Determinants of coronary events in patients with stable angina: Results from the Impact of Nicorandil in Angina Study

Background IONA was a randomized trial of nicorandil (20 mg twice daily) versus placebo in 5126 patients with stable angina of effort. We present the characteristics as measured at baseline that were found to be associated with increased risk of major outcomes. Methods The primary end point of the study was coronary heart disease death, nonfatal myocardial infarction (MI), or unplanned hospitalization for cardiac chest pain. The secondary outcome excluded the softer outcome of unplanned hospitalization for chest pain. Potential prognostic factors included nicorandil treatment, sex, smoking, severity of angina (Canadian Cardiovascular Society [CCS] grading), previous MI, coronary artery bypass graft/percutaneous transluminal coronary angioplasty (CABG/PTCA), left ventricular dysfunction, left ventricular hypertrophy (LVH) on electrocardiography (ECG), histories of diabetes or hypertension, baseline cardiovascular drugs, age, blood pressures, heart rate, height, weight, and body mass index. Results A total of 5047 patients had complete baseline information. There were 724 primary outcomes and 240 secondary outcomes. The strongest determinants of the hard secondary end point were CCS score (hazards ratio [HR] 2.25, 95% confidence intervals [CI] 1.50-3.38) for grades III and IV versus grade I, age (HR 1.23, 95% CI 1.13-1.33) for 5-year risk, and previous MI (HR 2.05, 95% CI 1.48-2.85). The results for the primary outcome were similar, with stronger associations with LVH on ECG and smoking, and a weaker association with age. Conclusions We present models of risk factors for coronary outcomes in a population with angina of effort. The strongest risk factors were the CCS score and previous MI.