SAN DIEGO — Anemia is an independent risk factor for long-term mortality after myocardial infarction in both diabetic and nondiabetic patients, a large Canadian study has found.
Researchers at Queen Elizabeth II Health Sciences Centre, Dalhousie University, in Halifax, N.S., studied outcomes in 7,466 patients who were admitted with acute MI.
Of these, 1,431 had anemia but no diabetes, 1,646 had diabetes but no anemia, and 964 had diabetes and anemia.
The remaining 3,425 patients had neither diabetes nor anemia.
Patients fared worse if they had both anemia and diabetes, with greater than 25% mortality at 1 month post admission, and greater than 35% mortality within 30 months, S. Ali Imran, M.B., of the division of endocrinology at the university, reported in a poster displayed at the annual meeting of the Endocrine Society.
Diabetes was a strong independent risk factor for both 30-day and long-term (31 days to 30 months) mortality.
Anemia, defined as a hemoglobin level of less than 120 g/L in females and 140 g/L in males, did not independently predict short-term mortality, but that may have been because mild degrees of anemia were included.
However, “any degree of anemia has an adverse effect on long-term mortality post myocardial infarction,” with each lower quintile of hemoglobin at the time of an MI admission associated with an increased risk of death, noted Dr. Imran.
Long-term mortality in patients with anemia approached 30%, compared with about 13% in patients who did not have anemia or diabetes at admission. The authors pointed out that patients with anemia tended to be older and male and had worse renal function than did other MI patients.
“Since anemia is a marker of an underlying disorder, the etiology of the anemia may explain an increased risk of mortality,” they wrote.
The primary cause of death for all patients, including the group with anemia, was cardiovascular.
“Further research examining the potential of correcting anemia is needed in the hopes of reducing long-term mortality,” the researchers concluded.