Altered dietary salt intake for people with chronic kidney disease
McMahon EJ
Published in Cochrane Database of Systematic Reviews
Methodology
Cochrane systematic review and meta-analysis; Cochrane Renal Group Specialised Register searched to 13 January 2015 for randomised trials comparing two or more levels of salt intake at any stage of chronic kidney disease; random-effects models with risk ratios for dichotomous and mean differences for continuous outcomes; duplicate independent eligibility and risk of bias assessment.
Key Findings
This Cochrane review pooled eight randomised trials with 258 people with chronic kidney disease comparing higher and lower salt intake over 1 to 26 weeks. Low salt intervention cut 24-hour sodium excretion by 105.86 mmol/day (95% CI -119.20 to -92.51) and lowered systolic blood pressure by 8.75 mmHg (95% CI -11.33 to -6.16) and diastolic by 3.70 mmHg (95% CI -5.09 to -2.30), with consistently reduced urinary protein. Salt restriction raised plasma renin activity by 1.08 ng/mL/h and serum aldosterone by 6.20 ng/dL, and allowed antihypertensive dose reduction, while eGFR, creatinine clearance, serum creatinine, body weight and total cholesterol were unchanged. No trial was long enough to test effects on death, cardiovascular events or progression to end-stage kidney disease.
Conclusions
Salt reduction lowered blood pressure and extracellular fluid volume, but trials were too short for hard outcomes.
Limitations
Trials lasted only 1 to 26 weeks with 258 participants in total, so hard endpoints could not be assessed; three trials had high risk of bias from baseline differences, two were industry funded and one had potential carryover from its crossover design.
Related Health Concerns
Study Details
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