PHOSPHATE REMOVAL BY PERITONEAL DIALYSIS: THE EFFECT OF TRANSPORTER STATUS AND PERITONEAL DIALYSIS PRESCRIPTION

{Background: Interventional trials failed to demonstrate that increasing urea clearance improved peritoneal dialysis (PD) patient survival. Hyperphosphatemia is a well-recognized predictor of cardiovascular and all-cause mortality in PD patients. Simplification of PD small solute clearance targets focuses away from larger solutes, including phosphate. In the US and UK, increasing use of automated peritoneal dialysis (APD) cyclers with shorter dwell times could also potentially reduce peritoneal phosphate removal compared to continuous ambulatory peritoneal dialysis (CAPD). Methods: Total phosphate and peritoneal phosphate clearances were measured in a prospective observational cohort of 380 adult PD patients attending a tertiary university hospital between 1996 and 2013 for routine assessment of PD adequacy. Results: Eighty-seven patients (22.9%) were hyperphosphatemic. Taking the mean 4-hour dialysate to plasma (D/P) ratio for phosphate, 193 (50.8%) were fast and fast-average transporters and 187 (49.2%) were slow and slow-average transporters (compared to 276 [72.6%] and 104 [27.4%], respectively, for peritoneal creatinine transporter status). Faster peritoneal phosphate transporter status was associated with over-hydration (odds ratio [OR] = 2.45 [1.43-4.20]