A Multinational Clinical Validation Study of Pd Adequest 2.0

Abstract

Objective To clinically validate the use of the newly released kinetic modeling program, PD ADEQUEST 2.0 for Windows (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.), by assessing the level of agreement between measured and modeled values of urea and creatinine clearances (CCr), glucose absorption, total drain volumes, and net ultrafiltration for all forms of peritoneal dialysis. Design A nonrandomized, multinational, prospective longitudinal study. Patients The study involved 104 adult patients [41 on continuous ambulatory peritoneal dialysis (CAPD), 63 on automated peritoneal dialysis (APD)] from 16 centers in 7 countries. All patients underwent a 4-hour peritoneal equilibration test (PET) but with varying percentage dextrose concentrations (1.5% or 2.5% dextrose) and varying fill volumes (range 1.5 – 2.5 L). Patients with a residual renal function greater than 10 mL/min were excluded, as were patients who had peritonitis within 6 weeks prior to baseline. Main Outcome Measures Correlation coefficients and Bland–Altman limits of agreement were used to assess the level of agreement between measured and modeled values of weekly peritoneal urea Kt/V (pKt/V) and total Kt/V, weekly peritoneal creatinine clearance (pCCr, L/week/ 1.73 m2) and total CCr (L/week/1.73 m2), daily drain volume (L/day), net ultrafiltration (UF, L/day), daily peritoneal urea and creatinine mass removal (g/day), and daily peritoneal glucose absorption (g/day). Measured values were obtained from three repeat 24-hour urine and dialysate collections per patient, while modeled values were calculated using the Baxter PD ADEQUEST 2.0 program in conjunction with kinetic parameters estimated from a 4-hour PET and long-dwell exchange independent of the 24-hour collections. Results The results show there is excellent agreement between measured and modeled urea Kt/V and CCr with concordance correlation coefficients ranging from 0.83 to 0.97 among CAPD and APD patients. There was also excellent agreement between measured and modeled values of glucose absorption and total drain volumes (concordance correlations of 0.90 and 0.98, respectively). This level of agreement was further supported by a Bland– Altman analysis of individual differences, including differences between measured and modeled net UF (coefficient of clinical agreement ranged from 0.66 to 0.92). Conclusions Data from a carefully performed PET and overnight exchange can, in combination with a scientifically and clinically validated kinetic model, provide clinicians with a powerful mathematical tool for use in CAPD and APD prescription management. Although not intended to replace actual measurements, kinetic modeling can prove useful as a means for quickly estimating approximate levels of clearance for a wide variety of alternative prescriptions. This, in turn, should speed up the process by which a physician can optimize the dose of dialysis suitable for a given patient and his/her lifestyle.