Responsiveness of the foot and ankle ability measure (FAAM) in individuals with diabetes

Background: The impact of diabetes on physical function pose a challenge in assessing clinical outcomes. Objective: The purpose of this study was to provide evidence of responsiveness for the foot and ankle ability measures (FAAM) in individuals with diabetes mellitus. Methods: The two most recent FAAM scores of 155 diabetic patients treated for foot/ankle pathology were analyzed. Based on physical component summary (PCS) scores of the SF-36, subjects were categorized as improved (>7-point positive change), worsened (>7-point negative change), or unchanged (<7-point change). Analyses of the worsened and improved groups were compared to the unchanged group using two-way repeated measures ANOVAs and ROC curve analyses. Results: The ANOVAs demonstrated a significant difference between groups (P= 0.001). ROC curves analysis for detecting an improvement or decline in status were 0.73 (95% CI 0.62-0.84) and 0.70 (95% CI 0.59-0.81), respectively. An increase in FAAM score of 9 points represented the minimal clinically important difference (MCID) with 0.64 sensitivity and 0.78 specificity. A decrease in FAAM score of 2 points represented a MCID with 0.65 sensitivity and 0.61 specificity. Conclusions: The FAAM demonstrated responsiveness to change in individuals with orthopedic foot and ankle dysfunction complicated by diabetes and can be used to measure patient outcomes over a 6-month period.