Anemia and 1y Mortality With Acute Myocardial Infarction
Background: Limited data are available on the effect of anemia on mortality in patients with acute myocardial infarction (MI).
Methods: We examined the association of anemia with mortality at 1 year among 30,341 patients hospitalized with acute MI in 1986 (prethrombolytic era, n = 15,584) and 1996 (thrombolytic era, n = 14,757). The records were obtained from the Myocardial Infarction Data Acquisition System, a database of all patients with MI admitted to nonfederal hospitals in New Jersey.
Results: Anemia was present in 996 patients (6.4%) in 1986 and 1510 patients (10.2%, P<.0001) in 1996. In both years, patients with anemia were older, more frequently female and nonwhite, and more likely to have left ventricular dysfunction, non-Q MI and coronary artery bypass graft. In addition, in 1996, patients with anemia were more likely to undergo percutaneous transluminal coronary angioplasty and less likely to have a history of MI. One-year mortality was lower overall in 1996 compared with 1986 (1996 23.6%, 95% CI 22.9-24.3 vs 1986 24.9%, 95% CI 24.2-25.6, P = .0001). In both years, patients with anemia had significantly higher unadjusted risk for 1-year mortality (RR = 1.40, P = .0001 in both years). However, after controlling for demographics, left ventricular dysfunction, arrhythmias, Q versus non-Q MI, comorbid conditions, and revascularization procedures in a multivariable regression model, 1-year mortality in the anemia group was similar to the nonanemia group in both years.
Conclusion: In the Myocardial Infarction Data Acquisition System database, anemia appears to have no significant direct effect on 1-year mortality. The higher unadjusted mortality observed among patients with acute MI and anemia is probably the result of older age, higher comorbidity, and more left ventricular dysfunction.
The association of anemia with short- and long-term mortality has been studied in patients with end-stage renal diseases, post-coronary artery bypass graft (CABG), in critically ill patients, and perioperatively, but not in patients with acute coronary syndromes. One recent study of Medicare beneficiaries with acute myocardial infarction (MI) found that transfusing patients with hematocrit values below 30% was associated with reduced 30-day mortality. The prognostic importance of anemia in the setting of acute MI is not well defined, and the impact of anemia on long-term survival after MI has not been studied.
A prospective observational study of 2202 patients undergoing CABG in the United States found higher postoperative hematocrit values (>34%) were associated with higher rates of postoperative MI, left ventricular dysfunction (LVD), and mortality. In patients with end-stage renal disease, anemia is associated with the development of left ventricular hypertrophy. Correction to near-normal hemoglobin values or to values above 10 g/dL was associated with fewer cardiovascular events, longer duration to first MI, regression of left ventricular hypertrophy, and decreased resting and exercise induced angina. However in a randomized, open-label prospective trial with 29-month follow-up of 1233 patients with end-stage renal disease and history of heart disease, administration of erythropoietin to maintain a normal hematocrit (>42%) was associated with higher rates of acute nonfatal MI and a higher mortality rate compared to low hematocrit of 30%. The above studies assessed the association of anemia with short-term mortality and were not conducted in the setting of acute MI.
This retrospective cohort study was conducted to evaluate the effect of anemia on 1-year mortality in patients with acute MI admitted to nonfederal hospitals in New Jersey. Two patient cohorts were investigated: from 1986 (prethrombolytic era) and 1996 (thrombolytic era), as this database lacks information about the use of thrombolytic therapy. This is a major confounder because thrombolytic use is associated with improved survival as well as with a greater chance of developing anemia during hospitalization.
Background: Limited data are available on the effect of anemia on mortality in patients with acute myocardial infarction (MI).
Methods: We examined the association of anemia with mortality at 1 year among 30,341 patients hospitalized with acute MI in 1986 (prethrombolytic era, n = 15,584) and 1996 (thrombolytic era, n = 14,757). The records were obtained from the Myocardial Infarction Data Acquisition System, a database of all patients with MI admitted to nonfederal hospitals in New Jersey.
Results: Anemia was present in 996 patients (6.4%) in 1986 and 1510 patients (10.2%, P<.0001) in 1996. In both years, patients with anemia were older, more frequently female and nonwhite, and more likely to have left ventricular dysfunction, non-Q MI and coronary artery bypass graft. In addition, in 1996, patients with anemia were more likely to undergo percutaneous transluminal coronary angioplasty and less likely to have a history of MI. One-year mortality was lower overall in 1996 compared with 1986 (1996 23.6%, 95% CI 22.9-24.3 vs 1986 24.9%, 95% CI 24.2-25.6, P = .0001). In both years, patients with anemia had significantly higher unadjusted risk for 1-year mortality (RR = 1.40, P = .0001 in both years). However, after controlling for demographics, left ventricular dysfunction, arrhythmias, Q versus non-Q MI, comorbid conditions, and revascularization procedures in a multivariable regression model, 1-year mortality in the anemia group was similar to the nonanemia group in both years.
Conclusion: In the Myocardial Infarction Data Acquisition System database, anemia appears to have no significant direct effect on 1-year mortality. The higher unadjusted mortality observed among patients with acute MI and anemia is probably the result of older age, higher comorbidity, and more left ventricular dysfunction.
The association of anemia with short- and long-term mortality has been studied in patients with end-stage renal diseases, post-coronary artery bypass graft (CABG), in critically ill patients, and perioperatively, but not in patients with acute coronary syndromes. One recent study of Medicare beneficiaries with acute myocardial infarction (MI) found that transfusing patients with hematocrit values below 30% was associated with reduced 30-day mortality. The prognostic importance of anemia in the setting of acute MI is not well defined, and the impact of anemia on long-term survival after MI has not been studied.
A prospective observational study of 2202 patients undergoing CABG in the United States found higher postoperative hematocrit values (>34%) were associated with higher rates of postoperative MI, left ventricular dysfunction (LVD), and mortality. In patients with end-stage renal disease, anemia is associated with the development of left ventricular hypertrophy. Correction to near-normal hemoglobin values or to values above 10 g/dL was associated with fewer cardiovascular events, longer duration to first MI, regression of left ventricular hypertrophy, and decreased resting and exercise induced angina. However in a randomized, open-label prospective trial with 29-month follow-up of 1233 patients with end-stage renal disease and history of heart disease, administration of erythropoietin to maintain a normal hematocrit (>42%) was associated with higher rates of acute nonfatal MI and a higher mortality rate compared to low hematocrit of 30%. The above studies assessed the association of anemia with short-term mortality and were not conducted in the setting of acute MI.
This retrospective cohort study was conducted to evaluate the effect of anemia on 1-year mortality in patients with acute MI admitted to nonfederal hospitals in New Jersey. Two patient cohorts were investigated: from 1986 (prethrombolytic era) and 1996 (thrombolytic era), as this database lacks information about the use of thrombolytic therapy. This is a major confounder because thrombolytic use is associated with improved survival as well as with a greater chance of developing anemia during hospitalization.
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