Background: Beliefs about type 2 diabetes (T2D) medications predict treatment adherence; yet, factors that influence these beliefs are poorly understood. Further, prior studies reduce the complex interplay between beliefs about treatment necessity and medication-related concerns to a single dimension by using a difference score. This study examined correlates of T2D medication beliefs and modeled the multidimensional associations of beliefs and adherence.
Methods: Participants were 812 primarily disadvantaged and ethnic minority adults with T2D (Female = 56.9%; Latino = 86.5%; Mean [SD] Age and A1C = 59.2 [10.8], 9.3 [1.8], respectively) recruited for a self-management trial. Informed by the Common Sense Model and prior research, relations of patient- and illness-related factors with medication beliefs (Horne, Weinman, Hankins, 1999) were examined using linear regression. Confirmatory and exploratory polynomial regression examined associations of medication beliefs and self-reported adherence.
Results: Hispanic ethnicity (p < .01) , insulin use (p < .05) , greater number of medications (p < .05) , and lower levels of education (p < .05) were associated with stronger necessity beliefs. Lower income (p < .05) and Hispanic ethnicity (p < .01) were associated with greater concerns. Adherence was lowest among those with strong concerns and weak necessity beliefs. Non-reciprocal effects were also observed, which could not have been assessed using a difference score. Patients with ambivalent beliefs had lower adherence than those with indifferent beliefs.
Discussion: Indicators of lower SES were associated with concerns about T2D medications. Increased disease severity and Hispanic ethnicity were associated with stronger necessity beliefs. However, Hispanics also reported more concerns about their medications. Results further support use of polynomial regression to assess medication beliefs and adherence. Addressing concerns, in particular, may enhance T2D medication adherence.
A.G.Asman: None. L.A.Phillips: None. E.A.Walker: None. L.D.Pappalardo: None. J.S.Gonzalez: Consultant; Virta Health Corp.
National Institutes of Health (R18 DK098742) Einstein–Mount Sinai Diabetes Research Center (P30 DK020541) New York Regional Center for Diabetes Translation Research (P30 DK111022) J.S.G. is supported by National Institutes of Health (RDK104845, RDK121298, RDK121896)