Risk of Cardiovascular Event and Mortality in Relation to Refill and Guideline Adherence to Lipid-lowering Medications Among Patients with Type 2 Diabetes Mellitus in Sweden

Objective: To analyze the risk of cardiovascular (CV) events and mortality in relation to adherence to lipid-lowering medications by healthcare centers and patients with type 2 diabetes mellitus (T2DM).

Research Design And Methods: We included 121 914 patients (12% secondary prevention) with T2DM reported by 1363 healthcare centers. Patients initiated lipid-lowering medications between July 2006 and December 2012 and were followed from cessation of the first filled supply until multidose dispensed medications, migration, CV events, death or December 2016. The study period was divided into 4-month intervals through 2014, followed by annual intervals through 2016. Adherence measures were assessed for each interval. Patients' (refill) adherence was measured using the medication possession ratio (MPR). Healthcare centers' (guideline) adherence represented the prescription prevalence of lipid-lowering medications according to guidelines. The risk of CV events and mortality was analyzed for each interval using Cox proportional hazard regression and Kaplan-Meier.

Results: Compared with high-adherent patients (MPR >80%), low-adherent primary prevention patients (MPR ≤80%) showed higher risk of all outcomes: 44%-51 % for CV events, doubled for all-cause mortality and 79%-90% for CV mortality. Corresponding risks for low-adherent secondary prevention patients were 17%-19% for CV events, 88%-97% for all-cause and 66%-79% for CV mortality. Primary prevention patients treated by low-adherent healthcare centers (guideline adherence <48%) had a higher risk of CV events and CV mortality. Otherwise, no difference in the risk of CV events or mortality was observed by guideline adherence level.

Conclusions: Our results demonstrate the importance of high refill adherence and thus the value of individualized care among patients with T2DM.