PURPOSE: Recent reports suggest that decreased functional capacity in patients with heart failure may be associated with abnormalities in glucose metabolism. We followed patients with coronary artery disease who participated in the Bezafibrate Infarction Prevention study to determine the incidence of diabetes by baseline functional status during a 7.7-year follow-up. METHODS: The sample comprised 2616 nondiabetic patients aged 45 to 74 years with a fasting blood glucose level <7 mmol/L (126 mg/dL). They were divided into three groups by New York Heart Association (NYHA) criteria: class I (n = 1986 patients), class II (n = 518), and class III (n = 112). The detection of a fasting blood glucose level ≥7 mmol/L during follow-up was defined as the criterion for the development of diabetes. RESULTS: The study groups had similar demographic and clinical characteristics, except that patients with symptomatic heart failure (NYHA class II or III) were more likely to have angina. During follow-up, diabetes developed in 259 patients (13%) in NYHA class I, 76 (15%) in class II, and 22 (20%) in class III (P for trend = 0.05). At the last visit, patients in NYHA class III were twice as likely (17% [n = 19]) to have fasting blood glucose levels ≥7 mmol/L as those in NYHA class I (7.8% [n = 154]) or class II (8.7% [n = 45]) (P = 0.005). In a multivariate analysis, NYHA class III was associated with a 1.7-fold (95% confidence interval [CI]: 1.1 to 2.6) increase in the rate of development of diabetes, but NYHA class II was not (hazard ratio = 1.0; 95% CI: 0.8 to 1.3). CONCLUSION: Among patients with coronary artery disease, advanced heart failure (NYHA class III) is associated with a significantly increased risk of developing diabetes during a 6- to 9-year follow-up.