New-onset diabetes after transplant: Incidence, risk factors and outcome

Background. The outcome of renal transplantation depends on achieving effective immunosuppression while minimising the consequences of such treatment. The occurrence of new-onset diabetes in the post-transplant period has been associated with several risk factors including some immunosuppressive medication. Better understanding of the clinical and genetic risk factors associated with new-onset diabetes after transplant (NODAT) could enable risk stratification of patients in the pre-transplant period, with the goal of applying measures that will reduce the incidence. Objectives. To ascertain the incidence of and clinical and genetic risk factors that predispose to NODAT, and to examine its effect on the outcome of renal transplantation. Methods. We performed a retrospective cohort review of all renal transplants at Groote Schuur Hospital, Cape Town, South Africa, between 2004 and 2008. Patients who were lost to follow-up or had pre-transplant diabetes or primary non-function were excluded. A subset of the cohort who gave informed consent was enlisted for genetic tests. Results. We identified 111 patients who met the inclusion criteria. The incidence of NODAT was 18.0% ( n =20 patients). Risk factors for NODAT included age at transplant ( p =0.03), body weight ( p =0.04), treatment for acute cellular rejection ( p =0.02) and polycystic kidney disease as the cause of renal failure ( p =0.005). None of the genes investigated ( TCF7L2 rs11196205 , rs12255372 and rs7903146 and HNF1β rs1800575 , rs121918671 and rs121918672 ) was found to be significantly associated with the risk of NODAT. The genotype frequencies for the single-nucleotide polymorphisms studied were closer (although not identical) to those reported for Caucasians than to those reported for the Yoruba (black) population in West Africa. Overall patient survival was 78% at five years, while graft survival was 72%. There was no significant difference in patient or graft survival between the group with NODAT and the group without. Conclusions. NODAT was common in renal transplant recipients. Some risk factors predate transplant and could be used to risk-stratify patients to determine appropriate risk-reduction strategies. The genetic determinants for NODAT in this population may differ from those reported elsewhere. NODAT had no impact on patient or graft survival in this cohort.