Prolonged clopidogrel use improves clinical outcomes following drug eluting but not bare metal stent implantation

Purpose: Current guidelines recommend clopidogrel for 6-12 months following drug eluting stent (DES) implantation. The role of clopidogrel beyond 12 months is unclear. Methods: We linked hospital administrative, community pharmacy and cardiac revascularization data to determine clopidogrel use and outcomes for all patients receiving a coronary stent in British Columbia 2004 - 2006 with follow-up to 5 years. Cox proportional hazard regression analysis was performed to determine the effect of prolonged clopidogrel use (>12 months) on outcomes. Patients who died ≤12 months from index stent placement were excluded. Results: 15,629 patients were included in the study. Of 3,599 patients who received at least 1 DES and 12030 patients who received only bare metal stents (BMS), 1326 (37%) and 2121 (18%) respectively filled a prescription for clopidogrel >12 months from the index procedure. The mean duration of clopidogrel prescription in patients who received clopidogrel >12 months was 406±35 days in the DES group and 407±37 days in the BMS group, compared with 217±115 days (p<0.0001) and 117±116 days (p<0.0001) respectively for those who did not. Compared with ≤12 months clopidogrel, prolonged clopidogrel use was associated with a reduction in mortality (HR 0.67, 95% CI [0.46–0.98], p=0.038), mortality and readmission for myocardial infarction combined (HR 0.70, 95% CI [0.54–0.92], p=0.01) and an indication of a reduction in readmission for myocardial infarction alone (HR 0.70, 95% CI [0.49–1.00], p=0.051) in patients treated with DES, but not with BMS alone. ![Figure][1] Conclusions: In contrast to BMS, clopidogrel use beyond 12 months following DES implantation was associated with improved clinical outcomes. Our data support a longer duration of clopidogrel therapy for patients treated with DES. [1]: pending:yes