Anemia is associated with increased risk of all-cause mortality in older populations. However, the relationship between
hemoglobin and major adverse cardiovascular events (
MACE), and whether this is modulated by
frailty, is unclear.
METHODS: CHAMP (Concord Health and Ageing in Men Project) is a prospective study of community-dwelling men aged ≥ 70 years. The relationship between
hemoglobin and 7-year
MACE was analysed by means of Cox regression. The Youden index was used to determine the optimal
hemoglobin cutoff point in predicting
MACE.
Frailty was assessed with the use of the Fried criteria.
RESULTS: The cohort comprised 1604 men (mean ± SD age 76.9 ± 5.5 years). Decreasing
hemoglobin was associated with increased comorbidity,
frailty, and
MACE (P < 0.001), with 140 g/L the optimal cutoff point for predicting
MACE.
Hemoglobin, age, and
frailty independently predicted
MACE (all P < 0.001). Each 10 g/L decrement in
hemoglobin level was associated with increased risk of
MACE (hazard ratio [HR] 1.13, 95% confidence interval [CI] 1.06-1.20; P < 0.001), all-cause mortality (HR 1.20, 95% CI 1.12-1.29; P < 0.001), cardiovascular mortality (HR 1.07, 95% CI 1.01-1.14; P = 0.025),
myocardial infarction (HR 1.17, 95% CI 1.09-1.25; P < 0.001), and
heart failure (HR 1.17, 95% CI 1.09-1.25; P < 0.001). When stratified into
hemoglobin quintiles, men in the lowest 2 quintiles (Hb 133-140 g/L and < 132g/L, respectively) were at increased risk of
MACE, cardiovascular mortality,
myocardial infarction, and
heart failure (all P < 0.05). This relationship for
MACE was independent from
frailty status, with the test for interaction between
frailty and
hemoglobin not reaching significance (P = 0.24).
CONCLUSIONS: Low
hemoglobin was associated with increased
MACE in community-dwelling older men independently from
frailty. A
hemoglobin cutoff point of 140 g/L, a level that is above contemporary definitions of
anemia, predicted long-term
MACE.