MO813: The Validity of Combined Urea and Phosphate Kinetic Modelling in Estimation of Daily Protein and Phosphate Intake in Haemodialysis Patients

Abstract

Abstract BACKGROUND AND AIMS The interpretation of patient dietary records, laboratory results in haemodialysis units to manage their phosphate and nutritional status is time and effort consuming and needs strictly compliant patients. This justifies the need of estimates of these parameters with accepted validity and applicability. METHOD In 100 haemodialysis patients [50 with residual kidney function (RKF) and 50 anuric patients], Daugirdas [1, 2] supposed urea and phosphate kinetic models’ estimates were extracted and correlated with the actual dietary records, phosphate binder dosage and dialysis prescription parameters. The estimates of interest were, daily ingested phosphorus (DIP), estimated phosphorus removed, intradialytic time averaged phosphate level, normalized protein catabolic ratio (nPCR) and dialysis estimated kt/v. RESULTS Modeled DIP is significantly correlated to calculated phosphate intake from average 3-day dietary records in both anuric and RKF patients (r = 0.89 and r = 91, respectively; P < .001). Also, the nPCR is significantly correlated with daily protein intake/kg in both study groups (r = 0.85 in anuric, r = 0.78 in RKF; P < .001). Estimated phosphorus removed is positively correlated to dialysis kt/v in both study groups (r = 0.51 in anuric, r = 0.52 in RKF; P < .001). Patients with RKF had significantly lower pre-dialysis serum phosphate (5.78 ± 1.05 versus 4.39 ± 0.78; P < .001), calcium-based phosphate binders’ dosage (2616.28 ± 390.93 mg/day versus 1937.5 ± 395.29 mg/day; P < .001), estimated phosphate removed in haemodialysis (1271.86 ± 274.5 mg/day versus 1016.82 ± 198.42 mg/day; P < .001) and intradialytic average phosphate levels (4.052 ± 0.87 mg/dL versus 3.26 ± 0.61 mg/dL; P < 0.001) than the anuric group. CONCLUSION Modeled DIP and nPCR can be used as estimates for phosphate and protein intake in haemodialysis patients with or without RKF. RKF has a positive impact on the phosphate measures and decreases the need for phosphate binders. For each patient is shown the mean result after CC treatment and after SO treatment. The red bold line represents mean values. (A) Bone turnover estimated from whole-body 18F-NaF PET/CT as Ki at lumbar vertebrae 1–5 in 20 participants. (B) Bone volume estimated as CT-derived HU at lumbar vertebrae 1–5 in 21 participants. * Significance level < 0.05.