NZHTA REPORT August 2004 Volume 7 Number 6 Evidence Based Review of Weight Loss Medicines: A report commissioned by the New Zealand Accident Compensation Corporation (ACC) Pamela Smartt New Zealand Health Technology Assessment Department of Public Health and General Practice Christchurch School of Medicine Christchurch, NZ. Division of Health Sciences, University of Otago NEW ZEALAND HEALTH TECHNOLOGY ASSESSMENT (NZHTA) Department of Public Health and General Practice Christchurch School of Medicine, Christchurch, New Zealand Evidence Based Review of Weight Loss Medicines: A report commissioned by the New Zealand Accident Compensation Corporation (ACC) Pamela Smartt NZHTA REPORT August 2004 Volume 7 Number 6 This report should be referenced as follows: Smartt, P. Evidence based review of weight loss medicines: a report commissioned by the New Zealand Accident Compensation Corporation (ACC). NZHTA Report 2004 ; 7(6) . 2004 New Zealand Health Technology Assessment (NZHTA) ISBN 1-877235-70-9 ISSN 1174-5142 i Acknowledgements This report was prepared by Dr Pamela Smartt (Principal Investigator) who conducted the critical appraisals and prepared the project report. Dr Ray Kirk (NZHTA Director until February 2005) also provided comment on various drafts and coordinated the overall project. Dr Robert Weir (NZHTA Acting Director from February 2005) coordinated the project from February 2005. Ms Margaret Paterson (NZHTA Information Specialist) developed and undertook the search strategy and coordinated retrieval of documents. Mrs Ally Reid (NZHTA Administrative Secretary) provided document formatting. The Canterbury Medical Library assisted with the retrieval of articles. NZHTA is a Research Unit of the University of Otago funded under contract to the Ministry of Health. Disclaimer New Zealand Health Technology Assessment (NZHTA) takes great care to ensure the information supplied within the project timeframe is accurate, but neither NZHTA, the University of Otago, nor the contributors involved can accept responsibility for any errors or omissions. The reader should always consult the original database from which each abstract is derived along with the original articles before making decisions based on a document or abstract. All responsibility for action based on any information in this report rests with the reader. NZHTA and the University of Otago accept no liability for any loss of whatever kind, or damage, arising from reliance in whole or part, by any person, corporate or natural, on the contents of this report. This document is not intended as personal health advice. People seeking individual medical advice are referred to their physician. The views expressed in this report are those of NZHTA and do not necessarily represent those of the University of Otago or the New Zealand Ministry of Health. Copyright Copyright © to Accident Compensation Corporation 2005. All rights reserved. No part of this report may be reproduced or distributed by any person without prior written permission and/or licence from the Accident Compensation Corporation. http://www.acc.co.nz/ EVIDENCE BASED REVIEW OF WEIGHT LOSS MEDICINES: A REPORT COMMISSIONED BY THE NEW ZEALAND ACC ii Contact details New Zealand Health Technology Assessment (NZHTA) Department of Public Health and General Practice Christchurch School of Medicine and Health Sciences PO Box 4345 Christchurch New Zealand Tel: +64 3 364 3696 Fax: +64 3 364 3697 Email: [email protected] Web Site: http://nzhta.chmeds.ac.nz/ EVIDENCE BASED REVIEW OF WEIGHT LOSS MEDICINES: A REPORT COMMISSIONED BY THE NEW ZEALAND ACC iii Contents Contents ..................................................................................................................iii Executive Summary ............................................................................................... vii Recommendations ................................................................................................ viii Background...............................................................................................................1 Definition and measurement of obesity........................................................................1 The health consequences of obesity..............................................................................1 Factors influencing body weight....................................................................................2 Clinically significant weight reduction...........................................................................3 Obesity and Injury............................................................................................................3 Obesity trends in NZ.......................................................................................................3 The economic cost of obesity.........................................................................................4 Benefits associated with weight loss..............................................................................4 Review questions ..................................................................................................... 7 Pharmacological treatments for obesity .................................................................. 9 Pharmacological interventions registered in New Zealand........................................9 Phentermine (Duromine TM , Umine Timedcaps)..........................................................9 Diethylpropion hydrochloride (Tenuate Dospan).....................................................10 Sibutramine hydrochloride (Reductil ®, Meridia ®) ......................................................11 Orlistat (Xenical ®)...........................................................................................................12 Meal replacement plans..................................................................................................14 Methodology ...........................................................................................................15 Systematic review............................................................................................................15 Search strategy and information sources ....................................................................16 Study selection criteria...................................................................................................17 Methods of the review...................................................................................................17 Levels of evidence..........................................................................................................18 Results.....................................................................................................................19 Meal replacement plans: weight loss and co-morbidity risk reduction...................19 Phentermine hydrochloride: weight loss and co-morbidity risk reduction............20 Diethylpropion: weight loss and co-morbidity risk reduction.................................22 Orlistat: weight loss and co-morbidity risk reduction...............................................23 Sibutramine: weight loss and co-morbidity risk reduction.......................................28 Comparative drug studies..............................................................................................34 Combined drug studies..................................................................................................39 Safety/Side effects ..................................................................................................41 Safety and side effects of sibutramine therapy...........................................................41 Safety and side effects of orlistat therapy ...................................................................42 Safety and side effects of phentermine therapy .........................................................43 EVIDENCE BASED REVIEW OF WEIGHT LOSS MEDICINES: A REPORT COMMISSIONED BY THE NEW ZEALAND ACC iv Safety and side effects of diethylpropion therapy......................................................43 Summary of potential harms of pharmacotherapy intervention .............................44 Safety and side effects of meal replacement programs.............................................44 Practice recommendations and guidelines ............................................................47 National Institute of Health, USA...............................................................................47 The National Institute for Clinical Excellence (NICE), UK ...................................47 High profile clinical trials.......................................................................................49 Completed studies..........................................................................................................49 Childhood obesity ..........................................................................................................49 Ongoing trials..................................................................................................................50 Other anti-obesity therapies ...................................................................................51 Horizon Scan ..........................................................................................................53 Economic considerations .......................................................................................55 The direct cost of medication.......................................................................................55