studies were conducted from 3 different viewpoints in the same population , and randomization was not performed in 1 study .
finally , 8 studies were included for further meta - analysis in accordance with the prisma flow chart .
we re - analyzed the data of included studies with the methodology , the summary receiver operating characteristic ( sroc ) , and the bivariate approach . in 8 studies
included , there were 10 self - reporting questionnaires ( such as phq-2 , phq-9 , phq categorical algorithm , hads - d , bdi , bdi - ii , bdi - ii - cog , ces - d , scl-90 , 2 simple yes / no items ) and 1 observer rating scale ( ham - d ) . in some self - reporting questionnaires ,
the data were insufficient to calculate the sroc and the pooled statistic sensitivity and specificity of each screening tool and different cut - off values .
thus , the positive lr , negative lr , positive predictive value ( ppv ) , negative predictive value ( npv ) , and prevalence were calculated using revman 5.1 . as shown in table 2 , for mdd alone , the sensitivity and specificity of different screening tools at the validity and optimal cut - off point varied from 0.34 [ 0.19 , 0.52 ] to 0.96 [ 0.78 , 1.00 ] and from 0.69 [ 0.65 , 0.73 ] to 0.97 [ 0.93 , 0.99 ] , respectively .
the quadas was used to assess the quality of included studies , in which the patient spectrum , diagnostic criteria , disease progression bias , verification bias , clinical review bias , incorporation bias , test execution , study withdrawals , and indeterminate results were evaluated .
assessment of the spectrum bias showed that participants in 8 studies were representative of chd patients .
although 5 different diagnostic criteria , such as the revised clinical interview schedule ( cis - r ) , the mini international neuropsychiatric interview ( mini ) , the structure clinical interview for dsm - iv axis disorders ( scid ) , the diagnostic interview schedule ( dis ) and the structure clinical interview ( sci ) , were used in the 8 studies , patients met the criterion standard for mdd according to dsm - iv or icd-10 .
ideally , the results of the index test and the reference standard should be collected from the same patients at the same time .
if this is impossible and a delay occurs , misclassification may be present due to spontaneous recovery or disease progression .
in addition , there was no partial verification bias , differential verification bias , or incorporation bias .
sufficient description of index test and the reference standard were present in all the studies .
assessment of review bias showed 4/8 studies were blinded between index test and reference standard , which can be used in practice when test results are interpreted .
there was explanation of withdrawals and no report of test results that were intermediate or could not be interpreted in any of the studies .
in this study , 8 studies conducted in chd patients from primary care settings and hospitals were systemically reviewed .
the sensitivity and specificity of screening tools were different from the diagnostic criteria in identifying mdd .
the screening tools had the highest sensitivity without affecting the specificity in identifying the greatest number of true - positives . for screening ,
sensitivity should be maximized when choosing a screening tool for depression so that cases are not missed . in our study ,
ces - d ( 16 ) and scl-90 ( 25 ) had high sensitivity and npv as compared to other screening tools , with the sensitivity of 93% and 96% , respectively , and npv of 97.54% and 99.24% , respectively .
however , the low ppv of these 2 tools ( 54.79% and 32.35% , respectively ) meant that only about half of patients who have a positive result on the screening meet the diagnostic criteria for major depression .
thus , any patient who has positive results on depression screening should be followed up to confirm the diagnosis of depression . for diagnosis ,
the ppv depends , in part , on the prevalence of the disorder in the population . due to the relatively low number of depressed patients
as compared to non - depressed patients in all the studies , the ppvs ( 22.99% to 70.59% ) were much lower than npvs ( 84.31% to 79.24% ) .
a cut - off value of 10 on phq-9 had the sensitivity of only 54% in 2 studies , but its high specificity ( 90% and 91% ) and high ppv ( 57.58% and 60.20% ) mean that patients who screen positive do not need a follow - up for confirming the diagnosis of depression .
it has been found that up to 30% of patients having stable heart disease also develop depression [ 14 ] .
the prevalence of mdd in chd patients in the included studies varied from 4.38%   to 22.05% .
the study with the lowest prevalence ( 4.38% ) was performed in chd patients from primary care settings   and is similar to the 12-month prevalence of 4% to 7% in the communities , as previously reported .
the optimal cut - off value is another important factor in the comparisons of the accuracy among various measures . for phq-9 ,
the optimal cut - off value of 10 for the identification of mdd was consistent in 2 included studies .
a study   on the phq-9 indicated that a lower cut - off value ( 8 ) resulted in an increased sensitivity with only modest reduction in the specificity when compared with the recommended cut - off value ( 10 ) .
some optimal cut - off values were lower than generally recommended , particularly in the screening for mdd .
lowering the cut - off value substantially improves the sensitivity of these tools while retaining the specificity , thereby improving their usefulness in screening for depression in chd patients . in the study of haddad et al .
, results showed that the performance of hads - d at a standard cut - off value ( 8 )   was weaker , with a sensitivity of 53% and specificity of 91% , a large proportion of depression patients were not diagnosed under this condition , and the satisfactory performance was found when the cut - off value was 5 or above ( 8 ) with the sensitivity of 81.3% and specificity of 76.7% . however , there were no subgroups in the assessment of mdd and the accuracy of hads - d was not evaluated .
the other 3 studies on hads - d showed that the recommended cut - off value was 5 in 2 studies   and 4 in 1 study .
the sensitivity of 77% , 86% , and 87% , respectively , and the specificity of 69% , 75% , and 75% , respectively , were comparable among 3 studies .
for bdi - ii , cut - off values were different in 3 included studies . the recommended cut - off value for bdi - ii ( 14 ) was used in the studies of bunevicius et al .   and
frasure - smith et al . , and their results showed it was effective to screen mdd with good sensitivity ( 89% and 74% , respectively ) and specificity ( 91% and 78% , respectively ) . in the study of huffman et al . , the cut - off value of 14 resulted in sensitivity of 88.2% and specificity of 84.2% .
however , a bdi - ii score of 16 , which had equivalent sensitivity ( 88.2% ) and better specificity ( 92.1% ) , was recommended for mdd . both cut - off
values resulted in very few cases with a false - negative ( npc=98.13% for 16 and npv=97.96 for 14 ) , which is important for a good screening tool . using a cut - off of 16 ,
62.5% of patients with a positive result in screening were found to have mdd , and the cut - off value of 14 had a lower ppv ( 45.45% ) .
depression is under - recognized in chd patients because healthcare providers rarely use standardized screening tools   and there is no consensuses which of the available screening tools should be used . in 2008 , the aha recommended systematic screening using phq-2 for depression in all chd patients .
however , this guideline is challenged because there remains a paucity of evidence that systematic screening for depression is helpful to improve the outcomes of chd patients [ 3840 ] .
patients with false - positive results in the screening are at increased risk for receiving unnecessary anti - depressive treatment .
studies have demonstrated that although primary providers can provide effective therapies without referral for up to 75% of patients with depression , most patients are unrecognized or inappropriately treated . after appropriate referral , psychosocial interventions may improve the physiological function   and decrease the cardiovascular morbidity and mortality in chd patients .
first , meta - analysis was not performed to assess the pool - statistic such as sensitivity , specificity , and predictive values because of the small number of each tool in studies that met the inclusion criteria .
second , studies included in this review only targeted the identification of mdd rather than minor depression , depression syndrome , and depression of different severities .
apart from mdd , minor depression also has an influence on the morbidity and mortality of chd patients .
third , there are different semi - structured methods used to determine the interview - based diagnosis , including cis - r , mini , acid , and dis , all of which have different diagnostic accuracies .
another limitation is the lack of cost - effectiveness analysis in the identification of mdd , and thus whether the cost also influences the false - positives of screening tools is still unclear .
in the absence of systematic screening to recognize ( and thus treat ) chd is difficult for the front - line clinicians in the in - patient and primary case settings . to the best of our knowledge ,
this is the first systematic review in which various depression screening tools were compared with the diagnostic criteria in identification of mdd among chd patients . in our study , phq-9 ( 10 ) , bdi - ii ( 14 or 16 ) , and hads - d ( 5 or 4 )
when the performance of a screening tool is evaluated , the high sensitivity and npv should be balanced with the high specificity and ppv , which will provide useful guidance for the application of appropriate tools and optimal cut - off value in the identification of depression in chd patients .
taking into account psychometric properties and ease of use , effective screening tools should be integrated into clinical care . after screening , further diagnosis ,
 backgroundmajor depressive disorder ( mdd ) is common in patients with coronary heart disease ( chd ) and there is no consensus on the optimal screening tool for use in identifying mdd . 
 this study aimed to systematically review the performance of various screening tools in the identification of mdd.material/methodseligible studies published before 31 dec 2013 were identified from the following databases : ovid medline , embase , psycinfo , scopus , cochrane library , cinahl plus , and web of science.resultseight studies aiming to identify mdd in chd patients were included , and there were 10 self - reporting questionnaires ( such as phq-2 , phq-9 , phq categorical algorithm , hads - d , bdi , bdi - ii , bdi - ii - cog , ces - d , scl-90 , 2 simple yes / no items ) and 1 observer rating scale ( ham - d ) . for mdd alone , the sensitivity and specificity of various screening tools at the validity and optimal cut - off point varied from 0.34 [ 0.19 , 0.52 ] to 0.96 [ 0.78 , 1.00 ] and 0.69 [ 0.65 , 0.73 ] to 0.97 [ 0.93 , 0.99 ] . 
 results showed phq-9 ( 10 ) , bdi - ii ( 14 or 16 ) , and hads - d ( 5 or 4 ) were widely used for screening mdd in chd patients.conclusionsthere is no consensus on the optimal screening tool for mdd in chd patients . when evaluating the performance of a screening tool , balancing the high sensitivity and negative predictive value ( npv ) between specificity and positive predictive value ( ppv ) for screening or diagnostic purpose 
 should be considered . after screening , 
 further diagnosis , appropriate management , and necessary referral may also improve cardiovascular outcomes . 