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.