OBJECTIVES:

Diabetes patients are recommended to maintain their LDL cholesterol below 100mg/dL to prevent cardiovascular (CV) events. Therefore, atorvastatin is reimbursed for diabetes patients having LDL cholesterol ≥100mg/dL in Korea. We aimed to assess the real-world effectiveness of atorvastatin for the primary prevention of CV events in type 2 diabetes mellitus (T2DM) patients using population-based database.

METHODS:

A retrospective cohort study was conducted using the National Health Insurance Service Customized data during 2008–2018. Atorvastatin users were defined as T2DM patients with continuous use of atorvastatin for 3 months during 2009–2012, and no previous atorvastatin use or CV events within 1 year. Statin non-users were defined as T2DM patients without statin prescriptions during 2009–2012 and previous CV events within 1 year. Cancer patients were excluded from both groups. Propensity score matching was conducted with a 1:1 ratio by using patient baseline characteristics. Patients were followed up until 2018 to ascertain the incidence of CV events. As proportional hazard assumption was not met, extended Cox model was used with heaviside function of time (split at 3 years) to assess the association between atorvastatin use and incidence of CV events.

RESULTS:

During 6–10 years of follow-up, CV event rates were 1.21 and 1.43 per 100 person-years in atorvastatin users (n=41,024) and statin non-users (n=41,024), respectively. For composite CV events, hazard ratio (HR) comparing atorvastatin users and statin non-users was not significant before 3 years (0.975; 95% confidence interval [CI], 0.904–1.052), whereas it became significant after 3 years (0.760; 95% CI, 0.719–0.803). HRs after 3 years were lower for stroke (0.746; 95% CI, 0.693–0.803) compared to coronary heart disease (0.779; 95% CI, 0.716–0.847).

CONCLUSIONS:

Atorvastatin was associated with reduced risk of CV events after 3 years from the treatment initiation in real-world T2DM patients.