The Disablement in the Physically Active Scale, part II: the psychometric properties of an outcomes scale for musculoskeletal injuries

Outcomes assessment is an integral part of ensuring quality in athletic training, but few generic instruments have been specifically designed to measure disablement in the physically active. To assess the psychometric properties of the Disablement in the Physically Active Scale (DPA), a patient-report, generic outcomes instrument. Observational study. We collected data in 5 settings with competitive and recreational athletes. Participants entered into the study at 3 distinct points: (1) when healthy and (2) after an acute injury, or (3) after a persistent injury. Measures were obtained from 368 baseline participants (202 females, 166 males; age = 20.1 ± 3.8 years), 54 persistent participants (32 females, 22 males; age = 22.0 ± 8.3 years), and 28 acutely injured participants (8 females, 20 males; age = 19.8 ± 1.90 years). We assessed internal consistency with a Cronbach α and test-retest reliability with intraclass correlation (2,1) values. The scale's factor structure was assessed with a hierarchical confirmatory factor analysis. Concurrent validity was assessed with a Pearson correlation. Responsiveness was calculated using a receiver operating characteristic curve and a minimal clinically important difference value. The Cronbach α scores for the DPA were 0.908 and 0.890 in acute and persistent groups, respectively. The intraclass correlation (2,1) value of the DPA was 0.943 (95% confidence interval = 0.885, 0.972). The fit indices values were 1.89, 0.852, 0.924, 0.937, and 0.085 (90% confidence interval = 0.066, 0.103) for the minimum sample discrepancy divided by degrees of freedom, goodness-of-fit index, Tucker-Lewis Index, comparative fit index, and root mean square error of approximation, respectively. The DPA scores accounted for 51% to 56.4% of the variation in global functioning scores. The area under the curve was statistically significant, and the minimally clinically important difference values were established. The DPA is a reliable, valid, and responsive instrument.