Impact of smoking on cardiovascular events in patients with coronary disease receiving contemporary medical therapy (from the Treating to New Targets [TNT] and the Incremental Decrease in End Points Through Aggressive Lipid Lowering [IDEAL] trials)

Abstract

To define the incremental risk of cigarette smoking in patients with coronary disease receiving contemporary medical therapy, we performed a post hoc analysis of 18,885 patients by combining data from the Treating to New Targets (TNT) and the Incremental Decrease in End Points through Aggressive Lipid Lowering (IDEAL) trials. These studies compared high-dose treatment (atorvastatin 80 mg/day) to moderate-dose treatment (atorvastatin 10 mg/day in TNT and simvastatin 20 to 40 mg/day in IDEAL) in patients with established coronary heart disease. The primary end point of this pooled analysis was major cardiovascular events, a composite of cardiac death, myocardial infarction, stroke, or resuscitated cardiac arrest. At baseline 4,196 patients had never smoked, 11,513 were ex-smokers, and 3,176 were current smokers. The adjusted hazard ratio for current smokers compared to never smokers was 1.68 (95% confidence interval 1.46 to 1.94) and that for current smokers compared to ex-smokers was 1.57 (95% confidence interval 1.41 to 1.76). Event rates for current smokers compared to ex-smokers were similarly increased in each treatment group. The difference in absolute event rates between current and ex-smokers in this pooled analysis was 4.5%, which is >2 times as large as the decrease in absolute event rates between high-dose and moderate-dose statin therapy found in the IDEAL (1.7%) and TNT (2.2%) trials, respectively. In conclusion, in patients with coronary disease receiving modern medical therapy, smoking cessation is of substantial benefit with a number needed to treat of 22 to prevent a major cardiovascular event over 5 years. Smoking cessation deserves greater emphasis in secondary prevention.