Short-term studies show that bariatric surgery causes remission of diabetes.
The long-term outcomes for remission and diabetes-related complications are not known.
Dr Lars Sjöström and colleagues determined the long-term diabetes remission rates, and the cumulative incidence of microvascular and macrovascular diabetes complications after bariatric surgery.
The Swedish Obese Subjects (SOS) is a prospective matched cohort study conducted at 25 surgical departments and 480 primary health care centers in Sweden.
Of patients recruited between 1987 and 2001, 260 of 2037 control patients and 343 of 2010 surgery patients had type 2 diabetes at baseline.
For the current analysis, diabetes status was determined at SOS health examinations until 2013.
|The diabetes remission rate 2 years after surgery was 72% for bariatric surgery patients|
|Journal of the American Medical Association|
Information on diabetes complications was obtained from national health registers until 2012.
Participation rates at the 2-, 10-, and 15-year examinations were 81%, 58%, and 41% in the control group, and 90%, 76%, and 47% in the surgery group.
For diabetes assessment, the team found that the median follow-up time was 10 years and 10 years in the control and surgery groups, respectively.
For diabetes complications, team noted that the median follow-up time was 17 years, and 18 years in the control and surgery groups, respectively.
Adjustable or nonadjustable banding, vertical banded gastroplasty, or gastric bypass procedures were performed in the surgery group, and usual obesity and diabetes care was provided to the control group.
The team's main outcome measures included diabetes remission, relapse, and diabetes complications.
Remission was defined as blood glucose <110 mg/dL and no diabetes medication.
The diabetes remission rate 2 years after surgery was 16% for control patients, and 72% for bariatric surgery patients.
At 15 years, the team noted that diabetes remission rates decreased to 7% for control patients, and to 30% for bariatric surgery patients.
With long-term follow-up, the cumulative incidence of microvascular complications was 42 per 1000 person-years for control patients, and 21 per 1000 person-years in the surgery group.
The research team observed macrovascular complications in 44 per 1000 person-years in control patients, and 32 per 1000 person-years for the surgical group.
Dr Sjöström's team comments, "In this very long-term follow-up observational study of obese patients with type 2 diabetes, bariatric surgery was associated with more frequent diabetes remission and fewer complications than usual care."
"These findings require confirmation in randomized trials."