Validation of the Shortened Perceived Medical Condition Self-Management Scale in Patients With Chronic Disease

Self-efficacy, or perceived competence, has been identified as an important factor in self-management behaviors and health outcomes in patients with chronic disease. Measures of self-management self-efficacy are currently available for multiple forms of chronic disease. One established measure is the 8-item Perceived Medical Condition Self-Management Scale (PMCSMS). This study investigated the use of the PMCSMS in samples of patients with a chronic disease to develop an abbreviated version of the scale that could be more readily used in clinical contexts or in large population health cohort studies. The PMCSMS was administered as either a generic scale or as a disease-specific scale. The results of analyses using item response theory and classical test theory methods indicated that using 4 items of the scale resulted in similar internal consistency (alpha =.70-0.90) and temporal stability (test-retest r =.75 after 2 to 4 weeks) to the 8-item PMCSMS (r =.81 after 2 to 4 weeks). The 4 items selected had the greatest discriminability among participants (alpha parameters = 2.49-3.47). Scores from both versions also demonstrated similar correlations with related constructs such as health literacy (r =.13-0.29 vs. 0.14-0.27), self-rated health (r =.17-0.48 vs. 0.26-0.50), social support (r =.21-0.32 vs. 0.25-0.34), and medication adherence (r =.20-0.24 vs. 0.20-0.25). The results of this study indicate that 4-item PMCSMS scores are equally valid but more efficient, and have the potential to be beneficial for both research and clinical applications. Public Significance Statement This study demonstrates, through the use of both traditional and modern evaluations of test items, the effectiveness of a shortened version of an existing scale designed to measure self-management self-efficacy of patients with chronic disease.