Adaptation and validation of a German version of the Multimorbidity Treatment Burden Questionnaire

Background Patients with multiple long-term conditions often face a variety of challenges arising from the requirements of their health care. Knowledge of perceived treatment burden is crucial for optimizing treatment. In this study, we aimed to create a German version of the Multimorbidity Treatment Burden Questionnaire (MTBQ) and to evaluate its validity. Methods The steps to translate the MTBQ included forward/back translation, cognitive interviews (n = 6) and a pilot test (n = 7). Psychometric properties of the scale were assessed in a cross-sectional survey with primary care patients aged 65 and older with at least 3 long-term conditions (n = 344). We examined the distribution of responses, dimensionality, internal reliability and construct validity. Results Cognitive interviewing and piloting led to minor modifications and showed overall good face validity and acceptability. As expected, we observed a positively skewed response distribution for all items. Reliability was acceptable with McDonald's omega = 0.71. Factor analysis suggested one common factor while model fit indices were inconclusive. Predefined hypotheses regarding the construct validity were supported by negative associations between treatment burden and health-related quality of life, self-rated health, social support, patient activation and medication adherence, and positive associations between treatment burden and number of comorbidities. Treatment burden was found to be higher in female participants (Mdn(1) = 6.82, Mdn(2) = 4.55; U = 11,729, p = 0.001) and participants with mental health diagnoses (Mdn(1) = 9.10, Mdn(2) = 4.55; U = 3172, p = 0.024). Conclusions The German MTBQ exhibited good psychometric properties and can be used to assess the perceived treatment burden of patients with multimorbidity.