Patient Population Under Consideration
This recommendation applies to adults aged 18 years or older. The
USPSTF uses the following terms to define categories of increased BMI:
overweight is defined as a BMI of 25 to 29.9 kg/m2, and obesity is defined as a BMI of 30 kg/m2 or higher.
Interventions
The USPSTF found that the most effective interventions were
comprehensive and were of high intensity (12 to 26 sessions in a year).
Although the USPSTF could not determine the effectiveness of other
specific intervention components, most of the higher-intensity
behavioral interventions included multiple behavioral management
activities, such as group sessions, individual sessions, setting
weight-loss goals, improving diet or nutrition, physical activity
sessions, addressing barriers to change, active use of self-monitoring,
and strategizing how to maintain lifestyle changes.
Weight-loss outcomes improved when interventions involved more
sessions (12 to 26 sessions in the first year). Behavioral intervention
participants lost an average of 6% of their baseline weight (4 to 7 kg
[8.8 to 15.4 lb]) in the first year with 12 to 26 treatment sessions
compared with little or no weight loss in the control group
participants. A weight loss of 5% is considered clinically important by
the U.S. Food and Drug Administration (FDA).
For obese patients with elevated plasma glucose levels, behavioral
interventions decreased the incidence of diabetes diagnosis by about 50%
over 2 to 3 years (number needed to treat, 7). Behavioral interventions
also demonstrated some improvement in intermediate health outcomes,
such as blood pressure, waist circumference, and glucose tolerance.
Interventions that combine pharmacologic agents (orlistat or
metformin) with behavioral interventions resulted in weight loss and
improvement in physiologic outcomes. Orlistat led to an average weight
loss of about 2.6 kg (5.7 lb), a 1.9-cm decrease in waist circumference,
and a decrease in fasting glucose level. However, there are concerns
about the potential harms of orlistat because of recent FDA reports of
rare severe liver disease and a lack of long-term safety data1.
Metformin led to a 1.5-cm greater decrease in waist circumference;
however, its use for obesity is not approved by the FDA and is thus
considered an off-label use. In addition, sufficient data were lacking
about the maintenance of improvement after discontinuation of
medications. As a result, the USPSTF is unable to recommend medication
use.
Results of trials were not stratified by BMI category, making it
difficult to ascertain the certainty of benefit in overweight (BMI of 25
to 29.9 kg/m2) groups. Although some studies included overweight participants, the mean BMI across trials was in the obese range (≥30 kg/m2).
Therefore, the USPSTF was unable to examine differential effects of
interventions on both overweight and obese patients. However, the
recommended interventions may also lead to weight loss in some
overweight patients. Compared with that of obesity, less is known about
the association of overweight and long-term health outcomes.
Screening Intervals
No evidence was found regarding appropriate intervals for screening.