Benefit of Bariatric Surgery for Obesity and Diabetes Maintained After Five Years
By David Fiore, MD
Professor of Family Medicine, University of Nevada, Reno
Dr. Fiore reports no financial relationships relevant to this field of study.
SYNOPSIS: In this five-year follow-up of bariatric surgery (sleeve gastrectomy and gastric bypass) vs. medical management for overweight and obese patients with diabetes, those who underwent surgery experienced sustained weight loss and reductions in glycated hemoglobin, medication use, and improved quality of life.
SOURCE: Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery versus intensive medical therapy for diabetes - 5-year outcomes. N Engl J Med 2017;376:641-651.
Previous studies by these investigators and others have demonstrated short- and mid-term (up to three years) benefits of bariatric surgery over medical management alone for type 2 diabetes and obesity.1-5 In this report, Schauer et al examined five-year outcomes in the final analysis of the STAMPEDE trial, a non-blinded, randomized study of 150 obese diabetics at a single institution. All patients received intensive medical therapy and were assigned to either just medical therapy, Roux-en-Y gastric bypass, or sleeve gastrectomy. The mean body mass index (BMI) was 37 kg/m2, but surprisingly, the inclusion criteria included patients with diabetes and a BMI of only 27-43 kg/m2. The primary outcome was the ability to maintain a glycated hemoglobin (HbA1c) of ≤ 6% without medication. Prespecified secondary outcomes included measures of glycemic control, weight loss, blood pressure, lipid levels, renal function, ophthalmologic outcomes, medication use, adverse events, and quality of life using the 36-Item Short Form Survey (SF-36).
Of the 134 patients who completed the five years of follow-up, a HbA1c of < 6% was achieved in only two of 38 of patients in the medical therapy-only group, compared to 14 of 49 patients in the gastric bypass group and 11 of 47 in the sleeve-gastrectomy group. The surgical groups also contained more participants achieving an HbA1c of ≤ 6% without medication (remission), ≤ 6.5% without medication, and ≤ 7% with diabetes medication. Importantly, the reductions in HbA1c were similar in patients, regardless of whether their BMI was greater than or less than 35 kg/m2.
Other secondary outcome measures also showed greater improvement with surgery compared to medical management. Mean HbA1c levels after five years were 8.5% in the medical group and 7.0% in the surgical group. Weight loss was greater in the surgery groups (medical management -5.3 kg, gastric bypass -23.2 kg, and sleeve gastrectomy -18.6 kg). Triglycerides also improved more in the surgical groups, but low-density lipoprotein was not different significantly between groups, nor was blood pressure. There were no major differences in renal or ophthalmologic outcomes. Lastly, quality of life was measured with the SF-36. Patients in both surgical groups demonstrated improvement in their physical functioning, general health, bodily pain, and energy-fatigue scores. Patients in the medical groups did not improve on any scales and worsened on bodily pain and emotional well-being (patients in the gastric bypass group also worsened in emotional well-being).
There were minimal adverse events reported in all groups. Four patients in the surgical intervention groups required repeat surgery in the first year, and one additional patient required late surgery to repair a gastric fistula. One patient in the medical therapy group died of a heart attack, and one patient in the sleeve-gastrectomy group died of a stroke. Mild anemia was more common in the surgical groups. Excessive weight gain occurred in 19% of the medical group and none in the surgical group.
This study was well-conducted and produced impressive results favoring bariatric surgery over medical management at five years. Patients in both surgical groups lost more weight, used fewer medications, achieved lower HbA1c measurements, and reported a better quality of life. There were few complications with either medical or surgical therapy, but anemia was more common in the surgical groups. One other important finding was that duration of diabetes for less than eight years was associated with maintaining a HbA1c of < 6%. Another important component of this study, which contrasts it to most studies on diabetes and bariatric surgery, is that the investigators enrolled diabetic patients with a BMI as low as 27 kg/m2. Unfortunately, the authors did not report on outcomes based on BMI, so it is impossible to draw any conclusions on what the possible BMI break point is for when to consider surgery in a diabetic patient.
As a primary care physician, I am both enheartened and disheartened by the results of this study. We can now be confident that there is therapy available to our overweight and obese diabetic patients that will help them lose weight and improve their HbA1c with fewer medications. However, it seems counterintuitive that surgery is the answer to a public health “epidemic” such as obesity. It seems that for an individual patient, we now can discuss the pros and cons of bariatric surgery compared with aggressive medical management with a fair bit of certainty about expected outcomes. Weighing our patients’ preferences, we can make a joint decision about which treatment would be best. What this study doesn’t tell us is whether surgery will lower the complications of diabetes, such as nephropathy, retinopathy, and heart disease, nor does it tell us how surgery compares with aggressive lifestyle modification, which may be the most important (but most difficult) intervention.
- Dixon JB, O’Brien PE, Playfair J, et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: A randomized controlled trial. JAMA 2008;299:316-323.
- Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery versus intensive medical therapy for diabetes — 3-year outcomes. N Engl J Med 2014;370:2002-2013.
- Schauer PR, Burguera B, Ikramuddin S, et al. Effect of laparoscopic Roux-en Y gastric bypass on type 2 diabetes mellitus. Ann Surg 2003;238:467-484.
- Brethauer SA, Aminian A, Romero-Talamás H, et al. Can diabetes be surgically cured? Long-term metabolic effects of bariatric surgery in obese patients with type 2 diabetes mellitus. Ann Surg 2013;258:636-637.
- Schauer PR, Kashyap SR, Wolski K, et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes. N Engl J Med 2012;366:1567-1576.
It seems that for an individual patient, clinicians now can discuss the pros and cons of bariatric surgery compared with aggressive medical management with a fair bit of certainty about expected outcomes.
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