Metabolic Surgery Superior to Drug Therapy at Controlling Type 2 Diabetes, Study Says

Metabolic surgery is more effective than conventional medical therapy in the long-term control of type 2 diabetes (T2D), according to results of a 10-year follow-up study of a randomized controlled trial published in The Lancet.

Bariatric surgery, or metabolic surgery, has long been considered a treatment option for improving short-term to mid-term symptoms of those with T2D. Several randomized controlled trials showed the surgery can lead to improved hyperglycemia, prolonged disease remission, reduced cardiometabolic risk, reduced hypertension, and lower incidence of chronic kidney disease.

However, “although observational studies of traditional bariatric surgery suggest that diabetes remission can persist long term, it is difficult to extrapolate these findings to the broader population of patients with T2D,” researchers wrote.

As there are currently no data published beyond 5 years from randomized controlled trails on the efficacy of metabolic surgery for T2D, investigators aimed to report 10-year outcomes of patients with advanced T2D who underwent Roux-en-Y gastric bypass (RYGB) or biliopancreatic diversion (BPD) and compare them with patients who received medical therapy plus lifestyle interventions.

The open-label, single-center trial was conducted at a tertiary hospital in Rome, Italy. All participants were between ages 30 and 60, had a body mass index (BMI) of 35 kg/m² or greater, a history of T2D lasting at least 5 years, and glycated hemoglobin (A1c) concentrations of 7% or higher. Individuals were randomly assigned (1:1:1) to either medical therapy, RYGB, or BPD by a computerized system.

Over the course of 10 years, medical therapy options were updated and included administration of various oral hyperglycemic agents, insulin, glucagon-like peptide 1 (GLP-1) analogues and sodium-glucose cotransporter-2 (SGLT-2) inhibitors. Patients in this arm also were managed by a team of diabetologists, dieticians, and nurses, advised to reduce overall energy and fat intake, and to increase physical activity.

All participants completed visits at baseline, at 1, 3, 6, 9, and 12 months, every 6 months until 60 months had passed, and every year thereafter. After 2 years, patients with poorly controlled diabetes who requested surgical treatment were permitted to cross over to the surgery group.

The study’s primary outcome was durability of diabetes remission at 10 years, defined as the combination of fasting plasma glucose less than 100 mg/dL and A1c less than 6.5% without continuous pharmacological therapy for at least 1 year.

A total of 60 patients were randomized to the 3 groups between April 30, 2009 and October 31, 2011; 57 completed the 10-year follow-up. Of the 40 patients who underwent surgery, 15 (37.5%) maintained remission after 10 years.

Analyses revealed:

• 10-year remission rates in the intention to treat (ITT) population were 5.5% for medical therapy (95% CI, 1–25.7; 1 participant went into remission after crossover to surgery); 50% for BPD (95% CI, 29.9–70.1); and 25% for RYGB (95% CI, 11.2–46.9; P = .0082)
• 20 (58.8%) of 34 participants who were observed to be in remission at 2 years had a relapse of hyperglycemia during the follow-up period (BPD 52.6% [95% CI, 31.7–72.7]; RYGB 66.7% [95% CI, 41.7–84.8])
• All individuals with relapse maintained adequate glycemic control at 10 years, with mean A1c of 6.7% (0.2)
• Median diabetes-free survival time was 5 years (95% CI, 4 to infinite value) in RYGB and 9 years (95% CI, 5 to infinite value) in BPD; a log-rank test (P = .25) indicated no difference between the 2 surgical groups
• Participants in the RYGB and BPD groups had fewer diabetes-related complications than those in the medical therapy group (relative risk, 0.07; 95% CI, 0.01–0.48, for both comparisons)
• Serious adverse events occurred more frequently among participants in the BPD group (odds ratio [OR] for BPD vs medical therapy 2.7; 95% CI, 1.3–5.6; OR for RYGB vs medical therapy, 0.7; 95% CI, 0.3–1.9

After 10 years, patients who underwent surgery exhibited significantly greater A1c percentage reduction from baseline than those in the medical arm, while target A1c of less than 7% was met in 87.5% of patients who underwent surgery and in none in the medical therapy group.

Patients who underwent surgery also had significantly lower body weight, BMI and waist circumference, and reduced diabetes-related complications and cardiovascular risk at 10 years. In addition, these patients exhibited better kidney function, quality of life, and reduced medication use compared with those who did not have surgery.

“The deterioration of glycemic control observed in the medical therapy group after 5 years, despite no substantial weight regain and increased use of effective modern drugs, is a reminder of the progressive nature of T2D and, by contrast, attests to the remarkable anti-diabetes potency of metabolic surgery,” researchers noted.

The American Diabetes Association defines a diabetes cure as persistent remission of hyperglycemia without need for any pharmacological therapy for more than 5 years. Therefore, “The findings from this study provide the most robust scientific evidence yet that full-blown T2D is a curable disease, not inevitably progressive and irreversible,” said Francesco Rubino, MD, the chair of bariatric and metabolic surgery at King’s College London and senior study author. “In addition to representing a major advance in the treatment of diabetes, metabolic surgery is our best lead to the elusive cause of the disease.”

The study’s small sample size marks a limitation, in addition to the fact it was conducted at a single center. Data also show the risk of relapse appeared to be highest within the first 5 years after surgery but declined significantly thereafter. More data is needed to corroborate this finding and larger prospective observations are warranted to help define when or if surveillance frequency can be reduced post-surgery.

As BPD and RYGB resulted in a reduction in long-term medication use, cardiovascular risk factors and diabetes-related complications, authors noted results support the notion metabolic surgery can be a cost-effective approach to treating T2D.

“Metabolic surgery is arguably the most effective available therapy for T2D and can be a life-saving option for many patients,” Rubino said. “It should be appropriately prioritized in times of pandemic and beyond."

Reference

Mingrone G, Panunzi S, De Gaetano A, et al. Metabolic surgery versus conventional medical therapy in patients with type 2 diabetes: 10-year follow-up of an open-label, single-centre, ransomised controlled trial. Lancet. 2021;397(10271):293-304. doi:10.1016/S0140-6736(20)32649-0