Dietary Sodium Restriction in the Management of Chronic Kidney Disease: A Meta-Analysis of RCTs

Abstract

Introduction: Non-pharmacological strategies such as lowering sodium intake aim to protect renal function and delay the initiation of renal replacement therapy. It might also be a cost-effective method to improve Chronic Kidney Disease (CKD) prognosis. We decided to perform a meta-analysis of Randomized Controlled Trials (RCTs) to evaluate the effects of low versus high sodium intake in adults with CKD. Methodology: We searched the online databases – PUBMED, Cochrane Kidney and Transplant Specialized Register, Cochrane Library and Google Scholar to 31st December 2020 for RCTs to be included in the study. Meta- Analysis was performed for the intervention groups for each arm against the control. Inverse variance methods were applied for analysis using random effects models due to the high heterogeneity among the studies. Results: Our search strategy yielded seven studies from six countries with 465 participants. The overall effect on restricted sodium intake favored reduction in systolic blood pressure with an overall mean difference of -6.14(95% CI: -9.52, -2.76) and reduction in diastolic blood pressure with a mean difference of -3.08 (95% CI: -4.62, -1.55). There was lowering of estimated Glomerular Filtration Rate (eGFR), however the same was not statistically significant. Conclusion: The study found that restricted salt intake could significantly reduce systolic and diastolic BP. Further, multi-center RCTs for longer durations across different stages of CKD could effectively assess the effects of restricted sodium intake on vital parameters. Such study designs could also help clinicians identify the optimal intake of dietary sodium to achieve better renal and cardio vascular outcomes.