Prevalence of Antierythropoietin Antibodies in Patients with Stage 5 CKD Undergoing Hemodialysis

Background: Anemia is a common and clinically significant complication of chronic kidney disease (CKD), often managed with erythropoiesis-stimulating agents (ESAs). However, the development of anti-erythropoietin (anti-EPO) antibodies may impair therapeutic efficacy and contribute to treatment resistance. Methods: A descriptive observational study was conducted involving 80 patients with stage 5 CKD on maintenance hemodialysis at a tertiary hospital in Jalisco, Mexico, from January 2024 to December 2025. All participants had received ESA therapy for at least one month. Anti-EPO antibodies were measured using a sandwich ELISA. Results: The prevalence of anti-EPO antibodies was 50%. Among antibody-positive patients, 27.5% had low titers (1.48–5.95 ng/mL), and 72.5% had moderate to high titers (>5.95 ng/mL). Antibody-positive patients were significantly older (p = 0.02), exhibited a higher prevalence of secondary hyperparathyroidism (p = 0.001), and had elevated serum calcium levels (p = 0.01). No significant associations were found between antibody titers and hemoglobin, ferritin, transferrin saturation, or ESA dose. However, trends suggested that longer dialysis duration and higher ferritin levels might be related to increased immunogenicity. Conclusion: A high prevalence of anti-EPO antibodies was observed in this cohort of hemodialysis patients, with significant associations to age, mineral-bone disorder parameters, and ESA exposure. These findings underscore the need for routine immunological monitoring in ESA-treated CKD patients and warrant further investigation into the clinical impact of anti-EPO antibodies on anemia management and patient outcomes.