Is hemoglobin variation a linear predictor of mortality in acute coronary syndrome?

Coronary artery disease is a common health problem. The aim of this study was to evaluate the prognosis impact on mortality of the variation of hemoglobin (Hb) levels during hospitalization time. The retrospective observational study included 2640 patients admitted for acute coronary syndrome in a single coronary care unit from May 2004 until June 2013. The primary endpoint was all cause of death at 1 year of follow up time, and secondary endpoint was all cause of death at 2 years of the follow up time. Four groups were created according to the quartiles of Hb variation (admission Hb minus lowest Hb value) during the hospitalization time: group 1: ≥ 2.1 g/dL with 627 patients; group 2: > 1.1 and < 2.1 g/dL with 666 patients; group 3: > 0.3 and ≤ 1.1 g/dL with 686 patients and group 4: ≤ 0.3 g/dL with 661 patients. A total of 84 patients (3.2%) died during the first year of the follow up. More patients died in group 1 and 4 (6.4% vs 3.7% vs 3.7% vs 6.8%, Log-Rank = 0.023). At 2 years of follow-up, the results were similar, with higher mortality in group 4 (7.3% vs 4.3% vs 4.6% vs 9.2%, Log-Rank = 0.003). Multivariate analysis showed that Hb variation > 1.1 was an independent predictor of mortality (hazard ration = 0309 95% confidence interval, 0.136–0.702; P = 0.005). The patients with the lower baseline hemoglobin and the variability of Hb highest than 1.1 mg/dL had the worse prognosis with high mortality rate during the follow up time.