Metabolic surgery may be more effective than medical therapy for long-term control of type 2 diabetes

1. 10-year remission rates were significantly higher for Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD) than medical therapy.

2. Patients in the BPD and RYGB groups had fewer diabetes-related complications. 

Evidence Rating Level: 1 (Excellent)

Study Rundown: Compared to conventional therapy, metabolic surgery results in significant short-term improvements among patients with type 2 diabetes. However, there is little evidence to investigate the long-term efficacy of metabolic surgery. This single-centre, randomized controlled trial aimed to compare outcomes at 10-year follow-up after surgery by Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD) with medical therapy plus lifestyle interventions for the treatment of type 2 diabetes. The primary endpoint for this study was durability of diabetes remission at 10 years, while secondary outcomes included overall glycemic control, change in markers of metabolic syndrome, and glomerular filtration rate (GFR). Remission of diabetes was defined as a fasting plasma glucose < 100 mg/dL and HbA1c < 6.5% without pharmacotherapy for one year. According to study results, patients in the RYGB and BPD groups had higher 10-year remission rates and fewer diabetes-related complications than those in the medical therapy group. Additionally, surgery resulted in significant decreases in weight, BMI, and waist circumference compared to medical therapy. This study was limited by a small sample size and lack of generalizability as patients from a single hospital were assessed. It is likely that findings were skewed by demographics of the population assessed. Nonetheless, this study provided valuable insight into the use of surgery for long-term control of type 2 diabetes.

Click to read the study in The Lancet

Relevant Reading: Bariatric Surgery versus Intensive Medical Therapy for Diabetes — 5-Year Outcomes

In-depth [randomized controlled trial]: Between April 30, 2009, and Oct 31, 2011, 72 patients were assessed for eligibility at a single tertiary hospital in Italy. Included were those aged 30-60 years with a BMI ≥ 35 kg/m2, type 2 diabetes for at least 5 years, and HbA1c ≥ 7.0%. Patients with type 1 diabetes, previous bariatric surgery, pregnancy, and severe medical comorbidities were excluded. Altogether, 60 patients (20 in conventional medical therapy, 20 in BPD, and 20 in RYGB) were enrolled into the study. 95.0% (57 of 60) patients completed the 10-year follow-up.

Of all patients who were surgically treated, 37.5% (n=15) maintained diabetes remission throughout the study period. Specifically, in the intention-to-treat analysis, 10-year remission rates for BPD (50.0%, 95% confidence interval [CI] 29.9-70.1) and RYGB (25.0%, 95% CI 11.2-46.9) were significantly higher than that for medical therapy (5.5%, 95% CI 1.0-25.7, p=0.0082). Relative risks were 9.0 (95% CI 1.3-63.5) for BPD vs. medical therapy and 4.5 (0.58-35.0) for RYGB vs. medical therapy. 58.8% (20 of 34) patients who were observed to be in remission at 2 years after surgery had a relapse of hyperglycemia during the follow-up period (BPD 52.6%, 95% CI 31.7-72.7 vs. RYGB 66.7%, 95% CI 41.7-84.8). Compared to the medical therapy group (mean HbA1c 7.6±0.5%), patients in the surgery groups reported better glycemic control at 10-year follow-up (BPD mean HbA1c 6.4±0.3% and RYGB mean HbA1c 6.7±0.3%). A similar pattern was reported for HbA1c percentage reduction from baseline (-0.8±1.0% for medical therapy vs. -2.4±1.6% for BPD vs. 1.9±1.6% for RYGB, p<0.0097), 10-year percentage weight loss (-4.2±8.8% for medical therapy vs. -29.2±8.9% for BPD vs. -28.0±8.0% for RYGB), cardiovascular risk, and estimated GFR. Medically treated patients had a significantly higher incidence of diabetes-related complications than surgically treated patients (72.2%, 95% CI 49.1-87.5 vs. 5.0%, 95% CI 0.9-23.6). However, the risk of serious adverse events was greater in the BPD group than in the medical therapy group (odds ratio [OR] 2.7, 95% CI 1.3-5.6). Findings from this study suggest that metabolic surgery should be considered by clinicians in long-term management of patients with type 2 diabetes.

Image: PD

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