Relationship between inpatient hyperglycemia and insulin treatment after kidney transplantation and future new onset diabetes mellitus

Background and objectives: Approximately two-thirds of kidney transplant recipients with no previous history of diabetes experience inpatient hyperglycemia immediately after kidney transplant surgery; whether inpatient hyperglycemia predicts future new onset diabetes after transplant (NODAT) is not established. Design, setting, participants, & measurements: A retrospective study was conducted to determine the risk conferred by inpatient hyperglycemia on development of NODAT within 1 year posttransplant. All adult nondiabetic kidney transplant recipients between June 1999 and January 2008 were included. Posttransplant inpatient hyperglycemia was defined as any bedside capillary blood glucose ≥ 200 mg/dl or insulin therapy during hospitalization. NODAT was defined as HbA1C ≥ 6.5%, fasting venous serum glucose ≥ 126 mg/dl, or prescribed diet or medical therapy for diabetes mellitus. Results: The study cohort included 377 patients. NODAT developed in 1 (4%) of the 28 patients without inpatient hyperglycemia, 4 (18%) of the 22 patients with inpatient hyperglycemia but not treated with insulin, and in 98 (30%) of the 327 of the patients who were diagnosed with inpatient hyperglycemia and were treated with insulin. In adjusted analyses, requirement of insulin therapy during hospitalization posttransplant was associated with a 4-fold increase in NODAT (relative risk 4.01; confidence interval, 1.49 to 10.7; P = 0.006). Conclusion: Development of inpatient hyperglycemia after kidney transplantation in nondiabetic patients significantly increased the risk of NODAT. Additionally, we observed a significantly increased risk of cardiovascular events in patients who developed NODAT.