Unexplained Anemia of Aging

Etiology, Health Consequences, and Diagnostic Criteria

Jack Guralnik MD, PhD; William Ershler MD; Andrew Artz MD; Alejandro Lazo-Langner MD; Jeremy Walston MD; Marco Pahor MD; Luigi Ferrucci MD, PhD; William J. Evans PhD


J Am Geriatr Soc. 2022;70(3):891-899. 

In This Article


Anemia is prevalent in men and women over the age of 65 years and becomes progressively more common with age. Anemia is associated with reductions in functional capacity and quality of life, as well an increased risk of death from all causes. Roughly one third of anemia in older patients is unexplained (UAA). Although the WHO diagnostic thresholds for anemia are most frequently used, evidence supports the use of a single criterion of Hb < 13 g/dl in both older men and postmenopausal women. Even mild anemia (Hb 11.0–12.9) is associated with poor clinical outcomes, lower QOL, and elevated mortality. Although UAA is currently diagnosed by exclusion of identifiable causes for anemia, the diagnostic criteria for UAA are clearly defined, and the UAA patient population experiences significant functional decline, morbidity, and mortality. In part due to the lack of consensus on the etiology of UAA, treatment options are extremely limited at present. Novel therapies are currently in development for the treatment of this highly prevalent condition. Finally, we strongly recommend routine assessment of functional capacity and quality of life in all older patients by healthcare providers, particularly those suffering from anemia, using standardized tools that will help to identify functional deficits and changes in functional capacity in older patients with anemia.