Long-term impact of bariatric surgery on glycemic control and glucose-lowering therapy for people with type 2 diabetes: population-based cohort study

Background — Randomized controlled trials have demonstrated that bariatric surgery improves glycemic control among people with diabetes. However, evidence from randomized controlled trials may not be generalizable to real-world clinical care with unselected patients in routine clinical practice.

Objectives — To examine long-term glycemic control and glucose-lowering drug regimens following bariatric surgery for people with type 2 diabetes in unselected patients in routine clinical practice.

Setting — Population-based cohort study using linked routinely-collected real-world data from Ontario, Canada.

Methods — Individuals with type 2 diabetes who were assessed for bariatric surgery at any referral center in the province between February 2010 and November 2016 were identified, and divided into those who received surgery within 2 years of the initial assessment and those who did not.

Results — There were 3,674 people who had bariatric surgery with 1,335 who did not. By 2 years, people who had undergone surgery had a significantly lower A1c (6.3±1.2 % versus 7.8±1.8 %, p<0.0001), and this difference persisted at 3, 4, 5 and 6 years. Even by 6 years, half of those who had undergone surgery remained on no glucose-lowering drugs, and they were nearly 6 times less likely to be on insulin than those who had not undergone surgery.

Conclusions — In real-world clinical care, bariatric surgery was associated with large and sustained improvements in glycemic control.