Minimal clinically important difference in 6-minute walk distance estimated by multiple methods in inpatients with subacute cardiovascular disease

BACKGROUND: Identifying the minimal clinically important difference (MCID) contributes to the ability to determine the efficacy of physiotherapy interventions and make good clinical decisions. PURPOSE: The purpose of this study was to estimate the MCID for 6-minute walking distance (6MWD) among inpatients with subacute cardiac disease using multiple anchor-based methods. METHODS: This study was a secondary data analysis using only data from a multicenter longitudinal observational study in which 6MWD was measured at two time points. Based on the changes in 6MWD between baseline measurement and follow-up approximately 1 week after baseline measurement, the global rating of change scales (GRCs) of patients and physiotherapists, anchor method receiver operator operating characteristic curves, predictive models, and adjusted models were used to calculate the MCID. RESULTS: Participants comprised 35 patients. Mean (standard deviation) 6MWD was 228.9 m (121.1 m) at baseline and 270.1 m (125.0 m) at follow-up. MCID for each GRC was 27.5-35.6 m for patients and 32.5-38.6 m for physiotherapists. CONCLUSION: The MCID in 6MWD in patients with subacute cardiovascular disease is 27.5-38.6 m. This value may be useful in determining the effectiveness of physiotherapy interventions and for decision-making.