Hemoglobin concentration on admission influences the rate of inhospital 30-day mortality and complications in patients with acute myocardial infarction: a retrospective analysis of 660 Chinese patients

Objective

To determine the association between hemoglobin concentrations on admission and inhospital 30-day cardiac mortality and complications among patients with acute myocardial infarction during their hospital course.

Methods

We conducted a retrospective study of data on 660 Chinese patients who were hospitalized with acute myocardial infarction. Patients were categorized according to the hemoglobin concentration on admission, and data were evaluated to determine whether there was an association between the hemoglobin concentrations on admission and inhospital 30-day mortality and complications. Complications were defined as cardiogenic shock, congestive heart failure, arrhythmia, ventricular tachycardia or fibrillation and pneumonia.

Results

Patients with hemoglobin values between 140 and 159 g/l were used as the reference; cardiovascular mortality increased as hemoglobin levels fell below 140 g/l or rose ≥ 160 g/l. The inhospital 30-day mortality was 25.0% in patients with hemoglobin concentrations <100 g/l, 20.4% in patients with hemoglobin concentrations of 100–119 g/l, 10.6% in patients with hemoglobin concentrations of 120–139 g/l, 4.3% in patients with hemoglobin concentrations of 140–159 g/l, and 8.5% in patients with hemoglobin concentrations of 160 g/l or greater. The increase in risk of complications associated with a low hemoglobin concentration was more pronounced in patients with anemia than in patients without. Compared with patients with hemoglobin concentrations of 140–159 g/l, those with hemoglobin concentrations <140 g/l had more inhospital complications and those with hemoglobin concentrations ≥ 160 g/l also had more arrhythmia and pneumonia (P < 0.001, respectively). As expected, a significant inverse correlation between hemoglobin concentrations and ages (r = -0.51; P < 0.001) was observed, and a significant positive correlation between hemoglobin concentrations and albumin concentrations and in the patients with acute myocardial infarction.

Conclusion

It is demonstrated in this study that a reverse J-shaped relationship between baseline hemoglobin values and major adverse cardiovascular events is observed in patients with acute myocardial infarction. There is a greater incidence of patients with a hemoglobin concentration on admission in the elderly population than that in the younger one.