Low-salt diet cuts risk of adverse renal outcomes in chronic kidney disease

A low-salt diet appears to be beneficial to patients with chronic kidney disease (CKD), with a study showing that the diet helps reduce the incidence of renal composite outcome events.

Researchers performed a systematic review and meta-analysis of studies that evaluated the effect of a low-salt diet on the renal composite outcomes (more than 50 percent decline in estimated glomerular filtration rate [eGFR] during follow-up, doubling of serum creatinine, or end-stage renal disease), rate of eGFR decline, change in proteinuria, all-cause mortality events, cardiovascular (CV) events, and changes in systolic blood pressure and diastolic blood pressure.

A total of 33 studies (13 randomized controlled trials and 19 cohort studies) with 101,077 participants (average age 56 years, 60 percent male) were included in the meta-analysis. The median follow-up was 6 months, and the average eGFR of the participants was 47.45 mL/min/1.73 m². Twelve studies involved a usual care or usual diet control, while 21 studies compared different levels of sodium intake.

Pooled data showed that a low-salt diet conferred a 28-percent reduction in renal composite outcome events (relative risk [RR], 0.72, 95 percent confidence interval [CI], 0.58–0.89).

However, the diet produced no marked improvement in other outcomes, including proteinuria (standardized mean difference [SMD], −0.71, 95 percent CI, −1.66 to 0.24), rate of eGFR (decline mean difference, 1.16, 95 percent CI, −2.02 to 4.33), all-cause mortality (RR, 0.92, 95 percent CI, 0.58–1.46), and CV events (RR, 1.01, 95 percent CI, 0.46–2.22).

More trials targeting patients with different CKD stages are needed to establish the optimal dietary salt intake for different CKD stages.