Abstract P121: Meta-analysis of the Randomized Controlled Trials of Sodium Intake Reduction and Urinary Albumin Excretion

Abstract

Background: Urinary albumin excretion (UAE) is a predictor of chronic kidney disease and of higher cardiovascular morbidity and mortality. A number of studies investigated the effect of reduced dietary sodium intake on UAE but their results were not consistent. Therefore, our study assessed the effect of sodium restriction on UAE and/or on albumin/creatinine ratio (ACR) through an updated meta-analysis of the available randomised controlled trials (RCT). Methods: A systematic search of the on-line databases was conducted including RCTs that assessed UAE/ACR at the start and the end of the trial and outcomes expressed as difference between the effect of two different sodium intake regimens. For each study, the mean difference (MD) and 95% confidence intervals (95%CI) were extracted and pooled using a random effect model. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed. Results: Nine studies were identified, providing 21 cohorts with overall 454 participants and 1-6 weeks follow-up time. In the pooled analysis, lower sodium intake was associated with a 26.7% (95% CI: -40.7 to -12.6) reduction of UAE, with no evidence of publication bias.The effect of lower sodium intake was highest in the cohorts including patients on concomitant RAAS-blocking therapy (-37.7%; -56.5 to -19.9), in those with intervention lasting at least 2 weeks (-32.4%; -47.2 to -17.7), and among participants with evidence of kidney damage (-32.6%; -47.5 to -17.6). The changes in BP occurring during intervention were a significant source of heterogeneity. >The analysis of changes in ACR, where available, provided similar results. Conclusions: This meta-analysis indicated that sodium intake reduction markedly reduces albumin excretion, more so among patients with hypertension and/or kidney damage and during concomitant RAAS-blocking therapy.