2005 04 en

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Surgical treatment of morbid obesity

An update

AGENCE D’ÉVALUATION DES TECHNOLOGIES

ET DES MODES D’INTERVENTION EN SANTÉ

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Surgical Treatment of Morbid Obesity

An Update

August 2006

(Original French version published in October 2005)

Report prepared for AETMIS by

by Raouf Hassen-Khodja and Jean-Marie R. Lance

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This report was translated from an offi cial French publication of the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS). Both the original report, titled Le traitement chirurgical de l’obésité morbide : mise à jour and the English report are available in PDF format on the Agency’s Web site.

Scientifi c review

Dr. Véronique Déry, Chief Executive Offi cer and Scientifi c Director Translation

Jocelyne Lauzière, M.A., Certifi ed Translator Editorial supervision

Suzie Toutant Page layout Jocelyne Guillot Proofreading Frédérique Stephan Bibliography research Denis Santerre Co-ordination Lise-Ann Davignon

Communications and dissemination Diane Guilbault

For further information about this publication or any other AETMIS activity, please contact:

Agence d’évaluation des technologies et des modes d’intervention en santé 2021, Union Avenue, Suite 1040

Montréal (Québec) H3A 2S9 Telephone: (514) 873-2563 Fax: (514) 873-1369

E-mail: [email protected] www.aetmis.gouv.qc.ca

How to cite this document:

Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS). Surgical Treatment of Morbid Obesity:

An Update. Report prepared by Raouf Hassen-Khodja and Jean-Marie R. Lance (AETMIS 05-04). Montréal: AETMIS, 2006, xvii-113 p.

Legal deposit

Bibliothèque et Archives nationales du Québec, 2006 National Library of Canada, 2006

ISBN 2-550-45724-2 (Print) (French edition ISBN 2-550-45464-2) ISBN 2-550-45725-0 (PDF) (French edition ISBN 2-550-45465-0)

This report may be reproduced in whole or in part provided that the source is cited.

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MISSION

The mission of the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS) is to contribute to improving the Québec health-care system and to participate in the implementation of the Québec government’s scientifi c policy. To accomplish this, the Agency advises and supports the Minister of Health and Social Services as well as the decision-makers in the health-care system, in matters concerning the assessment of health services and technologies. The Agency makes recommendations based on scientifi c reports assessing the introduction, diffusion and use of health technologies, including assistive devices for disabled persons, as well as the modes of providing and organizing services. The assessments take into account many factors, such as effi cacy, safety and effi ciency, as well as ethical, social, organizational and economic implications.

EXECUTIVE

Dr. Luc Deschênes

Cancer Surgeon, President and Chief Executive Offi cer of AETMIS, Montréal, and Chairman, Conseil médical du Québec, Québec

Dr. Véronique Déry

Public Health Physician, Chief Executive Offi cer and Scientifi c Director

BOARD OF DIRECTORS Dr. Jeffrey Barkun

Associate Professor, Department of Surgery, Faculty of Medicine, McGill University, and Surgeon, Royal Victoria Hospital (MUHC), Montréal Dr. Marie-Dominique Beaulieu

Family Physician, Holder of the Dr. Sadok Besrour Chair in Family Medicine, CHUM, and Researcher, Unité de recherche évaluative, Hôpital Notre-Dame (CHUM), Montréal

Dr. Suzanne Claveau

Specialist in microbiology and infectious diseases, Hôtel-Dieu de Québec (CHUQ), Québec

Roger Jacob

Biomedical Engineer, Coordinator, Capital Assets and Medical Equipment, Agence de la santé et des services sociaux de Montréal, Montréal

Louise Montreuil

Assistant Executive Director, Direction générale de la coordination ministérielle des relations avec le réseau, ministère de la Santé et des Services sociaux, Québec

Dr. Jean-Marie Moutquin

Obstetrician/Gynecologist, Research Director, and Executive Director, Département d’obstétrique- gynécologie, CHUS, Sherbrooke

Dr. Réginald Nadeau

Cardiologist, Hôpital du Sacré-Cœur, Montréal, Board Member of the Conseil du médicament du Québec

Guy Rocher

Sociologist, Professor, Département de sociologie, and Researcher, Centre de recherche en droit public, Université de Montréal, Montréal

Lee Soderström

Economist, Professor, Department of Economics, McGill University, Montréal

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Dr. Reiner Banken

Physician, Deputy Chief Executive Offi cer, Development and Partnerships

Dr. Alicia Framarin

Physician, Deputy Scientifi c Director

Jean-Marie R. Lance

Economist, Senior Scientifi c Advisor

Lucy Boothroyd

Epidemiologist, Scientifi c Advisor

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FOREWORD

SURGICAL TREATMENT OF MORBID OBESITY: AN UPDATE

Obesity is now considered a major public-health problem and has even been declared a “global epidemic” by the World Health Organization (WHO). This chronic disease, which results from numerous biological, environmental and behavioural factors, leads to several health problems, including hypertension, dyslipidemia, diabetes and some cardiovascular disorders. Québec has not been spared from this epidemic, with a rate of obesity that reached 21.8% in 2004.

In practice, obesity is defi ned as a body-mass index (BMI) greater than 30 kg/m². A more critical threshold is attained when the BMI reaches 40, or even only 35 if it is associated with co-morbidities.

This is referred to as morbid obesity. In such cases, behavioural and medical therapy fail to achieve long-term weight reduction and, according to the WHO, surgery is the only effective treatment.

However, owing to the expanding range of surgical techniques and the recent introduction of laparoscopic approaches, legitimate questions have been raised about the effi cacy and risks of these major procedures.

As early as 1998, the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS) had produced a report on the surgical treatment of morbid obesity, or bariatric surgery. At that time some techniques had been classifi ed as accepted technologies, but another, performed in a Québec hospital, was still considered experimental. The rapid evolution of bariatric surgery and of the scientifi c evidence on this topic has prompted the need for an update. Moreover, faced with the growing prevalence of morbid obesity and concerned about the effi cacy of the different techniques and the need to provide effective management for those affected by this health problem, the Ministère de la Santé et des Services Sociaux (MSSS) asked AETMIS to assess this surgical treatment.

This report examines the effi cacy and risks of complications pertaining to the four major types of procedures, including those performed in Québec. It also compares abdominal-incision approaches with laparoscopic approaches, and deals with the economic aspects of this treatment. The primary sources for this analysis were scientifi c articles and health-technology assessment reports published since 1998.

Results confi rm the long-term effi cacy of surgical treatment in terms of maintaining weight loss and reducing co-morbidities. The different techniques available in Québec are considered effi cacious and safe. Some have proven effi cacy, while others continue to require close follow-up so that patient indications and eligibility may be better identifi ed. In conclusion, AETMIS recommends that an action plan be developed to clearly defi ne the needs for bariatric surgery and establish the means to meet those needs; that key conditions be determined to ensure that hospital centres offer high-quality bariatric treatment; and that a registry on morbid obesity and its management be established.

In submitting this report, AETMIS hopes to contribute to improving the health and quality of life of people with morbid obesity.

Dr. Luc Deschênes

President and Chief Executive Offi cer

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ACKNOWLEDGEMENTS

This report was prepared at the request of AETMIS by Raouf Hassen-Khodja, MD, MSc (health administration), physician (hemobiology) and consultant researcher, and by Jean-Marie R. Lance, MSc (economics), senior scientifi c advisor.

AETMIS would like to thank the following external reviewers for their valuable comments on this report:

Mitiku Belachew, MD

Professor, University Surgery Department, Centre hospitalier régional de Huy, Huy , Belgium Nicholas V. Christou, MD

Surgeon and professor of surgery, McGill University Health Centre, Montréal, Québec Slim Haddad, MD

Associate professor, Department of Social and Preventive Medicine, Faculty of Medicine, and economist, Université de Montréal, Montréal, Québec

Picard Marceau, MD

Professor, Department of Surgery, Université Laval, and surgeon, Hôpital Laval, Quebec City, Québec

Jean Mouïel, MD

Professor, Nice Faculty of Medicine, and specialist in digestive surgery, Centre de chirurgie et laparoscopie, Nice, France

Nicola Scopinaro, MD

Professor, Department of Surgery, Faculty of Medicine, Università di Genova, Ospedale San Martino, Genoa, Italy

Rudolf Steffen, MD

FMH specialist in visceral surgery, Bern, Switzerland

DISCLOSURE OF CONFLICTS OF INTEREST None declared.

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SUMMARY

MORBID OBESITY

Since 1998, in the wake of a report by the World Health Organization (WHO), obesity has been considered a major public-health problem and has even been declared a “global epidemic.” The WHO even calls it a chronic disease requiring long-term strategies for effective prevention and management. Obesity is the result of complex interactions of metabolic, endocrine, genetic, socio-economic, environmental, cultural, psychological and behavioural factors. It causes many diseases, including hypertension, hyperlipidemia, diabetes, some cardiovascular disorders, sleep apnea, osteoarthritis and some cancers, and even death.

Defi nition

Obesity is characterized by excess body fat and is generally defi ned by the body-mass index (BMI), which takes into account weight and height. This index is expressed in kilograms per square metre (kg/m²). The term obesity applies when the BMI is greater than or equal to 30 kg/

m². A BMI between 25 and 29.9 kg/m² is called overweight. Morbid obesity refers to a BMI that is greater than or equal to 40, or 35 kg/m²if associated with co-morbidities.

Prevalence

The prevalence of obesity (BMI ≥ 30) in the household population aged 18 and older (excluding pregnant women) is growing steadily.

Whereas obese people accounted for only 13.8% of Canada’s population in 1978–1979, this proportion rose to 23.1% in 2004; these fi gures are based on directly measured height and weight. The gap between men and women is small: 22.9% vs 23.2%. The situation is comparable in Québec, which has an overall rate of 21.8% (20.9% for men and 22.7% for women). Morbid obesity (BMI ≥ 40) has also risen dramatically in Canada, from 0.9% in

1978–1979 up to 2.7% in 2004, with women being more affected by this problem (3.8% vs 1.6% for men). This fi gure is not available for Québec.

Consequences

Obesity gives rise to a considerable epidemiological and economic burden.

According to studies in the United States, where the rate of obesity during the 1999–2002 period reached 31.1% among people aged 20 to 74, this problem caused at least 112,000 deaths per year, although other estimates combining overweight and obesity yielded more than 300,000 deaths.

Controversy persists over the magnitude of this burden. From an economic viewpoint, Canada’s 1997 direct medical costs attributable to adult obesity were estimated to be $1.8 billion, or 2.4% of total direct medical costs. One study estimated that obesity in Québec led to expenditures totalling $700 million, or 5.8% of the province’s health-care budget (1999–2000 fi scal year), and to productivity losses in excess of $800 million.

ROLE OF SURGICAL TREATMENT IN THE THERAPEUTIC APPROACH TO OBESITY

The therapeutic approach to obesity is multi- faceted and complex. It requires a specially adapted treatment structure and the availability of a multidisciplinary team.

Management of obesity

Obesity management is based on a minimum of three key measures:

1) intensive patient education on improving food patterns;

2) counselling on the need for regular physical activity; and

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3) behavioural approaches designed to help people better regulate the lifestyle habits needing to be modifi ed.

Weight-loss objectives must be clearly defi ned with the patient. Physicians may suggest drug therapy for patients unable to meet their target objectives through diet and physical activity.

Management of morbid obesity

The multi-dimensional approach described above is not effective for treating morbid obesity. According to the WHO, the only effective treatment is bariatric surgery (from the Greek word baros, which means weight).

Bariatric surgery currently encompasses a range of techniques that can be classifi ed into two main types of procedures:

gastric-restriction techniques, which decrease food intake by reducing gastric capacity:

gastroplasty: a pouch or partition is

created by horizontal or vertical stapling or banding (vertical banded gastroplasty), gastric banding: a fi xed or adjustable band is inserted to form a small-volume gastric reservoir;

hybrid techniques, which combine gastric restriction with the principle of intestinal malabsorption by creating either a bypass or a diversion system:

gastric bypass techniques, including Roux- en-Y, the most common variant performed worldwide,

biliopancreatic diversion with distal gastrectomy or duodenal switch.

Although all these surgical techniques were developed for the abdominal-incision, or open-surgery, approach (laparotomy), surgeons continued to explore new ways of performing this procedure, chiefl y in terms of the surgical approach. As a result, laparoscopic techniques appeared in the mid-1990s and soon became widely used in several countries. In fact, according to an international survey, 62.85% of

the procedures performed worldwide in 2003 were done laparoscopically, especially gastric bypass and adjustable gastric banding.

Although the effi cacy and safety of each of these techniques, whether open or laparoscopic, are established to varying degrees, they still raise legitimate questions.

ASSESSMENT OBJECTIVES

In 1998, the Conseil d’évaluation des technologies de la santé (the predecessor of AETMIS) published a report on the surgical treatment of morbid obesity. The need to clarify the status of biliopancreatic diversion with duodenal switch (the procedure used in Québec), the rapid expansion of laparoscopic techniques and the growing prevalence of morbid obesity are the reasons for this update. This report also responds to a request from the MSSS asking AETMIS to examine the evolving effi cacy of bariatric-surgery techniques and the best conditions for managing people with severe obesity. Lastly, this assessment explores the economic aspects of this treatment.

METHODOLOGY

This report is based on a review of the scientifi c literature and health-technology assessments published between 1998 (publication date of the previous report) and April 2005. Standard databases—Medline, Cochrane Library and HTA Database—were searched on the following keywords: obesity, morbid obesity, surgical treatment, bariatric surgery, gastroplasty, gastric bypass, gastric banding.

The search retrieved a large number of studies published since 1998. However, given the scarcity of comparative trials, whether randomized or not, and the predominance of case series, studies were selected by means of a simplifi ed grid containing the following elements: study design, publication date, number of patients treated, length of follow-up, and relevance of clinical outcome measures.

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The main evaluation criteria for this analysis were:

Clinical effi cacy: excess weight loss (EWL), defi ned in relation to ideal weight, or, alternatively, weight loss and a decrease in body-mass index;

Safety: complications characterized by their onset (short, medium or long term), type and severity;

Co-morbidity: reduction or not of associated conditions;

Consumption of health goods or services or other resources: days of hospitalization, mean length of stay, operating time;

Effi ciency: resource costs or savings; cost- effectiveness and cost-utility ratios.

RESULTS

Surgical treatment in general

Despite the large number of primary studies on the surgical treatment of morbid obesity, most cover either treatments with established effi cacy or new approaches, especially laparoscopic procedures. Few provide long-term outcomes, however. A single major study (Swedish Obese Subjects Intervention Study, or SOS) compares surgical treatment with the medical approach.

It uses a prospective design with 18 subject- matching variables. The other comparative studies, some of which were randomized, examined either the effects of the surgical approach (open or laparoscopy) or variants of the same technique. The studies are therefore mostly retrospective case series, while a few are prospective.

Surgical treatment is currently recognized as being a more effective therapeutic option than non-surgical treatment for patients who are morbidly obese. Although most of the evidence refers to short-term outcomes, several studies are beginning to demonstrate long-term sustained weight loss. Moreover, the SOS (the best controlled study available) found that bariatric surgery achieved a sustained weight loss of 16.1% in people with BMIs of at least 40,

or at least 35 if associated with co-morbidities, including diabetes, hyperlipidemia and

hypertension. Surgery itself has some potentially serious complications. Although these adverse effects are generally managed appropriately, they require continual assessment.

Bariatric surgery remains an expensive

procedure because it requires a multidisciplinary team, a specialized technical platform and long- term follow-up. In return, the resulting weight loss decreases the prevalence of co-morbidities and their consequences (prescription drug spending), serving to reduce productivity losses caused by sick leave and disability, and improves quality of life. Nevertheless, the favourable cost-effectiveness (or cost-utility) ratio and the effi ciency suggested by the current state of the evidence need to be confi rmed by longer-term well-designed economic studies.

Surgical techniques

Although bariatric surgery relies on a wide range of techniques, current evidence does not yet favour any one over the others, owing to the variety of contexts in which they are applied, the diversity of patient characteristics and the lack of well-designed controlled studies. Moreover, a single procedure may involve several techniques.

The choice of surgical technique depends on a number of factors:

Patient profi le: age, personality, BMI, food patterns, personal understanding and commitment, co-morbidities, contra- indications;

Reversibility or non-reversibility of the technique;

Risks linked to each technique (e.g., wound dehiscence, hernias, device slippage, staple- line failure);

Potential effects of nutritional defi cits;

Availability of human and material resources;

Support provided by the expertise of a multidisciplinary team; and

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Surgical team’s experience in bariatric surgery and, where applicable, in laparoscopy, which requires a lengthy learning curve.

In terms of overall effi cacy, current evidence generally indicates that hybrid techniques combining gastric restriction and intestinal malabsorption are superior to those designed only to restrict gastric capacity. The following provides details regarding the main techniques under review, of which three are used in Québec.

Roux-en-Y gastric bypass (RYGB): This technique has proven effi cacy in terms of stable weight loss, low complication rates and reduction of co-morbidities. Considered the gold standard of weight-loss surgery, the RYGB is the most commonly used gastric-bypass technique.

Vertical banded gastroplasty (VBG): Although this technique has established effi cacy, it has achieved lower than expected weight loss and has lost favour with North American surgeons (including those in Québec). Combined with the RYGB, VBG yields good long-term results.

Adjustable gastric banding (AGB): This technique is generally recognized as being effective in terms of both weight loss and low complication rates. It has the advantage of being reversible and is increasingly replacing VBG.

Biliopancreatic diversion with duodenal switch (BPD-DS): Despite the fact that this technique is used only in a few centres because of its stringent requirements for post-operative patient management and follow-up, its long years in use (over 20 years), the cumulative number of procedures performed to date and its positive weight-reduction results mean that this procedure is no longer considered experimental.

In addition, some studies suggest that BPD-DS would be appropriate for super-obese patients with BMIs over 50.

Laparoscopic approach

Laparoscopic procedures offer many advantages: they reduce hospital stays and decrease, if not eliminate, complications

associated with open surgery; however, they do have other types of complications. Surgeons must train in the best conditions to master this approach.

The two most advanced laparoscopic techniques are Roux-en-Y gastric bypass (LRYGB) and adjustable gastric banding (LAGB), and they are no longer considered experimental. They must nonetheless be introduced in an environment that permits the ongoing study of their effects.

After one year of follow-up, the LRYGB

achieves the same outcomes as the open version, and their early complications differ only slightly.

However, it is still necessary to obtain longer- term comparative.

The LAGB techniques appear to be safe and effective (in terms of excess weight loss) and have the extra advantage of being reversible.

Furthermore, major complications are rare, and complication and re-operation rates are acceptable. Yet these effects have been measured only in the short term and need to be confi rmed by longer studies.

The other laparoscopic techniques are still classifi ed as experimental, owing to the uncertainty surrounding their effects.

Lastly, in addition to offering no comparisons, the evidence on the surgical treatment of adolescents and children with morbid obesity is insuffi cient to draw valid conclusions.

Although this assessment has not examined the consequences of substantial weight loss (e.g., the need for reconstructive plastic surgery), this aspect must not be overlooked in the therapeutic treatment plan because it has a potentially signifi cant psychological impact.

COST EFFECTIVENESS OF BARIATRIC SURGERY

According to the current state of evidence, even if the published economic studies and models have their limitations, the surgical treatment of morbid obesity would appear to be a cost-effective procedure. Although this

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type of surgery is relatively expensive, mostly because of the costs incurred by the procedure itself and by the management of early or late complications than can result, and because of the requirement for annual follow-ups and the possible need for plastic surgery, the positive effects linked to weight reduction would appear to compensate for these costs. Indeed, bariatric surgery lowers the prevalence of co- morbidities (e.g., cardiovascular diseases and diabetes) and their impact on resource utilization (hospitalizations, drug expenditures). It also reduces productivity losses caused by sick leave and disability, and improves quality of life.

These initial results must nevertheless be confi rmed by more well-designed economic evaluations based on factual data on long-term effectiveness and resource utilization and on valid comparisons of the different surgical techniques and approaches (laparoscopy or open surgery).

CHALLENGES FOR QUÉBEC’S MEDICAL PRACTICE

Different bariatric-surgery techniques are currently being used in Québec by highly experienced surgeons in the fi eld. Yet there is a lack of data on the quality and effectiveness of these procedures and on the population of treated patients. The supply of services also appears insuffi cient, given the steady growth of waiting lists and wait times. In such a context:

it is crucial to know and share all the different information about the treated population and the outcomes achieved in bariatric-surgery centres;

it is necessary to effectively measure the evolution and extent of bariatric-surgery needs resulting from the growing prevalence of morbid obesity;

it is advisable to promote the development of practice guidelines on the management of patients with morbid obesity in order to ensure that service offerings are of high quality.

Québec’s Association of General Surgeons (QAGS) has developed a policy on the surgical treatment of morbid obesity. The QAGS emphasizes the following points: need for an interdisciplinary team; designation of referral centres; information and training for surgical residents; and increased bariatric-surgery training opportunities. Furthermore, it would be advisable, in the management of any bariatric- surgery plan, to anticipate the potential need for reconstructive plastic surgery.

RECOMMENDATIONS

1) It is recommended that the Ministère de la Santé et des Services Sociaux and other decision makers concerned with the problem of morbid obesity identify current and future needs in bariatric surgery, establish an action plan to increase the capacity to provide this treatment, and ensure that patients in the different settings and regions have fair access to these services.

2) It is recommended that, at the organizational level, all hospital bariatric-surgery programs comply with the conditions listed below, which will be subject to a quality-assurance process. Such programs must:

Establish a strict patient-selection process (e.g., patients who have BMIs of 40 kg/m² or more, or 35 with co-morbidities, who have acceptable operative risks, who are motivated and well informed of the inherent risks of the procedure and of the need for lifelong follow-up) and a system for prioritizing patients on scheduled waiting lists.

Have available facilities and equipment adapted to the specifi c profi le of the patients concerned (e.g., recovery rooms, intensive-care units, beds and furniture, diagnostic investigation tables, operating tables, and adapted surgical instruments).

Have an experienced multidisciplinary team capable of supplying the full range of care and services tied to this type of

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treatment: surgical team, psychologist, nutritionist, medical specialists (e.g., diabetologists, cardiologists, pneumologists).

Provide closely monitored lifelong follow-up, and cover the physical and psychological dimensions of this treatment, which consequently includes consultations linked to the need for plastic surgery.

3) It is recommended that a Québec registry on morbid obesity and its management be established. This registry will offer key support in implementing a regional follow-up program for operated patients by linking the different health-care structures (hospitals, health centres) and by including specifi c patient education on nutritional approaches appropriate for this type of patient. This data source will make it possible to determine the prevalence and categorization of the different patients, to evaluate the surgical procedures that are currently being performed and to rule on the new bariatric-surgery approaches.

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AGB Adjustable gastric banding AHAL Ad hoc alimentary limb

AHFMR Alberta Heritage Foundation for Medical Research AHRQ Agency for Healthcare Research and Quality

AHS Ad hoc stomach

ALOS Average hospital length of stay

ANAES Agence Nationale d’Accréditation et d’Évaluation en Santé AOT Average operating time

ASBS American Society of Bariatric Surgery

ASERNIP-S Australian Safety and Effi cacy Register of New International Procedures – Surgical BMI Body mass index (kg/m²). It is calculated by dividing weight (in kilograms) by

height squared (in metres).

BPD Biliopancreatic diversion (open procedure) BPD-DS Biliopancreatic diversion with duodenal switch

DG Distal gastrectomy

DS Duodenal switch

EWL Excess weight loss

FDA Food and Drug Administration

GB Gastric banding

GBP Gastric bypass (open procedure) GPI Genuine Progress Index

INAHTA International Network of Agencies for Health Technology Assessment LAGB Laparoscopic adjustable gastric banding

LBPD Laparoscopic biliopancreatic diversion

LBPD-DS Laparoscopic biliopancreatic diversion with duodenal switch LGBP Laparoscopic gastric bypass

LRYGB Laparoscopic Roux-en-Y gastric bypass

LSAGB Laparoscopic Swedish adjustable gastric banding LVBG Laparoscopic vertical banded gastroplasty MAS Medical Advisory Secretariat

LIST OF ABBREVIATIONS

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MSAC Medical Services Advisory Committee MUHC McGill University Health Centre NAGB Non-adjustable gastric banding

NHMRC National Health and Medical Research Council NICE National Institute for Clinical Excellence

OHTAC Ontario Health Technology Advisory Committee QAGS Québec Association of General Surgeons QALY Quality-adjusted life year

RYGB Roux-en-Y gastric bypass

SAGB Swedish adjustable gastric banding SF-36 36-Item Short Form Health Survey

SOS Swedish Obese Subjects Intervention Study TEC Technology Evaluation Center

VBG Vertical banded gastroplasty or silastic ring vertical gastroplasty VBG-RYGB Vertical banded gastroplasty combined with Roux-en-Y gastric bypass WHO World Health Organization

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GLOSSARY

Anastomosis

Connection between two vessels and, by extension, between two conduits of the same type or between two nerves. It may be natural or surgically created.

Conversion

In this report, conversion refers to a surgical intervention that begins as a laparoscopic procedure and is completed as an open procedure.

Dentition

Set of natural teeth.

Dumping syndrome

Syndrome involving the rapid early gastric emptying of the operated stomach (partial gastrectomy and/or gastrojejunal anastomosis). It occurs when food or liquid passes too quickly into the intestine, causing digestive problems, discomforts, etc.

Excess weight

Excess weight in relation to ideal weight calculated according to height and sex.

Excess weight loss (EWL)

Excess weight loss achieved through diet or through medical or surgical treatment. EWL is

measured by weight units (pounds or kilograms) or by a percentage (initial weight – current weight) / (initial weight – ideal weight).

Ideal weight

This weight is based on the tables produced by the Metropolitan Life Insurance Company (1979). It is evaluated according to average values that take into account height and sex.

Laparoscopy

Visual examination directly in the abdominal cavity previously distended by means of an endoscope introduced through the abdominal wall for diagnostic or therapeutic purposes.

Laparotomy

Surgical incision through the abdominal wall and peritoneum. (Also called open surgery.) Plication

Surgical technique which consists in folding an anatomical structure or organ to modify its position, shape or function, or to modify the position, shape or function of an adjacent organ.

Quality-adjusted life year (QALY)

Calculation method allowing situations to be compared in relation to two criteria taken into account simultaneously, that is, effi cacy (number of life years gained) and the quality of life of those years.

Secretin

Hormone produced in the duodenum that activates the secretion of pancreatic juices (especially alkaline salts) and, to a lesser extent, bile, intestinal juices and saliva.

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1 INTRODUCTION

Since 1998, in the wake of a report prepared by the World Health Organization (WHO) from the work of the International Obesity Task Force, obesity has been considered a major public-health problem and has even been declared a “global epidemic.” The WHO even calls it a chronic disease requiring long- term strategies for effective prevention and management: obesity is the result of complex interactions of metabolic, endocrine, genetic, socio-economic, environmental, cultural, psychological and behavioural factors. Obesity causes many diseases, including hypertension, hyperlipidemia, diabetes, some cardiovascular disorders, sleep apnea, osteoarthritis, some cancers, and even death [WHO, 2003].

1.1 DEFINITION OF OBESITY

Obesity is characterized by excess body fat and is generally defi ned by the body mass index (BMI), which takes into account weight and height. This index is calculated by dividing weight in kilograms by height in metres squared:

it is therefore expressed in kilograms per square metre (kg/m²). The term obesity applies when the BMI is greater than or equal to 30 kg/m². If the BMI is between 25 and 29.9 kg/m², it is called overweight. According to the International Obesity Task Force, obesity can be divided into three categories: Obese Class I (BMI from 30.0 to 34.9 kg/m²), Obese Class II (from 35.0 to 39.9) and Obese Class III (greater than or equal to 40 kg/m²). Morbid obesity refers to Obese Class III, or to Obese Class II if it is associated with other co-morbidity factors.

1.2 BURDEN OF OBESITY

1.2.1 Prevalence

In the United States, the incidence of obesity (BMI ≥ 30) in the population aged 20 to 74 has

been growing steadily: the rate of obesity rose from 15.1% (age-standardized rate) in the years 1976–1980 to a mean of 23.3% between 1988 and 1994, and to 31.1% in the 1999–2002 period [NCHS, 2004].

In Canada, the percentage of obese people (BMI ≥ 30) in the household population aged 18 and older (excluding pregnant women) in 2004 was estimated to be 23.1%, while it was 13.8%

in 1978–1979. These rates are respectively estimated to be 5.1% and 2.3% for people with BMIs between 35 and 39.9 kg/m², and 2.7% and 0.9% when the BMI is greater than or equal to 40. Although the difference in the obesity rate between men (22.9%) and women (23.2%) is small, it is larger for people with BMIs greater than or equal to 40 kg/m²: 1.6% for men and 3.8% for women. The base data used to calculate these rates were obtained by directly measured height and weight, although an adjustment was necessary to minimize non-response bias (42.5%), (owing to those who did not respond to that part of the survey) [Tjepkema, 2005].

In Québec, according to the data from the 1998 Québec social and health survey, 29.0% (34.1%

of men and 23.5% of women) of the population aged 20 to 64 was overweight (BMI ≥ 27 kg/m²).

This rate rose to 12.7% (13.5% for men and 11.7% for women) for a BMI ≥ 30 kg/m², and to 3.0% for a BMI ≥ 35 kg/m² [Institut de la statistique du Québec, 2001]. Note that these data were collected through a self- administered questionnaire, a method which tends to yield lower obesity rates. In 2004, according to Canadian source data, the obesity rate (BMI ≥ 30 kg/m²) in the Québec household population aged 18 and older was 21.8%, the rate in women (22.7%) being higher than that in men (20.9%) [Tjepkema, 2005]. That publication does not provide more detailed statistics for each class of obesity in Québec.

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1.2.2 Mortality and economic impact In the United States, obesity causes a large number of deaths each year, owing both to its complications and to its co-morbidities, although its estimation sparked a major controversy. While a fi rst report by researchers from the Centers for Disease Control and Prevention (CDC) estimated that the number of deaths attributable to overweight and obesity was 365,000 per year [Mokdad et al., 2004], a second report by other CDC researchers yielded a fi gure of 111,909 for obesity alone (BMI ≥ 30) [Flegal et al., 2005]. Even if several factors explain a large part of this difference, it is motivating researchers to develop even more rigorous approaches to estimating mortality attributable to obesity.

Obesity carries an economic burden representing from 5.5% to 7.0% of total health-care spending [Thompson and Wolf, 2001]; it accounted for 27% of the rise in actual spending per person between 1987 and 2001 [Thorpe et al., 2004]. According to a study that examined the relationship between the BMI of people aged 18 to 65 and Medicare spending for these same people at age 65 and older, obese people (30 ≤ BMI < 35) and severely obese people (BMI ≥ 35) generated costs totalling US$9,612 and US$12,342 per person per year respectively, compared with US$6,224 for non-overweight people (18.5 ≤ BMI < 25) [Daviglus et al., 2004].

In Canada, for 1997 alone, direct medical costs attributable to obesity (BMI greater than or equal to 27) in adults were estimated to be

$1.8 billion, or 2.4% of total direct medical costs [Birmingham et al., 1999]. A study by the research group Atlantic GPI (Genuine Progress Index), which adopted and refi ned Birmingham’s method, estimated Québec’s direct health-care costs to be $700 million, or 5.8% of the province’s health-care budget (1999–2000 fi scal year). Costs attributable to productivity losses were evaluated as being in excess of $800 million, and the sum of these two estimates could represent nearly 1% of Québec’s gross domestic product [Colman and Dodds,

2000]. Colman also provided the same estimates for seven other provinces.¹

1.3 ROLE OF SURGICAL

TREATMENT IN THE THERAPEUTIC APPROACH TO OBESITY

The therapeutic approach to obesity is multi- faceted and complex. It requires an adapted treatment structure and the availability of a multidisciplinary team.

Management of obesity

Obesity management is based on a minimum of three key measures:

1) intensive patient education aimed at improving food patterns;

2) counselling on the need for regular physical activity; and

3) behavioural approaches designed to help people better regulate the lifestyle habits needing to be modifi ed [Kushner, 2003;

NHLBI/NIH, 1998].

Weight-loss objectives must be clearly defi ned with the patient [Snow et al., 2005].

Physicians may suggest drug therapy for obese patients unable to meet their target objectives through diet and physical activity. The use of a pharmacological agent requires a doctor–patient discussion before such treatment is initiated.

The side effects of the prescribed medication, the lack of long-term safety data and the modest weight loss associated with it are all points that must be covered [Snow et al., 2005]. According to a recent meta-analysis (April 2005) of the pharmacological treatment of obesity, the mean weight loss achieved, after adjustment for the placebo effect, is less than 5 kg after one year [Li et al., 2005].

Management of morbid obesity

In the latest WHO technical report on the prevention and management of obesity, surgery

1. Colman’s articles are available online: http://www.gpiatlantic.

org/publications/health.shtml#obesity.

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is considered to be the only effective treatment for morbid obesity. This type of surgery is called bariatric surgery (from the Greek word baros, which means weight). Besides its positive effects on weight loss and its acceptable rates of weight-loss maintenance, bariatric surgery is the treatment offering the best cost-effectiveness ratio in the medium term [WHO, 2003; Näslund et al., 2001]. Bariatric surgery encompasses a wide range of techniques, and the effectiveness of each is relatively well established. The choice of one technique over the other is subject to a number of criteria, such as the patient’s clinical and psychological characteristics, the availability of the appropriate infrastructure, the surgeon’s preference and the medical team’s expertise.

The growing “epidemic” of obesity and morbid obesity has prompted the medical body to take greater interest in bariatric surgery and to explore new treatment methods, not only in terms of the techniques themselves but also in terms of the surgical approach, especially laparoscopy. This development has led to a sharp rise in the number of surgical procedures being performed in this fi eld. In the United States, for example, the American Society of Bariatric Surgery (ASBS) reports that this fi gure reached 140,640 in 2004, or more than double the number recorded in 2002

(63,100 procedures) [Colwell, 2005]. This rise can be explained in part by the greater availability of services (e.g., membership in the American Society of Bariatric Surgery doubled between 2000 and 2002 [ASBS, 2001]), but also by a greater reliance on laparoscopy. Moreover, even if the criteria defi ning obesity and the established and generally recognized surgical- candidate profi le have not changed, waiting lists (which may vary according to the surgeon’s expertise) have been growing.

1.4 OBJECTIVE

This is the particular context in which AETMIS proposed to update its information on the effi cacy of the surgical techniques used in the treatment of morbid obesity, which it had already examined in a previous report when it was known as the Conseil d’évaluation des technologies de la santé [CETS, 1998]. In the present update, special attention will be given to laparoscopic techniques, which had barely begun to enter into practice at that time and had therefore not been examined. This report also responds to an assessment request from the Ministère de la Santé et des Services sociaux asking AETMIS to examine the evolution of bariatric surgery and the best patient-care conditions for people with morbid obesity.

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2 METHODOLOGY

This study is interested in both the reports produced by the different assessment agencies that have dealt with the topic of bariatric surgery and the more recent studies published since the release of the fi rst AETMIS report. A literature search was performed using the major databases:

Medline, Cochrane Library, HealthStar (a database that ceased to exist in October 2003) and HTA Database (a health-technology assessment database created jointly by the Centre for Reviews and Dissemination based at the University of York in England, and the INAHTA (International Network for Agencies in Health Technology Assessment). Keywords used were obesity, morbid obesity, surgical treatment, bariatric surgery, gastroplasty, gastric bypass, gastric banding.

The search identifi ed a large number of studies published since 1998. However, given the scarcity of controlled trials, whether randomized or not, and the predo minance of case series, studies were selected by means of a simplifi ed grid containing the following elements:

study design;

publication date;

number of patients treated;

length of follow-up;

relevance of clinical and economic outcome measures.

The main outcome measures for bariatric surgery selected for this analysis were the following (not all were applicable to each of the studies):

Clinical effi cacy: excess weight loss (EWL), defi ned in relation to ideal weight,² or a decrease in body mass index (BMI);

2. In studies, ideal weight is often based on the tables produced by the Metropolitan Life Insurance Company. It is evaluated according to mean values that take into account height and sex (see Appendix I).

Safety: complications characterized by their time of onset (short, medium or long term) and by their type and severity;

Co-morbidity: reduction or not of diseases associated with obesity;

Consumption of health goods or services or other resources: hospitalization days, mean length of hospital stay, operating time (average length of the surgical procedure) (these criteria can be evaluated as clinical health-status indicators or resource- utilization indicators from an economic perspective), days of absenteeism from work, etc.;

Cost effectiveness: resource costs or savings;

cost-effectiveness and cost-utility ratios.

To defi ne the study designs, we used a basic classifi cation system adapted from the one proposed by the Agence Nationale d’Accréditation et d’Évaluation en Santé³ [ANAES, 2001]. This system identifi es a large number of non-comparative studies, regardless of quality:

Randomized comparative study (RC);

Non-randomized comparative study (C), which may be either controlled (CC) or non-controlled (NCC), depending on how much effort was made to ensure that the study groups were as comparable as possible. In addition, the temporal aspect, either prospective (P) or retrospective (R), is indicated by the addition of its corresponding letter:

PCC or RCC PNCC or RNCC

Prospective non-comparative study (P);

Retrospective non-comparative study (R).

3. On January 1, 2005, this agency was granted additional mandates and renamed the Haute Autorité de Santé.

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Here are a few salient facts about the articles selected for this analysis.

Most of the published studies deal with surgical techniques that have established effi cacy, or with new approaches, especially laparoscopic procedures.

This analysis selected 83 studies published between January 1998 and April 2005;

however, after 2000, most studies deal with adjustable gastric banding.

Most of the studies rely on a methodological design that from the outset is not conducive to achieving the most valid results

(non-randomized studies, mostly non- comparative).

Less commonly, some of the studies compare various open or laparoscopic techniques (different types of adjustable bands) or yet again two approaches to the same surgical procedure.

The eight randomized studies compare the laparoscopic and open approaches for the same surgical technique, or different techniques for implanting gastric bands.

Two meta-analyses published in 2004 and 2005, respectively, compare the effi cacy of the main procedures. One of them also deals with their impact on the progression of obesity co-morbidities.

A single study compares surgical treatment with non-surgical treatment, and has given rise to several publications dealing with different aspects of the study.

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3 SURGICAL TECHNIQUES

gastric banding: a fi xed or adjustable band is implanted to form a small-volume gastric reservoir;

hybrid or mixed techniques. These combine gastric restriction with the principle of intestinal malabsorption by creating a bypass system or a diversion system. This group includes:

gastric bypass,

biliopancreatic diversion.

3.2.1 Gastric-restriction techniques 3.2.1.1 GASTROPLASTY

According to the level of the procedure, there are two types of gastroplasty:

Horizontal gastroplasty: Many variants have been proposed, from Mason’s model, which consists in partitioning the stomach horizontally (lesser curvature) by leaving a narrow outlet (stoma) for food passage, to Gomez’s model, which consists in placing a staple line transversely across the proximal part of the stomach and creating a reinforced opening at the level of the greater curvature. Although the sutures were reinforced, the staples often failed and the conduits re-expanded. This type of procedure is no longer performed.

Vertical banded gastroplasty: As described by Mason, vertical banded gastroplasty has the advantage of being easy to perform. This technique consists in creating a small gastric pouch (15–20 ml) that empties into the residual portion of the stomach through a small channel built along the lesser curvature of the stomach and calibrated by means of a polypropylene collar (Figure 1). Patients must not only have good dentition, they must also restrict themselves to eating food in small quantities.

Those patients affl icted with frequent vomiting suffer from vitamin and mineral defi ciencies,

3.1 OBJECTIVES OF THE SURGICAL TREATMENT OF MORBID OBESITY

Bariatric surgery is based on the principle of restricting food intake (by decreasing the gastric reservoir) or of reducing nutrient absorption (by decreasing the contact time between the food bolus and the digestive juices and bile by shortening the section of the intestine that promotes such contact). The effi cacy of surgical treatment is often measured as a percentage of excess weight loss (EWL) in relation to ideal weight: a technique is considered effective if the EWL is greater than or equal to 50% (based on the criteria defi ned by Reinhold [1982]) [CETS, 1998; Hall et al., 1990]. The outcome is excellent if the EWL is greater than 75%, good if between 50% and 75%, and fair if between 25% and 50%.

Most medical associations recommend that bariatric surgery be reserved for obese patients who meet a certain number of criteria, such as:

body mass index (BMI) greater than or equal to 40, or 35 if associated with other co-morbidity factors;

presence of severe co-morbidities;

failure of a diet followed for several years;

acceptance of long-term (even lifelong) follow-up and the inherent risks involved in this type of procedure.

3.2 DESCRIPTION OF THE TECHNIQUES

The two most commonly performed bariatric- surgery procedures are:

techniques based on gastric restriction. These decrease food intake by reducing gastric capacity. This group includes:

gastroplasty: a pouch or partition is created by stapling or banding,

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including iron. Lost weight is frequently regained. Gastric leaks are considered surgical emergencies (risk of septicemia and death).

3.2.1.2 GASTRICBANDING

Silicone gastric banding has been performed for nearly 20 years. The objective of this

procedure is to achieve, by means of a restrictive mechanism, a reduction in dietary intake by creating a small gastric pouch. The gastric fi bres of this pouch stretch more quickly, which stimulates the vagus nerve fi bres and triggers satiety refl exes. In 1987, a silicon part was added to this system, which helps adjust and calibrate the collar that controls the speed of food passage from the upper gastric pouch to the lower portion of the stomach (hour-glass shape). The band can be adjusted by injecting liquid into a subcutaneous reservoir (Figure 2).

This procedure is relatively easy to perform and also reversible, which explains why it is used so frequently. There are a few types of adjustable gastric bands, which basically have differing elasticity and closure systems. The main

trademarks are Lap-Band, SAGB and Heliogast.

Only the Lap-Band is commercially available in Canada.

Improvements in surgical techniques (type, fi xation method and band placement) and the laparoscopic approach have both contributed to signifi cantly reducing complications. Of these, dilatation of the newly formed gastric pouch, whether or not associated with band slippage, remains the most frequent (5–20% of cases).

Adjustable gastric banding is the bariatric- surgery technique that is most often performed laparoscopically.

FIGURE 1 FIGURE 2

Vertical banded gastroplasty Silicone gastric band with injection reservoir and

calibration tube

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3.2.2 Gastric bypass

The key objective of gastric bypass is to reduce the digestion of absorbed nutrients. This procedure induces marked weight loss but is associated with complications that are more or less severe, depending on the technique used.

Techniques combining gastric restriction and malabsorption are used more frequently with morbidly obese patients with BMIs greater than 50.

3.2.2.1 GASTRIC-BYPASSPROCEDURES

Since the 1960s, several modifi cations have been made to Mason’s gastric bypass (Figure 3), which consisted in creating a small proximal gastric pouch by surgically dividing the stomach and its duodenal opening (gastric bypass with retrocolic loop). Other gastric-bypass models consist in creating a reservoir by stapling.

This type of procedure leads to leaks and the dumping syndrome (an adverse event that

occurs with all hybrid techniques that include gastric bypass).

3.2.2.2 ROUX-EN-Y GASTRICBYPASS

Now considered the gold standard in bariatric surgery, this technique consists in creating a small proximal gastric pouch anastomosed to a segment of the jejunum. This system is shaped like a Y; hence the name Roux-en-Y gastric bypass (RYGB). This technique has several variants, one of which involves creating a small pouch with a line of staples (Figure 4). Different RYGB procedures are performed, including short-limb (50–100 cm) Roux-en-Y gastric bypass and long-limb Roux-en-Y gastric bypass, considered by some authors to be biliopancreatic diversions. The main complications associated with RYGB are metabolic, and they require patients to take supplemental vitamins

(especially vitamin B₁₂) and minerals (calcium and iron).

FIGURE 3 FIGURE 4

Basic gastric bypass Roux-en-Y gastric bypass

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3.2.2.3 BILIOPANCREATICDIVERSION

3.2.2.3.1 Scopinaro’s biliopancreatic diversion

Scopinaro et al. [2000] showed that it was possible to decrease nutrient absorption by shortening the intestine and to reduce fat (lipids) absorption by diverting bile juices and decreasing the contact between food and enzymes. Scopinaro’s biliopancreatic diversion shares many similarities with RYGB, but differs in that it involves a complete resection of the lower, or distal, portion of the stomach (Figure 5). The Scopinaro procedure is in fact a biliopancreatic diversion combined with a distal gastrectomy (BPD-DG).

3.2.2.3.2 Biliopancreatic diversion with duodenal switch

Unlike Scopinaro’s biliopancreatic diversion with distal gastrectomy, this technique applies a duodenal switch with an end-to-end duodeno- ileal anastomosis (Figure 6). In theory,

biliopancreatic diversion with duodenal switch (BPD-DS) has the advantage of permitting near- normal functioning of the stomach and avoiding a gastro-enteric anastomosis [Hess and Hess, 1998]. This type of procedure conserves normal vagal innervation (control of the satiety centre) and preserves the antropyloric junction, which plays a role in triggering the secretion of secretin (Table 1). A duodenal switch involves resecting the gastric fundus, helping to reduce the

secretion of hydrochloric acid. Maintaining both the integrity of this junction and a small portion of the duodenum (a few centimetres of the fi rst duodenal loop) seems to prevent gastroduodenal ulcers, perforations and the dumping syndrome [DeMeester et al., 1987]. In 1992 Marceau et al., from the Hôpital Laval in Quebec City, modifi ed this technique by eliminating plication in creating the anastomosis and by replacing it with an end-to-end anastomosis [Baltasar et al., 1995; Marceau and Biron, 1993]. Post-operative complications are most often metabolic, and supplemental vitamins and calcium are required.

FIGURE 5

Biliopancreatic diversion with distal gastrectomy (Scopinaro)

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FIGURE 6

Biliopancreatic diversion with duodenal switch

TABLE 1

Difference between distal gastrectomy (DG) (Scopinaro) and duodenal switch (DS)

DG (SCOPINARO) DS^*

Insertion Stomach/ileum Duodenum/ileum

Common limb 50 cm 100 cm

Vagal innervation Not preserved Preserved

* In 1992 Marceau abandoned plication for an end-to-end anastomosis.

3.2.3 Laparoscopic techniques

In theory, laparoscopic surgery techniques have the advantages of shorter recovery times and lower peri-operative and post-operative complications. Other than the surgical approach itself, laparoscopic techniques are generally identical to open-surgery techniques. While the most commonly used laparoscopic techniques since 1990 are based on gastric restriction, procedures targeting malabsorption are recent and still infrequent.

Vertical banded gastroplasty (VBG) and adjustable gastric banding (AGB) are the

most frequently performed laparoscopic procedures. The LVBG⁴ technique requires considerable expertise in both bariatric surgery and laparoscopy, and it is increasingly being replaced by LAGB, a technique that has been greatly improved in recent years.

Gastric bypass (LGB) is also one of the bariatric surgeries most frequently performed laparoscopically. It is therefore expected that LRYGB performed by experienced surgeons will become a therapeutic option to consider.

4. LVBG: laparoscopic VBG. The same type of abbreviation is used for the other laparoscopic techniques: LAGB, LDG, LRYGB

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Laparoscopic biliopancreatic diversion (LBPD) is used only in exceptional cases because of its complexity and recent entry into the arsenal of bariatric surgery.

3.2.4 Bariatric surgery with hand-assisted laparoscopy

This technique combines two surgical approaches. First, a small incision (6–8 cm) is made to the abdomen. This incision, which

is large enough to fi t a hand, allows the surgeon to palpate the organs and makes it easier to mobilize them (e.g., the colon). The essential part of the procedure is then done laparoscopically (resection, ligature, etc.). This novel approach remains limited to some centres or is used as a training tool before surgeons proceed to exclusively laparoscopic procedures [DeMaria et al., 2002b; Bleier et al., 2000;

Naitoh et al., 1999; Memon and Fitzgibbons, 1998; Watson and Game, 1997].

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4 STUDY OUTCOMES

4.1 SURGICAL VS NON-SURGICAL TREATMENT OF MORBID OBESITY

As part of the major prospective SOS study, Ågren et al. [2002b] compared patients who had undergone open surgery (vertical banded gastroplasty, gastric banding, gastric bypass) with patients who had followed medical (non-surgical) therapy. The SOS study was initially designed to compare, over a 20-year period, 2010 surgically treated obese patients and 2037 matched patients who were offered conventional treatment in primary-care centres.

Control subjects were matched according to 18 basic anthropometric variables or to variables linked to risk factors for morbidity and mortality. The researchers fi nally studied the fi rst 962 consecutive obese patients (BMI > 34 kg/m² for men and > 38 kg/m²for women) aged 37 to 60. These patients were recruited between 1987 and 1991, and were followed for at least six years. The study examined therapeutic effectiveness in relation to weight loss and hospital costs associated with each of the treatment options: bariatric surgery vs services commonly offered to obese patients in primary-care centres (conventional treatment). No specifi c information was given on the treatments actually received by the

“conventional treatment” group. Comparisons of hospital costs will be covered in Chapter 5 on economic outcomes.

Results show that, at one year, the surgical patients had lost more weight (mean weight loss of 25.1 ± 10.1% for 450 patients) than those in the conventionally treated group (mean weight loss of 0.7 ± 6.5% for 425 patients). This major benefi t of bariatric surgery was maintained after six years (mean weight loss of 16.7 ± 11.8% for 401 patients, compared with a mean weight gain of 0.9 ± 10.1% for 344 non-surgical patients).

Virtually all the studies on bariatric surgery are of adult subjects after the failure of conventional treatment (diet and medical therapy) and after review of the patient’s psychological profi le.

Until recently, bariatric surgery for adolescents (ages 11 to 17) with morbid obesity was used only in exceptional circumstances [Abu- Abeid et al., 2003]. A recent meta-analysis of the surgical treatment of morbid obesity identifi ed 12 case series with a combined total of 172 adolescents. However, insuffi cient data and a lack of comparators do not permit valid conclusions to be drawn [Maggard et al., 2005].

Among all the articles identifi ed and selected for the present assessment, a single study compared the effi cacy of surgical vs non-surgical treatment for patients with morbid obesity: the Swedish Obese Subjects (SOS) Intervention Study [Sjöström et al., 2004; Ågren et al., 2002b].

The outcomes of this comparative study, which is of good quality although non-randomized, confi rm that surgery has a role to play in the management of morbid obesity. This study includes a clinical component and an economic component. The economic component will be covered in Chapter 5.

The studies dealing with the impact of bariatric surgery on obesity co-morbidities will be analyzed in section 4.4.

This section begins by examining study outcomes by type of procedure and then deals with comparisons of the effi cacy of different techniques. Given that the techniques used are the same, whether open or laparoscopic, the effi cacy outcomes will not be presented separately by approach. However, special attention will be given to post-operative length of hospital stay and to some complications that do depend on the type of surgical approach taken.