Convergent validity and responsiveness of the Canadian Occupational Performance Measure for the evaluation of therapeutic outcomes for patients with carpometacarpal osteoarthritis

Study Design: This is a longitudinal, observational, multicenter, cohort study. Introduction: Thumb carpometacarpal (CMC) osteoarthritis (OA) is associated with more pain and restrictions than other hand OA. The use of patient-identified occupational performance goals to guide hand therapy treatment and to measure clinical outcomes is fundamental for a patient-centered intervention. The COPM enables subjects to identify goals for hand therapy and engage in a subject-specific therapeutic process. Purpose of the Study: The purpose of this study is to evaluate the convergent validity and responsiveness of the COPM to evaluate the relationship between the patient's self-perception and satisfaction of performance in everyday living and pain intensity, upper limb function, and manual ability. Methods: Eligible participants to multiple hand therapy centers were recruited. Outcomes measures (VAS scale, QuickDASH, MAM-36, and the COPM questionnaire) were measured at the baseline and 3 months after. Results: One hundred forty-five (n = 145) consecutive patients for five different hand rehabilitation centers with symptomatic thumb CMC OA were screened for eligibility criteria. COPM-P and COPM-S were the most responsive instruments, with an area under the curve of 0.88 (95% CI 0.79-0.96) and 0.88 (95% CI 0.80-0.96), respectively. Conclusions: Although more investigation in this area is necessary to conclude that the COPM is the best option to evaluate the effectiveness of hand therapy interventions for thumb OA. The COPM focuses on function and occupation and, in comparison with others upper limb scales, does not require the use of another complementary scale for addressing both satisfaction and ADL status. COPM is an instrument with a good convergent validity and responsiveness to evaluate the relationship between the patient's self-perception and satisfaction in thumb CMC OA.