Psychometric Properties of the Patient-Specific Functional Scale in Patients with Low Back Pathology: A Systematic Review and Meta-Analysis

Purpose: This systematic review and meta-analysis identifies, critically appraises, synthesizes, and meta-analyses the reported psychometric properties of the Patient-Specific Functional Scale (PSFS) in patients with low back pain or pathology. Method: The MEDLINE, Embase, PubMed, and Google Scholar databases were searched from their inception to September 2019. We included prospective measurement studies that reported on the psychometric properties (reliability, validity, responsiveness) of the PSFS in people with low back pain or pathology. We followed the COnsensus-based Standards for the selection of health Measurement INstruments 2018 guideline for systematic reviews. We performed both quantitative and qualitative syntheses in which the results were summarized on the basis of the reported measurement properties and study quality. Results: Ten eligible studies were included. The pooled PSFS reliability measure was excellent (intra-class correlation coefficient = 0.89; 95% CI: 0.75, 0.95). Validity measures displayed correlations that ranged from -0.47 to 0.69 when compared with other patient-reported outcome measures (PROMs) or other tests. Eight studies had assessed the responsiveness of the PSFS. Effect sizes reported were large (≥ 0.91). Conclusions: The PSFS is a reliable, valid, and responsive PROM for patients with low back pain or pathology.