Unmasking anemia in the elderly: A systematic review of prevalence, causes, and consequences

Anemia is a prevalent condition in the elderly (aged ≥65 years), associated with increased morbidity, mortality, and reduced quality of life. Despite its impact, comprehensive data on its prevalence, etiology, and outcomes in this population are limited.

To synthesize evidence on the prevalence, etiology, and clinical outcomes of anemia in individuals aged 65 years and older, informing clinical practice and future research.

A systematic search was conducted across PubMed, Scopus, Web of Science, and Google Scholar (2004-2024), identifying 47 studies (observational, cohort, cross-sectional, and review). Inclusion criteria focused on anemia in the elderly, reporting prevalence, etiology, or outcomes. Quality was assessed using the Newcastle-Ottawa Scale and AMSTAR 2. Narrative synthesis, supported by biostatistical analyses (pooled prevalence, hazard ratios [HRs], odds ratios, 95% confidence intervals [CIs]), was performed, with heterogeneity assessed via I² statistics.

Anemia prevalence ranged from 10% to 50% (pooled prevalence 27.8%, 95% CI: 22.1-33.5, I² =92%), higher in hospitalized patients (37.4%, 95% CI: 29.8-45.0) than community-dwelling elderly (23.1%, 95% CI: 18.2-28.0). Iron deficiency anemia (27.5%, 95% CI: 21.3-33.7), anemia of chronic disease (20.1%, 95% CI: 15.6-24.6), and unexplained anemia (34.2%, 95% CI: 28.0-40.4) were predominant. Anemia increased all-cause mortality (pooled HR: 2.85, 95% CI: 2.10-3.87, I² =78%) and cardiovascular events (pooled HR: 3.12, 95% CI: 2.34-4.16, I² =65%).

Anemia in the elderly, particularly unexplained anemia, is a significant health burden, necessitating targeted diagnostic and therapeutic strategies.