Long-term prognosis of patients after kidney transplantation: a comparison of those with or without diabetes mellitus.

BACKGROUND: Compared with non-diabetic subjects, patients with type 2 diabetes and end-stage renal disease (ESRD) have seldom been selected for renal transplantation. It was the aim of this study to compare the long-term prognoses of the two groups of patients after transplantation and to identify factors associated with allograft rejection. METHODS: In a retrospective analysis, we studied all 333 consecutive patients who received a kidney transplant at our centre since 1992. Mean follow-up in 302 out of 333 patients (91%) was 3.3+/-1.5 (0.1-11.7) years. At the time of transplantation, diabetes mellitus (type 1, n=3; type 2, n=46) was known in 49 patients. RESULTS: Patients with diabetes mellitus were older patients without diabetes (n=253) vs patients with diabetes (n=49), 52.2+/-12.6 vs 58.8+/-13.1 years, respectively; P=0.002], but they had very good diabetes control haemoglobin A1c (HbA1c) of patients with diabetes 6.3+/-0.9% vs those without diabetes 5.2+/-1.0%, P=0.03]. Even during their follow-up, patients with diabetes showed a tendency to further improvement (HbA1c for patients with diabetes 5.7+/-0.9% vs those without diabetes 5.5+/-0.9%, P=0.30). At the end of follow-up also, there were no differences between the groups with respect to blood pressure control (patients with diabetes 135.3+/-28.2/79.6+/-17.2 mmHg vs patients without diabetes 130.9+/-28.7/78.8+/-17.1 mmHg, P=0.33/0.78) and renal function (creatinine, 142.9+/-61.6 vs 151.8+/-68.2 micromol/l, P=0.38; glomerular filtration rate, 63.1+/-23.3 vs 59.1+/-24.0 ml/min/1.73 m(2), respectively, P=0.30). In total, 26 patients had acute transplant rejections eight patients with diabetes (prevalence 16.3%) vs 18 patients without diabeteses (prevalence 7.1%), P=0.11]. In multivariate analysis, the most important parameter associated with the incidence of transplant rejections was the preceding fasting blood glucose (R2=0.044, beta=0.21, P=0.009). All other parameters included in the model (body mass index, time since transplantation, diabetes duration, immunosuppressive therapy, HbA1c and HLA mismatch) revealed no associations. CONCLUSIONS: Following kidney transplantation, the prevalence of rejections in patients with diabetes mellitus is slightly but not significantly higher than in non-diabetic subjects. One of the most important risk factors seems to be fasting blood glucose. Hence, following renal transplantation, treatment strategies should focus not only on optimal immunosuppressive therapy and HLA matching, good HbA1c and blood pressure control, but also on maintaining near-normal fasting blood glucose levels.