USPSTF Posts Draft Recs for Treatment of Adults With Obesity

Tara Haelle

February 20, 2018

Primary care clinicians should refer adults with a body mass index of 30 kg/m2 or higher to "intensive, multicomponent behavioral programs" for weight management, according to new draft recommendations from the US Preventive Services Task Force published online today.

The evidence review by the task force revealed the most effective programs to be those combining multiple activities along with group sessions, according to a statement by task force member Chyke A. Doubeni, MD, MPH. The task force did not consider evidence related to surgical interventions or nonsurgical devices, such as gastric balloons.

The task force designated the recommendation as B grade, meaning "there is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial," according to their grade definitions. The public may post comments on the draft recommendations from February 20, 2018, to March 19, 2018.

Obesity affected more than 35% of men and 40% of women from 2013 to 2014, according to a National Center for Health Statistics data brief, and 1 in 13 Americans has a body mass index of at least 40 kg/m2.. Obesity, which is clinically defined as a body mass index of at least 30 kg/m2, increases the risk for type 2 diabetes, cancer, heart disease, gallstones, sleep apnea, venous thrombosis, atrial fibrillation, reflux disease, renal disease, disability, and death, according to the task force. Eating disorders and psychological stigma are also linked to obesity.

"The leading causes of death among adults with obesity include ischemic heart disease, type 2 diabetes, respiratory diseases, and cancer (e.g., liver, kidney, breast, endometrial, prostate, and colon cancer)," the task force writes in the draft recommendations.

For the evidence review, the group evaluated all interventional, controlled clinical trials published through June 6, 2017, that had at least 12 months of follow-up to determine effectiveness. In addition, they included cohort, case-control, and event-monitoring studies with shorter follow-up to assess harms. Of the 124 studies included, 83 were new whereas 41 were included in the 2012 USPSTF review.

"The USPSTF found adequate evidence that behavior-based weight loss interventions in adults with obesity can lead to clinically significant improvements in weight status and reduced incidence of type 2 diabetes among adults with obesity and elevated plasma glucose levels," they write. They note, however, that the effects were moderate. A minimum of 5% weight loss qualifies as clinically important, according to the US Food and Drug Administration.

On the basis of 67 behavioral-based weight loss trials involving 22,065 participants and 12 to 18 months of follow-up, intervention groups had 5.3 pounds (2.39 kg) more weight loss than control groups.

"The mean absolute change in weight ranged from −0.5 kg (−1.1 lb) to −9.3 kg (−20.5 lb) among intervention groups and from 1.4 kg (3.1 lb) to −5.6 (−12.3 lb) among control groups," the task force reports.

Participants in an intervention group were nearly twice as likely to lose 5% of their baseline weight as were participants in control groups at 12 to 18 months, resulting in a number needed to treat of 8. The trials included a diversity of group, individual, mixed, print-based, and technology-based interventions, including 19 trials without any in-person contact.

Adults undergoing behavioral interventions to maintain weight loss also saw less weight gain after completing the interventions than those in the control groups. The evidence also suggested little to no harms, particularly as the programs are noninvasive, the task force writes.

Combining pharmacotherapy with behavioral interventions led to increased weight loss and improved weight loss maintenance for 12 to 18 months, according to 32 fair-quality trials, but these had high attrition and lacked generalizability. They used highly selective criteria for enrollment, such as documented compliance for medication and meeting preenrollment weight loss targets. Drugs assessed in the studies included liraglutide, lorcaserin, naltrexone and bupropion, orlistat, and phentermine-topiramate.

"In addition, data were lacking about the maintenance of improvement after discontinuation of pharmacotherapy," the task force notes.

The vast majority of the evidence relied on 80 behavior-based weight loss trials, most of which lasted 1 to 2 years and occurred in the United States. Other trials occurred in Europe, Japan, Australia, and Canada. Participants (from n=30 to n=2161 across the trials), had mean baseline body mass indexes ranging from 25 to 39.2 kg/m2 and mean ages from 22 to 66 years. No significant differences in cardiovascular events, mortality, and health-related quality of life existed between intervention and control groups in the few studies that assessed these outcomes.

Of the 13 behavior-based weight loss trials that tracked type 2 diabetes incidence, one good-quality study involving 1295 participants found a nearly twofold higher prevalence in the placebo groups at 3-year follow-up as in the intervention groups (28.9% vs 14.4%). To prevent one case of diabetes, 6.9 patients needed to be treated. Similarly, a study with 523 participants found a 40.0% reduction in type 2 diabetes incidence in the intervention group compared with control at 9 years.

The authors have disclosed no relevant financial relationships. The USPSTF and evidence synthesis were funded by Agency for Healthcare Research and Quality in the US Department of Health and Human Services.

US Preventive Services Task Force. Draft Recommendation Statement: Weight Loss to Prevent Obesity-Related Morbidity and Mortality in Adults: Behavioral Interventions. Published online February 20, 2018.

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