Abstract
Background: The Canadian Occupational Performance Measure (COPM) is widely used to assess client-centered outcomes in occupational therapy. However, its psychometric properties, particularly responsiveness and minimal important change (MIC), require further validation in specific populations.
Objective: This study aimed to determine the MIC values for COPM performance (COPM-P) and satisfaction (COPM-S) scores using MICpredict and MICadjust methods in a Japanese home rehabilitation context, and to evaluate the responsiveness of the COPM compared to the EQ-5D-5L.
Methods: A multicenter prospective cohort study was conducted with 45 participants who received home-based rehabilitation services. MIC values were calculated using predictive modeling methods, whereas responsiveness was assessed using standardized response means (SRM) and Spearman's correlation coefficients with EQ-5D-5L scores.
Results: MICpredict values were 1.35 (95% CI: 0.88-1.80) for COPM-P and 1.37 (95% CI: 0.81-1.88) for COPM-S, with adjusted values (MICadjust) accounting for unequal group proportions at 1.23 (95% CI: 0.73-1.72) and 1.24 (95% CI: 0.60-1.77), respectively. The COPM demonstrated high responsiveness (SRM: 1.09 COPM-P and 1.01 for COPM-S), whereas no significant correlations were found between COPM change scores and EQ-5D-5L scores. These findings reflect the individualized nature of COPM and its sensitivity to client-specific outcomes.
Conclusions: This study underscores the utility of MICpredict and MICadjust in establishing MIC values tailored to the Japanese home-based rehabilitation population. The results highlight strong responsiveness of the COPM and the complementary use of individualized and comprehensive patient-reported outcomes for a holistic evaluation of rehabilitation outcomes.
