Effects of Dietary Sodium Restriction in Kidney Transplant Recipients Treated With Renin-Angiotensin-Aldosterone System Blockade: A Randomized Clinical Trial

Background In patients with chronic kidney disease receiving renin-angiotensin-aldosterone system (RAAS) blockade, dietary sodium restriction is an often-used treatment strategy to reduce blood pressure (BP) and albuminuria. Whether these effects extend to kidney transplant recipients is unknown. We therefore studied the effects of dietary sodium restriction on BP and urinary albumin excretion (UAE) in kidney transplant recipients receiving RAAS blockade. Study Design Two-center randomized crossover trial. Setting & Participants Stable outpatient kidney transplant recipients with creatinine clearance > 30mL/min, BP ≥120/80mmHg, receiving stable RAAS blockade therapy. Intervention 6-week regular-sodium diet (target, 150mmol/24 h) and a 6-week low-sodium diet (target, 50mmol/24 h). Outcomes & Measurements Main outcome parameters were systolic and diastolic BP, UAE, and estimated glomerular filtration rate (eGFR) at the end of each diet period. Dietary adherence was assessed by 24-hour urinary sodium excretion. Results We randomly assigned 23 kidney transplant recipients, of whom 22 (mean age, 58±8 [SD] years; 50% men; mean eGFR, 51±21mL/min/1.73m 2 ) completed the study. One patient withdrew from the study because of concerns regarding orthostatic hypotension on the low-sodium diet. Sodium excretion decreased from 164±50mmol/24 h during the regular-sodium diet to 87±55mmol/24 h during the low-sodium diet (mean difference, −77 [95% CI, −110 to −44] mmol/24 h; P P P P =0.9) or eGFR. Limitations No hard end points; small study; small proportion of patients willing to test the intervention; adherence to sodium diet was achieved in 86% of patients. Conclusions In stable kidney transplant recipients receiving RAAS blockade, dietary sodium restriction effectively reduces BP without affecting eGFR. Dietary sodium restriction is relevant to BP management in kidney transplant recipients receiving RAAS blockade.