Abstract
Dietary sodium intake can increase risk of hypertension, a leading cause of kidney failure in individuals with chronic kidney disease. The objective of this systematic review was to examine the effect of sodium-specific medical nutrition therapy provided by a registered dietitian nutritionist or international equivalent on blood pressure and urinary sodium excretion in individuals with chronic kidney disease, stages 2 through 5, receiving maintenance dialysis and posttransplant. Medline, the Cumulative Index to Nursing and Allied Health Literature, Cochrane Cochrane Central Register of Controlled Trials, and other databases were searched to identify eligible controlled trials published in the English language from January 2000 until June 2020 that addressed the research question. Risk of bias was assessed using the RoB 2.0 tool and quality of evidence was examined by outcome using the Grading of Recommendations Assessment, Development, and Evaluation method. Of the 5,642 articles identified, eight studies were included in the final analyses. Six studies targeted clients who were not dialyzed, including one with clients who were posttransplantation, and two studies with clients receiving maintenance hemodialysis. Sodium-specific medical nutrition therapy from a registered dietitian nutritionist significantly reduced clinic systolic blood pressure (mean difference –6.7, 95% CI –11.0 to –2.4 mm Hg; I2 = 51%) and diastolic blood pressure (mean difference –4.8, 95% CI, –7.1 to –2.4 mm Hg; I2 = 23%) as well as urinary sodium excretion (mean difference –67.6, 95% CI –91.6 to –43.6 mmol/day; I2 = 84.1%). Efficacy was limited to individuals who were not dialyzed, including posttransplantation, but the intervention did not significantly improve blood pressure in individuals receiving maintenance hemodialysis. Adults with chronic kidney disease should begin to work with registered dietitian nutritionist early in the course of disease to receive individualized, effective counseling to improve risk factors and, ultimately, health outcomes.