In this nationwide cohort study of patients with chronic heart failure in Denmark, Gislason et al identified comprehensive use of nonsteroidal anti-inflammatory drugs (NSAIDs) between 1995 and 2004 using pharmacy claim data. Risk of death, myocardial infarction, and readmission for heart failure associated with NSAID use was analyzed using multivariate time-dependent Cox regression models. Notably, 34% of the population claimed a prescription for NSAIDs during the period. The risk of death was disturbingly high, with hazard ratios of 1.70, 1.75, 1.31, 2.08, and 1.22 for rofecoxib, celecoxib, ibuprofen, diclofenac, and naproxen, respectively. There was a dose-dependent increase in risk of death and increased risk of myocardial infarction and readmission for heart failure. These results should raise awareness about NSAID use among physicians caring for patients with heart failure.