Factors related to adherence to statin therapy.

Background: Retrospective database analyses have revealed that 50% of patients receiving statins discontinue therapy after one year of treatment. Typically, these data do not focus on patient-specific reasons for discontinuation.

Objective: To examine the reasons that patients discontinue statins and compare the patient and clinical factors of those who do and do not discontinue therapy.

Methods: All patients with a new statin prescription between January 1, 2004, and March 31, 2004, were identified through pharmacy claims. Patients who had discontinued and continued statin therapy were identified. Medical records were reviewed to determine whether there were documented reasons for statin discontinuation. Subsequently, telephone surveys addressing statin knowledge, relationships, communication with healthcare providers, and general health status were conducted.

Results: At one year, 47.5% (n = 671) of patients had obtained fewer than 80% of the refills of their prescribed statin. We reviewed 435 medical records and conducted 255 patient surveys. A total of 29.9% of discontinuers had reasons documented in the medical record. Compared with continuers, fewer discontinuers had follow-up and/or laboratory visits with a provider within 6 months after the start of statin therapy. The surveys indicated that more continuers than discontinuers trusted their providers (p < 0.05) and felt that providers had adequate knowledge to answer their questions (p < 0.001). In contrast, more discontinuers felt the statin was of limited benefit/unsure of the benefit (p < 0.001) and believed that their providers were not interested in their input on their medical condition (p < 0.01).

Conclusions: Utilizing pharmacy claims records alone to determine statin nonadherence may not only overestimate the percentage of patients who are nonadherent, but also prevent healthcare providers from understanding the reasons that patients discontinue or continue statin therapy. Statin adherence is complex and affected by several factors. Interventions to improve adherence should focus on patient communications, education, and follow-up.