Diabetes Treatment Often Discontinued, or Simplified, After Bariatric Surgery

Obese individuals who undergo bariatric surgery are significantly less likely to start taking medications for type 2 diabetes, or more likely to be able to stop using them if they are taking them already, the results of large-scale French study suggest.

The findings follow two recent studies indicating that bariatric surgery reduces long-term rates of hypertension, type 2 diabetes, and other conditions, although, as reported by Medscape Medical News, it appeared that the overall effect might not persist beyond 5 years.

In the current study of more than 30,000 patients, the researchers focused on rates of antidiabetes medication usage up to 6 years after bariatric surgery, finding that those patients who had the procedure were at least four times more likely than control patients to discontinue treatment for diabetes.

Bariatric surgery patients were also substantially less likely than control patients to initiate such treatment during follow-up. In both cases, the greatest effect was seen with gastric bypass, although sleeve gastrectomy and adjustable gastric banding also significantly improved outcomes.

The research, by Anne Fagot-Campagna, MD, PhD, from the Caisse Nationale d’Assurance Maladie des Travailleurs Salarieés, Paris, France, and colleagues, is published online today in JAMA Surgery.

However, the team warns that, despite the encouraging findings with bariatric surgery, “patients and physicians should be aware that morbid obesity remains a chronic disease even after bariatric surgery because 50.1% of patients with preexisting antidiabetes treatment remained on treatment 6 years after surgery.”

“Our study highlights the message that these patients require careful lifelong follow-up to monitor obesity complications,” they stress.

In an accompanying invited commentary, Michel Gagner, MD, from the Department of Surgery, Herbert Wertheim School of Medicine, Florida International University, Miami, wonders whether some of the billions of dollars spent on diabetes medications could be redirected to fund more bariatric surgeries, as only a minority of patients who could qualify for such operations actually undergo them, he notes.

He calculates that the $38.8 billion annual expenditure on antidiabetic drugs in the United States alone could pay for surgical treatment in an extra 1.3 million patients.

Diabetes Treatment Often Discontinued, or Simplified, After Bariatric Surgery

To determine the longer-term effect of bariatric surgery on treatment for diabetes, Fagot-Campagna and colleagues examined data from the Système National d’Information Inter-régimes de l’Assurance Maladie health insurance database, which covers the entire French population.

They identified all patients who underwent bariatric surgery during 2009, classifying them according to the procedure performed. The patients were matched by age, sex, body mass index, and diabetes treatment with the same number of control individuals who were hospitalized for obesity in 2009 but did not undergo bariatric surgery between 2005 and 2015.

The researchers gathered follow-up data for the period 2008 to 2015, counting as medication users those who received at least three diabetes drug reimbursements during a 12-month period.

After exclusions, the team identified 15,650 patients who underwent primary bariatric surgery in 2009, of whom 84.6% were women. The mean age was 38.9 years.

The most common bariatric surgery procedure was gastric band, performed in 48.5% of patients, followed by gastric bypass in 27.7%, sleeve gastrectomy in 22.0%, and other procedures in 1.8%.

Of the 1633 bariatric surgery patients receiving antidiabetes treatment at baseline, 30.2% had a gastric band fitted, 40.1% had bypass, 26.5% had sleeve gastrectomy, and 3.2% underwent other procedures.

Since the start of this study, gastric banding has fallen out of favor, and sleeve gastrectomy and gastric bypass are now the two most commonly performed procedures.

There were no significant differences between the bariatric surgery and control groups in terms of age, sex, body mass index, socioeconomic score, and antidepressant and antidiabetes treatment, with metformin the most commonly used glucose-lowering medication in both groups.

However, bariatric surgery patients were less likely than control patients to be receiving antihypertensive, lipid-lowering, anxiolytic, and opioid therapies.

In those receiving medication for diabetes at baseline, bariatric surgery patients had significantly higher rates of treatment discontinuation after 6 years of follow-up than control patients, at −49.9% vs −9.0% (P < .001).

Multivariate analysis adjusted for age, sex, body mass index, and social precarity showed that bariatric surgery was also significantly associated with antidiabetes medication discontinuation, at an odds ratio, vs no surgery, of 16.7 for gastric bypass, 7.3 for sleeve gastrectomy, and 4.3 for gastric banding

The team also notes that even when diabetes medication was not discontinued, “it was often simplified,” with 40.0% of patients switching from insulin to another treatment and 57.0% switching from dual therapy to monotherapy, or to no antidiabetes treatment.

For patients not receiving diabetes treatment at baseline, bariatric surgery patients were significantly less likely than control patients to have initiated diabetes treatment by the 6-year follow-up, at 1.4% vs 12.0% (P < .001).

Multivariate analysis revealed that bariatric surgery was protective against starting glucose-lowering medication, at an odds ratio, vs no surgery, of 0.06 for bypass, 0.08 for sleeve gastrectomy, and 0.16 for gastric banding.

Can Bariatric Surgeons Do What Cardiac Surgeons Did?

In his commentary, Gagner points out that there are notable differences between the French and US bariatric surgery landscapes.

For example, just 11% of patients with type 2 diabetes in France undergo such surgery compared with approximately 30% in the United States, and French surgeons are much less likely to perform Roux-en-Y gastric bypass, preferring instead sleeve gastrectomy.

Although Gagner says that sleeve gastrectomy has an “excellent antidiabetic effect,” he notes that the benefit appears to diminish with increasing follow-up.

He also laments the lack of data in the current analysis on duodenal switch, as “it has been associated with the highest resolution of diabetes of any surgical procedure.”

However, a larger issue is that only 800 patients in the study experienced resolution of their diabetes with bariatric surgery, which, when compared with the almost 3 million people in France affected by type 2 diabetes, represents merely “a drop in the ocean.”

Hence, he wonders whether healthcare dollars spent on antidiabetes medication could instead be used to fund more weight loss surgeries.

 “Is this the beginning of a battle of giants, a Titanesque clash between a pharmaceutical industry of billions of dollars that protects its interests vs a much smaller surgical devices group?” he asks.
“Can we do better? Surgeons did in the past by responding to the challenge of coronary artery disease by providing operations to millions of patients. Why can’t we do the same for type 2 diabetes? Nothing should prevent us from doing it except ourselves,” he concludes.
The authors have disclosed no relevant financial relationships.

JAMA Surg. Published online February 14, 2018. Article full text, Commentary extract

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