In general, however, she considers the recommendations to be important and of value, particularly given the rise in obesity, the fact that many obese patients are unaware that they are obese, and the fact that obesity not only is associated with increased mortality, but also is associated with increased disability and decreased quality of life.
The USPSTF reports that since the late 1970s, the prevalence of obesity and overweight in the U.S. have increased by 134% and 48%, respectively, with the prevalence of obesity now exceeding 30% in most age-and sex-specific groups, and with about 1 in 20 Americans having a BMI greater than 40 kg/m2.
As for the recommendations on behavioral counseling to promote a healthful diet and physical activity in adults without preexisting cardiovascular disease, the USPSTF update states that in determining which patients should be counseled, clinicians should consider risk factors for cardiovascular disease, a patient’s readiness for change, social support and community resources that help create change, and other health care and preventive service priorities.
These recommendations are based on grade C evidence, indicating moderate certainty that the interventions produce a small net benefit, and are based on the findings of 25 healthful diet counseling trials, 30 physical activity counseling trials, and 17 combined lifestyle counseling trials.
"Although the correlation among healthful diet, physical activity and the incidence of CVD is strong, existing evidence indicates that the health benefit of initiating behavioral counseling in the primary care setting to promote a healthful diet and physical activity is small," Dr. Moyer reported in a separate article on behalf of the USPSTF (Ann. Intern. Med. 2012;157. [Epub ahead of print 26 June 2012]).
Specifically, the evidence that medium- to high-intensity counseling interventions directly decrease rates of mortality or CVD events is inadequate, the task force noted.
In cases when CVD risk is uncertain, the USPSTF recommends using calculators and models, such as the Framingham-based Adult Treatment Panel III calculation.
"Persons with a 10-year risk for CVD greater than 20% are generally considered to be at high risk, those with a 10-year risk less than 10% are considered to be at low risk, and those in the 10% to 20% range are considered to be at intermediate risk. Persons at higher risk may benefit from counseling intervention more than persons at low risk, because even small improvements in intermediate outcomes in those at higher risk may result in clinically meaningful reduction in CVD events," according to the task force.
The strongest evidence for improvement of physiologic outcomes was for high-intensity counseling interventions that were not provided by the primary care clinician in any of the studies that were reviewed.
"Rather, counseling interventions took place in other sectors of the health care system or community settings," they wrote.
Thus, while medium- or high-intensity behavioral interventions to promote a healthful diet and physical activity may be provided to select individual patients in the primary care setting, strong links between the primary care setting and community-based resources may improve delivery of services, they said. Future studies should examine the combined effects of clinical and community-based interventions and the association between small physiologic changes and long-term health outcomes.
"Consistent measurement and reporting of behavioral and risk factor outcomes would also improve the evidence base for behavioral counseling recommendations," they wrote.
Disclosures from individual USPSTF members were not available at press time.