Zinc supplementation as an adjunct to standard therapy in childhood nephrotic syndrome - a systematic review

AIM: To evaluate the role of zinc as add on treatment to the “recommended treatment” of nephrotic syndrome (NS) in children. METHODS: All the published literature through the major databases including Medline/Pubmed, Embase, and Google Scholar were searched till 31(st) December 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved papers concerning the role of zinc in childhood NS were reviewed by the authors, and the data were extracted using a standardized data collection tool. Randomized trials (RCTs) comparing zinc vs placebo was included. Effect of zinc was studied in both steroid sensitive and steroid dependent/frequent relapsing NS. The primary outcome measure was the risk of relapse in 12 mo. The secondary outcome measures were mean relapse rate per patient in 12 mo, mean relapse rate per patient in 6 mo, risk of infection associated relapse in 12 mo, cumulative dose of steroids in two groups, mean length of time to next relapse, adverse effects of therapy, and change in serum zinc levels. RESULTS: Of 54 citations retrieved, a total of 6 RCTs were included. Zinc was used at a dose of 10-20 mg/d, for the duration that varied from 6-12 mo. Compared to placebo, zinc reduced the frequency of relapses, induced sustained remission/no relapse, reduced the proportion of infection episodes associated with relapse with a mild adverse event in the form of metallic taste. The GRADE evidence generated was of “very low-quality”. CONCLUSION: Zinc may be a useful additive in the treatment of childhood NS. The evidence generated mostly was of “very low-quality”. We need more good quality RCTs in different country setting as well different subgroups of children before any firm recommendation can be made.