Background: We hypothesized that the use of HbA1c testing would help identify postrenal transplant diabetes (PTDM).
Methods: In all, 199 adult kidney transplant recipients at least 3 months posttransplant without previous history of diabetes or elevated fasting blood sugar were studied. Medical history, a fasting blood glucose, calcineurin inhibitor blood level, and HbA1c were obtained. Primary outcome was the incidence of subjects with HbA1c > or =6.1%. The covariates were use of cyclosporine or tacrolimus, time posttransplant, body mass index (BMI) at transplant and change since transplant, current steroid dose, history of graft rejection, current fasting glucose, age, and race. Proportions were compared between HbA1c <6 and > or =6.1% using Fisher's exact test. Means were compared using Student's t test. Logistic regression was used to identify risk factors associated with elevated HbA1c.
Results: Twenty subjects (10.1%) had an elevated HbA1c. High normal fasting glucose (P=0.003) and African American race (P=0.08, marginally significant) were found to be associated with an elevated HbA1c. Subjects with normal and abnormal HbA1c levels were otherwise similar. There was no difference in HbA1c in tacrolimus versus cyclosporine treated subjects or in the percent of subjects with elevated HbA1c between these groups.
Conclusions: HbA1c levels were found to be more a more sensitive test than fasting blood glucose levels in PTDM, with 10.1% of all patients and 19.4% of blacks found to have an elevated HbA1c. HbA1c testing should be considered as a screening test for PTDM, especially in African Americans.