The World Health Organization (WHO) criteria for anemia may not be appropriate for elderly persons, because their hemoglobin levels are lower as a function of aging. Izaks and associates evaluated whether the WHO criteria for anemia were appropriate for persons who were at least 85 years old.

All persons in Leiden, the Netherlands, who were at least 85 years of age were eligible for the study. No one who was willing to join the study was excluded. Information about medical history, daily functioning level and cognitive function was obtained, and each participant who consented had blood drawn for a red blood cell count. Anemia was defined by WHO criteria; the reference interval for hemoglobin concentration was 120 to 160 g per L (7.5 to 10.0 mmol per L) for women and 130 to 180 g per L (8.1 to 11.2 mmol per L) for men. During the 10-year follow-up period, mortality rates and cause of death information were collected.

A total of 956 people were interviewed, with 872 consenting to participate in the study. Of these, 755 were evaluated for anemia. Seventeen percent of the women and 28 percent of the men were found to have anemia, most commonly the normocytic type. Baseline information revealed medical problems—specifically, malignancy, infection and peptic ulcer disease—that were known to be associated with anemia. These conditions affected persons with anemia more often than those who did not have anemia. However, no clinical disease was reported in 21 percent of persons with anemia or in 26 percent of those without anemia.

Mortality risk in the first five years was higher in those with anemia than in those with a normal hemoglobin concentration. The type of anemia was not related to risk. Women with anemia were at increased mortality risk if their hemoglobin concentration was less than 128 g per L (8.0 mmol per L), but that risk increased if the concentration was less than 104 g per L (6.5 mmol per L). In men, the levels of risk increased at hemoglobin concentrations below 136 g per L (8.5 mmol per L) and were highest when the concentration was below 104 g per L. Eighty-six percent of the persons with anemia died during the follow-up period, compared with 65 percent of the those who did not have anemia.

The authors conclude that the WHO criteria for anemia are valid in persons over 85 years of age. Mortality risk is higher in elderly persons who have anemia compared with those who do not, regardless of functional level or comorbidities. Therefore, they encourage additional evaluation of an elderly patient with anemia, even if the patient has no apparent underlying disease.