The Impact of Selenium and Zinc Levels on Erythropoiesis-Stimulating Agent Response in Chronic Kidney Disease Patients: A Comparative Study of Predialysis, Hemodialysis, and Peritoneal Dialysis Patients.

Objectives: This study investigated serum selenium and zinc levels across three groups of chronic kidney disease patients and examined their associations with inflammation, nutrition parameters, and erythropoiesis-stimulating agent response.

Methods: This retrospective cross-sectional study included 298 patients (98 hemodialysis (HD), 92 peritoneal dialysis (PD), and 108 predialysis). We analyzed demographic data andlaboratory parameters, including selenium, zinc, hemoglobin, and erythropoietin resistance index (ERI). Multivariable linear regression analyses evaluated independent associations between trace elements and ERI while controlling for potential confounders.

Results: Selenium levels were significantly lower in PD patients compared to HD and predialysis patients, while zinc levels were highest in HD patients. In PD patients, selenium demonstrated a significant negative correlation with ERI (r = -0.32, P = .009), which remained significant in multivariable regression analysis (β = -0.13, P = .008) after adjusting for confounders. Partial correlation analysis revealed significant positive associations between urine output and selenium levels in PD (r_p = .29, P = .005) and predialysis patients (r_p = .21, P = .028). Albumin showed positive correlations with selenium across all groups.

Conclusions: Selenium and zinc levels vary significantly across patient groups. Selenium levels showed a significant independent negative correlation with ERI in PD patients, suggesting its potential involvement in erythropoiesis. The association between selenium and nutritional markers suggests that nutritional status plays a crucial role in maintaining adequate trace element levels. Residual renal function appears to significantly influence selenium levels, particularly in PD patients.