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.