Serum homocysteine concentration as an indicator of survival in patients with acute coronary syndromes

Background: Circulating homocysteine levels are predictive of survival in patients with stable coronary artery disease. The prognostic value of serum homocysteine levels, obtained in the acute phase in patients with myocardial infarction or unstable angina, is unknown. Objective: To test the hypothesis that circulating homocysteine levels, obtained during the first 24 hours following hospital admission in patients with acute coronary syndromes, are predictive of long-term mortality. Methods: To test this hypothesis we performed a prospective inception cohort study at a teaching hospital in Gothenburg, Sweden. A total of 579 patients (179 women and 400 men; median age, 67 years) were included (Q-wave myocardial infarction in 163 patients, non-Q-wave myocardial infarction in 210 patients, unstable angina pectoris in 206 patients). Main Outcome Measure: All-cause mortality. Results: During a median follow-up of 628 days, 65 patients died. The serum homocysteine level (mean [SDI) was significantly lower in long-term survivors (n=514) than in nonsurvivors (n=65) (12.3 [7.0] vs 14.3 [5.9] mu mol/L; P=.003). The relative risk tall-cause mortality) for patients with homocysteine levels in the upper quartile was 2.4 (95% confidence interval, 1.5-4.0) compared with that of patients in the 3 lower quartiles. After adjustment for relevant confounders, the relative risk estimate remained significant (relative risk=1.69; 95% confidence interval, 1.02-2.80). In a stepwise model the homocysteine level provided prognostic information additional to that of patient age, diabetes mellitus, and diuretic usage prior to hospital admission (P=.03). Conclusion: The serum homocysteine level on hospital admission is an independent predictor of long-term survival in patients with acute coronary syndromes.