In-hospital acquired anemia in acute coronary syndrome. Predictors, in-hospital prognosis and one-year mortality.

INTRODUCTION AND OBJECTIVES: Anemia at hospital admission predicts a poor outcome in patients presenting with acute coronary syndrome. It remains unclear whether in-hospital hemoglobin levels decrease (nosocomial anemia) not related to bleeding also implies a poor prognosis. We aimed to identify predictors of nosocomial anemia and its prognostic significance. METHODS: We prospectively included 221 acute coronary syndrome patients admitted in our institution during the years 2009-2010, with normal hemoglobin levels at admission. Nosocomial anemia was defined as a decrease in hemoglobin levels to <13 g/dL in men and <12 g/dL in women in the absence of apparent bleeding. Clinical variables and hematological inflammatory parameters were assessed in order to identify predictors for the development of nosocomial anemia. We compared the clinical outcome after a 1-year follow-up period of patients without anemia as opposed to those who developed nosocomial anemia. RESULTS: Nosocomial anemia was registered in 25% of study patients. A >3.1 mg/dL value of C-reactive protein was highly predictive of developing nosocomial anemia (odds ratio=5.9; 95% confidence interval, 2.6-13.4; P<.001). The incidence of mortality and cardio-vascular morbidity was higher in the patients who developed nosocomial anemia (34.5% vs 9%; P<.001). Nosocomial anemia was a strong predictor of cardio-vascular morbidity and mortality in the long-term follow-up (hazard ratio=2.47; 95% confidence interval, 1.23-4.96; P=.01). CONCLUSIONS: Nosocomial anemia predicts a poorer outcome in patients with acute coronary syndrome. Increased C-reactive protein levels, indicating inflammatory state, are predictive of developing in-hospital anemia unrelated to apparent bleeding.