Anaemia Among Elderly Inpatients: Clinicopathological Spectrum and Characteristics of Unexplained Anaemia

Background: Anaemia in older adults is common, clinically important, and often multifactorial. A proportion of patients remain without an identifiable cause despite evaluation and are classified as having unexplained anaemia. Objective: To describe the clinico-haematological profile, morphological patterns, aetiological spectrum, and diagnostic implications of anaemia in elderly hospitalised patients, with special emphasis on unexplained anaemia. Methods: This hospital-based observational study included 367 elderly inpatients (≥60 years) with anaemia at a tertiary care teaching hospital in South Gujarat. Clinical findings, complete blood count, peripheral smear, reticulocyte count, iron studies, vitamin B12 and folate levels, renal and liver function tests, and other relevant investigations were reviewed. Unexplained anaemia was diagnosed after exclusion of identifiable causes. Results: The mean age was 68.48 ± 7.46 years and 59.9% were male. Moderate anaemia was most common (54.2%). Normocytic normochromic morphology predominated (40.33%). Iron deficiency anaemia was the leading identifiable cause (17.98%), followed by anaemia of chronic disease (13.35%), unexplained anaemia (12.81%), and vitamin B12 deficiency (12.53%). Among unexplained cases, 40.43% were aged ≥80 years, 82.98% showed normocytic morphology, and 76.60% had reticulocyte counts of 1–2%. Conclusion: Anaemia in elderly inpatients is heterogeneous and frequently multifactorial. Unexplained anaemia accounted for 12.81% of cases and was characterised by advanced age, normocytic morphology, and limited reticulocyte response, highlighting the need for structured evaluation and follow-up.