The Disablement in the Physically Active Scale, Part II: The Psychometric Properties of an Outcomes Scale for Musculoskeletal Injuries

Abstract

Abstract Context: 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. Objective: To assess the psychometric properties of the Disablement in the Physically Active Scale (DPA), a patient-report, generic outcomes instrument. Design: Observational study. Setting: 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. Patients or Other Participants: 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). Main Outcome Measure(s): 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. Results: 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. Conclusions: The DPA is a reliable, valid, and responsive instrument.