The effects of zinc sulfate supplementation on serum copeptin, c-reactive protein and metabolic markers in zinc-deficient diabetic patients on hemodialysis: a randomized, double-blind, placebo-controlled trial

We aimed to investigate the association between zinc (Zn) supplementation and serum levels of copeptin, high-sensitive C-reactive protein (hs-CRP), glycemic control, anthropometric parameters and renal function in Zn -deficient diabetic hemodialysis patients (DHPs). This randomized, double-blind, placebo-controlled trial (RCT) was conducted on 46 DHPs with Zn-deficiency. The Zn supplement group (n = 21) received a 220-mg/day Zn sulfate capsule (containing 50 mg Zn), and the control group (n = 25) received a placebo capsule (220 mg corn starch), for 8 weeks. Fasting, predialysis blood samples were taken at baseline and after 8 weeks to assess fasting blood glucose (FBG), serum insulin, copeptin, high-sensitive C-reactive protein (hs-CRP), blood urea nitrogen (BUN), creatinine (Cr) concentrations, and homoeostatic model assessment (HOMA-IR) and quantitative insulin-sensitivity check index (QUICKI). Compared to controls, serum copeptin (P < 0.001), hs-CRP (P < 0.001), BUN (P < 0.001), Cr (P < 0.001), Zn (P < 0.001), FBG (P < 0.001) levels, BMI (P < 0.001), and body weight (P < 0.001) were significantly affected following ZnSO4 supplementation for 8 weeks. In contrast, QUICKI (P = 0.57), HOMA-IR (P = 0.60), and serum insulin (P = 0.55) were not affected following Zn supplementation in comparison with patients receiving placebo. Zn sulfate supplementation appears to have favorable effects on serum copeptin and hs-CRP, FBG, and renal function in Zn-deficient DHPs. Iranian Registry of Clinical Trials Identifier: IRCT20190806044461N1