What Constitutes Normal Hemoglobin Concentrations in Community-Dwelling Older Adults?

OBJECTIVES: To assess the relationship between hemoglobin concentration and cause-specific mortality.

DESIGN: Cohort study.

SETTING: Data from the government-sponsored Annual Geriatric Health Examination Program.

PARTICIPANTS: Community-dwelling Taipei citizens aged 65 and older followed up between 2006 and 2010 (N = 77,532).

MEASUREMENTS: Mortality was determined by matching participants' medical records with national death files. Cox proportional hazards regression models were used to evaluate the relationship between hemoglobin concentration (World Health Organization (WHO)-defined anemia and 7 hemoglobin concentrations) and cause-specific mortality.

RESULTS: The mortality risk of WHO-defined anemia increased substantially in both sexes for all-cause and cancer mortalities (men, hazard ratio (HR) = 1.86, 95% confidence interval (CI) = 1.71-2.02 for all-cause mortality; HR = 1.94, 95% CI = 1.69-2.22 for cancer mortality; for women, HR = 1.63, 95% CI = 1.43-1.86 for all-cause mortality; HR = 1.74, 95% CI = 1.38-2.19 for cancer mortality). Men with hemoglobin concentrations of 15.0 to 15.9 g/dL and women with hemoglobin concentrations of 13.0 to 13.9 g/dL had the lowest risks of all-cause, cardiovascular, and cancer mortality. Risks of all-cause and cancer mortality increased significantly when hemoglobin concentrations were less than 14 g/dL in men and less than 12 g/dL in women. Even mild anemia (11.0-11.9 g/dL) was associated with greater mortality risk. Stratification according to age, body mass index, estimated glomerular filtration rate, and presence of comorbidities did not lead to any substantial changes.

CONCLUSION: Hemoglobin concentrations associated with optimal survival in older adults were identified and additional data provided regarding the relationship between hemoglobin concentrations and cause-specific mortality risks in older adults.