Comparative effectiveness of generic and brand-name statins on patient outcomes: a cohort study.

BACKGROUND

Statins are effective in preventing cardiovascular events, but patients do not fully adhere to them.

OBJECTIVE

To determine whether patients are more adherent to generic statins versus brand-name statins (lovastatin, pravastatin, or simvastatin) and whether greater adherence improves health outcomes.

DESIGN

Observational, propensity score-matched, new-user cohort study.

SETTING

Linked electronic data from medical and pharmacy claims.

PARTICIPANTS

Medicare beneficiaries aged 65 years or older with prescription drug coverage between 2006 and 2008.

INTERVENTION

Initiation of a generic or brand-name statin.

MEASUREMENTS

Adherence to statin therapy (measured as the proportion of days covered [PDC] up to 1 year) and a composite outcome comprising hospitalization for an acute coronary syndrome or stroke and all-cause mortality. Hazard ratios (HRs) and absolute rate differences were estimated.

RESULTS

A total of 90,111 patients who initiated a statin during the study was identified; 83,731 (93%) initiated a generic drug, and 6380 (7%) initiated a brand-name drug. The mean age of patients was 75.6 years, and most (61%) were female. The average PDC was 77% for patients in the generic group and 71% for those in the brand-name group (P<0.001). An 8% reduction in the rate of the clinical outcome was observed among patients in the generic group versus those in the brand-name group (HR, 0.92 [95% CI, 0.86 to 0.99]). The absolute difference was -1.53 events per 100 person-years (CI, -2.69 to -0.19 events per 100 person-years).

LIMITATION

Results may not be generalizable to other populations with different incomes or drug benefit structures.

CONCLUSION

Compared with those initiating brand-name statins, patients initiating generic statins were more likely to adhere and had a lower rate of a composite clinical outcome.

PRIMARY FUNDING SOURCE

Teva Pharmaceuticals.