Outcomes for Adults with Type 1 Diabetes Referred with Severe Hypoglycaemia and/or Referred for Islet Transplantation to a Specialist Hypoglycaemia Service

Islet transplantation alone (ITA) is indicated for patients with type 1 diabetes (T1D) with disabling severe hypoglycaemia (SH) despite optimised medical therapy. We examined outcomes for patients referred to an islet transplant unit with recurrent SH. Retrospective case note audit of 45 patients with 1 SH per year who were referred to our ITA unit between 2009-2012; 36 patients attended follow-up appointments. The cohort was 52.8% male, mean (+/- SD) age 43.9 (+/- 11.4) years, and duration of diabetes 26.5 (+/- 12.9) years. Baseline HbA1c was 8.3% (+/- 1.7) (67.2mmol/mol), median (IQR) frequency of SH was 6.0 (2.0-24.0) per/patient/year and 83.3% had impaired awareness of hypoglycaemia (IAH). 80.6% of patients were referred from other secondary diabetes services, 22.2% had completed structured education, and 30.6% were using continuous subcutaneous insulin infusion (CSII). Seventeen patients were optimised with conventional therapy; SH reduced from 2.0 (1.5-9.0) to 0.0 (0.0-0.5) episodes/patient/year; p<0.001, and there was concurrent improvement in HbA1c (8.1-7.7%; 65.0 vs. 60.7mmol/mol; p=0.072). Ten patients were listed for transplantation as they were not optimised despite structured education, CSII, and continuous glucose monitoring (CGM). The remaining 9 had a reduction in SH [7.0 (4.8-40.5) to 4.0 (2.5-6.3) episodes/patient/year; p=0.058] and either left the service (n=5) or are still being optimised (n=4). In conclusion, 47.2% of patients presenting with problematic hypoglycaemia resolved with optimal medical therapy, with a further 25% achieving clinically relevant improvement, however 27.8% required transplantation despite access to all therapies. Provision of expertise in hypoglycaemia management is essential to focus limited transplant resources on those who need it most.