Megan Davidson

Psychosocial predictors of failure to return to work in non-chronic non-specific low back pain: a systematic review

Objectives: To identify psychosocial predictors of failure to return to work in non-chronic (lasting less than 3 months) non-specific low back pain (NSLBP). Methods: A systematic review of prognostic studies was carried out. Medline, Embase, PsychINFO, CINAHL and PEDro electronic bibliographic databases up to April 2006 were searched. Included studies took baseline measures in the non-chronic phase of NSLBP (ie, within 3 months of onset), included at least one psychosocial variable and studied a sample in which at least 75% of participants had NSLBP. Baseline measures had to be used to predict at least one work-specific outcome. Results: The search identified 24 studies meeting the inclusion criteria. From these studies there is strong evidence that recovery expectation is predictive of work outcome and that depression, job satisfaction and stress/psychological strain are not predictive of work outcome. There is moderate evidence that fear avoidance beliefs are predictive of work outcome and that anxiety is not predictive of work outcome. There is insufficient evidence to determine whether compensation or locus of control are predictive of work outcome. Conclusions: To predict work outcome in non-chronic NSLBP, psychosocial assessment should focus on recovery expectation and fear avoidance. More research is needed to determine the best method of measuring these constructs and to determine how to intervene when a worker has low recovery expectations.

A systematic review of the Human Activity Profile

Objective: To review the measurement properties (reliability, validity, responsiveness) of the Human Activity Profile (HAP), a self-report measure of energy expenditure or physical fitness. Data sources: MEDLINE, CINAHL and EMBASE were searched up to September 2005 and the reference lists of included studies were checked for additional relevant studies. Review method: Studies were included that reported Human Activity Profile scores, test-retest reliability, correlations with other measures, or responsiveness (sensitivity to change). Of 83 potentially relevant articles, 39 articles were included plus the test manual. Two independent reviewers extracted data from the included studies. Results: The Human Activity Profile has been used to evaluate physical activity in a wide variety of clinical populations and in healthy individuals. The change in score required to be 90% confident that change is beyond measurement error was estimated to be 7.8 for the Maximum Activity Score and 6.8 for the Adjusted Activity Score. The construct validity of the Human Activity Profile was supported by a large number of studies, although evidence for criterion validity was limited to four studies. No studies have investigated a priori the responsiveness or minimum clinically important difference of the Human Activity Profile. Conclusion: The Human Activity Profile appears to be a useful indicator of physical activity levels in people with chronic pain, arthritis, renal failure, various neurological and cardiorespiratory conditions, as well as in healthy older people.

The interpretation of diagnostic tests: A primer for physiotherapists

This paper outlines a practical approach to assist physiotherapists to interpret the results of diagnostic or screening tests. Diagnostic tests are used during clinical assessment to increase or decrease the clinicians estimate of the likelihood that a client has a particular condition. A negative result for a test that is 100% sensitive can rule a condition out (SnOUT), and a positive result for a test that is 100% specific can rule a condition in (SpIN). However, tests are rarely 100% accurate, and false positive and false negative results can occur. The examining therapist needs to estimate the probability that a client has a particular condition (the pre–test probability), then estimate the extent to which they are more or less certain given a positive or negative test result (the post–test probability). The likelihood ratio, which combines the information provided by a tests sensitivity and specificity, is the most useful tool for the clinical interpretation of test results.

Rasch Analysis of the Barthel Index in the Assessment of Hospitalized Older Patients After Admission for an Acute Medical Condition

OBJECTIVE To investigate the validity of item score summation for the original and modified versions of the Barthel Index. DESIGN Rasch analysis of Barthel Index data. SETTING General medical wards at 2 acute care hospitals in Australia. PARTICIPANTS Consecutive older medical patients (N=396). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Activity limitation was assessed by using the Barthel Index at hospital admission and discharge. At 1 hospital site, the original Barthel Index was used, and at the other hospital site the Modified Barthel Index (MBI) was used. RESULTS More than half of the items showed misfit to the Rasch model for both versions of the Barthel Index. The continence items appear to measure a different construct to the other items. After the removal of the continence items, data for the remaining items still did not fit the Rasch model. Neither the original nor the MBI are unidimensional scales. An exception to this occurred when the original Barthel Index was rescored and only then for discharge and not for admission Barthel Index data. CONCLUSIONS Because clinicians do not typically rescore outcomes obtained by using the Barthel Index, these findings, combined with unacceptable ceiling effects, render the Barthel Index an assessment tool with limited validity for measuring and monitoring the health of older medical patients.

The Assessment of Physiotherapy Practice (APP) is a valid measure of professional competence of physiotherapy students: a cross-sectional study with Rasch analysis

QUESTION Is the Assessment of Physiotherapy Practice (APP) a valid instrument for the assessment of entry-level competence in physiotherapy students? DESIGN Cross-sectional study with Rasch analysis of initial (n=326) and validation samples (n=318). Students were assessed on completion of 4, 5, or 6-week clinical placements across one university semester. PARTICIPANTS 298 clinical educators and 456 physiotherapy students at nine universities in Australia and New Zealand provided 644 completed APP instruments. RESULTS APP data in both samples showed overall fit to a Rasch model of expected item functioning for interval scale measurement. Item 6 (Written communication) exhibited misfit in both samples, but was retained as an important element of competence. The hierarchy of item difficulty was the same in both samples with items related to professional behaviour and communication the easiest to achieve and items related to clinical reasoning the most difficult. Item difficulty was well targeted to person ability. No Differential Item Functioning was identified, indicating that the scale performed in a comparable way regardless of the students age, gender or amount of prior clinical experience, and the educators age, gender, or experience as an educator, or the type of facility, university, or clinical area. The instrument demonstrated unidimensionality confirming the appropriateness of summing the scale scores on each item to provide an overall score of clinical competence and was able to discriminate four levels of professional competence (Person Separation Index=0.96). Person ability and raw APP scores had a linear relationship (r(2)=0.99). CONCLUSION Rasch analysis supports the interpretation that a students APP score is an indication of their underlying level of professional competence in workplace practice.

Validity, responsiveness and the minimal clinically important difference for the de Morton Mobility Index (DEMMI) in an older acute medical population

BackgroundThe de Morton Mobility Index (DEMMI) is a new mobility instrument that overcomes the limitations of existing instruments. It is the first mobility instrument that accurately measures the mobility of all older adults. The aim of this study was to provide a detailed report of investigations of the validity, responsiveness to change and minimal clinically important difference (MCID) of the DEMMI during its development in an older acute medical population.MethodsThis study was conducted using a head to head comparison design in two independent samples of older acute medical patients (development sample, n = 86; validation sample, n = 106). Consecutive patients (≥ 65 years) were assessed using the DEMMI, Barthel Index (BI) and Hierarchical Assessment of Balance and Mobility (HABAM) within 48 hours of hospital admission and discharge. Convergent and discriminant validity were investigated using Spearmans rho and known groups validity was investigated using a independent t test to compare DEMMI scores for patients who were discharged to home compared to inpatient rehabilitation. Criterion and distribution based methods were employed for estimating instrument responsiveness to change and the MCID.ResultsSignificant moderate to high correlations were identified between DEMMI and BI scores (r = 0.76 and r = 0.68) and DEMMI and HABAM scores (r = 0.91 and r = 0.92) in both samples. In both samples, DEMMI scores for patients who were discharged to home were significantly higher than for patients discharged to inpatient rehabilitation and provided evidence of known groups validity. Patients who were discharged to inpatient rehabilitation (n = 8) had a mean DEMMI score of 50.75 (sd = 11.29) at acute hospital discharge compared to patients who were discharged to home (n = 70) with a mean DEMMI score of 62.14 (sd = 18.41). MCID estimates were similar across samples using distribution and criterion based methods. The MCID for the DEMMI was 10 points on the 100 point interval scale. The DEMMI was significantly more responsive to change than the BI using criterion and distribution based methods in the validation sample.ConclusionThis study has validated the DEMMI in two independent samples of older acute medical patients. Estimates of its responsiveness and MCID have also been established. This study confirms that the DEMMI overcomes the limitations of the BI and HABAM and provides an advanced method for objectively assessing mobility for older acute medical patients.

A critical appraisal of instruments to measure outcomes of interprofessional education

Interprofessional education (IPE) is believed to prepare health professional graduates for successful collaborative practice. A range of instruments have been developed to measure the outcomes of IPE. An understanding of the psychometric properties of these instruments is important if they are to be used to measure the effectiveness of IPE.

Patient-reported outcome measures (PROMs): how should I interpret reports of measurement properties? A practical guide for clinicians and researchers who are not biostatisticians

This paper will help clinicians and researchers to understand studies on the validity, responsiveness and reliability of patient-reported outcome measures (PROMs) and to interpret the scores and change scores derived from these and other types of outcome measures. Validity studies provide a method for assessing whether the underlying construct of interest is adequately assessed. Responsiveness studies explore the longitudinal validity of a test and provide evidence that an instrument can detect change in the construct of interest. Reliability is commonly assessed with correlation indices, which indicate the stability of repeated measurements and the ‘noise’ or error in the measurement. Proposed indicators for clinical interpretation of test scores are the minimum clinically important difference, the standard error of measurement and the minimum detectable change. Studies of the Victorian Institute of Sports Assessment questionnaire for patellar tendinopathy and other PROMs are used to illustrate concepts.

Reliability and validity of shoulder function outcome measures in people with a proximal humeral fracture

Abstract Purpose: Investigate test--retest reliability and validity of five shoulder outcome measures in people during their active rehabilitation after a shoulder fracture. Method: This prospective longitudinal study assessed shoulder function in 20 people (16 women, mean age 68.1 years) with surgical or conservative management at 6, 12 and 13 weeks post proximal humeral fracture using three patient-reported (Disabilities of Arm, Shoulder and Hand; Oxford Shoulder Score; Subjective Shoulder Value) and two clinician-administered (Constant Score; UCLA Shoulder score) outcome measures. Results: Content analysis categorised items into multiple domains of functioning for each outcome measure. Construct validity testing between measures found moderate to strong correlations (r = 0.43–0.92). Longitudinal validity (responsiveness), represented by correlations between change scores, was moderate to strong (r = 0.44–0.83). Although ICCs2,1 for test–retest reliability ranged from 0.75 to 0.93, Limits of Agreement between measurements were relatively wide (10–23% of available range of scores). Minimal clinically important difference estimates varied between anchor- and distribution-based methods. Conclusions: The five outcome measures assessing shoulder function provided values for reliability and validity that meet measurement requirements for use in groups of people after a proximal humeral fracture. However, the use of these outcome measures might be limited by low absolute agreement between measurements and their content covering multiple domains of functioning. Implications for Rehabilitation Linking the International Classification of Functioning, Disability and Health (ICF) to the content of common shoulder function outcome measures showed that multiple domains of functioning are combined into a single score. This might not be preferred for measurement of the single construct of “shoulder function”. Currently available shoulder function outcome measures may not be sufficiently reliable to monitor change in an individual after a proximal humeral fracture during the rehabilitation phase.

Individualised physiotherapy as an adjunct to guideline-based advice for low back disorders in primary care: a randomised controlled trial

Background Many patients with low-back disorders persisting beyond 6 weeks do not recover. This study investigates whether individualised physiotherapy plus guideline-based advice results in superior outcomes to advice alone in participants with low-back disorders. Methods This prospective parallel group multicentre randomised controlled trial was set in 16 primary care physiotherapy practices in Melbourne, Australia. Random assignment resulted in 156 participants receiving 10 sessions of physiotherapy that was individualised based on pathoanatomical, psychosocial and neurophysiological barriers to recovery combined with guideline-based advice, and 144 participants receiving 2 sessions of physiotherapist-delivered advice alone. Primary outcomes were activity limitation (Oswestry Disability Index) and numerical rating scales for back and leg pain at 5, 10, 26 and 52 weeks postbaseline. Analyses were by intention-to-treat using linear mixed models. Results Between-group differences showed significant effects favouring individualised physiotherapy for back and leg pain at 10 weeks (back: 1.3, 95% CI 0.8 to 1.8; leg: 1.1, 95% CI 0.5 to 1.7) and 26 weeks (back: 0.9, 95% CI 0.4 to 1.4; leg: 1.0, 95% CI 0.4 to 1.6). Oswestry favoured individualised physiotherapy at 10 weeks (4.7; 95% CI 2.0 to 7.5), 26 weeks (5.4; 95% CI 2.6 to 8.2) and 52 weeks (4.3; 95% CI 1.4 to 7.1). Responder analysis at 52 weeks showed participants receiving individualised physiotherapy were more likely to improve by a clinically important amount of 50% from baseline for Oswestry (relative risk (RR=1.3) 1.5; 95% CI 1.2 to 1.8) and back pain (RR 1.3; 95% CI 1.2 to 1.8) than participants receiving advice alone. Conclusions 10 sessions of individualised physiotherapy was more effective than 2 sessions of advice alone in participants with low-back disorders of ≥6 weeks and ≤6 months duration. Between-group changes were sustained at 12 months for activity limitation and 6 months for back and leg pain and were likely to be clinically significant. Clinical trial registration ACTRN12609000834257.