Clinical Characteristics and Management of Anemia in Nonagenarians: A Retrospective Cohort Study

Introduction The global increase in the older adult population has been accompanied by a rising prevalence of anemia, which is a condition linked to various negative health outcomes. This study assessed anemia in hospitalized patients aged 90 and older, aiming to assess its age-related characteristics. Methods This retrospective cohort study was conducted at a chronic-phase care hospital, focusing on patients aged 90 years or older who were hospitalized in November 2024. Patients with active cancer, autoimmune diseases, hematological disorders, or iron deficiency anemia were excluded. Data related to age, sex, hemoglobin, estimated glomerular filtration rate (eGFR), and albumin levels were extracted from routine blood test results of the target patient population. Based on these results, a statistical analysis of the factors affecting anemia was conducted. Results Pearson's correlation analyses revealed that age and eGFR were not significantly correlated with hemoglobin. In contrast, serum albumin exhibited a significant positive correlation with serum hemoglobin (r = 0.329, 95%CI: 0.116 to 0.513, p = 0.003). In the multiple linear regression analysis, serum albumin remained a significant independent predictor of serum hemoglobin after adjusting for other variables (β = 1.3, 95%CI 0.56 to 2.1, p < 0.001). Our results also indicated that many cases exhibited no evidence of anemia despite a significant reduction in eGFR. Conversely, anemic cases presumably attributable to decreased erythropoietin production were observed even among patients with high eGFR values. Conclusions Anemia in the older adult population is primarily related to inflammation and malnutrition, with additional contributions from age-related changes in individual organs such as the kidneys and bone marrow. In the management of geriatric anemia, it is essential to consider organ-specific aging processes associated with underlying inflammatory conditions, with particular attention to impaired erythropoietin production that occurs independently of eGFR decline.