Comparison of early type 2 diabetes improvement after gastric bypass and sleeve gastrectomy: medication cessation at discharge predicts 1-year outcomes

Background: Although weight loss-dependent type 2 diabetes (T2D) improvement after sleeve gastrectomy (SG) is well documented, whether SG has a weight-independent impact on T2D is less studied.

Objectives: To evaluate early, weight-independent T2D improvement after SG and Roux-en-Y gastric bypass (RYGB) and its relationship to longer-term T2D outcomes.

Setting: University Hospital, United States.

Methods: We completed a retrospective cohort study of patients with T2D who underwent SG (n = 187) or RYGB (n = 246) from 2010 to 2015. Pre- and postoperative parameters, including demographic characteristics, T2D characteristics, and T2D medication requirements, blood glucose, glycosylated hemoglobin, weight, and body mass index, were reviewed.

Results: T2D improved within days after both SG and RYGB, with more patients off T2D medications after SG than RYGB (39% versus 25%, respectively; P < .01) at the time of discharge (2.5 ± .8 versus 2.7 ± 1 d; P = .04). Over the initial postoperative 12 months, T2D medication cessation rates remained relatively stable after SG but continued to improve after RYGB (at 12 mo: 52% versus 68%, respectively; P < .05). T2D medication cessation at discharge predicts 12-month T2D medication cessation (92% [RYGB] and 78% [SG] positive predictive value). In a mixed-effects regression model adjusting for weight loss and severity of diabetes, discharge T2D medication cessation remained a significant predictor of T2D outcomes after both RYGB (odds ratio, 51; 95% confidence interval, 16.1-161; P < .0001) and SG (6.4; 95% confidence interval, 2.8-14.7; P < .0001).

Conclusions: Both SG and RYGB lead to high rates of T2D medication cessation within days of surgery, suggesting both operations activate weight loss-independent anti-T2D pathways. T2D medication cessation at discharge is predictive of 12-month T2D outcomes, particularly in noninsulin requiring patients. By 1 year after the surgery, RYGB leads to more weight loss and higher rates of T2D medication cessation than SG.