The Longitudinal Assessment of Bariatric Surgery (LABS) consortium conducted a multicenter, observational study to evaluate the 30-day safety outcomes in patients who underwent an initial bariatric surgical procedure. Approximately one-third of U.S. adults are considered obese based on their body mass index or BMI (a measure of weight relative to height); these individuals have increased risk for type 2 diabetes, coronary heart disease, stroke, fatty liver disease, certain types of cancer, and other diseases. Used as a treatment for extreme obesity, bariatric surgical procedures modify the digestive tract to limit the amount of food that can enter the stomach, decrease absorption of nutrients, or both. Currently, bariatric surgery appears to be the only intervention that consistently results in substantial and sustained weight loss in people who are extremely obese, and it has been linked to remission of diabetes, decreases in cardiovascular risk factors, and a significant reduction in mortality over time. Like most surgical procedures, however, bariatric surgery presents risks of complications and death that must be considered when deciding whether to undergo the procedure.
In this study, LABS-1, the consortium followed 4,776 patients who had bariatric surgery, from before their surgery through the first 30 days following surgery, to evaluate the death and complication rates. All of the patients participating in the study were adults and were obese, and most had a BMI measurement reflecting extreme obesity. Similar to most populations undergoing bariatric surgery, the majority of the patients in the LABS study were white and female. The study took place over two years at 10 medical centers located throughout the U.S., with one center coordinating data collection and analysis. Within 30 days of surgery, 4.1 percent of patients had at least one major adverse outcome, defined as development of blood clots in the deep veins of the legs or the pulmonary artery of the lungs, repeat surgeries, not being discharged from the hospital within 30 days, or death. Mortality rates were low: less than 1 percent (0.3 percent) of patients died within 30 days. The risk of complications varied depending upon whether or not patients had certain health conditions prior to the surgery and how obese they were. Although the rate of adverse events also appeared to vary with the type of surgical procedure, differences in patient characteristics may have accounted for much of the variation in risk among the procedures. Further investigation may help clarify any such differences.
This evaluation highlights the level of short-term risks associated with bariatric surgery, an effective weight loss procedure that is increasingly popular as a treatment for extreme obesity. The safety of such surgery is an important consideration with risks examined in the context of long-term benefits. The LABS-1 study will help health care providers and patients make personalized decisions about the potential risks and benefits of bariatric surgery by taking into account a patient’s characteristics. Another study being conducted by the LABS consortium, LABS-2, will follow a subset of the patients to gather longer-term data that will further inform decisions about the surgery.
The Longitudinal Assessment of Bariatric Surgery (LABS) Consortium: Perioperative Safety in the Longitudinal Assessment of Bariatric Surgery. N Engl J Med. 361:445-54, 2009.