Discontinuation of statins among patients with type 2 diabetes

Background: Statins play an important role in the prevention of cardiovascular disease in type 2 diabetes. Several studies have reported low adherence with statins among patients with type 2 diabetes. Studies comparing discontinuation of statins compared with discontinuation of oral anti-diabetics within the same individuals before and after initiation of oral anti-diabetic drugs are not available. The aim of this study was to describe discontinuation among patients with type 2 diabetes prescribed statins prior to and after initiation of oral anti-diabetics and to compare statin discontinuation with discontinuation of oral anti-diabetics.

Methods: We report an observational cohort study among patients initiating treatment with statins prior to or after initiation of oral anti-diabetics between 1999 and 2007. Patients were classified as starting statins prior to initiation (Prior users) or after initiation (After users) of anti-diabetics. Discontinuation was defined as an interval of 180 days or more between the theoretical end date of a statin/anti-diabetic prescription and the dispensing date of the next statin/anti-diabetic prescription.

Results and conclusions: We included 3323 starters with oral anti-diabetic drugs in our study; 2072 patients initiated statins in the period of observation. Discontinuation rates for statins were higher compared with oral anti-diabetics (52.1 vs 15.0%). After users discontinued statin therapy more frequently compared to prior users (62.8 vs 48.2%). Discontinuation of statins is higher compared with anti-diabetic discontinuation. Patients starting statins after the initiation of oral anti-diabetic treatment are more likely to discontinue treatment than patients who initiate statins before the start of oral anti-diabetics.