Comparison of Icodextrin and 2.5% Glucose in Potassium Metabolism by Acute K+ load via Dialysate in Continuous Ambulatory Peritoneal Dialysis Patients

This study aimed to compare the increment in plasma potassium concentration ([K(+)]) as well as the role of internal K(+) balance for its changes following acute K(+) supplementation between conventional 2.5% glucose (GD) and non-glucose containing dialysate (icodextrin, ID) in continuous ambulatory peritoneal dialysis (CAPD) patients. A total of 9 stable CAPD patients (5 men and 4 women; age, 56±13 years; 7 type-2 diabetics and 2 non-diabetics) on daily 4 exchanges of 2 L of glucose dialysate underwent the 6-hr dwell on fasting in the morning with 2 L of 2.5% glucose mixed with 20 mEq/L of KCl, and then the same regimen was repeated with icodextrin after 1-wk interval. The degree of intraperitoneal absorption was comparable, 65±2% in GD and 68±2% in ID, respectively (p=NS). However, despite the similar plasma K(+) levels at the baseline of both regimens, its increment was significantly less in GD than ID, which was accompanied by more marked increase in the calculated intracellular K(+) redistribution (68±3% vs. 52±3%, p<0.05). The basal levels of insulin were similar between the GD and ID groups. However, the change, checked up after 2 hours' dwell, from the basal insulin levels was much lower on ID. ID with a lesser degree of transcelluar K(+) shift by the decreased secretion of insulin is more effective than the conventional glucose solution for acute K(+) repletion via dialysate during CAPD. Furthermore, these results suggested that the role of insulin for the internal K(+) balance was intact even in type-2 diabetic patients on CAPD.