Nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with a first hospitalization of congestive heart failure (CHF). Based on the pathophysiology of NSAID-induced CHF, however, it seems more likely that NSAIDs may precipitate relapsing CHF in patients with prevalent heart failure and that NSAIDs are less likely to induce a first occurrence of heart failure. Therefore, Feenstra and colleagues estimated the risk of NSAID-induced CHF in patients with incident CHF as well as in patients with prevalent CHF in a prospective population-based cohort study. Current use of NSAIDs was associated with a relative risk of incident CHF of 1.1 (95% confidence interval [CI], 0.7-1.7) after adjustment for age, sex, and concomitant medication. In patients with prevalent heart failure who filled at least 1 NSAID prescription since being diagnosed as having CHF, the univariate and adjusted relative risks of a relapse of CHF were, respectively, 3.8 (95% CI, 1.1-12.7) and 9.9 (95% CI, 1.7-57.0). The authors conclude that NSAIDs are not associated with an increased risk of incident CHF. In patients with prevalent CHF, current use of NSAIDs is associated with a substantially increased risk of relapsing CHF.