Progression to Insulin Requirement at One Year After Kidney-Alone Transplantation in Insulin-Independent Type 2 Diabetes: Implications for SPK Candidate Selection

This single-center retrospective cohort study investigated the incidence and predictors of insulin requirement following kidney transplantation in patients with type 2 diabetes who were insulin-independent at the time of surgery. Eligible patients were aged ≤65 years with BMI ≤30 kg/m 2 , matching our center's inclusion criteria for simultaneous pancreas-kidney (SPK) transplantation. We analyzed 132 adult recipients transplanted between 2015 and 2023. One-year post-transplantation, 90.9% (120/132) progressed to maintenance insulin therapy, including all patients on oral antidiabetic agents at transplant (n=48). Recipient age, BMI and donor characteristics did not significantly predict progression to insulin therapy. This finding is likely attributable to our stringent inclusion criterion. Pre-transplant HbA1c (mean 6.1%) and c-peptide (mean 9.4 ng/mL) were also similar between groups. Patients requiring insulin had significantly higher one-year glycated hemoglobin than those who remained insulin-free. In a comparison group of 449 kidney transplant recipients without diabetes, the incidence of new-onset diabetes was only 8%. These results indicate that pre-transplant insulin independence in patients with diabetes is a deceptive marker, likely due to altered insulin clearance in end-stage renal disease (ESRD). The near-universal progression to insulin requirement suggests the need to re-evaluate the current selection criteria for SPK transplantation to include this high-risk population, especially those oral hypoglycemic agents whether SPK improves outcomes relative to kidney transplantation with intensive medical therapy in this population remains unestablished.