Improved survival in patients with type 1 diabetes mellitus after renal transplantation compared with hemodialysis: a case-control study

BACKGROUND: Diabetes mellitus is the leading cause of renal failure worldwide. The question of which treatment modality-hemodialysis versus renal transplantation-is associated with the lowest risk of cardiovascular morbidity and mortality in the diabetic end-stage renal disease (ESRD) population has not yet been investigated in a controlled trial. METHODS: We therefore conducted a case-control study of patients with ESRD caused by type 1 diabetes mellitus. The case patients were diabetics who received a renal graft between 1978 and 1997, whereas the controls were registered for renal transplantation but stayed on maintenance hemodialysis without ever undergoing transplantation. The groups were matched for age, sex, duration of diabetes, length of hemodialysis (up to the registration), and date of registration for renal transplantation. RESULTS: Kaplan-Meier life table analysis, based on 46 case patients and 46 controls, demonstrated a highly significant (P=0.0001) poorer survival in the control group compared with the case group. Logistic regression showed that hemodialysis was a significant risk factor for death (P=0.0002) and cardiovascular morbidity (P=0.0023). Patients with cardiovascular complications such as coronary artery and peripheral vascular events were significantly more frequent in the control group. Additionally tested risk factors for cardiovascular complications (serum cholesterol, arterial blood pressure, number of antihypertensive drugs, serum calcium, serum phosphate, and glucose control [hemoglobin A(1c)]) showed no significant correlation to survival or morbidity in either group by logistic regression. CONCLUSIONS: Renal transplantation is associated with a significantly improved survival compared with hemodialysis in patients with ESRD caused by type 1 diabetes mellitus. This seems to be a result of a reduced incidence of cardiovascular complications after renal transplantation.