Self-Efficacy as Moderator and Mediator Between Medication Beliefs and Adherence in Elderly Patients with Type 2 Diabetes

PURPOSE: Poor antidiabetic medication adherence remains a great barrier to effective diabetes self-management among aging adults. This study investigates the mediation and moderation effects of self-efficacy on the relationship between medication beliefs and adherence in elderly patients with type 2 diabetes. METHODS: This cross-sectional study evaluated a sample of 309 hospitalized elderly patients who completed the assessment of medication beliefs, self-efficacy for medication uses and medication adherence in a tertiary hospital in Shanghai, China. A bootstrapping sampling method and hierarchical moderator regression analysis were used to verify the hypothesis of mediation and moderation effects of self-efficacy on the relationship between medication beliefs and adherence. RESULTS: Self-efficacy for medication use acted as a moderator (B=−0.063, t=−2.215, p=0.028) and partial mediator (CI(total effect)=4.5–16.63, p=0.001; CI(indirect)=1.524–5.323, p=0.014; CI(direct)=2.151–11.817, p=0.001) on the relationship between general harm medication beliefs and medication adherence. Participants with lower general harm medication beliefs may develop higher self-efficacy, which, in turn, results in a higher level of medication adherence, and higher self-efficacy may attenuate the negative effect of high general harm medication beliefs on medication adherence. CONCLUSION: Self-efficacy for medication use not only mediated the relationship between general harm beliefs about medication and medication adherence, but moderated it negatively. The findings of this study indicate an opportunity to improve the prognosis of elderly Chinese patients with type 2 diabetes through improved medication adherence by strengthening factors such as self-efficacy for appropriate medication use and general harm beliefs about medication.