Usefulness of Hemoglobin Level to Predict Long-Term Mortality in Patients With Asymptomatic Carotid Narrowing by Ultrasonography

Anemia is associated with the cardiovascular outcome in healthy subjects but its impact on outcome in patients with cardiovascular disease has not yet been fully understood. Therefore, we assessed the long-term influence of hemoglobin on all-cause and cardiovascular mortality in patients with atherosclerotic disease. We prospectively studied 1,065 of 1,286 consecutive patients with asymptomatic carotid narrowing. During a median follow-up of 6.2 years, corresponding to 5,551 overall person-years, 275 patients (25.8%) died. Continuous measures of hemoglobin displayed a significant inverse effect on all-cause mortality and cardiovascular mortality (adjusted hazard ratio [HR] for increase of 1 SD of hemoglobin 0.73, 95% confidence interval [CI] 0.64 to 0.83; p <0.001) and adjusted HR 0.76, 95% CI 0.64 to 0.89; p = 0.001, respectively). The cumulative 6-year survival rate was 61%, 79%, 80%, and 81% in the first, second, third, and fourth quartile of hemoglobin (log-rank p <0.001). Patients within the first quartile (<12.9 g/dl) had a significantly increased risk of all-cause mortality (adjusted HR 1.93, 95% CI 1.46 to 2.54, p <0.001) and cardiovascular mortality (adjusted HR 1.68, 95% CI 1.19 to 2.36, p = 0.003) compared to patients with greater levels. In conclusion, our study has demonstrated a significant association with hemoglobin levels and all-cause and cardiovascular mortality in patients with carotid narrowing. Nevertheless, additional research, in terms of randomized controlled trials, is needed to warrant these findings and to evaluate potential therapeutic interventions.