Coronary artery disease
Anemia for Risk Assessment of Patients With Acute Coronary Syndromes

https://doi.org/10.1016/j.amjcard.2008.10.023Get rights and content

In patients admitted with acute coronary syndromes, those with anemia are at higher risk. However, current risk score systems do not take into account the presence of anemia. The impact of anemia on mortality was studied, and its incremental predictive value was evaluated. Demographic, clinical, and biologic characteristics at admission, as well as treatments and mortality, were recorded for 1,410 consecutive patients with acute coronary syndromes. The incremental value of adding anemia information to risk score evaluation was determined using changes in the appropriateness of Cox models when anemia was added. Anemia was detected in 381 patients (27%). They were older, had more co-morbidities, had higher Global Registry of Acute Coronary Events (GRACE) risk scores, received fewer guideline-recommended treatments, and, as a result, had 4-fold higher mortality. When included in a prediction model based on the GRACE risk score, anemia remained an independent predictor of mortality. The addition of anemia improved both the discriminatory capacity and calibration of the models. According to the GRACE risk score, the population was divided into 4 groups of different risk levels of <1%, 1% to <5%, 5% to <10%, and ≥10%. The addition of anemia to the model made it possible to reclassify 9%, 43%, 47%, and 23% of patients into the different risk categories, respectively. In conclusion, our data confirmed that anemia was an independent predictive factor of mortality and had incremental predictive value to the GRACE score system for early clinical outcomes.

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Methods

The study population was part of the Registre Franc Comtois des Syndromes Coronariens Aigus, an ongoing prospective ACS registry, that included all patients admitted for ACSs in any of the 10 cardiology centers in the region of Franche-Comté in Eastern France with a population of 1.2 million inhabitants. All patients gave informed consent. ACSs included ST-elevation myocardial infarction and non–ST-elevation myocardial infarction according to the European Society of Cardiology universal

Results

During 12 months (December 2005 to December 2006), 1,610 patients were admitted with a final diagnosis of acute myocardial infarction, 1,410 of whom had complete data and 30-day clinical follow-up. The distribution of hemoglobin was normal (Figure 1), with a mean of 13.5 ± 1.8 g/dl and median of 13.7 (interquartile range 12.4 to 14.8). Anemia was detected in 381 patients (27%).

Patients with anemia were older and had more previous co-morbidities, had more cardiovascular risk factors, and more

Discussion

Our data confirmed that anemia was an independent predictive factor for mortality, had incremental predictive value to the GRACE score system for early clinical outcomes, and allowed reclassification of a large proportion of patients into different risk categories.

The higher risk linked to anemia can be explained by the decrease in oxygen delivery to the myocardium18 and resulting increase in myocardial oxygen demand.19 Furthermore, it can be partially accounted for by patient characteristics.

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