Iron Deficiency Is a Common Cause of Anemia in Elderly Outpatients, However Iron Repletion Frequently Does Not Fully Correct the Anemia.
Authors: Price Elizabeth A , Mehra Renee , Schrier Stanley L. 
Published: October 2019

Abstract
Abstract 5080

BACKGROUND
Anemia in the elderly is common, and associated with substantial morbidity and even mortality. Approximately one third of patients with anemia will have no discernable etiology for their anemia, that is, so-called unexplained or idiopathic anemia of aging. Prior reports have suggested that 5-15% of elderly patients with anemia will have an underlying myelodysplastic syndrome (MDS). The purpose of this study was to prospectively evaluate a cohort of elderly outpatients for underlying causes of anemia.

METHODS
Men and women 65 years and older with anemia as defined by World Health Organization (WHO) criteria and seen either at Stanford Hospital and Clinics (SHC) or VA Palo Alto Health Care Systems (VAPAHCS) underwent a comprehensive hematologic evaluation to determine the etiology of the anemia. Assessment included a complete blood count, red cell indices, review of the peripheral smear, and evaluation of iron and cobalamin status and renal function. Patients were categorized as having MDS if diagnosed by WHO criteria. If a bone marrow evaluation was not performed or was nondiagnostic, patients were categorized as “suspicious for MDS” if the MCV was > 100 fl without an alternate explanation, the platelet count was < 130 K/αL, the WBC was < 4 K/αL, or there was dysplasia on the peripheral smear. If no etiology was found, patients were categorized as having “unexplained anemia” of aging.

RESULTS
A total of 196 patients have enrolled, and 156 have completed their diagnostic evaluation to date. Of these 156, 52 (33%) had unexplained anemia, 33 (21%) were found to have anemia related to a definite or suspected underlying hematologic malignancy, 24 (15%) had anemia related to a nonhematologic malignancy, 20 (13%) had previously unrecognized iron deficiency anemia, and 8 (5%) had anemia due to renal insufficiency. Additional etiologies included anemia of chronic inflammation (5 patients), thalassemia (2 patients), alcohol abuse (1 patient), B12 deficiency (1 patient), hypogonadism (1 patient), other (2 patients). In 7 patients (4%) the evaluation was not complete. Of those categorized with anemia related to an underlying hematologic malignancy, 12 of 33 (36%) were given a formal diagnosis, including acute myeloid leukemia, chronic myelomonocytic leukemia, Waldenstrom's, and, in 8 patients, MDS. An additional 21 of 33 (64%) were categorized as being “suspicious for MDS”. One patient initially categorized as being “suspicious for MDS” developed worsening cytopenias and underwent bone marrow evaluation which confirmed the diagnosis of MDS. Those suspected but not confirmed to have MDS had a median WBC of 4.9 K/αL, median hemoglobin (hgb) of 10.8 g/dL, median platelets of 170 K/αL, median mean corpuscular volume (MCV) of 96 fL, and median red cell distribution width (RDW) of 14%. In comparison, those confirmed to have MDS had a similar median WBC of 5.3 K/αL, lower median hgb of 10.3 g/dL, similar median platelet count of 199 K/αL, higher median MCV of 106.3 fL,and broader median RDW of 17%. Of the 20 patients with iron deficiency anemia, the diagnosis was made by standard laboratory iron indices in 14 (70%), by response to iron supplementation in 3 (15%), and by bone marrow aspirate and clinical diagnosis, respectively, in 1 patient (5%) each. Six of the 20 (30%) patients normalized their hgb following iron repletion, 5(25%) increased the hgb by at least one g/dL but did not reach a normal hgb level, and in 9 (45%) this information was not available.

DISCUSSION
In our study of elderly community-dwelling patients referred to an outpatient hematology clinic, 8% of patients were formally diagnosed with an underlying hematologic malignancy, and 13% were suspected to have MDS based on a high MCV, dysplasia on the peripheral smear, or additional cytopenias. Thus, overall, 21% were likely to have an underlying hematologic malignancy. Of the patients suspected to have MDS, none required specific therapy. Thirteen percent of patients were diagnosed with iron deficiency anemia, primarily by iron indices. A high proportion (25%) of these patients did not normalize their hemoglobin with iron repletion, suggesting additional underlying disease processes. The clinical advantage of recognizing that iron deficiency has been corrected is that further potentially expensive and invasive evaluation such as additional endoscopy can be avoided.

Disclosures
Price: NIH: Research Funding. Mehra:NIH: Research Funding. Schrier:NIH: Research Funding.