The purpose is to determine the economic, clinical and quality of life outcomes of bariatric surgery and describe the consequences of protracted wait-times (~ 2 years) for this procedure.

Severe obesity affects approximately 3% of Canadians (nearly 1 million people) and is becoming increasingly common and costly. Surgery for severe obesity, known as bariatric surgery, substantially reduces weight and the risk of death, decreases obesity-related health problems and increases quality of life. However, surgery carries a 0.5-2% up-front risk of death, has potentially serious short and long-term complications, and an uncertain cost-to-benefit ratio. Surgery is becoming increasingly popular, programs are being initiated or expanded across the country, and waiting lists are several years long. Provincial governments, unable to keep pace with surgical demand, are sending patients to the US for surgery and patients are petitioning governments for increased access to care.

By collecting data from a clinical obesity program that services an entire Canadian health region of over 1 million people and linking these data to provincial and regional data sources, this study aims to:

1. Determine whether surgery improves 2-yr medical and patient-centered outcomes (such as quality of life, satisfaction, and others) compared to both medical and community wait-list control patients;
2. Comprehensively compare the 3-yr costs of surgical and non-surgical care;
3. Determine the impact of 2-yr wait times for surgery on patient health and wellness, including quality of life and patient satisfaction.

This study will provide essential data to accurately determine the benefits, risks, and costs of bariatric surgery in the Canadian context for patients, care providers, and decision makers. Equally important, it will determine whether the health and quality of life of Canadians waiting for surgery is adversely affected because of extended wait-times. Results will directly influence and streamline patient care, will be applicable to similar programs across the country, and serve as an important foundation for future research and data collection.

Inclusion Criteria:

1. 18-60 years old
2. Male and Female
3. BMI Levels greater than or equal to 35 kg/m2 and a major medical comorbidity OR BMI levels greater than or equal to 40 kg/m2
4. Able to provide written informed consent

Exclusion Criteria:

1. Pregnant or nursing
2. Previously enrolled in this study (e.g Community Control Arm)
3. Currently participating in a clinical trial
4. Individual expected to have difficulty with follow-up visits, completion of questionnaires, etc.
5. Any contraindications to bariatric surgery and/or anti-obesity medical treatment
6. Ability and willingness to complete questionnaires.
7. Any other medical, social or geographic condition, which, in the opinion of the investigator would not allow safe completion of the study protocol.
8. Patients in whom protein sparing very low calorie diet therapy is planned.

Three participant goups (n=500:)

Bariatric Surgery(Sx):150 participants. Patients approved for bariatric surgery in an Adult Weight Management Clinic (AWMC) will be eligible (BMI ≥35 kg/m2 and a major medical comorbidity or BMI ≥ 40 kg/m2). Contraindications to surgery are pregnancy, unstable psychiatric disease, patients deemed too medically high-risk, age > 60 years, active substance abuse, or an active eating disorder.

Medical Treatment(Mx):200 participants. Patients will be approached for the study upon their first visit in the AWMC.

Both medical and surgical patients receive intensive lifestyle counseling (diets, exercise, behavioral modification) delivered according to current recommendations. Other than receiving extra education about surgery and post-operative diets, there is no difference in care between the medical and surgical arms.

Community Wait-List Control(Wx):150 participants will be enrolled from the list of newly referred patients to the AWMC.