Diabetes is an Increasingly Common Issue After Heart Transplantation: A Case for Integrated Diabetes Care.

Background: Orthotopic heart transplantation (OHT) survival rates have improved with advances in immunosuppression over the last 20 years. With these improvements, there has been a greater focus on post-transplant care. Diabetes is common after transplantation and may be pre-existing (type 2 diabetes mellitus [T2DM]) or develop after transplant (post-transplant diabetes mellitus [PTDM]). The aim of this study was to compare the incidence and prevalence of diabetes in OHT recipients in two cohorts separated by 20 years.

Methods: Retrospective audit comparing the prevalence of T2DM and cumulative 2-year incidence of PTDM in 88 consecutive OHT recipients in 1996-1998 and 141 consecutive OHT recipients in 2015-2018 at the same tertiary referral teaching hospital.

Results: The prevalence of pre-transplant T2DM at the time of OHT increased three-fold between 1998 and 2018, from 6% (n=5) to 18% (n=25) respectively (p=0.009). Similarly, the incidence of PTDM increased from 16% (n=13) in 1998 to 36% (n=42) in 2018 (p=0.001). OHT recipients who developed PTDM were older in 2018 vs 1998 (mean age 52 [±11] vs 44 [±9] years; p=0.03). The mean age was not different between individuals with T2DM between the 1998 and 2018 eras. Body mass index was not different between the 1998 and 2018 eras in any of the diabetes status subgroups.

Conclusions: The incidence and prevalence of diabetes after OHT at our Australian institution has increased over 20 years. With improved OHT survival and rates of diabetes, endocrinologists should be incorporated into the care teams of heart transplant recipients. Further studies of glucose-lowering therapies in patients with diabetes after transplantation are warranted.