The Minimal Clinically Important Difference for the “Patient Activation Measure”

Introduction: Patient activation is the knowledge, skills, and confidence required to manage one's own health. In chronic kidney disease (CKD), the most frequently used measure of patient activation is the 13-item “Patient Activation Measure” (PAM-13). To help better determine an intervention's clinical effectiveness, trials can interpret changes in patient-derived outcomes using the “minimal clinically important difference” (MCID), defined as the smallest change important to the patient. In this study, we establish the MCID and minimal detectable change (MDC) for PAM-13 in patients with nondialysis CKD using established methodology. Methods: This was a retrospective secondary analysis of a randomized control trial investigating the effects of a digital health intervention in a nondialysis CKD population. The MCID was estimated using anchor-based (using changes in health status from the Short Form-12 [SF-12] survey as the anchor) and distribution-based approaches (SD and effect size methods). The MDC was calculated to measure absolute reliability. Results: To calculate the MCID, we included n = 136 participants (age: 61.7 ± 12.9, n = 60 [44.1%] females, estimated glomerular filtration rate [eGFR]: 37.3 ± 14.9 ml/min per 1.73 m2, and mean PAM-13 score: 62.6 ± 13.6). The MCID for the PAM-13 to maintain or improve health was estimated at 5.4 (± 12.1) (95% confidence interval [CI]: 3.4–7.4) points. The MDC of the PAM-13 at an individual level (MDCindv) was 7.2 points and at a group level (MDCgroup) was 0.8 points. Conclusion: These values should allow researchers and health care professionals to better interpret improvements from a patient's perspective and could be beneficial in determining whether changes in PAM-13 scores are clinically meaningful to a CKD population.