n-3 fatty acids and cardiovascular outcomes in patients with dysglycemia

BACKGROUND: The use of n-3 fatty acids may prevent cardiovascular events in patients with recent myocardial infarction or heart failure. Their effects in patients with (or at risk for) type 2 diabetes mellitus are unknown. METHODS: In this double-blind study with a 2-by-2 factorial design, we randomly assigned 12, 536 patients who were at high risk for cardiovascular events and had impaired fasting glucose, impaired glucose tolerance, or diabetes to receive a 1-g capsule containing at least 900 mg (90% or more) of ethyl esters of n-3 fatty acids or placebo daily and to receive either insulin glargine or standard care. The primary outcome was death from cardiovascular causes. The results of the comparison between n-3 fatty acids and placebo are reported here. RESULTS: During a median follow up of 6.2 years, the incidence of the primary outcome was not significantly decreased among patients receiving n-3 fatty acids, as compared with those receiving placebo (574 patients [9.1%] vs. 581 patients [9.3%] ; hazard ratio, 0.98 ; 95% confidence interval [CI], 0.87 to 1.10 ; P=0.72). The use of n-3 fatty acids also had no significant effect on the rates of major vascular events (1034 patients [16.5%] vs. 1017 patients [16.3%] ; hazard ratio, 1.01 ; 95% CI, 0.93 to 1.10 ; P=0.81), death from any cause (951 [15.1%] vs. 964 [15.4%] ; hazard ratio, 0.98 ; 95% CI, 0.89 to 1.07 ; P=0.63), or death from arrhythmia (288 [4.6%] vs. 259 [4.1%] ; hazard ratio, 1.10 ; 95% CI, 0.93 to 1.30 ; P=0.26). Triglyceride levels were reduced by 14.5 mg per deciliter (0.16 mmol per liter) more among patients receiving n-3 fatty acids than among those receiving placebo (P