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27-12-2011 | Cardiology | Article

Anemia linked to increased short- and long-term mortality risk in ACS

Abstract

Free abstract

MedWire News: Anemia is an important predictor of in-hospital and long-term mortality in patients with acute coronary syndromes (ACSs), researchers say.

In addition, since the 1980s, the in-hospital outcomes of patients with ACS and anemia have improved, report Ron van Domburg and colleagues from the Erasmus Medical Center in Rotterdam, the Netherlands.

Their analysis included 5304 consecutive patients with a mean age of 61 years who were admitted to a coronary care unit for ACS between 1985 and 2008, and were followed-up for a median of 10 years.

Those with anemia (defined according to the World Health Organization as a serum hemoglobin level of <13 g/dL for men and <12 g/dL for women) were divided into tertiles of condition severity: mild (12.2-13.0 g/dL in men, 11.2-12.0 g/dL in women), moderate (10.9-12.1 g/dL in men, 10.3-11.1 g/dL in women), and severe (≤10.8 g/dL in men, ≤10.2 g/dL in women).

Overall, anemia was present in 2016 (38%) patients, of whom 655 had mild anemia, 717 had moderate anemia, and 646 had severe anemia.

The mean hemoglobin level at baseline in nonanemic patients was 14.2 g/dL and in anemic patients was 11.0 g/dL.

Compared with patients who did not have anemia, those who had moderate anemia had a significant 40% increased risk for 30-day mortality, while those with severe anemia had a significant 67% increased risk, after adjustment for baseline characteristics including renal insufficiency, hypertension, and Type 2 diabetes.

Patients with moderate anemia also had a significant 13% higher risk for 20-year mortality than those who did not have anemia, while those with severe anemia had a 39% increased risk, even after adjusting for renal insufficiency on mortality (hazard ratio [HR]=2.28), note the authors.

They also found that survival during hospitalization improved over time. Indeed, the cumulative 30-day survival rate for patients with anemia improved from 87.2% in 1985-1990 to 91.3% in 1991-2000 (p=0.002) and to 94.1% in 2001-2008 (p<0.001).

Further analysis confirmed that 30-day hospital mortality during the 1990s and 2000s was lower than in the 1980s, at adjusted HRs of 0.52 and 0.36, respectively.

By contrast, the cumulative 20-year survival rate did not change significantly from 1985 to 1990, although in 2001-2008 it was significantly lower compared with earlier cohorts.

"Anemia has the potential to worsen the myocardial ischemic insult in acute myocardial infarction and other ACSs by decreasing the oxygen content of the blood supplied to the endangered myocardium and by increasing myocardial oxygen demand from a necessity for a larger cardiac output to maintain adequate systemic oxygen delivery," explain the authors.

They attribute the improved survival rate seen in anemic and ACS patients over the years to new medical therapies such as antiplatelet agents, angiotensin-converting enzyme inhibitors, and beta blockers, as well as surgical interventions including percutaneous coronary intervention.

By Piriya Mahendra

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