Mildly Obese Diabetics: Surgery May Offer 5-Year Control

Marlene Busko

September 18, 2015

In a study of mildly obese East Asian patients with type 2 diabetes, 64% of patients who had bariatric surgery attained complete or partial diabetes remission that lasted 5 years, and they maintained a mean weight loss of 21%. In contrast, fewer than 3% of patients in a comparison medical-care group had diabetes remission, and their mean body mass index (BMI) was virtually unchanged.

Thus, "for mildly obese patients with [type 2 diabetes], the improvement in glycemic control from metabolic surgery lasts at least 5 years," Dr Chih-Cheng Hsu (China Medical University, Taichung, Taiwan) and colleagues report in their study, published online September 16 in JAMA Surgery.

"Weight loss for sure is the cornerstone of diabetes remission after surgery," senior author Dr Wei-Jei Lee (Min-Sheng General Hospital, Taoyuan, Taiwan) told Medscape Medical News in an email.

But 5-year survival was not better in patients who underwent surgery. "What we don't know is whether [bariatric surgery] can bring [a] reduction of mortality and prevent end-organ damage in this group of patients," Dr Lee said. "We think it may take 10 years to see the difference [in survival]."

"The question remains: should [metabolic and bariatric surgery] be more widely adopted?" Dr Robin P Blackstone (University of Arizona College of Medicine, Phoenix) asks rhetorically in an accompanying editorial. "The long-term solution to the management of obesity…awaits discovery, [and] additional answers need to be urgently sought and tested," he concludes.

In the meantime, "we need to carefully provide this treatment option to mildly obese type 2 diabetes patients with not well-controlled disease," Dr Lee maintains. "The practice should be performed under a clinical-trial setting with detailed monitoring. We need more studies and reports before a conclusion can be made [about which patients benefit most and which type of surgery is best]."

Metabolic Complications at a Lower BMI in Asians

Fewer than half of all patients with type 2 diabetes can maintain a therapeutic goal of an HbA1c below 7% with medical therapy, Dr Hsu and colleagues write. Bariatric surgery can successfully treat type 2 diabetes in morbidly obese patients with a BMI above 35.

However, no published studies have looked at glycemic control in patients with a BMI below 35 who had bariatric surgery and were followed for more than 3 years. Thus, Dr Hsu and colleagues aimed to investigate this.

"Taiwanese, as other Asians,…tend to have obesity-related metabolic complications at a lower BMI [than non-Asians]," Dr Lee explained. The incidence of obesity is also lower in Taiwan than in the United States, although the incidence of type 2 diabetes is similar (around 10% of the population), he added.

Different BMI cut points are used to define obesity in Asians: BMI > 24 is overweight, BMI > 27 is mildly obese, and BMI > 32 is moderately obese, Dr Lee explained.

"The BMI range is appropriate, as East Asian patients and citizens of Asian ancestry in the United States are affected by diabetes at a much lower BMI than other groups," Dr Blackstone commented.

The researchers identified a group of 33 patients (63.5%) who underwent gastric bypass and 19 patients (36.5%) who underwent laparoscopic sleeve gastrectomy during 2007 or 2008 at a regional hospital and were followed until 2013. The patients had HbA1c greater than 6.5% and a BMI of less than 35 and were aged 18 to 67.

They also identified a group of 299 patients treated medically in the Diabetes Management Through an Integrated Delivery System clinical trial who had a similar age range, baseline diabetes, and BMI.

There were more women in the surgical group compared with the medical group (78.8% vs 51.2%), and the surgery patients were younger (mean age, 44.2 vs 51.2 years) and had had diabetes for a longer time (5.0 vs 2.7 years). They also had a higher initial BMI (31.0 vs 29.1) and poorer glycemic control (HbA1c 9.1% vs 8.1%).

At 5 years, the mean BMI dropped from 31.1 to 24.5 in the surgical group but was relatively unchanged (from 29.1 to 28.8) in the medical group (P < .001 for surgical vs medical groups).

Similarly, the mean HbA1c decreased from 9.1% to 6.3% in the surgical group vs almost no change (from 8.1% to 8.0%) in the medical group (P < .001).

Strikingly, at the 5-year follow-up, 18 patients (36%) in the surgical group attained complete diabetes remission (HbA1c < 6%) and 14 patients (28%) attained partial remission of diabetes (HbA1c 6.0% to 6.5%).

In the medical group, only three patients (1.2%) and four patients (1.6%) attained complete and partial diabetes remission, respectively.

Bypass Patients More Likely to Lose Weight

At the 5-year follow-up, compared with patients who underwent sleeve gastrectomy, those who underwent gastric bypass lost more weight (a mean loss of 18.7 vs 14.2 kg; P = .008) and had a greater change in BMI (a drop of 7.4 vs 5.1; P = .001).

They were also more likely to achieve complete diabetes remission (46.9% vs 16.7%; P = .03), and they were equally likely to achieve partial diabetes remission (21.9% vs 38.9%; P = .20).

The mortality rate was similar between the surgical and medical groups: one patient who underwent surgery (1.9%), specifically gastric bypass, died, and nine patients in the medical group (3.0%) died (P = .66). The incidence of end-stage renal disease was also similar in the medical group (one patient; 1.9%) and surgical group (two patients; 0.7%; P = .37).

According to Dr Blackstone, barriers to bariatric surgery include cost, complications, lack of surgical labor resources, poor access to financially supported care, weight regain, and clinician and payer bias against surgery.

Scientists studying molecular genetics may someday be able to find a way to overcome the "genetic reset" that occurs when people lose a lot of weight but then have to consume fewer calories than slim people to maintain the weight loss, he suggests.

"Surgery will not be the answer for any epidemic disease" such as obesity, Dr Lee agreed. "We need…society, medicine, [families], and [people to] work together to solve the [obesity epidemic]," he said.

However, "surgery might provide some help for some patients at this moment."

This work was supported by grants from Min-Sheng General Hospital and the National Health Research Institutes. The authors and editorialist have no relevant financial relationships.

JAMA Surg. Published online September 16, 2015. Abstract, Editorial


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