A Model To Estimate Glucose Absorption in Peritoneal Dialysis: A Pilot Study

Background Glucose absorption in patients on peritoneal dialysis (PD) may contribute to adverse metabolic effects. Previous studies on glucose absorption were done on patients on continuous ambulatory PD, with a long dwell time. However, the growing majority of contemporary patients on PD perform automated PD with a short dwell time. Moreover, membrane characteristics and dwell time determine small-solute transport across the peritoneal membrane. Methods In our pilot study, we used data from the peritoneal equilibration test (PET) to develop a model to estimate glucose absorption. In six randomly selected patients on PD, we calculated actual glucose absorption from directly measuring effluent glucose concentration. We then used the R programming language to create a nonlinear, least-squared regression model, inputting PET data, D2/D0, and D4/D0 to generate an exponential decay curve. This model was then used to estimate the fraction of glucose remaining in the dialysate at a particular dwell time t (Dt/D0). Daily glucose absorption was calculated by multiplying 1-Dt/D0 with the amount of glucose the patient was exposed to in 24 hours. Results We observed the mean glucose absorption (89.7±28.8 g/d), as measured from the effluent, very close to our estimate (88.12±28.9 g/d), and the difference between the glucose estimation and actual absorption was not statistically significant (P>0.05), with "W"value of 8. After validating our hypothesis, we randomly selected an independent cohort of 11 patients with ESKD who were on various PD modalities and analyzed their data. We observed that the mean daily glucose absorption of 62.7±24.5 g (27.98-110.35 g), much lower than that reported in the literature, depends on dwell times and membrane characteristics in addition to the amount of glucose absorption in the cohort. Conclusions Our model provides a simple tool for estimating glucose absorption and caloric load in contemporary patients on PD. Hopefully, the accurate estimation of caloric load and the incorporation of it into the daily caloric intake of the individual will help to reduce metabolic consequences of hyperglycemia and weight gain and improve overall outcomes of PD.