Examining whether the information-motivation-behavioral skills model predicts medication adherence for patients with a rare disease.

The information-motivation-behavioral skills (IMB) model has been used to explain and promote medication adherence among patients with diabetes and HIV. The objective of this study was to examine whether the IMB model predicted medication adherence among vasculitis patients. Adult vasculitis patients (n=228) completed online questionnaires at baseline and 3-month follow-up. Linear regressions were calculated to determine the direct effects of information and motivation on medication adherence (P<0.05). A mediation analysis using a bootstrapping approach was used to test whether behavioral skills significantly mediated the effect of information and motivation on medication adherence. Participants reported high levels of information (M=4.0; standard deviation [SD]=0.68), moderate levels of motivation (M=2.7; SD=1.00), and high levels of behavioral skills (M=4.1; SD=0.74). In the regression model, only behavioral skills (B=0.38; P<0.001) were significantly associated with medication adherence; however, mediation analysis revealed that behavioral skills significantly mediated the effects of information and motivation on medication adherence. The results support the IMB-hypothesized relationships between information, motivation, behavioral skills, and medication adherence in our sample. Findings suggest that providers should work with vasculitis patients to increase their medication-related skills to improve medication adherence.