Determination of Creatinine in PETs and Laboratory Calculations of the Peritoneal Dialysis Adequacy

Since our Department for Dialysis performs the Peritoneal Equilibration Test （PET） to monitor peritoneal dialysis adequacy, our Laboratory has been asked to collaborate on calculating clearances and transport characteristics of patients. This collaboration is ongoing since 2003, despite the Baxter-PD Adequest software having appeared. Our aim is to emphasize the importance of the laboratory in the selection of formulas and specifically in solving the problem of determining creatinine concentration in PETs, and to recommend the cooperation between the laboratory and the dialysis department. Since creatinine determination is encumbered by recommendations for correcting elevated creatinine levels because of the influence of glucose in PETs, we compared results of dialysates determined as serum and as urine. Until now we had 86 patients on continuous ambulatory peritoneal dialysis （CAPD）. Method for determining patients＇ creatinine remains Jaffe kinetic uncompesated although the analyzers and the corresponding reagenses were changed in the laboratory. We have achieved the complete cooperation and confidence in the result, and with the PET test performed strictly according to the protocol, increasingly better results for clearences, Kt/V and transport characteristics. All this helps with treatment planning and analyzing patients＇ quality of life.

Peritoneal Membrane Transport Characteristics in Uni-PET with Preceding Icodextrin Dwell as Compared to Classic PET with Preceding Glucose Dwell: A Prospective Study

Background: In subjects on CAPD who use icodextrin for long night dwell, it has been recommended that nocturnal exchange be replaced by dextrose dwell whenever PET is to be performed as preceding exchange with icodextrin temporarily increases peritoneal membrane permeability and therefore, gives high D/PCr and low D/D0 glucose values. Whether this temporary change is also seen with use of Uni-PET (which involves one hour dwell of 1.5% dextrose followed by 4-hour dwell of 4.25% dextrose) is not known. Methods: In this self, controlled study, subjects on CAPD, who were using icodextrin for long nocturnal dwell for at least 3 months, were screened for enrolment. Pregnancy or lactation, history of any PD related infectious complication in the past one month, present or past malignancy, and poor functional status were exclusion criteria. Enrolled subjects underwent classic PET with preceding 2.5% dextrose long nocturnal dwell on day 1 followed by Uni-PET with preceding 7.5% icodextrin long nocturnal dwell on day 2. Difference in D/PCr and D/D0 glucose between the two PETs was primary objectives. The study was approved by Institute Ethics Committee. Results: 15 out of 26 screened subjects were enrolled over a period of 18 months (July 2015-December 2016). The mean (±SD) age of study population was 60.8±9.1 years. Majority were males and diabetes was the most common cause of CKD. Mean D/PCr were 0.68 ± 0.11 and 0.64 ± 0.08 in classic PET and Uni-PET, respectively. The difference between the two values was not significant [mean difference between D/PCr (classic PET-Uni-PET): 0.040 ± 0.86;95% CI (-0.007 to 0.088);p = 0.09]. Similarly, D/D0 glucose between classic PET and Uni-PET was also similar [mean difference between D/D0 glucose (classic PET-Uni-PET): -0.02 ± 0.09;95% CI (-0.06 to 0.03);p = 0.448]. Conclusion: Peritoneal membrane small solute transport characteristics in Uni-PET with preceding icodextrin dwell are similar to classic PET with preceding glucose dwell. If Uni-PET is used, it may not be necessary to replace preceding nocturnal exchange of icodextrin with that of dextrose as is currently advised.

Influence of Peritoneal Transport Characteristics on Nutritional Status and Clinical Outcome in Chinese Diabetic Nephropathy Patients on Peritoneal Dialysis

Background： High peritoneal transport status was previously thought to be a poor prognostic factor in peritoneal dialysis （PD） patients. However, its effect on diabetic nephropathy PD patients is unclear in consideration of the adverse impact of diabetes itself. The purpose of this study was to investigate the influence of peritoneal transport characteristics on nutritional status and clinical outcome in diabetic nephropathy patients on PD. Methods： One hundred and two diabetic nephropathy patients on PD were enrolled in this observational cohort study. According to the initial peritoneal equilibration test result, patients were divided into two groups： Higher transport group （HT, including high and high average transport） and lower transport group （LT, including low and low-average transport）. Demographic characteristics, biochemical data, dialysis adequacy, and nutritional status were evaluated. Clinical outcomes were compared. Risk factors for death-censored technique failure and mortality were analyzed. Results： Compared with LT group （n = 37）, serum albumin was significantly lower and the incidence of malnutrition by subjective global assessment was significantly higher in HT group （n = 65） （P 〈 0.05）. Kaplan-Meier analyses showed that death-censored technique failure and mortality were significantly increased in HT group compared with that in LT group. On multivariate Cox analyses, higher peritoneal transport status and lower residual renal function （RRF） were independent predictors of death-censored technique failure when adjusted for serum albumin and total weekly urea clearance （Kt/V）. Independent predictors of mortality were advanced age, anemia, hypoalbuminemia, and lower RRF, but not higher peritoneal transport status. Conclusions： Higher peritoneal transport status has an adverse influence on nutrition for diabetic nephropathy patients on PD. Higher peritoneal transport status is a significant independent risk factor for death-censored technique failure, but not for mortality in diabetic nephropathy patients on PD.