Weight-Loss Surgery May Not ‘Cure’ Diabetes
This from MedPageToday’s overview of a manuscript published in Obesity Surgery
Although bariatric surgery is increasingly touted as a cure for type 2 diabetes, its remission was only temporary in about one-third of patients, researchers said.
Follow-up of 2,254 patients who showed complete remission of type 2 diabetes following bariatric surgery indicated that 35.1% (95% CI 32.0% to 38.4%) developed renewed symptoms within 5 years, according to David E. Arterburn, MD, MPH, of Group Health Research Institute in Seattle, and colleagues.
Moreover, the relapses did not appear to be closely related to subsequent regain of weight, the researchers reported online in Obesity Surgery.
Patients whose diabetes disappeared and then relapsed actually showed somewhat better weight control after surgery than patients with durable diabetes remission. The patients most likely to show significant weight regain were those whose diabetes never remitted, the analysis indicated.
“Patients should be counseled that bariatric surgery alone does not reliably ‘cure’ diabetes,” Arterburn and colleagues wrote.
Soon after bariatric surgery for obese patients was introduced, it was noticed that type 2 diabetes — a common comorbidity in this population — often seemed to resolve afterward, sometimes within days of the procedure. This observation has since been confirmed
in a variety of studies.
But the anti-diabetic effect’s durability had not been examined thoroughly over the long term.
Arterburn and colleagues obtained retrospective data on 4,434 patients with uncontrolled or adequately treated type 2 diabetes who had undergone bariatric surgery in three integrated health systems from 1995 to 2008. These included Minnesota-based HealthPartners and the Kaiser Permanente systems in northern and southern California.
Body mass index (BMI) values at surgery averaged about 45, dropping to approximately 35 after 1 year.
During the first year after undergoing such procedures — all either open or laparoscopic Roux-en-Y gastric bypass — 37.1% of patients showed complete remission of diabetes (95% CI 35.6% to 38.7%). Within 5 years, 68.2% had diabetes remission (95% CI 66.4% to 70.0%).
Complete remission was defined as both discontinuation of diabetes medications and fasting blood glucose levels of less than 100 mg/dL, and/or glycated hemoglobin less than 6.0% at least 90 days after the last filled prescription for diabetes drugs.
Median time to complete remission was 537 days, the researchers found.
But diabetic symptoms returned in 7.9% of patients within a year of reaching the remission threshold (95% CI 6.8% to 9.2%), and returned in 22.1% (95% CI 20.1% to 24.3%) within 3 years.
Median time to relapse was 8.3 years, Arterburn and colleagues reported.
Multivariate analysis identified several factors as predicting relapse:
- Older age at surgery
- Poor glycemic control prior to surgery
- Insulin therapy before surgery
- Longer diabetes duration
For the last factor, the researchers calculated a hazard ratio for relapse of 1.13 (95% CI 1.09 to 1.17) for each year of diabetes duration.
But one factor that did not predict relapse was significant regain of weight. Mean BMI among those who remitted and then relapsed remained near the low point achieved within a year of surgery, whereas it increased steadily both among patients who never showed remission and among those with durable diabetes remission.
In both of the latter groups, unadjusted BMI increased to an average of about 40 over the 6 years after surgery. Among the diabetic relapsers, though, mean BMI stayed at about 35.
The differences in BMI trajectories between these groups were somewhat attenuated after multivariate adjustment encompassing diabetes duration, age, insulin use, and other factors, but still remained noteworthy.
The researchers indicated that this “counterintuitive” result should be confirmed in future studies. They suggested that it could have been an artifact of the relatively short 4-year follow-up in patients with serial BMI data. But it could also be real, perhaps reflecting an effect of progressive beta-cell loss, they wrote.
Arterburn and colleagues concluded that durable diabetes remission was most achievable in patients undergoing bariatric surgery relatively soon after becoming diabetic.
“Overall, these data suggest that when the main goal of surgical treatment is durable diabetes remission, earlier surgical intervention is likely to be more effective,” they wrote.
But they also emphasized that it remains unknown whether the relapsers may still have obtained lasting benefit — in addition to the weight loss — from the temporary period of excellent glycemic control.
“It is possible that patients who eventually relapse their type 2 diabetes after bariatric surgery will still continue to experience reduced microvascular and macrovascular complications long term,” Arterburn and colleagues noted.
Limitations to the analysis included its retrospective, records-based design; possible unrecorded variations in surgical procedures that could influence the results; and lack of data on such outcomes such as diabetes-related mortality.
John Gever, MedPage Today