Sarmento-Dias M, Santos-Araújo C, Poínhos R, Oliveira B, Sousa M, Simões Silva L, Soares Silva L, Correia F and Pestana M
Aim: Increased FGF23 blood levels were found intact and biologically active in peritoneal dialysis (PD) patients. We aimed to evaluate in PD patients the associations between regulators of phosphate (Pi) metabolism including FGF23 and peritoneal daily Pi removal (PDPiR).
Methods: Sixty-four adult patients (male 56%, mean age 48 ± 13 years, median time on PD 3.4 months) were evaluated in a cross-sectional study (ST1). Daily Pi intake was assessed by food frequency questionnaire. Intact FGF23 blood levels were evaluated by ELISA (Immutopics, Inc., San Clemente, CA). The first 33 patients who completed 1 year after the first evaluation were re-evaluated. (longitudinal study, ST2).
Results: In ST1, both circulating FGF23 and Pi serum levels were associated with PDPiR (β=0.533, p=0.002 and β=0.342, p=0.045, respectively) independent of iPTH, dietary Pi intake, renal daily Pi removal, dialysate/plasma creatinine concentration ratio (D/P Cr), residual renal function (RRF), ultrafiltration volume, dwell volume, number of exchanges and dialysis vintage. In ST2, the increase in PDPiR was only correlated with the increase in FGF23 (β=0.480, p=0.012) independently of changes in serum Pi, RRF, renal daily Pi removal and D/P Cr.
Conclusions: Differences in circulating FGF23 and Pi serum levels contribute both independently to heterogeneity of PDPiR in PD patients
