Alexandra Chow1, Noah J Switzer1, Jerry T Dang1, Xinzhe Shi1, Christopher de Gara1, Daniel Birch1, Richdeep S Gill2, Shahzeer Karmali1. 1University of Alberta, 2University of Calgary
INTRODUCTION: We aimed to examine the literature regarding the efficacy of bariatric surgery for patients with type 1 diabetes (T1D). Bariatric surgery has been shown to be an effective treatment modality for obesity and its comorbidities, specifically type 2 diabetes (T2D). Remission of T2D after bariatric surgery has been attributed to gastrointestinal hormone modulation and improvements in residual beta-cell function. However, few data is available regarding the impact of bariatric surgery in patients with limited residual beta-cell function, as in T1D. Early small case reports suggest that bariatric surgery leads to reduction in insulin requirements, in addition to improvements in body mass index and other comorbidities.
METHODS AND PROCEDURES: A comprehensive search (limited to English and human) of MEDLINE, EMBASE, SCOPUS, the Cochrane Library, and Web of Science from 1946 to July 2015 was completed. Title searching was restricted to the following keywords/terms: bariatric surgery, gastric bypass, gastric band, sleeve gastrectomy and Type 1 Diabetes Mellitus. Inclusion criteria included human adult subjects with confirmed T1D who underwent a bariatric surgical procedure with diabetes specific outcomes reported.
RESULTS: Thirteen primary studies (86 patients) were included in the systematic review. Subjects had a mean age of 37.31 years with a mean BMI of 43.55 kg/m2. Post-operative bariatric surgery BMI at 12 months and at study endpoint dropped significantly to 29.55 kg/m2 (p<0.00001) and 30.63 kg/m2 (p<0.00001), respectively. Weighted mean pre-operative daily insulin requirement was 97 units, which dropped markedly to 35 units/day (p<0.00001) at 12 months and 42 units/day (p<0.00001) at study endpoint. Weighted mean pre-operative HbA1C was 8.46%, which dropped to 7.95% (p=0.01) and 8.129% (p=0.03) at 12 months and at study endpoint, respectively.
CONCLUSIONS: Bariatric surgery leads to marked weight loss in patients with T1D. Favourable post-operative metabolic effects lead to improvements in glycemic control and a reduction in exogenous insulin use.