Background: Low sodium intake is recommended for all patients with chronic kidney disease (CKD) by national and international guidelines. However, there has been no randomized controlled trial evaluating whether low sodium intake (<2.3g/day), compared to moderate intake (2.3-4.6g/day), is associated with renal benefits. Limited observational evidence suggests that low intake is not associated with a slower rate of progression of renal impairment than moderate intake, but studies are few, relatively small and not definitive. Recent evidence has raised major questions about whether low sodium intake is cardioprotective and suggests a J-shaped association with lowest cardiovascular risk at moderate intake. Low sodium intake is difficult to achieve and may have knock-on adverse effects on other important renal factors (activation of RAAS). Objective: In normotensive patients with CKD and moderate (average) sodium intake (2.3-4.6g/day), we propose to evaluate the effect of targeting low sodium intake (<2.3g/day), compared to moderate intake on renal outomes, over a mean of 2.5 years follow-up. Methods: Trial Design: Randomised-controlled, parallel, open-label, Phase IIb single-centre trial of 224 patients. Population and Recruitment: Patients with established, moderate CKD (eGFR 30-60ml/min/1.73m2 on ≥2 occasions three months apart) and baseline moderate sodium intake. Intervention: Participants with moderate sodium intake will be randomised to usual care or usual care plus a multi-component educational intervention to reduce sodium intake to <2.3g/day. Usual care includes dietary education on all other relevant dietary factors. Primary Outcome: Mean change in 24-hour creatinine clearance during follow-up. Secondary outcomes include change in proteinuria, eGFR and 24-hour blood pressure. Statistical Analyses: Intention-to-treat analysis using a two-sample repeated measures ANOVA. Clinical Importance: Our trial will determine whether low sodium diet slows progression of renal dysfunction in patients with CKD, and will provide information to guide future Phase III clinical trials with important implications for the management of CKD.
