Screening And Interventions For Overweight And Obesity In .

This report may be used, in whole or in part, as the basis for development of clinical practiceguidelines and other quality enhancement tools, or a basis for reimbursement and coveragepolicies. AHRQ or U.S. Department of Health and Human Services endorsement of suchderivative products may not be stated or implied.AHRQ is the lead Federal agency charged with supporting research designed to improve thequality of health care, reduce its cost, address patient safety and medical errors, and broadenaccess to essential services. AHRQ sponsors and conducts research that provides evidence-basedinformation on health care outcomes; quality; and cost, use, and access. The information helpshealth care decisionmakers—patients and clinicians, health system leaders, and policymakers—make more informed decisions and improve the quality of health care services.i

Systematic Evidence ReviewNumber 21Screening and Interventions for Overweight andObesity in AdultsPrepared for:Agency for Healthcare Research and QualityU.S. Department of Health and Human Services540 Gaither RoadRockville, MD 20850http://www.ahrq.govContract No. 290-97-0011Task No. 3Technical Support of the U.S. Preventive Services Task ForcePrepared by:Research Triangle Institute3040 Cornwallis RoadP.O. Box 12194Research Triangle Park, NC 27709Kathleen McTigue, MD, MPHRussell Harris, MD, MPHM. Brian Hemphill, MDAudrina J. Bunton, BALinda J. Lux, MPASonya Sutton, BSPHKathleen N. Lohr, PhDDecember 2003i

PrefaceThe Agency for Healthcare Research and Quality (AHRQ) sponsors the development ofSystematic Evidence Reviews (SERs) through its Evidence-based Practice Program. Withguidance from the U.S. Preventive Services Task Force (USPSTF) and input from Federalpartners and primary care specialty societies, the Evidence-based Practice Center at the OregonHealth Sciences University systematically review the evidence of the effectiveness of a widerange of clinical preventive services, including screening, counseling, and chemoprevention, inthe primary care setting. The SERs—comprehensive reviews of the scientific evidence on theeffectiveness of particular clinical preventive services—serve as the foundation for therecommendations of the USPSTF, which provide age- and risk-factor-specific recommendationsfor the delivery of these services in the primary care setting. Details of the process of identifyingand evaluating relevant scientific evidence are described in the “Methods” section of each SER.The SERs document the evidence regarding the benefits, limitations, and cost-effectiveness of abroad range of clinical preventive services and will help further awareness, delivery, and coverage ofpreventive care as an integral part of quality primary health care.AHRQ also disseminates the SERs on the AHRQ Web site(http://www.ahrq.gov/clinic/uspstfix.htm) and disseminates summaries of the evidence (summaries ofthe SERs) and recommendations of the USPSTF in print and on the Web. These are available throughthe AHRQ Web site and through the National Guideline Clearinghouse (http://www.ncg.gov).We welcome written comments on this SER. Comments may be sent to: Director, Center forPractice and Technology Assessment, Agency for Healthcare Research and Quality, 540 Gaither Road,Suite 3000, Rockville, MD 20850.Carolyn Clancy, M.D.DirectorAgency for Healthcare Reseach and QualityJean Slutsky, P.A., M.S.P.H.Acting Director, Center for Practice andTechnology AssessmentAgency for Healthcare Research and Quality The USPSTF is an independent panel of experts in primary care and prevention first convened by the U.S. PublicHealth Service in 1984. The USPSTF systematically reviews the evidence on the effectiveness of providing clinicalpreventive services--including screening, counseling, and chemoprevention--in the primary care setting. AHRQconvened the USPSTF in November 1998 to update existing Task Force recommendations and to address newtopics.i

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AcknowledgmentsThis study was supported by Contract 290-97-0011 from the Agency of HealthcareResearch and Quality (Task No. 3). We acknowledge at AHRQ the continuing support ofJacqueline Besteman, JD, MA, Director for the Evidence-based Practice Center program; DavidAtkins, MD, MPH, Chief Medical Officer of the AHRQ Center for Practice and TechnologyAssessment; and Jean Slutsky, PA, MSPH, the Task Order Officer for this project. We wouldalso like to acknowledge the guidance and assistance from our US Preventive Services TaskForce liaisons, Janet Allan, PhD, RN, CS, FAAN and Mark Johnson, MD, MPH.The investigators deeply appreciate the contributions of Loraine Monroe at RTI, forsuperior secretarial assistance. In addition, we are indebted to Timothy S. Carey, MD, MPH,Co-Director of the RTI-UNC Evidence-based Practice Center at the University of North CarolinaCecil G. Sheps Center for Health Services Research.We also owe our thanks to the following external peer reviewers, who providedconstructive feedback and insightful suggestions for improvement of this systematic evidencereview: David Arterburn, MD, University of Washington, Seattle, WA; James D. Douketis, MD,McMaster University, Hamilton, Onatario, Canada; Evelyn L. Lewis-Clark, MD Bowie, MD,representing the American Academy of Family Physicians; F. Xavier Pi-Sunyer, MD, MPH, StLuke’s/Roosevelt Hospital Center, New York, NY; Walter J. Pories, MD, East Carolina Schoolof Medicine, Greenville, NC; Bruce A. Reeder, University of Saskatchewan, Saskatoon, Canadaand representing the Canadian Task Force on Preventive Health Care; and Vincenza Snow, MD,American College of Physicians-American Society of Internal Medicine, Philadelphia, PA.vi

Structured AbstractBackgroundObesity, a condition characterized by excess body fat, carries substantial healthimplications for both chronic disease and mortality. This fact and its increasing prevalence makeobesity an important health problem.PurposeTo examine the evidence of the benefits and harms of screening and earlier treatment inreducing morbidity and mortality from overweight and obesity.Data SourcesWe developed an analytic framework and 6 key questions that represent a logical chainbetween screening and sustained weight reduction and reduced morbidity and mortality. Wesearched MEDLINE from January 1, 1994 (the end date for prior USPSTF searches), to July 31,2001, using the Medical Subject Heading obesity and overweight and combining this term withpredefined strategies to identify relevant English-language studies. We also searched theCochrane Library, contacted experts, and scanned review bibliographies. We found 4 recent,well-conducted systematic reviews and relied on their analyses of the studies they included.vii

Study SelectionWe included: (1) large, population-based surveys of the prevalence of overweight andobesity; (2) randomized controlled trials (RCTs) with at least 1 year follow-up (6 months forpharmacological studies) reporting weight reduction or health outcomes for treatment and harmsquestions. The shorter follow-up period for pharmacological studies was driven by the availableliterature: weight loss trials were frequently only of 6 months’ duration but were complementedby studies designed specifically to evaluate maintenance of that loss. When we found few or noRCTs, we examined cohort studies concerning the efficacy or harms of treatment. Tworeviewers examined all abstracts and articles to determine which met inclusion criteria.Data ExtractionTwo reviewers abstracted relevant information from each article, using standardizedabstraction forms. We graded the quality of all included articles according to criteria establishedby the U.S. Preventive Services Task Force.Data SynthesisNo RCT of screening for obesity has been performed. Obesity is most commonlymeasured as body mass index (BMI, weight in kilograms [kg] divided by height in meterssquared). Although other measures have been developed, BMI is the most consistently used inthe literature, and so we focused on it as the preferred screening tool. The prevalence of obesity(BMI 30) has been increasing; currently; at least 27% of the adult population is obese. Theprevalence of overweight (BMI 25-29.9) is about 34%. Among people with BMI of about 30 orvii

greater, intensive counseling and behavioral treatment for obesity is effective in reducing meanweight by about 3 kg to 5 kg after 1 year. Pharmacotherapy with sibutramine or orlistat is alsoeffective in reducing mean weight by about 3 to 5 kg. For people with BMI of 35 or greater,surgical therapy leads to dramatic reductions in weight of 20 kg or more.Both counseling-based and drug-based maintenance interventions were helpful inretaining weight loss. Weight reduction of 5% to 7% body weight is associated with lowerincidence of diabetes, reduced blood pressure, and improved dyslipidemia. Larger weight losshas been linked with more dramatic improvements in glycemic control and lipids in limitedsurgical outcomes data.We did not find evidence evaluating potential harms of counseling-based interventions.Sibutramine is sometimes associated with increased blood pressure (mean increase of 0-3.5 mmHg); orlistat causes gastrointestinal distress in 15% to 37% of people taking the drug. Surgicalprocedures lead to mortality in less than 1% of patients in pooled samples, but in up to 25%patients re-operation is necessary over 5 years.ConclusionsScreening with BMI would detect a large percentage of adults who are obese oroverweight. Limited evidence suggests that counseling interventions may promote modestweight loss in the overweight (BMI 25-29.9). Effective treatments for people with BMI 30include intensive counseling and behavioral interventions for lifestyle change, andpharmacotherapy. Surgery is effective in reducing weight for people with BMI of 35 or greater.Adverse effects include increased blood pressure and gastrointestinal distress with drugs and asmall percentage of serious side effects with surgeryviiiviii

Table of ContentsixContentsSystematic Evidence ReviewChapter 1. Introduction .1Background .1Cost of Obesity and Overweight . 5Prior Recommendations About Obesity Screening. 6Organization of This Review. 7Chapter 2. Methods. 13Analytic Framework and Key Questions .13Analytic Framework .13Key Questions. 14Literature Search Strategy and Synthesis . 14Search Terms . 14Inclusion and Exclusion Criteria. 15Article Review and Data Abstraction. 15Preparation of this Systematic Evidence Review . 16Chapter 3. Results . 21Key Question No. 1: Does Screening for Overweight and Obesity Affect Health Outcomes? . 21Key Question No. 2: What is the Prevalence of Overweight and Obesity? . 21Key Question No. 3: Is There a Reliable and Valid Screening Test?. 22Key Question No. 4a: Do Any Interventions Lead to Sustained Weight Reduction? . 24Counseling and Behavioral Interventions. 24Pharmacotherapy Interventions . 31Surgical Approaches . 37Key Question No. 4b: Do Interventions Improve Other Intermediate Health Outcomes?. 40Key Question No. 5: Do Interventions Improve Final Health Outcomes?. 43Key Question No. 6: What are the Harms of Screening and Treatment?. 44Screening or Counseling and Behavioral Interventions. 44Medications. 44Surgical Approaches . 46Chapter 4. Discussion . 51General Conclusions. 51Cross-cutting Findings and Future Research Issues . 53References. 58AppendicesAppendix A. Evidence Tables . A-1Appendix B. Counseling Intervention Descriptions.B-1Appendix C. Descriptions of Intensive Counseling and Behavioral Intervention Studies .C-1ix