Pharmacy-based predictors of non-persistence with and non-adherence to statin treatment among patients on oral diabetes medication in the Netherlands

Abstract

Aims: To evaluate statin non-persistence and non-adherence as discrete processes in diabetes patients, and identify pharmacy-based predictors of these processes in the first year after statin initiation.

Methods: We conducted a retrospective cohort study of statin initiators using a pharmacy database. Persistence and adherence were measured in the first, second and third year. Non-persistence was defined as a gap >180 days. Non-adherence was calculated in persistent patients and defined as a medication possession ratio <80%. Cox regression hazard ratios (HRs) and logistic regression odds ratios (ORs) were assessed for sociodemographic and medication-related factors as possible predictors.

Results: Of 12,741 initiators, 20.0% were non-persistent in the first year, while 9.0% and 7.5% were non-persistent in the second and third years. Non-adherence in persistent patients increased from 13.4% in the first to 15.6% and 18.1% in the second and third years. Predictors of non-persistence were female gender (HR: 1.10; 95% CI: 1.01–1.19), older age (HR: 1.52; 95% CI: 1.31–1.75), primary prevention (HR: 1.10; 95% CI: 1.00–1.20), initiating on low dose (HR: 1.44; 95% CI: 1.07–1.94) or standard dose (HR: 1.56; 95% CI: 1.16–2.10), and no cardiovascular co-medication (HR: 1.19; 95% CI: 1.07–1.33), while patients with four or more other medications were more likely to be persistent. Age <50 years (OR: 1.47; 95% CI: 1.22–1.77), low socioeconomic status (OR: 1.27; 95% CI: 1.12–1.45) and primary prevention (OR: 1.21; 95% CI: 1.07–1.38) were predictors of non-adherence, while females were more likely to be adherent (OR: 0.87; 95% CI: 0.77–0.98).

Conclusion: Non-persistence was the foremost problem in the first year after statin initiation, while non-adherence in persistent patients increased in the second and third years. Pharmacy-based predictors of statin non-persistence were different from predictors of non-adherence among persistent patients.

Keywords:

• Medication adherence
• diabetes mellitus
• hydroxymethylglutaryl-CoA reductase inhibitors

Transparency

Declaration of funding

S.D.A is supported by a scholarship from Indonesia Endowment Fund for Education (LPDP).

Author contributions: Conception and design (S.D.A., E.H., P.D.), analysis and interpretation of the data (S.D.A., P.W., C.C.M.S.-V., J.v.d.S., J.H.J.B., E.H., P.D.), the drafting of the paper (S.D.A., P.W., C.C.M.S.-V., J.v.d.S., E.H., P.D.), and the final approval of the version to be published (all authors). All authors agree to be accountable for all aspects of the work.

Declaration of financial/other relationships

S.D.A., P.W., C.C.M.S.-V., J.v.d.S., J.H.J.B., E.H. and P.D. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.