Pode a presença de anemia na admissão melhorar a capacidade preditiva do score GRACE para mortalidade a curto e médio prazo após síndrome coronária aguda?

Abstract

IntroductionIn patients admitted for acute coronary syndrome (ACS), the presence of anemia is a predictor of prognosis. However, risk scores used for prognostic stratification do not include this variable. ObjectivesTo evaluate whether the presence of anemia on admission in patients with ACS has additional value over the GRACE risk score in the prediction of short- and medium-term mortality. MethodsBetween January 2005 and December 2008, we assessed consecutive patients admitted to our intensive care unit for ACS and included in our single-center ACS registry. In all patients information was collected on demographic and anthropometric variables, risk factors for coronary artery disease, and clinical and laboratorial data on admission, including hemoglobin. Patients with anemia were identified (hemoglobin <12g/dl for women and <13g/dl for men). Patients were classified as low, intermediate or high risk on the GRACE risk score (<126, 126-154 and >154, respectively).In-hospital, 30-day and one-year mortality were analyzed. ResultsThe study population included 1423 patients with a mean age of 64±13 years, 69% male, anemia on admission being present in 27.7%. These patients were older and more often female, with a higher proportion of hypertensives and diabetics, and more often had a history of myocardial infarction, worse Killip class on admission and higher GRACE risk score. On the other hand, fewer were smokers, fewer presented ST-segment elevation myocardial infarction and they were less often treated with beta-blockers, statins and coronary angioplasty. They had more bleeding complications during hospital stay. In-hospital (10% vs. 4%), 30-day (12% vs. 5%) and one-year mortality (15% vs. 6%) were higher in the anemia group (p<0.001). In bivariate analysis, the presence of anemia was a predictor of in-hospital (OR 2.46, 95% CI 1.57-3.85, p<0.001), 30-day (OR 2.47, 95% CI 1.65-3.69, p<0.001) and one-year mortality (OR 2.66, 95% CI 1.83-3.86, p<0.001). However, after adjustment for other variables, this association was no longer significant. When we analyzed the presence or absence of anemia for each GRACE risk score group, there was only a difference in one-year mortality, which was higher in both the intermediate- and high-risk GRACE score groups (6.7% vs. 2.3%, p=0.024; 23.4% vs. 15.6%, p=0.022, respectively), with a trend for higher 30-day mortality in the high-risk group (19.6% vs. 13.5%, p=0.056). ConclusionsOur data confirm that anemia is an important predictor of short- and medium-term mortality after ACS, but non-significant after adjustment or when included in the GRACE risk score. However, combining this variable with the GRACE risk score can improve risk stratification in high-risk groups, and it should be included in the prognostic evaluation of these patients.