Pre-dialysis serum creatinine as an independent predictor of responsiveness to zinc supplementation among patients on hemodialysis

Background To investigate whether pre-dialysis level of serum creatinine (SCre) could indicate the responsiveness to zinc supplementation of patients on maintenance hemodialysis (MHD). Methods We retrospectively reviewed the results of our previous randomized study of 91 patients who had been on MHD and received zinc supplementation with either zinc acetate hydrate (ZAH; zinc, 50 mg/day) or polaprezinc (PPZ; zinc, 34 mg/day). A late response to zinc supplementation was defined as a serum zinc level of < 80 mu g/dL three months after the study began. Patients were divided into two groups: late response (serum zinc level < 80 mu g/dL) and early response (serum zinc level >= 80 mu g/dL). Factors independently associated with a late response to zinc supplementation were determined using inverse probability of treatment weighting (IPTW) multivariate logistic analysis. Results Of 91 patients, 86 continued to receive zinc supplementation after three months. The mean pre-dialysis SCre level was 10.0 mg/dL. The number of patients with a late response and response to zinc supplementation was 32 and 54, respectively. There was a significant negative correlation between the pre-dialysis SCre and the Delta serum zinc change for 3 months. (r = - 0.284,P = 0.008). IPTW multivariate analysis showed that a pre-dialysis SCre level >= 10.0 mg/dL (odds ratio, 3.71; 95% confidence interval; 1.24-11.1,P = 0.022) was an independent factor associated with a late response to zinc supplementation. Conclusions Pre-dialysis SCre level was independently associated with responsiveness to zinc supplementation after three months in patients on MHD.