The Treatment Burden for Multimorbidity Scale: A Development and Psychometric Validation Study

Existing instruments have limitations in comprehensively capturing multimorbidity treatment burden. This study aimed to develop and validate a new measure, the Treatment Burden for Multimorbidity Scale (TBMS). We developed preliminary items based on the literature review and existing instruments. Content validity was evaluated with experts and patients. A longitudinal survey design was used for psychometric testing, with data collected at baseline (n = 503) and at 6-month follow-up (n = 313). We examined reliability, construct validity, and responsiveness of the TBMS. One item was deleted after the content validity evaluation, resulting in 12 items. Factor analyses revealed two domains (healthcare tasks and impacts) aligned with the conceptual definition. Cronbach's alpha for the total scale was 0.93. TBMS scores significantly correlated with scores of the disease burden, an existing multimorbidity treatment burden measure, and self-care as hypothesized. Changes in TBMS scores over 6 months were associated with changes in self-care, depressive symptoms, physical function, and self-rated health. The TBMS demonstrates sound reliability, validity, and responsiveness, making it a valuable tool for assessing multimorbidity treatment burden in clinical practice.