As we've noted, bariatric surgery is probably the most effective means of dealing with obesity, and with obesity-linked Type 2 diabetes as well. But there are still unresolved issues related to the length of time benefits last, which type of surgery works best, and who should be considered eligible for the surgery. A couple of new reports in JAMA Surgery shed some light on such questions.
One report focused on data from about 570 people who had undergone some type of bariatric surgery between 2005 and 2012, who also had Type 2 diabetes (T2DM). All had started with a BMI of 35 or more (morbid obesity standard eligibility for such surgery). These folks were matched with diabetic patients who had not had surgery (1880 people), but were otherwise similar in terms of age when the operated people had surgery, sex and BMI. The main focus of the study was the extent to which T2DM remission occurred, and whether the level of hemoglobin A1c, or HbA1c, (a measure of long-term blood glucose control) decreased to less than 6.0 percent (any HbA1c over 6.5 percent is considered diabetes).
The investigators, led by Dr. Jan Peter Yska from the Medical Centre Leeuwarden, Leeuwarden, the Netherlands reported that 95 (out of the 570) persons with T2DM who underwent surgery were in remission compared to only five patients in the non-surgical group (1880 total). The results also depended on the type of bariatric surgery involved. Gastric bypass surgery was the most effective, followed by sleeve gastrectomy and then by gastric banding (for more information on the types of bariatric surgery, read here). Thus, the researchers found, the positive effects of bariatric surgery could be seen for at least two years post operation.
Although the standard cut point for bariatric surgery is usually a BMI of at least 35, some have queried whether or not such surgery would also benefit diabetes patients with lower BMIs. This question was investigated by Dr. Chih-Cheng Hsu from the China Medical University in Taiwan and colleagues. They examined records of 52 diabetic patients who received bariatric surgery either sleeve gastrectomies or gastric bypass and compared them to records of 299 T2DM patients whose conditions were managed medically. All patients had BMIs lower than 35.
By five years post-surgery, the operated group had lost 21 percent of their initial body weight, bringing their BMIs down from about 31 to 24.5. In addition, their average HBA1c levels dropped from 9.1 percent to 6.3 percent over the same period. Thirty-six percent of this group had complete remission of their T2DM. In contrast, only one person in the medically-managed group, had a complete remission of their disease, and their HBA1c was, on average, 8 percent still in the diabetic range. All differences between surgical and control groups were statistically significant.
Thus, these two studies link bariatric surgery with successful weight loss and T2DM remission, although as retrospective, observational studies that link cannot be said to be causal. Further, they extend this success to those with lower BMIs, and suggest that it may be long-lasting. Importantly, these results add to a growing body of literature supporting the use of this modality for dealing with the epidemic of obesity and T2DM that has been so widespread in recent years.