Anemia and mortality in older persons: does the type of anemia affect survival?

Anemia is a common condition among community-dwelling older adults. The present study investigates the effect of type of anemia on subsequent mortality. We analyzed data from participants of the Third National Health and Nutrition Survey who were aged ≥50 and had valid hemoglobin levels determined by laboratory measurement. Anemia was defined by World Health Organization criteria. 7,171 subjects met our inclusion criterion. Of those with anemia (n = 862, deaths = 491), 24% had nutritional anemia, 11% had anemia of chronic renal disease, 26% had anemia of chronic inflammation, and 39% had unexplained anemia. We found an overall relative risk (RR) for mortality of 1.8 (p < 0.001) comparing those with anemia to those without, after adjusting for age, sex, and race. After we controlled for a number of chronic medical conditions, the overall RR was 1.6. Compared to persons without anemia, we found the following RRs for the type of anemia: nutritional (2.34, p < 0.0001), chronic renal disease (1.70, p < 0.0001), chronic inflammation (1.48, p < 0.0001), and unexplained (1.26, p < 0.01). Anemia is common although not severe in older non-institutionalized adults. When compared with non-anemic older adults, those with nutritional anemia or anemia due to chronic renal disease have the highest mortality risk.