Abstract
Background:
The Ability to Perform Physical Activities of Daily Living Questionnaire (APPADL) measures the self-reported ability of individuals with type 2 diabetes mellitus (T2DM) and obesity to perform daily physical activities. The primary objective of this study was to estimate APPADL test–retest reliability, responsiveness, and minimal important change (MIC).
Subjects and Methods:
Study participants were individuals with T2DM and body mass index ≥30 kg/m2 enrolled in clinical weight loss programs in the United States. Data were obtained for clinical measures, APPADL, and other patient-reported instruments. APPADL test–retest reliability was estimated with intraclass correlation coefficient. To estimate responsiveness in a subgroup of participants, baseline and 6-month data were analyzed using paired t test and calculation of responsiveness indices (e.g., effect size [ES]). To estimate MIC, both distribution-based and anchor-based methods were used.
Results:
Test–retest data for 106 study participants (mean age, 52 years; 69% female; 31% white; mean body mass index, 38 kg/m2) yielded an intraclass correlation coefficient of 0.91. In the subgroup (n=40) used to estimate responsiveness, weight was significantly less at end point than at baseline (mean, 222.0 vs. 231.9 pounds; P<0.001, ES=0.24), and APPADL scores were significantly better than at baseline (mean, 77.0 vs. 70.8; P=0.01, ES=0.32). Results of distribution- and anchor-based methods to establish MIC suggest values of 6–14 points (0–100 scale).
Conclusions:
The APPADL has demonstrated reliability and validity. In addition, it has demonstrated responsiveness to weight loss in individuals with T2DM and obesity, thereby making it a potentially valuable tool in the evaluation of weight loss interventions (e.g., antihyperglycemic medications that produce weight loss) targeted toward patients with T2DM.
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