Minimal Clinically Important Difference of the Functional Gait Assessment in Older Adults

Background The Functional Gait Assessment (FGA) is commonly used to measure walking balance. The minimal clinically important difference (MCID) has yet to be determined for the FGA. Objective The purposes of this study were to determine: (1) the MCID in the FGA for older community-dwelling adults relative to patients' and physical therapists' estimates of change and (2) the extent of agreement between patients' and physical therapists' estimates of change. Design This study was a prospective case series. Methods Patients and physical therapists rated the amount of change in balance while walking after an episode of physical therapy for balance retraining on a 15-point global rating of change (GROC) scale. Weighted kappa statistics were calculated to express agreement between patients' and physical therapists' GROC ratings. Functional Gait Assessment change scores were plotted on receiver operating characteristic curves. A cutoff of +3 on the GROC was the criterion used for important change. The optimal FGA change cutoff score for MCID was determined, and sensitivity (SN), specificity (SP), and likelihood ratios (LRs) were calculated. Results One hundred thirty-five community-dwelling older adults (average age=78.8 years) and 14 physical therapists participated. There was poor agreement between the patients' and therapists' ratings of change (weighted kappa=.163). The estimated MCID value for the FGA using physical therapists' ratings of change as an anchor was 4 points (SN=0.66, SP=0.84, LR+=4.07, LR−=0.40). No accurate value for the FGA MCID could be determined based on the patients' ratings of change. Limitations The small sample size was a limitation. Conclusion Poor agreement between therapists' and patients' ratings indicate the need for further communication relative to patient goals. The 4-point MCID value for the FGA can be used for goal setting, tracking patient progress, and program evaluation.