Glucose challenge test (50-g GCT) in detection of glucose metabolism disorders in peritoneal dialysis patients: preliminary study.

Background: The aim was to evaluate the clinical utility of the oral glucose tolerance screening test (50-g GCT--glucose challenge test) for the detection of glucose metabolism disorders (GMD) in peritoneal dialysis (PD) patients with normal fasting glucose levels.
Methods: The 50-g GCT was performed in 20 prevalent patients without history of diabetes before PD treatment onset, who had been on dialysis for a median time of 15.34 months. In addition, other indicators of glucose metabolism were measured: C-peptide, fasting insulin serum concentration, and the glycated hemoglobin level (HbA1c). The patients were prospectively followed for a median time of 25.8 months.
Results: 50-g GCT revealed GMD in 15 studied patients (75%)--impaired glucose tolerance in 11 patients (55%) and diabetes mellitus in four patients (20%). HbA1c and insulin resistance, estimated by homeostasis model assessment, were elevated in two (10%) and seven (35%) patients, respectively. In patients with GMD, dietetic and pharmacologic interventions were performed. When the 50-g GCT was repeated at the end of the observation period, 12 (60%) patients reported GMD, with no case of diabetes.
Conclusion: 50-g GCT appears to be a simple and practical tool for the detection of GMD in PD patients with normal fasting glucose. Timely therapeutic intervention can effectively inhibit the progression of glucose intolerance during PD treatment.