Measurement properties of walking outcome measures for neurogenic claudication: a systematic review and meta analysis.

Background Context: Selecting a walking outcome measure for neurogenic claudication requires knowledge of its measurement properties.

Purpose: To systematically review and appraise the literature on the measurement properties of walking outcome measures for patients with neurogenic claudication.

Study Design: A systematic review and meta-analysis.

Methods: A systematic search was conducted on the following seven databases: PubMed, PsychINFO, Web of Science, Embase, CINAHL, MEDLINE, and Cochrane Central Register of Controlled Trials. Clinical studies that assessed a measurement property of a walking outcome measure for patients with neurogenic claudication were selected. The methodological quality of studies was assessed using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. Measurement property results were assessed using the adapted criteria from Terwee et al. (2007).

Results: Twelve studies that evaluated 15 separate walking outcome measures were included. Out of the 12 studies included, half had poor methodological quality. Four measures had acceptable test-retest reliability: the self-paced walking test (intraclass correlation coefficient, or ICC was 0.98, 95% CI: 0.95-0.99), Physical Function Scale (PFS) (pooled analysis ICC = 0.79, 95% CI: 0.77-0.89), PFS walk item (ICC = 0.81, 95% CI: 0.68-0.89), and Oswestry Disability Index (ODI) walk item (ICC = 0.86, 95% CI: 0.76-0.92). Responsiveness was assessed on five walking outcome measures, and three had adequate responsiveness: the ODI walk item (Area under the Curve, or AUC, was 0.76, SD 0.15), Treadmill test (AUC = 0.70), and PFS (AUC = 0.77, SD 0.14). A meta-analysis demonstrated the PFS had adequate test retest reliability (pooled ICC = 0.79, 95% CI: 0.77-0.89) and internal consistency (pooled Cronbach's αlpha (α) = 0.84, 95% CI: 0.81-0.86), but not criterion validity (pooled correlation coefficient = -0.59, 95% CI: -0.71, -0.45). Measures that recorded adequate criterion validity were the ODI walk item (pooled correlation coefficient = -0.71, 95% CI: -0.80, -0.58), Treadmill test (pooled correlation coefficient = 0.86, 95% CI: 0.78-0.91), and self predicted walking item (pooled correlation coefficient = 0.74, 95% CI: 0.63-0.82).

Conclusions: The results of our systematic review demonstrated that high-quality studies that asses the measurement properties of walking outcome measures for patients with neurogenic claudication are lacking. There was only limited evidence available for each walking measure, which prevented any single outcome from being confirmed as the gold standard measure of neurogenic claudication. Clinicians and researchers are recommended to use the self-paced walking test and ODI walk item until further evidence is available. Future research should focus on producing high-quality studies with excellent methodology and larger sample sizes.