Anemia is commonly observed in patients with acute coronary syndromes (ACS). In these patients, anemia is associated with higher risks of in-hospital and 30-day mortality. To improve ACS management in clinical settings, recent guidelines recommend risk stratification and the established use of risk scores, such as the Global Registry of Acute Coronary Events (GRACE) score to assess patient risk upon admission. However, these guidelines have not yet accounted for the impact of anemia on ACS stratification and categorization strategies. Therefore, a new study analyzed the impact of anemia on in-hospital and 30-day mortality, as well as the predictive value of anemia for determining prognosis parameters.

The study population included 1,410 patients who were admitted to cardiology centers in Eastern France with a final diagnosis of myocardial infarction. Baseline hemoglobin and demographic factors were recorded, as well as variables for estimating GRACE risk score including age, history of chronic heart failure, history of myocardial infarction, heart rate, and systolic blood pressure. Using the Cox proportional model, the association between variables and mortality was assessed, and the anemia information was subsequently added to current GRACE score classifications. Predicted mortality using the GRACE score with anemia information was then compared to GRACE scores without anemia information.

In general, patients with anemia were older, and mortality rates were four times higher in anemic patients compared to nonanemic patients. Also, when anemia information was included in a prediction model based on GRACE scores, anemia was shown to be an independent predictor of mortality. Importantly, the reclassification of risk categories after including anemia information brought mortality estimations closer to observed mortalities.

The higher risk of mortality reported in ACS patients with anemia can be explained by a number of factors, including decreased oxygen delivery to the myocardium, preexisting comorbidities (especially in elderly populations), increased rate of blood transfusion, and higher risks of bleeding. These factors certainly increase the complexity of risk scoring systems, but hemoglobin (Hb) and anemia data are readily available for ACS patients upon admission. The authors conclude that these data improve risk prediction in terms of mortality, and therefore, anemia information should be initially considered when designing treatment plans.

Meneveau N, Schiele F, Seronde MF, Descotes-Genon V, Oettinger J, Chopard R, Ecarnot F, Bassand JP; Reseau de Cardiologie de Franche Comte. Anemia for risk assessment of patients with acute coronary syndromes. Am J Cardiol. 2009 Feb 15;103(4):442-47.

NAAC Expert Commentary:
Sometimes, common clinical conditions that may have pathophysiological significance in other syndromes under certain circumstances may be missed even when the potential for an interaction is plausible and relatively self-evident. Numerous studies now suggest this may be true regarding anemia and cardiovascular disease. Although reduced Hb concentration is a frequent co-morbidity associated with heart failure, acute coronary syndrome, and hypertension, the potential of anemia to exacerbate these conditions was largely ignored until very recently. Fortunately, a number of investigators realized the potential for an interaction in patients with heart failure.¹ Subsequently, a number of studies have documented that reduced Hb is associated with increased risk of morbidity and mortality in patients with heart failure and reduced or preserved ejection fraction.^2,3 The critical role of reduced oxygen delivery in heart failure makes this interaction very plausible in retrospect. Now, a large-scale randomized trial is prospectively testing whether pharmacological treatment to augment Hb will lessen the risk of adverse outcomes in anemic patients with heart failure, due to systolic dysfunction.⁴

A number of investigators had the insight to pursue similar associations among anemia and adverse outcomes in patients with coronary artery disease and these studies have demonstrated findings consistent with those in heart failure.^5,6 The study of Meneveau and colleagues represents an important contribution by showing that the addition of anemia improves the risk stratification derived from the GRACE score.⁷ The risk classification of a number of patients was altered when anemia was added to the model. Risk stratification is increasingly important, for not only direct patient care decisions, but also in comparing patient populations to aid in assessment of quality of care and reimbursement. Depending upon the outcome of ongoing studies in heart failure, these observations along with a number of others may provide impetus for interventional trials to examine the potential therapeutic role that anemia correction serves in patients with ischemic syndromes.

References

1. Felker GM, Gattis WA, Leimberger JD, Adams KF, Cuffe MS, Gheorghiade M, O’Connor CM. Usefulness of anemia as a predictor of death and rehospitalization in patients with decompensated heart failure. Am J Cardiol. 2003 Sep 1;92:625-28. Link.
2. Al-Ahmad A, Rand WM, Manjunath G, Konstam MA, Salem DN, Levey AS, Sarnak MJ. Reduced kidney function and anemia as risk factors for mortality in patients with left ventricular dysfunction. J Am Coll Cardiol. 2001 Oct;38(4):955-62. Link.
3. Ezekowitz JA, McAlister FA, Armstrong PW. Anemia is common in heart failure and is associated with poor outcomes: insights from a cohort of 12 065 patients with new-onset heart failure. Circulation. 2003 Jan 21;107(2):223-25. Link.
4. van Veldhuisen DJ, McMurray JJV on behalf of the RED-HF executive committee. Are erythropoietin stimulating proteins safe and efficacious in heart failure? Why we need an adequately powered randomised outcome trial. Eur J Heart Fail. 2007 Feb;9(2):110-12. Link.
5. Sabatine MS, Morrow DA, Giugliano RP, Burton PB, Murphy SA, McCabe CH, Gibson CM, Braunwald E. Association of hemoglobin levels with clinical outcomes in acute coronary syndromes. Circulation. 2005 Apr 26;111(16):2042–49. Link.
6. Bindra K, Berry C, Rogers J, Stewart N, Watts M, Christie J, Cobbe SM, Eteiba H. Abnormal haemoglobin levels in acute coronary syndromes. QJM. 2006 Dec;99(12):851– 62. Link.
7. Granger CB, Goldberg RJ, Dabbous O, Pieper KS, Eagle KA, Cannon CP, Van De Werf F, Avezum A, Goodman SG, Flather MD, Fox KA, Global Registry of Acute Coronary Events Investigators. Predictors of hospital mortality in the global registry of acute coronary events. Arch Intern Med. 2003 Oct 27;163(19):2345–53. Link.

Last Updated: March 4, 2009