Bariatric Surgery. OHTAC Recommendation. Bariatric Surgery

Transcription

1 OHTAC Recommendation Bariatric Surgery January 21,

2 The Ontario Health Technology Advisory Committee (OHTAC) met on January 21, 2005 and reviewed bariatric surgery for morbid obesity. Obesity is defined as a body mass index (BMI) >30 kg/m 2. 1 Morbid obesity is defined as a BMI>40 kg/m 2 or >35 kg/m 2 with comorbidities. Comorbidities associated with obesity include diabetes, hypertension, dyslipidemias, obstructive sleep apnea, weight related arthropathies, and stress urinary incontinence. An expert estimated that there are approximately 160,000 people morbidly obese in Ontario. In the United States, the prevalence of morbid obesity is 4.7% ( ). Patients with morbid obesity may be considered for bariatric surgery of which there are a number of surgical procedures and several different variations on these procedures. The surgical interventions can be divided into 2 general types: malabsorptive (bypassing parts of the gastrointestinal tract to limit the absorption of food), and restrictive (decreasing the size of the stomach in order for the patient to feel satiated with a smaller amount of food). All these procedures may be performed either laparoscopically or through laparotomy. An example of a malabsorptive technique is Roux en Y gastric bypass. Examples of restrictive techniques are vertical banded gastroplasty and adjustable gastric banding. The term gastric bypass surgery is a general term that encompasses a variety of methods, all of which involve a reconfiguration of the digestive system. A new type of bariatric surgery involves adjustable gastric banding which is not an insured service in Ontario 1 Body mass index: Body weight expressed in kilograms (kg) divided by height expressed in square metres (m 2 ). 2

3 A systematic review of the literature and data by the Medical Advisory Secretariat (MAS) concluded: Bariatric surgery, in general, is effective for sustained weight loss averaging 16% and resolution of comorbidities for patients with BMI >40 and >35 with comorbidities (including diabetes, high lipid levels and hypertension) over 10 years. This is largely based on evidence from the prospectively designed Swedish Obesity Study which recently published 10 year outcomes for patients who received bariatric surgery compared to patients who received nonsurgical treatment. Regarding specific procedures, there is evidence that malabsorptive techniques are better than other banding techniques in terms of weight loss and resolution of comorbidities. However, there are no published prospective, long-term, direct comparisons available between these techniques. Extrapolating from 2003 U.S. experience, Ontario would require approximately 3,500 bariatric surgeries per year and currently provides approximately 508 per year including out-of-country referrals. Surgery for morbid obesity is considered an intervention of last resort for patients who previously attempted first line forms of medical management (diet, increased physical activity, behavioural modification and drugs). In the absence of direct comparisons of active nonsurgical intervention through caloric restriction versus bariatric techniques, the following observations are made: o A recent systematic review examining the efficacy of major commercial and organized self help weight loss programs in the United States concluded that the evidence to support the use of such programs was suboptimal, except for one trial on Weight Watchers. Furthermore, the programs were associated with high costs, attrition rates and probability of regaining >50% of the lost weight in 1 to 2 years. o A recent randomized controlled trial reported one year outcomes comparing weight loss and metabolic changes in severely obese patients assigned to either a low carbohydrate 3

4 diet or a conventional weight loss diet. At 1 year, weight loss was similar between the two groups (average 2-5 kilograms) and there was a favourable effect on triglyceride levels and glycemic control in the low carbohydrate diet group. o A decision analysis model showed bariatric surgery results in increased life expectancy in morbidly obese patients when compared to diet and exercise. o A cost-effectiveness model showed bariatric surgery costeffective relative to nonsurgical management. OHTAC recommends the following with regard to bariatric surgery: 1. OHTAC fully endorses the 2004 Chief Medical Officer of Health Report Healthy Weights, Healthy Lives, of the need to prevent obesity. 2. Bariatric surgery should be considered as an effective technique in the treatment of morbidly obese people (body mass index or BMI >40 and >35 with comorbidities) in whom prior nonsurgical approaches to weight loss have failed. Detailed selection criteria for patients considering bariatric surgery must be developed. 3. Bariatric surgery centres of excellence, with appropriate interior and exterior physical renovations, medical equipment and furniture to accommodate morbidly obese patients, should be established and have an interdisciplinary team of specialists (including surgeons, endocrinologists, dieticians, nurses, psychologists, etc.) to preoperatively assess and postoperatively monitor morbidly obese patients. Adjustable gastric banding should be considered an insured service at these centres of excellence. 4

5 4. The decision as to which of the bariatric procedures to use should be made following a discussion between the surgeon and patient that includes the risks and benefits for each procedure. 5. While bariatric surgery centres are being developed in Ontario, Provider Services Branch should consider establishing contracts with bariatric surgery centres in the United States for out-of-country referrals. 5