On the disturbances in carbohydrate metabolism in pre-dialysis patients with chronic renal failure

Abstract

We describe some of the aspects of impaired carbohydrate metabolism in predialysis uremic patients.

Methods: A total of seventy-five nondiabetic patients with chronic renal failure (CRF) were enrolled in the present study. The level of glycosylated hemoglobin was measured in 51 patients using kits from Merck and an oral glucose challenge test was performed in 20 according to a standard protocol. The levels of immunoreactive insulin and growth hormone (GH) were measured in all predialysis patients using original kits and an automatic minigamma counter (Abbott, USA). The results were compared with those from 30 healthy controls.

Results: In patients with first degree CRF the level of glycosylated hemoglobin was 5.9 +/- 05%. In patients with second and third degree CRF there was a trend towards higher glycosylated hemoglobin levels--6.3 +/- 0.6% (P > 0.05; u = 1.1) as compared with the controls--5.5 +/- 0.4%. The analysis of the results from the oral glucose challenge test revealed impaired glucose tolerance in 12 predialysis patients with CRF with blood glucose levels of 9.1 +/- 1.6 mmol/l at the second hour following the ingestion of glucose. Nine of those had second or third degree CRF. The baseline levels of plasma immunoreactive insulin showed a tendency towards increase in the patients with uremia as compared with the controls (7.2 +/- 1.1 IU/ml versus 6.4 +/- 0.7 IU/ml) whereas no significant difference was found at the 1st, 2nd or 3rd hour following the ingestion of glucose as compared with the healthy controls. Five of our patients had significantly elevated basal insulin levels. With regard to GH levels, we found similar baseline values in our study patients and the controls. At the 1st hour following the glucose challenge the GH values showed a tendency towards increase in the uremic patients--6.1 +/- 1.1 ng/ml. In 4 of our study patients we found significantly elevated GH levels at the 1st hour following the ingestion of glucose (6.6 +/- 0.7 ng/ml).

Conclusions: 1. No significant disturbances in carbohydrate metabolism were found in patients with mild (initial) CRF. 2. In patients with moderate and advanced CRF we found changes consistent with impaired carbohydrate metabolism and a tendency towards an increase in the basal immunoreactive insulin levels. 3. Growth hormone levels showed a different pattern of change in predialysis patients and those changes cannot be explained by the changes in carbohydrate metabolism.