Impact of islet transplantation on diabetic complications and mortality in patients living with type 1 diabetes

Objective. This study aimed to evaluate the impact of islet transplantation on diabetic complications, death and cancer incidence.

Research Design and Methods. This was a retrospective, multicentre, cohort study including patients from three IT clinical trials (intervention group) and from the French Healthcare database (SNDS) (control group). Two cohorts of IT recipients were analysed: IT recipients after kidney transplantation (IAK) and IT recipients alone (ITA). They were matched with patients living with T1D from the SNDS using a propensity score. The primary outcome was a composite criterion including death, dialysis, amputation, non-fatal stroke, non-fatal myocardial infarction and transient ischemic attack. Secondary outcome was cancer. Hazard Ratio (HRs) and p-values were obtained with Cox proportional hazards analysis and log-rank test respectively.

Results. The study included 61 ITA recipients matched to 610 T1D controls and 45 IAK recipients matched to 45 T1D controls, over a median follow-up period >10 years. Compared with T1D control subjects, ITA and IAK recipients had a lower composite outcome risk (HR, 0.39 [95%CI, 0.21-0.71]; p=0.002 and HR, 0.52 [0.30-0.88]; p=0.014 respectively), seem driven by reduced mortality (HR, 0.22 [0.09-0.54], p<0.001) for ITA and reduced dialysis (HR, 0.19 [0.07-0.50], p<0.001) for IAK. Both groups showed no significant changes in cancer risk.

Conclusions. This study suggests the long-term benefits of IT on diabetes-related outcomes. Furthermore, despite the use of immunosuppressive drugs following IT, we observed no significant increase in the risk of cancer. Altogether, these findings highlight a favourable risk-benefit ratio of IT in managing patients with unstable T1D.