Effect of a low-salt diet on chronic kidney disease outcomes: a systematic review and meta-analysis.
Study Goal
The researchers aimed to determine the effects of a low-salt diet on renal and cardiovascular outcomes in patients with chronic kidney disease (CKD).
Results Summary
A low-salt diet reduced renal composite outcome events by 28% but showed no significant effects on proteinuria, eGFR decline rate, all-cause mortality, or cardiovascular events.
Population
Patients with chronic kidney disease (CKD).
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
a low-salt diet | decrease | renal composite outcome events | patients with CKD | 28% | produced a 28% reduction | #1 |
a low-salt diet | no change | changes in proteinuria | patients with CKD | no significant change | No significant effects were found | #2 |
a low-salt diet | no change | rate of eGFR decline | patients with CKD | no significant change | No significant effects were found | #3 |
a low-salt diet | no change | risk of all-cause mortality | patients with CKD | no significant change | No significant effects were found | #4 |
a low-salt diet | no change | CV events | patients with CKD | no significant change | No significant effects were found | #5 |
OBJECTIVE: The benefits of a low-salt diet for patients with chronic kidney disease (CKD) are controversial. We conducted a systematic review and meta-analysis of the effect of a low-salt diet on major clinical outcomes. DESIGN: Systematic review and meta-analysis. DATA SOURCES: MEDLINE by Ovid, EMBASE and the Cochrane Library databases. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We included randomised controlled trials (RCTs) and cohort studies that assessed the effect of a low-salt diet on the renal composite outcomes (more than 50% 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. DATA EXTRACTION AND SYNTHESIS: Two independent researchers extracted data and evaluated their quality. Relative risks (RRs) with 95% CIs were used for dichotomous data. Differences in means (MDs) or standardised mean differences (SMDs) with 95% CIs were used to pool continuous data. We used the Cochrane Collaboration risk-of-bias tool to evaluate the quality of RCTs, and Newcastle-Ottawa Scale to evaluate the quality of cohort studies. RESULTS: We found 9948 potential research records. After removing duplicates, we reviewed the titles and abstracts, and screened the full text of 230 publications. Thirty-three studies with 101 077 participants were included. A low-salt diet produced a 28% reduction in renal composite outcome events (RR: 0.72; 95% CI: 0.58 to 0.89). No significant effects were found in terms of changes in proteinuria (SMD: -0.71; 95% CI: -1.66 to 0.24), rate of eGFR (decline MD: 1.16; 95% CI: -2.02 to 4.33), risk of all-cause mortality (RR: 0.92; 95% CI: 0.58 to 1.46) and CV events (RR: 1.01; 95% CI: 0.46 to 2.22). CONCLUSION: A low-salt diet seems to reduce the risk for renal composite outcome events in patients with CKD. However, no compelling evidence indicated that such a diet would reduce the eGFR decline rate, proteinuria, incidence of all-cause mortality and CV events. Further, more definitive studies are needed. PROSPERO REGISTRATION NUMBER: CRD42017072395.