Study question

In older patients discharged from hospital after acute myocardial infarction (MI), does concomitant use of a proton pump inhibitor (PPI) with clopidogrel lead to adverse events?

Study design

Design:

population-based, nested, case–control study with 69-month follow-up.

Setting:

Ontario, Canada.

Patients:

13 636 patients who were ⩾66 years of age (median age 76 y, 56% men) and had filled a prescription for clopidogrel within 3 days of hospital discharge after acute MI. Exclusion criteria were use of clopidogrel, ticlopidine, or dipyridamole in the year before admission; use of PPI combination products to eradicate Helicobacter pylori within 90 days of the index date (readmission for MI); or residence in a long-term care facility.

Risk factors:

prescription records were used to assess exposure to PPIs within 30 days (current), 31–90 days (previous), and 91–180 days (remote) of the index date.

Outcomes:

death or readmission for MI within 90 days …