Published in December 2013 Issue             

164 Studies,
161,756 Patients
Over Nearly 10 Years:
What Does This Add Up To?


A new meta-analysis of studies carried out between 2003 and 2012 shows higher remission rates of diabetes and high blood pressure and a lower mortality rate than previously reported. The study, published online in JAMA Surgery, is an update to a meta-analysis of studies conducted between 1990 and 2003 and published in the Journal of the American Medical Association (JAMA, Buchwald et. al.) back in October 2004.

Researchers from Washington University School of Medicine in St. Louis reviewed outcomes from nearly 162,000 patients in 164 studies (37 randomized clinical trials and 127 observational studies), over almost 10 years.

They discovered 92 percent of patients in randomized clinical trials experienced diabetes remission after surgery, slightly higher than the 86 percent remission rate found in observational studies, but significantly higher than the 76.8 percent remission rate found in the 2004 JAMA study.

Remission rates for hypertension were about 75 percent in both the randomized clinical trials and observational studies, while the remission rate in 2004 was 61.7 percent. Body Mass Index (BMI) loss five years after surgery ranged from 12 to 17 in the new study. Before surgery, patients had an average BMI of 45.62.

"With the 2004 study, we now have 22 years worth of data from over 180,000 patients and 300 studies," said study co-author J. Esteban Varela, MD, MPH, MBA, Fellow of the ASMBS. "The data continues to prove bariatric surgery is not only safe and effective in providing significant and sustainable weight loss, but is the most effective treatment today for diabetes, hypertension and an array of other diseases and conditions in people with obesity."

In the new study, 30-day mortality rate was 0.08 percent, down from the 0.3 percent reported in 2004. Complication rates ranged from 10 to 17 percent and the reoperation rate was about 7 percent. Complication and reoperation rates were not reported in the previous

By procedure, gastric bypass and sleeve gastrectomy resulted in the greatest weight loss, but had a higher rate of complications and mortality than adjustable gastric banding. Gastric banding had the highest reoperation rate (12% in randomized trials), while gastric bypass had the lowest at 3 percent, followed by sleeve gastrectomy, which had a reoperation rate of 9 percent. The new meta-analysis included sleeve gastrectomy, which was not available in the 1990s. Of note, sleeve gastrectomy had comparable weight loss to that of gastric bypass at 5 years.

"This is but the latest study to validate the high degree of safety and effectiveness of bariatric surgery," said Ninh T. Nguyen, MD, FACS, President of the American Society for Metabolic and Bariatric Surgery (ASMBS) and Vice-Chair of the Department of Surgery at UC Irvine School of Medicine. "Today we are performing operations that are as safe or safer than gallbladder and hernia repair surgery."

According to the Centers of Disease Control and Prevention (CDC), more than 78 million adults were obese in 2011–2012.1 The ASMBS estimates about 24 million people have severe or morbid obesity. Individuals with a BMI greater than 30 have a 50 to 100 percent increased risk of premature death compared to healthy weight individuals as well as an increased risk of developing more than 40 obesity-related diseases and conditions including type 2 diabetes, heart disease and cancer.2,3