Final Research Plan

Weight Loss to Prevent Obesity-Related Morbidity and Mortality in Adults: Behavioral Interventions

March 31, 2016

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

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The final Research Plan is used to guide a systematic review of the evidence by researchers at an Evidence-based Practice Center. The resulting Evidence Review forms the basis of the USPSTF Recommendation Statement on this topic.

The draft Research Plan was available for comment from December 10, 2015 until January 13, 2016 at 8:00 p.m., ET.

Abbreviation: HRQoL=health-related quality of life.

Text Description.

Figure 1 is the analytic framework that depicts the three Key Questions to be addressed in the systematic review. The figure illustrates how behavioral counseling or pharmacotherapy interventions for weight loss or weight loss maintenance may result in improved health outcomes, including obesity-related morbidity and mortality and health-related quality of life (KQ 1). Additionally, the figure illustrates how behavioral counseling or pharmacotherapy interventions for weight loss or weight loss maintenance may have an effect on intermediate outcomes (including weight loss and the incidence or prevalence of obesity-related conditions) (KQ 2). Further, the figure depicts whether behavioral counseling or pharmacotherapy interventions for weight loss or weight loss maintenance are associated with any adverse effects (KQ 3).

  1. Do primary care–relevant behavioral and/or pharmacotherapy weight loss and weight loss maintenance interventions lead to improved health outcomes among adults who are overweight or have obesity and are a candidate for weight loss interventions?
  2. Do primary care–relevant behavioral and/or pharmacotherapy weight loss and weight loss maintenance interventions lead to weight loss, weight loss maintenance, or a reduction in the incidence or prevalence of obesity-related conditions among adults who are overweight or have obesity and are a candidate for weight loss interventions?
  3. What are the adverse effects of primary care–relevant behavioral and/or pharmacotherapy weight loss and weight loss maintenance interventions in adults who are overweight or have obesity and are a candidate for weight loss interventions?

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. Does the predictive value of body mass index (BMI) for future mortality and health risks differ by specific population subgroups (i.e., by race/ethnicity or older age)?
  2. Does primary care–feasible assessment of central adiposity increase the predictive value of BMI for future mortality and health risks?
  3. What health effects (i.e., mortality and incidence of cardiovascular disease, type 2 diabetes mellitus, or cancer) are associated with intentional weight loss, BMI reduction, or both?

The Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the key questions (KQs).

  Include Exclude
Study aim Weight loss or weight loss maintenance
  • Primary prevention of overweight or obesity
  • Treatment of cardiovascular disease
  • Management of diabetes*
  • Treatment of cancer
Condition definition Overweight or obesity, as defined by BMI or other weight-related measurements  
Populations
  • Adults age ≥18 years who are candidates for weight loss/maintenance interventions selected based on an above normal BMI (e.g., ≥25 kg/m2) or other weight-related measure (e.g., waist circumference)
  • Patients may or may not have additional risk factors, including hypertension, dyslipidemia, or impaired glucose tolerance/fasting glucose (i.e., prediabetes)

Studies limited to:

  • Populations not selected based on weight-related measures
  • Adults with secondary causes of obesity, such as steroid use
  • Adults with a chronic disease for which weight loss/maintenance is part of disease management (e.g., osteoarthritis, known cardiovascular disease, diabetes mellitus, polycystic ovary syndrome, sleep apnea)
  • Adults with known chronic diseases that are not generalizable to the primary care population (e.g., eating disorder, cancer, chronic kidney disease, severe mental illness, cognitive impairment)
  • Children and adolescents
  • Parents (if intended behavior change is directed toward children)
  • Pregnant women
  • Adults in institutions
Settings
  • Studies conducted in or recruited from primary care or a health care system or that could feasibly be implemented in or referred from primary care
  • In order for an intervention to be feasible for primary care referral, it would need to be conducted as part of a health care setting or be widely available in the community at a national level (e.g., commercial weight loss programs, technology interventions)
 Studies conducted in or recruited from settings not generalizable to primary care (e.g., worksites, university classrooms, institutional settings), in a population with pre-existing social ties (e.g., from the same worksite or church), or in a setting where the intervention could not be reproduced in primary care or within a broader health system
Interventions Interventions focusing on weight loss/maintenance, including the following:
  • Behavioral counseling intervention, either alone or as part of a larger multicomponent intervention on healthful diet and nutrition, physical activity, sedentary behavior, or a combination thereof, including but not limited to: assessment with feedback, advice, collaborative goal-setting, assistance, exercise prescriptions (referral to exercise facility or program), arranging further contacts, or provider training
  • Pharmacologic interventions that are approved by the U.S. Food and Drug Administration as first-line, long-term weight loss/management medications:
    • Orlistat
    • Lorcaserin hydrochloride
    • Phentermine-topiramate extended release
    • Naltrexone hydrochloride and bupropion hydrochloride
    • Liraglutuide
  • Combination of these interventions
  • Interventions may be delivered via face-to-face contact, telephone, print materials, or technology (e.g., computer-based, text messages) and can be delivered by numerous potential interventionists, including but not limited to: physicians, nurses, exercise specialists, dietitians, nutritionists, and behavioral health specialists
  • Surgical procedures (laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, biliopancreatic diversion with duodenal switch, sleeve gastrectomy)
  • Nonsurgical devices and procedures (balloon system, vagus nerve stimulation)
  • Medications that are not approved by the U.S. Food and Drug Administration as long-term weight loss agents, including new agents currently under evaluation (e.g., leptin, peptide YY, oxyntomodulin, melanocortin-4 receptor agonists), agents taken off the market (e.g., fenfluramine, dexfenfluramine, sibutramine), and agents only approved for short-term weight loss (e.g., diethylpropion, phentermine, benzphetamine, phendimetrazine)
  • Medications only indicated for the treatment of type 2 diabetes (e.g., metformin, pramlintide, empagliflozin, albiglutide, dulaglutide, alogliptin, exenatide)
  • Complementary and alternative treatments (e.g., acupuncture, mindfulness)
  • Dietary supplements intended for weight loss (e.g., chitosan, guar gum, chromium, ginseng, glucomannan, green tea, hydroxycitric acid, L-carnitine, psyllium, pyruvate supplements, St. John’s wort, conjugated linoleic acid)
  • Broader community-based programs (e.g., mass media, social marketing, changes to the community built environment, legislation)
Comparisons For studies of behavioral interventions:
  • No treatment (e.g., wait-list control, usual care)
  • Attention control (e.g., similar format and intensity of intervention but different content area)
  • Minimal intervention comparable to usual care (including the use of generic print/electronic communications)

For studies of pharmacologic interventions:

  • Placebo
  • Two groups must participate in identical behavioral intervention component
 For studies of behavioral interventions:
  • Active comparators without a control (as defined in the inclusion criteria)

For studies of pharmacologic interventions:

  • Comparison of different pharmacologic interventions
Outcomes KQ 1: Health outcomes:
  • Mortality
  • Morbidity (e.g., diabetic amputation, hypertensive nephrosclerosis)
  • Depression
  • Emotional functioning, as measured by mental subscales of quality of life instruments
  • Physical functioning, as measured by physical subscales of quality of life measures
  • Disability measures (global measures only, such as activities of daily living)

KQ 2: Weight outcomes (required for inclusion) and incidence or prevalence of related conditions:

  • Measured weight (e.g., kilograms, pounds)
  • Relative weight (e.g., BMI, percent overweight, percent obese)
  • Total adiposity (e.g., dual-energy x-ray absorptiometry, underwater weighing)
  • Central adiposity (e.g., waist circumference, waist-to-hip circumference ratio)
  • Weight maintenance
  • Incidence or prevalence of obesity-related conditions (e.g., diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, sleep apnea)
  • Proportion of individuals taking medication for an obesity-related condition

KQ 3: Adverse outcomes

  • Treatment-related harms at any time point after intervention begins (e.g., death, medical issue requiring hospitalization or urgent medical treatment, inducement of eating disorder, nausea or other gastrointestinal effects, reduced bone mineral density, vitamin deficiency)
  • Discontinuation of medication due to adverse effects
  • Psychological adverse events related to counseling or medication
 KQ 1:
  • Functioning (except as enumerated under health outcomes)
  • Cost-effectiveness
  • Behavioral changes (e.g., physical activity, diet, smoking)

KQ 2: Cardiometabolic measures (e.g., glucose levels, blood pressure, lipid levels)
Timing of outcome assessment KQs 1, 2: ≥12 months after start of intervention or baseline assessment (if the intervention start cannot be determined)

KQ 3: No minimum followup

 KQs 1, 2: <12 months after baseline
Countries Studies conducted in economically developed countries, defined as member countries (2015) of the Organisation for Economic Co-Operation and Development (i.e., Australia, Austria, Belgium, Canada, Chile, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Japan, Korea, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom, United States)
  • Studies conducted in countries with populations not similar to the United States
  • Studies conducted in countries that are not a member of the Organisation for Economic Co-Operation and Development
Study designs KQs 1, 2: Randomized or controlled clinical trials, including cluster randomized trials

KQ 3:

  • Systematic reviews, including meta-analyses, of randomized or controlled clinical trials or cohort studies
  • Randomized or controlled clinical trials, including cluster randomized trials
  • Large cohort or case-control studies reporting serious adverse effects related to weight loss interventions
 KQs 1, 2: Any observational studies, ecological studies, case reports, case series, or other noncomparative reviews or letters to the editor

KQ 3: Ecological studies, case-series, and case reports
Publication language English Non-English
Study quality Fair or good (according to design-specific USPSTF criteria) Poor (according to design-specific USPSTF criteria)

* Studies that focus on the effectiveness of primary care interventions for the primary prevention of cardiovascular disease or treatment of diabetes are included in separate reviews commissioned by the USPSTF (available at www.uspreventiveservicestaskforce.org).

The draft Research Plan was posted for public comment on the U.S. Preventive Services Task Force (USPSTF) Web site from December 10, 2015 to January 13, 2016. Several comments suggested including studies among women during the postpartum period; the USPSTF changed the Research Plan to include postpartum women. A number of comments suggested including interventions with surgical and nonsurgical devices for the treatment of obesity. The use of surgical and nonsurgical devices is considered part of disease management for persons with severe obesity or related comorbid conditions, and is outside the scope of this review. In addition, several comments advocated for the inclusion of studies among adults with comorbid conditions, particularly those with diabetes and sleep apnea. The USPSTF chose to maintain the exclusion of studies specifically among population subgroups for whom weight loss interventions are part of the treatment and management of clinical disease, as this is considered outside the scope of the USPSTF’s recommendations (i.e., tertiary care). Many comments pertained to insurance coverage, which is outside the scope of this review.