The response to intravenous glucose of patients on maintenance hemodialysis: Effects of dialysis

Abstract

To learn whether a single dialysis can acutely improve the intravenous glucose tolerance (i.v.GTT) of chronically dialyzed patients, a standard i.v.GTT was performed on 10 nonobese uremic subjects on maintenance hemodialysis for 27 ± 9 (mean ± SEM) mo, and on a control group of 13 normal subjects. The uremic patients were tested first 0.2–17 (range) hr, and then 65–109 hr, from last dialysis. In the uremic sera, plasma glucose was analyzed by 4 methods; 2 reducing (neocuproine and ferricyanide) and 2 enzymatic (hexokinase and glucose oxidase). The reducing methods markedly overestimated plasma glucose concentration because of the presence of nonglucose, reducing substances (notably, creatinine). This interference was significantly cut down by dialysis. A single dialysis, on the other hand, failed to improve the glucose fractional decay rate (KG) computed from the glucose oxidase data (1.69 ± 0.2%/min before and 1.35 ± 0.1 after dialysis, versus 1.47 ± 0.1 of the normal subjects). The same conclusion was derived from the data measured by the other 3 methods of glucose assay. Fasting plasma insulin concentrations were, on average, above normal (5.5 ± 0.6 μU/ml) both before (12.3 ± 2.7, p < 0.05) and after (17.2 ± 3.5, p < 0.01) a single dialysis. Likewise, the area under the glucose-induced plasma insulin curve was significantly greater than normal (1.46 ± 0.21 mU/ml·min) both before (2.26 ± 0.34, p < 0.05), and after (2.86 ± 0.43, p < 0.01) dialysis. A single dialysis had little effect on either basal or glucose-stimulated insulin release, and no significant difference in the insulinogenic index (insulin area/glucose area) was found between the control and the uremic group in either test. Insulin response was not correlated with KG, whereas it was significantly associated with higher triglyceride levels. Creatinine, urea or methylguanidine did not appear to have any influence on KG, but lower serum potassium levels were significantly associated with poorer i.v.GTT's. Plasma calcium bore a reciprocal relation to the insulinogenic index. Chronically dialyzed subjects show some degree of tissue insulin resistance, which a single dialysis fails to correct. Electrolyte disturbances may play a role in this metabolic derangement.