Clinical measures of balance in people with type two diabetes: A systematic literature review
http:/dx.doi.org/10.1016/j.gaitpost.2017.08.022 Received 22 February 2017; Received in revised form 17 August 2017; Accepted 18 August 2017 Corresponding author at: Physiotherapy Department, School of Clinical Sciences, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand. E mail addresses: christinajdixon7@gmail.com (C.J. Dixon) tuiknight@live.com (T. Knight) lbinns@aut.ac.nz (E. Binns) bihaka@aut.ac.nz (B. Ihaka) daniel.obrien@aut.ac.nz, dobrien@aut.ac.nz (D. O'Brien) Abbreviations: ABC, activities specific balance confidence scale; BBS, Berg balance scale; BESTest, balance evaluation systems test; CASP, critical appraisal skills programme; CTSIB, clinical test of sensory interaction and balance; DGI, Dynamic Gait Index; DM, diabetes mellitus; DPN, diabetic peripheral neuropathy; FRT, functional reach test; NDC, non diabetic controls; POMA, Tinetti performance oriented mobility scale; T2DM, type II diabetes mellitus; TUG, timed up and go test Gait Posture 58 (2017) 325 332 0966 6362/ (c) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY NC ND license (http:/creativecommons.org/licenses/BY NC ND/4.0/ MARK Downloaded for Anonymous User (n/a) at Auckland University of Technology from ClinicalKey.com.au by Elsevier on December 04, 2017. For personal use only. No other uses without permission. Copyright (c)2017. Elsevier Inc. All rights reserved. interactions. This can cause endoneural hypoxia altering nerve perfusion particularly to glucose dependent tissue including peripheral nerves (resulting in diabetic peripheral neuropathy [DPN] the retina (resulting in diabetic retinopathy) and the vestibular system [3,8] DPN can alter movement perception as a result of diminished proprioceptive and cutaneous input from the skin, muscles and joints. Diabetic retinopathy can affect the sensory receptors in the retina responsible for providing visual information of the surrounding environment and orientation of the body [9] Diminished sensitivity in the vestibular system can alter perception regarding motion, equilibrium, and spatial orientation necessary to maintain posture [3] Additionally, prolonged hyperglycaemia can also lead to muscle weakness, joint stiffness and early degenerative changes in the brain [8,10] These are all factors that may further impair balance control in people with T2DM. Impaired balance is one of the top three risk factors for falling, and therefore associated with fear of falling, and reduced quality of life in people with T2DM [11,12] T2DM is also identified as an independent risk factor for falls in older adults [13,14] Balance is assessed to identify fall risk, the kind of balance disorder or the underlying physiological impairment contributing to the balance disorder, and to inform treatment choices. Treatments can then be targeted to the balance disorder at a functional level to reduce the impact of the impairment and facilitate function (such as virtual reality techniques, lifestyle modification and the removal of home hazards) or at a physiological level to improve a sensorimotor system (such as balance and strength retraining or vestibular rehabilitation [3,15 17] Although there are many valid clinical measures for assessing balance in the healthy population, the validity of these measures for use with people with T2DM is unclear [6,12] In the context of this study, validity is defined as the statistical certainty that a balance measure measures what it is said to measure and can be further defined as face, content, construct or criterion [18] Therefore, the aim of this study was to conduct a systematic review of clinical balance measures in people with T2DM and DPN. 2. Methods 2.1. Search strategy A comprehensive search of the following electronic databases was completed on 29 March 2015: CINAHL plus, MEDLINE, SPORTDiscus, Dentistry and Oral Sciences source, and SCOPUS. Search terms used were extrapolated from the key terms in the study question and included: Diabetes, balance, validity and outcome measure (Table 1) Search terms were combined with 'AND' The titles of all of the identified articles were screened independently by two members of the research team (CD and TK) Articles were retained if the title referred to the clinical assessment of balance in people with T2DM and/or DPN. Duplicates of articles were discarded. The abstracts of all retained articles were reviewed. If the abstract did not relate to the clinical assessment of balance in people with T2DM, the article was discarded. The full text of all remaining articles were read by two members of the research team (CD and TK) and reviewed for suitability using the following inclusion and exclusion criteria. The reference lists of the selected articles were screened for further studies that would merit inclusion in this systematic review. 2.2. Inclusion and exclusion criteria Articles were included if they were written in English, used a clinical measure of either balance or postural stability or fall risk, had participants with T2DM or diabetes with DPN, and had full text available. Articles were excluded if they only assessed gait or fall risk, were not published in a peer reviewed journal, or only used measures which required specialist equipment that may not be available to all clinicians working with people with T2DM (i.e. Biodex Stability System or forceplatform) 2.3. Study quality appraisal and data extraction All studies were critiqued using the Downs and Black critical appraisal tool [19] This tool includes 27 items, a 'Yes' response is allocated a '1' and a 'No' response is allocated a 0, therefore studies are rated out of a total of 27 points. In instances where a question did not apply to the methodology of a particular study, it was rated as not applicable (NA) The response of 'NA' was rated as 0 and was included in the total rating so that each paper remained rated out of a total of 27. The item and total Downs and Black scores for each paper was recorded. In addition to the appraisal of quality, all retained studies were subjected to the following data extraction process. The study design, participant characteristics, control group characteristics and interventions of each study were identified. The balance measures used in each study were also identified and validation of these measures was noted. An answer of 'Yes' indicated that the study had validated the measures it used and 'No' where they had not. The main findings of each of the studies were then summarised. Furthermore, a list of the balance measures used across all of the studies was collated and the balance system assessed by each measure were identified. 3. Results 3.1. Study selection A total of 105 studies were identified during the literature search. A further 22 studies were identified by reviewing the reference list of articles retained and reviewed in full text version. One hundred and seven studies were removed after reading the abstracts as they did not contain the key concepts of the study question. The majority of these studies were excluded either (i) because they focused on assessing fall risk, (ii) employed specialist equipment not typically found in a clinic or (iii) included participants with a variety of different illnesses meaning that the results were not exclusive to people with T2DM or diabetes with DPN. Twenty studies were believed to contain the key concepts of the study question, of these a further 12 studies were excluded. Eleven because they used specialised technology and one additional study because it only utilised fall risk measures (Fig. 1) Therefore, a total of eight studies were retained for the critical appraisal and data extraction. Table 1 Search terms. Diabetes search terms combined with "OR" (diabet* N5 2) (diabet* N5 "II" (diabet* N5 neuropathy) Balance search terms combined with "OR" balance fall* postur* Validity search terms combined with "OR" valid* reliab* psychometric Outcome measure search terms combined with "OR" Tool Test Measure Questionnaire Outcome Index Scale C.J. Dixon et al. Gait Posture 58 (2017) 325 332 326 Downloaded for Anonymous User (n/a) at Auckland University of Technology from ClinicalKey.com.au by Elsevier on December 04, 2017. For personal use only. No other uses without permission. Copyright (c)2017. Elsevier Inc. All rights reserved. 3.2. Methodological quality The Downs and Black scores ranged between 8 and 19/27 (Table 2) As shown in Table 2, most of the reviewed studies rated poorly on external validity, as the recruitment methods and study location were not clearly described. Furthermore, it was unclear whether participants were representative of the general diabetes population, as many of the studies did not compare study group characteristics to those of the general population. Studies also scored poorly on the rating of validity and reliability of the outcome measures used, as these were not well described in most of the studies. The intervention studies did not include blinding and did not describe participant compliance with the intervention. Overall, studies rated well for clear reporting methods and had a moderate rating of bias. Many studies scored poorly for confounding and external validity. However, three questions (questions 4, 14 and 19) were not rated as applicable to non interventional studies and a further three questions (9, 17 and 26) were not applicable to the studies that employed a cross sectional study design because there was no follow up. Furthermore, seven of the studies were unable to randomise participants to groups, so a further two questions were not applicable (question 23 and 24) 3.3. Extracted data Study characteristics data were extracted from the eight studies (Table 2) Additionally, data were extracted about the use and validation of balance measures. 3.3.1. Study design Four of the eight studies employed a cross sectional