Endocrine Abstracts

Background: Bariatric surgery significantly aids weight loss, improves glycaemic control and/or induces remission in Type 2 Diabetes patients. However, the impact of bariatric surgery in Type 1 diabetes (T1D) patients is less well-understood. With an increasing prevalence of obesity within the T1D population, it is important to identify whether bariatric surgery improves glycaemic control and prevents future complications.

Aim: To evaluate the effect on BMI, excess weight loss, HbA1c and insulin requirements over the course of a year following bariatric surgery, in patients with T1D in a large bariatric centre.

Methods: Between 2016-2020, 647 patients underwent bariatric surgery at Royal Berkshire Hospital, UK; 6 (0.9%, 83% female, mean age 49 years) had T1D and were retrospectively identified. The bariatric surgery type, BMI, HbA1c, basal insulin (BI) requirements and excess weight loss at time of referral, 6 and 12 months post-operatively were recorded. Information on short-acting insulin doses was not collected due to data inconsistencies.

Results: The majority of patients underwent a Roux-en-Y gastric bypass (n = 5) compared to gastric sleeve gastrectomy (n = 1). A sustained improvement in BMI was noted post-operatively, (-10 kg/m² at 6 months and -14 kg/m² at 12 months). A mean excess weight loss of 53.4% and 74.8% was achieved at 6 and 12 months, respectively. There was a reduction in mean daily BI requirement overall, with a 60% reduction in insulin noted at 6 months and 50% reduction at 12 months (38.8 units at referral vs 16.2 units at 6 months vs 19.2 units at 12 months post-operatively). HbA1c decreased at 6 months (mean -6 mmol/mol [-11 to +2 mmol/mol]) (pre-op mean 62mmol/mol) but this was not sustained at 12 months post-op compared to time of referral (mean -1 mmol/mol [-13 to +2 mmol/mol]). Conclusion Bariatric surgery resulted in a sustained improvement in excess weight loss and BMI in patients with T1D. Improvement in daily insulin requirements were noted, particularly in the short-term. However, the reduction in insulin requirements did not correspond with a reduction in HbA1c, with only short-term benefits seen. The majority of our patients had well-controlled diabetes at referral and improvement in glycaemic control was not the primary reason for surgery. The small number of patients and short follow-up may preclude definitive conclusions on the benefit of bariatric surgery in glycaemic control and complications in T1D patients in the long-term.