Low-Sodium Versus Standard-Sodium Peritoneal Dialysis Solution in Hypertensive Patients: A Randomized Controlled Trial

Background: Peritoneal dialysis (PD) solutions with reduced sodium content may have advantages for hypertensive patients; however, they have lower osmolarity and solvent drag, so the achieved Kt/V-urea may be lower. Furthermore, the increased transperitoneal membrane sodium gradient can influence sodium balance with consequences for blood pressure (BP) control.

Study Design: Prospective, randomized, double-blind clinical trial to prove the noninferiority of total weekly Kt/V-urea with low-sodium versus standard-sodium PD solution, with the lower confidence limit above the clinically accepted difference of 0.5. Setting & Participants: Hypertensive patients (1 antihypertensive drug, including diuretics, or office systolic BP 130 mm Hg) on continuous ambulatory PD therapy from 17 sites.

Intervention: 108 patients were randomly assigned (1:1) to 6-month treatments with either low-sodium (125 mmol/L of sodium; 1.5%, 2.3%, or 4.25% glucose; osmolarity, 338-491 mOsm/L) or standard-sodium (134 mmol/L of sodium; 1.5%, 2.3%, or 4.25% glucose; osmolarity, 356-509 mOsm/L) PD solution.

Outcomes: Primary end point: weekly total KtNurea; secondary outcomes: BP control, safety, and tolerability. Measurements: Total KtNurea was determined from 24-hour dialysate and urine collection; BP, by office measurement.

Results: Total Kt/Vurea after 12 weeks was 2.53 +/- 0.89 in the low -sodium group (n = 40) and 2.97 +/- 1.58 in the control group (n = 42). The noninferiority of total KtNurea could not be confirmed. There was no difference for peritoneal KtNurea (1.70 +/- 0.38 with low sodium, 1.77 +/- 0.44 with standard sodium), but there was a difference in renal KtNurea (0.83 +/- 0.80 with low sodium, 1.20 +/- 1.54 with standard sodium). Mean daily sodium removal with dialysate at week 12 was 1.188 g higher in the low-sodium group (P <0.001). BP changed marginally with standard -sodium solution, but decreased with low-sodium PD solution, resulting in less antihypertensive medication.

Limitations: Broader variability of study population than anticipated, particularly regarding residual kidney function.

Conclusions: The noninferiority of the low -sodium PD solution for total Kt/Vurea could not be proved; however, it showed beneficial clinical effects on sodium removal and BP. Am J Kidney Dis. 67(5):753-761. 2016 Fresenius Medical Care. Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgIlicenses/by-nc-nd14.01).