ABSTRACT
Introduction: Frequent relapses and steroid dependence are common treatment challenges of steroid-sensitive nephrotic syndrome (SSNS) in children. Acute respiratory infection (ARI) is the most frequently reported trigger of relapse. Given the role of zinc supplementation in preventing ARI, some studies show that this targeted intervention may reduce relapses in childhood SSNS. Aim: This systematic review aimed to determine if oral zinc supplementation can significantly reduce relapses in this disease. Methods: We searched the PubMed and Google Scholar electronic databases for interventional and observational analytical studies without limiting their year or language of publication. We selected studies with primary data that met our inclusion criteria, screened their titles and abstracts, and removed duplicates. We used a preconceived structured form to extract data items from selected studies and conducted a quality assessment of randomized controlled trials (RCTs) and non-randomized studies with the Cochrane collaboration tool and the Newcastle Ottawa Scale, respectively. We qualitatively synthesized the extracted data to validate the review's objective. Results: Eight full-text articles were selected, comprising four RCTs and four observational analytical studies. Two of the RCTs had a high risk of bias in three parameters of the Cochrane collaboration tool, while three non-randomized studies had low methodological quality. A total of 621 pediatric patients with SSNS were investigated in the eight studies: six participants dropped out in one study. Three RCTs indicate that zinc supplementation may lead to sustained remission or reduction in relapse rate. Similarly, three observational analytical studies suggest a significant relationship between reduced serum zinc levels and disease severity. Conclusion: Despite the association of zinc deficiency with increased morbidity in SSNS and the reduction of relapse rates with zinc supplementation, there is no robust evidence to recommend its use as a therapeutic adjunct. We recommend more adequately-powered RCTs to strengthen the current evidence.
ABSTRACT
BACKGROUND: Some studies have reported the possible role of vitamin D3 in ameliorating disease outcomes in childhood infectious diarrhea. However, findings about its effectiveness and the association of serum vitamin D levels with diarrhea risk appear inconsistent. We aimed to determine the efficacy of oral vitamin D3 as an adjunct in managing childhood infectious diarrhea and the relationship between vitamin D status and the disease. METHODS: We searched the PubMed and Google Scholar electronic databases for relevant articles without limiting their year of publication. We selected primary studies that met the review's inclusion criteria, screened their titles and abstracts, and removed duplicates. We extracted data items from selected studies using a structured data-extraction form. We conducted a quality assessment of randomized controlled trials (RCTs) and non-randomized studies with the Cochrane collaboration tool and the Newcastle Ottawa Scale, respectively. We assessed the strength of the relationship between serum vitamin D levels and diarrhea using the correlation model. We estimated the I2 and tau2 values to assess between-study heterogeneity. RESULTS: Nine full-text articles were selected, consisting of one RCT, three cross-sectional studies, two cohort studies, two longitudinal/prospective studies, and one case-control study. A total of 5,545 participants were evaluated in the nine studies. Six non-randomized studies provided weak evidence of the relationship between vitamin D levels and diarrhea risk as there was no correlation between the two variables. The only RCT failed to demonstrate any beneficial role of vitamin D3 in reducing the risk of recurrent diarrhea. The calculated I2 and tau2 values of 86.5% and 0.03, respectively suggested a high between-study heterogeneity which precluded a meta-analysis of study results. CONCLUSION: Oral vitamin D3 may not be an effective adjunct in managing childhood infectious diarrhea. Additionally, the relationship between vitamin D status and infectious diarrhea appears weak. We recommend more adequately-powered RCTs to determine the effectiveness of vitamin D3 as an adjunct therapy in infectious diarrhea.
