The impact of hyperhomocysteinemia as a cardiovascular risk factor in the prediction of coronary heart disease.

Coronary heart disease often occurs in the absence of traditional risk factors. Consequently, epidemiological studies exploring novel risk factors are necessary to improve the prediction of coronary heart disease. This study evaluated five promising markers of cardiovascular risk: homocysteine, C-reactive protein, fibrinogen, lipoprotein(a) (Lp(a)), free apolipoprotein(a) (apo(a)) and Lp(a) phenotypes. The study included 135 patients with angiographically confirmed atherosclerosis. The control group consisted of 93 sex- and age-matched individuals. The Mann-Whitney U-test was used for group comparison. New risk factors were evaluated by binary logistic regression. The odds ratios were calculated continuously for homocysteine in dependence on C-reactive protein. Low density lipoprotein (LDL)-cholesterol was nearly identical in controls and patients. Homocysteine, C-reactive protein, fibrinogen, high density lipoprotein (HDL)-cholesterol and Lp(a) discriminated highly significantly between both groups. The continuously calculated odds ratio for homocysteine demonstrated a distinct influence of C-reactive protein. In the group with high C-reactive protein levels, homocysteine levels above 9.6 micromol/l resulted in a markedly elevated risk (odds ratio 12), in the group with C-reactive protein levels below 5 mg/dl, a comparable risk increase was observed at a homocysteine level of 16.6 micromol/l. This data strongly suggests that plasma homocysteine helps identify individuals at risk, especially among those with elevated C-reactive protein levels.