Hyperhomocysteinemia is now regarded as an established risk factor for coronary 
artery disease and is present frequently in the general population. However, the 
diagnostic value of this risk factor relative to others has only occasionally 
been investigated. We compared the diagnostic value of classic risk factors and 
of homocysteine in a retrospective case-control study in 191 cases with 
angiographically established coronary artery disease and 231 healthy controls. 
Life style habits were assessed by a detailed questionnaire. Laboratory 
parameters including lipoproteins and blood lipids, homocysteine, folate, and 
vitamin B12 were measured and their diagnostic value compared with each other by 
use of receiver-operator characteristic analysis. Comparison of the 
receiver-operator characteristic curves revealed that homocysteine significantly 
discriminated between cases and control subjects. High-density-lipoprotein 
cholesterol, triglycerides and non-esterified fatty acids also had an area under 
the curve significantly different from 0.5 (the area under the curve 
representing no discrimination). Homocysteine was weakly related to folate, 
vitamin B12, age and serum creatinine concentration. We conclude that 
hyperhomocysteinemia is at least as important as conventional risk factors for 
coronary artery disease and that receiver operator characteristic analysis of 
homocysteine is suitable to determine patients at the highest risk for coronary 
artery disease. Clinical trials testing the effect of homocysteine lowering by 
vitamin supplementation in the prevention of coronary artery disease are needed.