The effect of dietary salt on blood pressure in individuals receiving chronic dialysis: a systematic review and meta-analysis of randomised controlled trials

Dietary salt reduction in the general population lowers blood pressure and cardiovascular risk. Despite being widely recommended, there is limited evidence as to whether this is applicable to individuals with end-stage renal disease (ESRD) receiving dialysis. Therefore, we carried out a systematic review and meta-analysis of randomised controlled trials (RCTs) investigating dietary salt reduction in individuals receiving dialysis. Studies were identified through search strategies for CENTRAL, MEDLINE, and EMBASE. Two authors independently assessed studies for eligibility with the inclusion criteria as follows: participants aged 18 years and over; a reduction in salt intake of at least 1 g/day over one week; no concomitant interventions during the study. The primary outcome was change in systolic and diastolic blood pressure. 848 reports were screened, from which 12 studies were selected for the systematic review. Four were RCTs (91 participants) that met the study inclusion criteria: three were conducted in haemodialysis patients and one in peritoneal dialysis patients; three were crossover trials and one was a parallel study. Dietary salt reduction was associated with an 8.4 mmHg reduction in systolic blood pressure (95% CI 4.8–12.0, Ι2 = 0%), and a 4.4 mmHg reduction in diastolic blood pressure (95% CI 2.2–6.6, Ι2 = 0%). In conclusion, few studies have investigated the role of dietary salt reduction in individuals with ESRD receiving dialysis, but these results suggest the importance of this intervention for lowering blood pressure in this group.