Caffeinated coffee consumption and mortality after acute myocardial infarction

Abstract

Previous studies have generally suggested no effect of coffee consumption on the risk of acute myocardial infarction. The effect of coffee consumption on prognosis after acute myocardial infarction is uncertain. In an inception cohort study, we observed 1935 patients who were hospitalized with a confirmed acute myocardial infarction between 1989 and 1994 at 45 community hospitals and tertiary care centers in the United States, as part of the Determinants of Myocardial Infarction Onset Study. Trained interviewers assessed self-reported caffeinated coffee consumption before infarction with a standardized questionnaire. We analyzed survival censored at December 31, 1995, using Cox proportional hazards regression. Of the 1902 patients for whom we had information on coffee intake, 315 (17%) died during a median follow-up period of 3.8 years. Coffee drinkers tended to be men, younger, and free of comorbidity, and they were more likely to be current smokers. Coffee consumption was not associated with an overall change in long-term post-infarction mortality rate. However, we did observe an unexpected and unexplained variation in the association between coffee consumption and mortality with time, with an apparent inverse association in the first 90 days after infarction. Self-reported coffee consumption has no overall association with post-infarction mortality. The unexpected time variation in the effect of coffee intake requires evaluation in other studies.