A prospective cohort study of predictive value of homocysteine in patients with type 2 diabetes and coronary artery disease

Background: Little evidence exists on the role of homocysteine as a predictor of mortality in patients with type 2 diabetes. The aim of this study was to investigate whether elevated plasma homocysteine levels are independently associated with all-cause or cardiovascular mortality in patients with type 2 diabetes and coronary artery disease. Methods: This is a prospective cohort study that included 507 patients with type 2 diabetes and angiographically proven coronary artery disease. Patients were divided into 2 groups according to homocysteine level above or below median value (12.4 mu mol/L): the high homocysteine group (255 patients) and the low homocysteine group (252 patients). The primary end-point of the study was all-cause mortality. Results: There were 103 deaths during a 4-year follow-up: 62 deaths in the high homocysteine group and 41 deaths in the low homocysteine group (Kaplan-Meier estimates of mortality 25.6% and 17.4%, respectively (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.03-2.27, P=0.031). Sixty-two of 103 deaths (60.2%) were of cardiovascular origin: 37 deaths (14.5%) occurred in the high homocysteine group and 25 deaths (9.9%) occurred in the low homocysteine group (P=0.115). Cox proportional hazards model showed that plasma homocysteine was not an independent correlate of all-cause (adjusted hazard ratio [HR] 1.10, 95% CI 0.89-1.33; P=0.397 for 5 mu mol/L increase in concentration) or cardiovascular (adjusted HR 1.04, 95% CI 0.80-1.36, P=0.753, for 5 mu mol/L increase in concentration) mortality. Conclusion: In patients with type 2 diabetes and coronary artery disease, elevated level of homocysteine is an associate of increased cardiovascular risk but not an independent predictor of cardiovascular mortality. (c) 2006 Elsevier B.V. All rights reserved.