The definition of anemia in older persons.

CONTEXT: Whether hemoglobin concentrations defined as anemia by the World Health Organization (WHO) are associated with increased mortality in older persons is not known.

OBJECTIVE: To investigate the association between hemoglobin concentration and cause-specific mortality in older persons.

DESIGN: Community-based study conducted from 1986 to 1996 (follow-up period, 10 years).

SETTING: Leiden, the Netherlands.

PARTICIPANTS: A total of 1016 community residents aged 85 years and older were eligible and 872 agreed to have a blood sample taken. Hemoglobin concentration was measured in 755 persons (74%).

MAIN OUTCOME MEASURES: Hemoglobin concentration, 10-year survival, and primary cause of death. According to the WHO criteria, anemia was defined as a hemoglobin concentration below 7.5 mmol/L (120 g/L) in women and below 8.1 mmol/L (130 g/L) in men.

RESULTS: Compared with persons with a normal hemoglobin concentration, the mortality risk was 1.60 (95% confidence interval [CI], 1.24-2.06; P<.001) in women with anemia, and 2.29 (95% CI, 1.60-3.26; P<.001) in men with anemia. In both sexes, the mortality risk increased with lower hemoglobin concentrations. In persons without self-reported clinical disease at baseline, the mortality risk of anemia was 2.21 (95% CI, 1.37-3.57; P=.002). Mortality from malignant and infectious diseases was higher in persons with anemia.

CONCLUSIONS: Anemia defined by the WHO criteria was associated with an increased mortality risk in persons aged 85 years and older. The criteria are thus appropriate for older persons. A low hemoglobin concentration at old age signifies disease.