Association between anemia and 3-year all-cause mortality among oldest old people in longevity areas in China

Abstract

To explore the association between anemia and 3-year all-cause mortality among the oldest old people in longevity areas in China. In August 2012, questionnaire survey, health examination and blood test were conducted among 929 old people aged ≥ 80 years in 7 longevity areas in China, who were included in Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2009. Cox regression model was used to evaluate the association between anemia or different hemoglobin levels and mortality. Among the 929 subjects, the prevalence of anemia was 49.6%, the main form of anemia was normocytic anemia. During the three year follow-up period, a total of 447 subjects died, the overall mortality was 49.8% (56.0% in subjects with anemia and 43.3% in subjects without anemia). Compared with the subjects without anemia, the mortality risk increased by 25% in the subjects with anemia after adjusting confounding factors (HR = 1.25, 95% CI: 1.03-1.52). Macrocytic anemia, simplex microcytic anemia and microcytic hypochromic anemia were all associated with the increased mortality in the oldest old people. Compared with the subjects with low hemoglobin concentration, the subjects with high hemoglobin concentration had a lower mortality risk, and the association was more obvious in women. Anemia and low hemoglobin concentration were associated with higher mortality risk in the oldest old people in China, indicating the importance of anemia prevention and treatment among this population.