Background: Obesity is a leading health concern in the United States. Because traditional treatment approaches for weight loss are generally unsuccessful in the long term, bariatric surgical procedures are increasingly being performed to treat extreme obesity. To facilitate research in this field, the National Institute of Diabetes and Digestive and Kidney Diseases responded to this knowledge gap by establishing the Longitudinal Assessment of Bariatric Surgery (LABS) consortium.

Methods: A competitive National Institute of Diabetes and Digestive and Kidney Diseases grant process resulted in the creation of a group of investigators with expertise in bariatric surgery, internal medicine, endocrinology, behavioral science, outcomes research, epidemiology, biostatistics, and other relevant fields. These investigators have worked closely to plan, develop, and conduct the LABS study. The LABS consortium protocol is a prospective, multicenter observational cohort study of consecutive patients undergoing bariatric surgery at 6 clinical centers. LABS includes an extensive database of information systematically collected preoperatively, at surgery, perioperatively during the 30-day postoperative period, and longer term.

Results: The LABS study has been organized into 3 phases. LABS-1 will include all patients > or =18 years of age who have undergone bariatric surgery by LABS-certified surgeons with the goal to evaluate the short-term safety of bariatric surgery. LABS-2, a subset of approximately 2400 LABS-1 patients, will evaluate the relationship of patient and surgical characteristics to the longer term safety and efficacy of bariatric surgery. LABS-3 will involve a subset of LABS-2 subjects who will undergo detailed studies of mechanisms involved in weight change. The rationale, goals, and approach to study bariatric surgery are detailed in this report, along with a description of the outcomes, measures, and hypotheses used in LABS-1 and -2.

Conclusion: The goal of the LABS consortium is to accelerate clinical research and understanding of extreme obesity and its complications by evaluating the risks and benefits of bariatric surgery. LABS investigators use standardized definitions, high-fidelity data collection, and validated instruments to enhance the ability of clinicians to provide meaningful evidence-based recommendations for patient evaluation, selection for surgery, and follow-up care.