Anemia independently predicted mortality in elderly

In people aged >85 years, anemia was associated with increased risk for death independent of comorbidity.

Prevalent anemia in people aged older than 85 years and incident anemia in the subsequent years were associated with an elevated risk for death, even after adjustment for comorbid conditions, according to the results of a study published in the Canadian Medical Association Journal.

Wendy P.J. den Elzen, MSc, and colleagues from Leiden University Medical Center, in the Netherlands, analyzed data from 562 participants from the Leiden 85-plus Study, a population-based, prospective, follow-up study of inhabitants of Leiden aged 85 years. Participants were followed for five years.

Associations between anemia and mortality and functional status, including disability in basic and instrumental activities of daily living, cognitive function and the presence of depressive symptoms, were measured.

Anemia was defined according to World Health Organization criteria: hemoglobin level <120 g/L for women and <130 g/L for men.

Anemia linked to mortality risk

At baseline, the prevalence of anemia was 26.7%. Participants with anemia had a higher risk for death than those without anemia (HR=1.71; 95% CI, 1.40-2.10). After adjustment for variables, including comorbid illnesses, those with anemia remained at higher risk (HR=1.41; 95% CI, 1.13-1.76).

Additionally, a dose-response relationship was observed between severity of anemia and mortality risk when participants were divided by mild, moderate or severe anemia, according to researchers.

There was no difference in functional decline between those with and without anemia; however, in adjusted analysis, anemia was linked to increased disability in basic activities, and instrumental activities of daily life.

During the follow-up period, incident anemia developed in 24.0% of participants who did not have anemia at baseline. In unadjusted (HR=2.16; 95% CI, 1.68-2.77) and adjusted analysis (HR=2.08; 95% CI, 1.60-2.70), participants who developed anemia had a twofold risk for mortality compared with those who did not develop anemia.

Incident anemia was associated with increased disability in basic activities of daily living (P<.01). In adjusted analysis, incident anemia remained a risk factor for increased disability in basic activities of daily living.

“For unexplained anemia in elderly patients, we may never be able to disentangle whether the underlying cause or the anemia is responsible for death,” Ora Paltiel, MSc, and A. Mark Clarfield, MD, wrote in an accompanying editorial.

Paltiel is an associate professor in the department of hematology and school of public health at Hadassah-Hebrew University, Jerusalem. Clarfield is a professor, faculty of health sciences at Ben-Gurion-University of the Negev, Israel.

“In their study, den Elzen and colleagues corrected for as many factors as possible, but the risk for residual confounding by underlying disease remains,” they wrote.

To determine the true and independent effect of the treatment of anemia on mortality and functional decline in the elderly population, randomized, controlled trials are necessary, according to the researchers.

Elzen PJ. CMAJ. 2009;doi:10.1503/cmaj.090040.

Paltiel O. CMAJ. 2009;doi:10.1503/cmaj.091199.