Hospital Variation in Premature Clopidogrel Discontinuation After Drug-Eluting Stent Placement in the Veterans Affairs (VA) Healthcare System

Background: Premature clopidogrel discontinuation after drug-eluting stent placement is associated with adverse outcomes. Little is known about patient and hospital factors associated with premature discontinuation or whether less variation in premature discontinuation exists in integrated health care systems such as the Veterans Affairs (VA). Methods and Results: We evaluated the frequency of premature clopidogrel discontinuation, defined as a gap between clopidogrel refills of ≥90 days during the first 6 months of treatment, among 12 707 patients who received drug-eluting stents in VA hospitals between 2008 and 2010. We evaluated the association between premature discontinuation and all-cause mortality and/or acute myocardial infarction, variation in the proportion of premature discontinuation among hospitals, the patient and hospital characteristics associated with premature discontinuation, and the extent to which unexplained hospital characteristics contribute to premature discontinuation. Of the patients, 963 (7.6%) discontinued clopidogrel prematurely. Premature discontinuation was associated with acute myocardial infarction and all-cause mortality (hazard ratio 1.65, 95% CI 1.37-1.99, P<0.001). The proportion of patients with premature discontinuation varied across hospitals from 0% to 16.5% (P<0.001). We found a median of 24% greater odds of patients with identical covariates with premature discontinuation at one randomly selected hospital compared with another (median odds ratio 1.24, 95% CI 1.17-1.44). Patient factors associated with premature discontinuation included lack of cardiology follow-up within 30 days of discharge and smaller initial clopidogrel fill. Conclusion: One in 13 patients prematurely discontinued clopidogrel, and variation in discontinuation across hospitals was observed. Patient factors were associated with premature discontinuation that may represent targets for quality improvement.