Non-Steroidal Anti-Inflammatory Drug Use and the Risk of Acute Myocardial Infarction in the General German Population

INTRODUCTION: Use of non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with an increased relative risk of acute myocardial infarction (AMI), but the label warnings refer particularly to patients with cardiovascular risk factors. The magnitude of relative AMI risk for patients with and without cardiovascular risk factors varies between studies depending on the drugs and doses studied.

OBJECTIVES: The aim of our study was to estimate population-based relative AMI risks for individual and widely used NSAIDs, for a cumulative amount of NSAID use, and for patients with and without a prior history of cardiovascular risk factors.

METHODS: Based on data from the German Pharmacoepidemiological Research Database (GePaRD) of about 17 million insurance members from four statutory health insurance providers, for the years 2004-2009, a nested case-control study was conducted within a cohort of 3,476,931 new NSAID users classified into current, recent, or past users. Up to 100 controls were matched to each case by age, sex, and length of follow-up using risk set sampling. Multivariable conditional logistic regression was applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Duration of NSAID use was calculated by the cumulative amount of dispensed defined daily doses (DDDs), and stratified analyses were conducted for potential effect modifiers.

RESULTS: Overall, 17,236 AMI cases were matched to 1,714,006 controls. Elevated relative AMI risks were seen for current users of fixed combinations of diclofenac with misoprostol (OR 1.76, 95% CI 1.26-2.45), indometacin (1.69, 1.22-2.35), ibuprofen (1.54, 1.43-1.65), etoricoxib (1.52, 1.24-1.87), and diclofenac (1.43, 1.34-1.52) compared with past use. A low cumulative NSAID amount was associated with a higher relative AMI risk for ibuprofen, diclofenac, and indometacin. The relative risk associated with current use of diclofenac, fixed combinations of diclofenac with misoprostol, etoricoxib, and ibuprofen was highest in the younger age group (<60 years) and similar for patients with or without major cardiovascular risk factors.

CONCLUSION: Relative AMI risk estimates differed among the 15 investigated individual NSAIDs. Diclofenac and ibuprofen, the most frequently used NSAIDs, were associated with a 40-50% increased relative risk of AMI, even for low cumulative NSAID amounts. The relative AMI risk in patients with and without cardiovascular risk factors was similarly elevated.