Exploring the Impact of Diabetes on Kidney Transplant: Patient Outcomes and Management Strategies

Diabetic kidney disease (DKD) is a serious consequence of diabetes mellitus (DM). If not managed effectively, DKD often develops into end-stage renal disease (ESRD). The most successful treatment for ESRD is kidney transplantation, offering improved quality of life and survival rates. For insulin-dependent diabetic patients with ESRD, simultaneous pancreas-kidney transplantation (SPKT) offers a treatment alternative that treats both kidney failure and the underlying diabetes. However, SPKT involves more complicated surgery, prolonged operative time, and a higher risk of complications. This review aims to highlight the impact of DM on kidney transplant recipients (KTRs) regarding post-transplant complications, graft survival, mortality rates, and the role of glucose-lowering medications and immunosuppressants. The incidence of urinary tract infections, cardiovascular complications, and diabetic foot disease was higher among KTRs. A decrease in graft survival rate at five years was observed among diabetics compared to non-diabetics, with similar graft survival rates among type 1 and type 2 DM. The mortality rate was notably higher among diabetic patients, with cardiovascular complications being the leading cause. The emergence of new-onset diabetes mellitus post-transplantation (NODAT) is a significant cause of concern. Certain risk factors, including a family history of DM, age >45 years, obesity, male gender, and immunosuppressive medications, have been linked to this phenomenon. Immunosuppression is a substantial challenge among diabetics as certain medications such as tacrolimus have shown to be considerably diabetogenic compared to cyclosporine and belatacept, and it is also postulated that corticosteroids can lead to hyperglycemia. Some studies proved that glucose-lowering medications, including insulin degludec, glucagon-like peptide-1 receptor agonists, thiazolidinediones, and sodium-glucose cotransporter 2 inhibitors, are safe and effective among KTRs. However, these studies are debatable and of low confidence. Hence, it is imperative to conduct large clinical trials and establish definitive guidelines to manage pre-existing diabetes and NODAT among KTRs with multidisciplinary care to help clinicians improve patient outcomes.