Verify the factor structure of the modified Disablement in the Physically Active Scale (mDPA) and compare the physical summary component (PSC) and mental summary component (MSC) in those with and without chronic ankle instability (CAI).Background
Patient-reported outcomes (PROs) provide information about a patient’s health status from the patient’s perspective. The mDPA has become a common PRO for physically active patients; however, the factor structure of this instrument has not been verified. Additionally, there is limited evidence that has examined generic PROs, such as the mDPA, in CAI patients.Methods and Measures
One hundred and eighteen people with CAI (females=79; age:23.56±4.88 y, height:169.80±10.09 cm, weight:73.38±15.45 kg) and 81 healthy controls (females=56; age:22.91±2.79 y, height:167.52±11.82 cm, weight:67.05±10.64 kg) participated. All subjects completed the 16-item mDPA, which included the PSC and MSC. On both subscales, higher scores represented greater disablement. To examine the model fit of the mDPA, single-factor and two-factor (i.e., PSC and MSC) structures were tested. Group differences were examined using independent t-tests with corresponding effect sizes (ES) (p≤0.05).Results
Inspection of model fit indices for both models showed the two-factor structure to possess adequate fit to the data, χ2(101)=275.58, p<0.001, CFI=0.91, RMSEA=0.09 (95%CI=0.08, 0.11), SRMR=0.06. All items loaded significantly and in expected directions on respective subscales (λ-range=0.59–0.87, all ps<0.001). The CAI group reported greater PSC (CAI:11.45±8.30, Healthy:0.62±1.80, p<0.001, ES=1.67 (95%CI=1.33, 1.99)) and MSC (CAI:1.75±2.58, Healthy:0.58±1.46, p<0.001, ES=0.53 (95%CI=0.24, 0.82)) scores.Conclusions
The two-factor structure of the mDPA was verified which confirms the use of the PSC and MSC. Individuals with CAI reported greater disablement; particularly on the PSC, when compared to healthy controls. The clinical relevance of the MSC group difference requires additional investigation based on the moderate ES. Overall, these results indicate the mDPA is a generic PRO that can be utilised in the evaluation and rehabilitation of patients with CAI.