Validation and adaption of an Information-Motivation-Behavioral Skills model of medication adherence in older patients with multimorbidity

To test and adapt the Information-Motivation-Behavioral Skills (IMB) model in explaining medication adherence for older patients with multimorbidity. Older patients with at least three chronic conditions (N = 254) were recruited from community health centers in Changsha, China. All participants completed a self-administrated questionnaire assessing adherence information, personal motivation, social motivation, behavioral skills, medication adherence, depressive symptoms, medication treatment satisfaction, treatment burden, and disease burden. Structural equation modeling was used to examine the hypothesized models and relationships between variables. The final extended IMB model could explain 52.0% of the variance in adherence. Personal motivation (β = 0.29, p < 0.001), behavioral skills (β = 0.36, p < 0.001), and medication treatment satisfaction (β = 0.23, p = 0.001) had a positive direct effect on adherence. Information, social motivation, personal motivation, medication treatment satisfaction, and treatment burden could also affect adherence indirectly through multiple pathways. This study demonstrated that an extended IMB model could be used to conceptualize determinants of medication adherence among older patients with multimorbidity. Adherence improvement programs might be more effective if targeting psychosocial factors, including adherence information, motivation, behavioral skills, treatment burden, and medication treatment satisfaction.