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Health Services Research & Development

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2009 HSR&D National Meeting Abstract

National Meeting 2009

1080 — Diabetes and Medication Adherence: Understanding the Association between Perceived Drug Costs and Dimensions of the Therapeutic Alliance

Zeber JE (VERDICT), Palmer RF (UTHSCSA Family Medicine), Parchman ML (VERDICT), Copeland LA (VERDICT), Hansis-Diarte A (VERDICT)

Medication adherence remains a significant problem in patients with diabetes, which requires balancing complex treatment demands with the patient’s ability to manage multiple drugs, reconciling treatment preferences with clinical decisions. Our prior research suggests that diabetic patients who actively participate in the medical encounter and enjoy better provider relationships can sustain better adherence, subsequently improving intermediate outcomes. This study examined the association between two dimensions of the therapeutic alliance, perceived drug costs, and medication adherence.

157 patients from 5 primary care offices were recruited into a study designed to improve care coordination and outcomes in type-2 diabetes. Measures included patient engagement in the clinical encounter (Lorig Communication scale), the extent their physician practiced patient-centered care (Kaplan questionnaire), and items regarding cost-related adherence restrictions (Piette). Controlling for patient demographics, structural equation models determined the association and mediation pathways between these measures, with the primary outcome of medication adherence defined by the validated Morisky instrument.

Overall, 35% of patients were poorly adherent, with one-third adjusting pharmacy use due to cost within the past year, and 45% spending over $100 monthly on their medications. Individuals experiencing financial barriers adopted several cost-related behaviors, including postponing fills (24%) or taking fewer pills than prescribed (32%). In the multivariable path analysis, a direct inverse relationship existed between perceived cost burden and adherence (p = .001). However, the patient-centeredness of the physician was associated with patient participation (p = .02), which in turn positively influenced medication adherence (p = .001). Therefore, the extent of cost-related adherence difficulty was partially mediated through higher levels of patient engagement in their own treatment.

Patients with diabetes currently take numerous medications for their chronic conditions and report a high burden of cost-related medication restriction. Fortunately, SEM models suggest that patients of physicians who recognize and take their preferences into account are more likely to participate in the medical encounter, thereby mitigating drug cost barriers and improving adherence.

While education efforts directly targeting metabolic outcomes often fail, intervention efforts focused on strengthening therapeutic relationships, particularly through empowering activated patients and initiating medication cost discussions, will better align treatment decisions to respect patient preferences, potentially benefiting clinical outcomes.

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