Serum Nickel Concentrations in Patients Receiving Chronic Hemodialysis

INTRODUCTION: Chronic nickel accumulation is harmful to multiple organ systems, and nickel is classified as a human carcinogen. Nevertheless, few studies have examined serum nickel concentrations in end-stage kidney disease (ESKD) patients receiving chronic hemodialysis, and the relationship of serum nickel with clinical outcomes remains unclear. METHODS: This prospective observational study recruited 409 hemodialysis patients in 2019 and followed them for 18 months. The patients were stratified into four quartiles, that is, < 2.9 μg/L (n = 92), 2.9 μg/L to < 3.4 g/L (n = 104), 3.4 μg/L to < 3.9 μg/L (n = 104), and ≥ 3.9 μg/L (n = 109), according to their serum nickel concentrations. Baseline demographic, hematologic, biochemical, dialysis-related, and mortality data were obtained for analysis. FINDINGS: The mean age of the patients was 62.9 ± 11.7 years. A total of 401 (98.04%) patients had elevated serum nickel concentrations, with an average level of 3.6 ± 1.3 μg/L. Higher quartiles of serum nickel were associated with longer dialysis vintage (p < 0.001), higher Kt/V values (p < 0.001), and higher urea removal rates (p < 0.001). Multivariate analysis identified albumin level and dialysis vintage as independent factors positively correlated with serum nickel concentrations (R = 0.163, p = 0.001; R = 0.212, p < 0.001, respectively). Nevertheless, no association was found between serum nickel levels and all-cause mortality. CONCLUSION: ESKD patients on hemodialysis commonly exhibit elevated serum nickel concentrations, possibly linked to serum albumin levels and dialysis vintage. Further studies are warranted.