From Medscape’s reportage of the study published in the New England Journal of Medicine on July 30th, 2009:

July 29, 2009 — Several risk factors may help identify factors linked to poor outcomes for bariatric surgery, according to the results of a prospective, multicenter, observational study reported in the July 30 issue of the New England Journal of Medicine.

From 2005 through 2007, the investigators evaluated 30-day outcomes in consecutive patients undergoing bariatric surgical procedures at 10 clinical US sites. For 4776 patients undergoing first-time bariatric surgery, the composite endpoint of 30-day major adverse outcomes included death; venous thromboembolism; percutaneous, endoscopic, or operative reintervention; and failure to be discharged from the hospital.

Mean age of the study sample was 44.5 years, 21.1% were men, 10.9% were nonwhite, and more than half had at least 2 comorbid conditions. Median body-mass index (BMI), defined as weight in kilograms divided by the square of the height in meters, was 46.5 kg/m².

The bariatric procedure performed was Roux-en-Y gastric bypass in 3412 patients (performed laparoscopically in 87.2% of these patients) and laparoscopic adjustable gastric banding in 1198 patients. The analysis excluded 166 patients who underwent other procedures. Among patients treated with Roux-en-Y gastric bypass or laparoscopic adjustable gastric banding, 30-day mortality rate was 0.3%, and 1 or more major adverse outcomes occurred in 4.3% of patients.

In an accompanying editorial, Malcolm K. Robinson, MD, from Harvard Medical School in Boston, Massachusetts, is hopeful that learning more about how bariatric surgery works may help develop even less invasive procedures.

“It is a sobering fact that some obese young adults may lose up to 20 years of life expectancy if they do not reduce their weight,” Dr. Robinson writes. “One must treat obesity aggressively, though thoughtfully, and with an eye toward developing effective prevention and better therapies that ideally would eliminate the need for surgery altogether. But until we get to that point, the weight of the evidence indicates that bariatric surgery is safe, effective, and affordable.”

The practice of bariatric surgery has increased more than 10-fold in the United States between 1994 and 2005, and an editorial by Robinson, which accompanies the current study, describes current indications for bariatric surgery. According to the National Institutes of Health, bariatric surgery may be considered for patients with a BMI of 40 kg/m² or more. Alternatively, surgery may also be considered among patients with a BMI of 35 kg/m² or more if they have another serious coexisting medical condition.

Some patients who meet these indications may be reticent to undergo surgery because of a concern regarding potential adverse events. The current study examines the rate of adverse events in the first 30 days after laparoscopic adjustable gastric banding and Roux-en-Y gastric bypass.

Study Highlights

• Study participants included patients 18 years or older undergoing bariatric surgery at 1 of 10 sites in the United States between 2005 and 2007. All sites had a high amount of experience with bariatric surgery.
  

  All participants underwent a baseline health survey, and chronic medical conditions were recorded through self-report of patients.
  

  The main outcome of the study was the composite of death, deep venous thromboembolism or pulmonary embolism, surgical reintervention, or failure to be discharged from the hospital in the 30 days after the surgery.
  

  3412 study participants underwent primary surgery with Roux-en-Y gastric bypass, and this surgery was performed laparoscopically in 87.2% of patients. A total of 1198 patients had laparoscopic adjustable gastric banding.
  

  The mean age of subjects was 44.5 years, and the median BMI was 46.5 kg/m²; 21.1% of patients were men.
  

  82.1% of all subjects had at least 1 coexisting medical condition, of which hypertension and obstructive sleep apnea were the most common.
  

  Patients undergoing Roux-en-Y gastric bypass had a higher mean BMI and mean number of coexisting medical conditions vs patients undergoing laparoscopic adjustable gastric banding.
  

  The 30-day mortality rate for all patients was 0.3%.
  

  The rates of the composite outcome among patients who received laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass, and open Roux-en-Y gastric bypass were 1.0%, 4.8%, and 7.8%, respectively.
  

  The most common events of the composite endpoint were abdominal reoperation and endoscopic intervention.
  

  Factors associated with a higher risk for the composite endpoint after multivariate analysis included Roux-en-Y gastric bypass surgery vs laparoscopic adjustable gastric banding, a previous history of deep venous thrombosis or pulmonary embolus, obstructive sleep apnea, and an inability to walk 200 feet. Baseline BMI or patient ethnicity did not affect the risk for the composite endpoint.

Clinical Implications

According to the National Institutes of Health, bariatric surgery may be considered for patients with a BMI of 40 kg/m² or more. Alternatively, surgery may also be considered among patients with a BMI of 35 kg/m² or more if they have another serious coexisting medical condition.

Variables associated with a higher risk for complications in the first 30 days among patients receiving bariatric surgery in the current study included Roux-en-Y gastric bypass surgery vs laparoscopic adjustable gastric banding, a previous history of deep venous thrombosis or pulmonary embolus, obstructive sleep apnea, and an inability to walk 200 feet.