ABSTRACT
BACKGROUND/AIMS: It has recently been suggested that proton pump inhibitors (PPIs) might reduce the inhibitory effect of clopidogrel on platelet aggregation. Co-administration of a PPI and clopidogrel in patients with ischemic heart disease may thus alter clinical outcome. We investigated the effect of concomitant use of a PPI with clopidogrel in Korean patients with ischemic heart disease. METHODS: This is a retrospective cohort study of 99 patients with acute coronary syndrome taking clopidogrel and PPIs after discharge from CHA Bundang Medical Center between January 1, 2003, and December 31, 2007. The control group consisted of 99 patients who were matched for age and sex but were not taking PPIs. RESULTS: Patients who received clopidogrel plus PPI had a greater than two times higher risk of re-admission or death (adjusted hazard ratio 2.51; 95% confidence interval [CI] 1.43~4.40; p = 0.001) than those who received clopidogrel alone. Lansoprazole use was associated with an increased risk of re-admission or death (adjusted hazard ratio 2.66; 95% CI 1.45~4.89; p = 0.002). Combined period of administration or Helicobacter pylori infection did not affect the risk of re-admission or death. CONCLUSIONS: Particular attention should be paid when patients with ischemic heart disease are prescribed a combination of clopidogrel and a PPI, since this combination was associated with an elevated risk of re-admission or death.