While short-term complications and death rates are low following bariatric surgery, according to the Longitudinal Assessment of Bariatric Surgery (LABS-1), patients with a preoperative history of sleep apnea remain at a greater risk of complications.

According to the study, funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health, less than 1% (0.3%) of patients died within 30 days of surgery. The findings support the short-term safety of bariatric surgery as a treatment for patients with extreme obesity.

"Evaluating the 30-day safety outcomes of bariatric surgery in large populations is an essential step forward," said coauthor Myrlene Staten, MD, senior advisor for diabetes translation research at NIDDK in an announcement. "And LABS-1 data are from all patients who had their procedure performed by a surgeon participating in the study, not from just a select few patients."

The LABS-1 consortium followed 4,776 patients having bariatric surgery for the first time, and evaluated complications and death rates within the first 30 days after surgery. Patients were at least 18 years old and had an average body mass index (BMI) of 44. The majority of LABS-1 patients were white and female, which, according to the NIDDK, is the most common population to undergo bariatric surgery. The study took place over 2 years at 10 medical sites, with one additional center coordinating data collection and analyses.

Within 30 days of surgery, 4.1% of patients had at least one major adverse outcome, defined as death, development of blood clots in the deep veins of the legs or in the pulmonary artery of the lungs, repeat surgeries, or failure to be discharged from the hospital within 30 days of surgery.

Thirty-day mortality was low but varied depending on the type of bariatric surgery performed. This ranged from no deaths in the laparoscopic adjustable gastric band group, to six (0.2%) in the laparoscopic Roux-en-Y gastric bypass group, to nine (2.1%) in those undergoing open Roux-en-Y gastric bypass. After adjusting for patient and center characteristics, there were no significant differences in complication risk that could be attributed to the type of procedure. Patient factors such as a preoperative history of deep vein blood clots and sleep apnea increased the risk of postoperative complications. Patients with a very high BMI were also at an increased risk: A patient with a BMI of 75 had a 61% higher risk of complications than those with a BMI of 53.

LABS-1 is part of the Longitudinal Assessment of Bariatric Surgery consortium, an NIDDK-funded study launched in 2003 to examine the short- and long-term benefits and risks of bariatric surgery for adults with extreme obesity.

Results appear in the July 30 issue of the New England Journal of Medicine.

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