Pretransplantation Oral Glucose Tolerance Test Can Prevent Posttransplant Diabetes Mellitus After Renal Transplantation: Preliminary Study

Abstract

Posttransplant diabetes mellitus (PTDM) adversely affects renal graft and patient survival. Fasting plasma glucose (FPG) alone underestimates diagnosis of glucose metabolism disorders (GMD) detected using the oral glucose tolerance test (OGTT-75). Prediabetes including impaired fasting glucose (IFG): 100 to 125 mg/dL (5.6-6.9 mmol/L) and impaired glucose tolerance (IGT): 140 to 199 mg/dL (7.8-11 mmol/L) 2 hours post 75-g OGTT in the pretransplant period can have a connection with the occurrence of PTDM after renal transplantation (RTx). The aim of our study was to assess the benefit of performing OGTT-75 in dialyzed chronic kidney disease (stage 5) patients on the waiting list for kidney transplantation as a useful tool to prevent PTDM.

Materials and methods: Pretransplant glucose testing using OGTT-75 was performed in nondiabetic dialyzed chronic kidney disease patients on the waiting list for renal transplantation in the southwest region of Poland. GMD were diagnosed according to current criteria. Patients with recognized prediabetic stage were recommended a low carbohydrate diet, lifestyle modification, and increased physical activity. In the 12-month posttransplant period we estimated the prevalence of PTDM in the study group based on FPG >126 mg/dL (7 mmol/L) in 2 measurements or random blood glucose >200 mg/dL (11.1 mmol/L).

Results: A total of 80 nondiabetic dialysis patients (65 hemodialysis/15 peritoneal dialysis; 47 male/33 female) met initial entry criteria. In pretransplant glucose testing prediabetes was found in 31 out of 80 patients (39%). Among them, 5 patients (6.25%) had combined IGT/IFG, 18 patients (22.5%) had IGT, and 8 patients (10%) had IFG. One year after RTx we recognized PTDM in 14% of all analyzed patients (11/80) and noticed a significant frequency of glucose disorders status change after RTx (P = .002).

Conclusion: Our findings suggest early detection of prediabetes using the OGTT-75 test in nondiabetic dialysis patients waiting for RTx to prevent occurrence of PTDM.