To the Editor: In their retrospective cohort study of concomitant clopidogrel and PPI use, Dr Ho and colleagues1 reported on the increased risk of adverse outcomes among patients using these agents together after hospitalization for acute coronary events. There were substantial differences in baseline characteristics between those discharged on clopidogrel without PPI and those who were either discharged on clopidogrel and PPI or had a PPI added to clopidogrel therapy during follow-up.
Hayes S. Adverse Outcomes Associated With Use of Proton Pump Inhibitors and Clopidogrel. JAMA. 2009;302(1):29-31. doi:10.1001/jama.2009.899