The effect of conflicting medication information and physician support on medication adherence for chronically ill patients

Objective: This article explores the effect of conflicting information, defined as contradictory information about medication topics from different sources, on medication adherence in a sample of chronically ill patients. We specifically investigate whether conflicting information and physician support directly affect medication adherence or whether the effect is mediated by adherence self-efficacy and outcome expectations for medications. Methods: Vasculitis patients (n = 228) completed two on-line questionnaires which contained measures of conflicting information, adherence self-efficacy, outcome expectations, physician support, and medication adherence. We conducted a mediation analysis using a bootstrapping approach to generate point estimates and 95% confidence intervals to test the significance of each mediated effect. Results: A majority of patients (51.3%) received conflicting medication information. Conflicting information had a direct negative effect on medication adherence, which was not mediated by self-efficacy or outcome expectations. Alternatively, self-efficacy mediated the positive effect of physician support on medication adherence. Conclusion: Patients who encounter conflicting medication information are less adherent to their medications. The presence of a supportive physician may counteract the negative effect of conflicting medication information. Practice implications: Physicians should initiate conversations about conflicting medication information with their patients. Consensus-based guidelines that address medication discrepancies may also reduce the availability of conflicting information. (C) 2009 Elsevier Ireland Ltd. All rights reserved.