Screening for Obesity in Adults: Recommendations from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Screening for Obesity in Adults: Recommendations and Rationale" and "Screening and Interventions for Obesity in Adults: Summary of the Evidence for the U.S. Preventive Services Task Force." They are in the 2 December 2003 issue of Annals of Internal Medicine (volume 139, pages 930-932 and pages 933-949). The first article was written by the U.S. Preventive Services Task Force; the second article was written by K.M. McTigue, R. Harris, B. Hemphill, L. Lux, S. Sutton, A.J. Bunton, and K.N. Lohr.

Who developed these guidelines?

The U.S. Preventive Services Task Force (USPSTF) is a group of health experts that reviews published research and makes recommendations about preventive health care.

What is the problem and what is known about it so far?

Excess weight leads to health problems. Body mass index (BMI) is a measure of the appropriateness of a person's weight. To calculate BMI, you divide weight in kilograms by the square of height in meters (BMI = weight in kilograms/height in meters ²). A BMI calculator from the National Heart, Lung, and Blood Institute is available at http://www.nhlbisupport.com/bmi. Normal BMI is 18.5 kg/m² to 24.9 kg/m². People with BMIs 25 kg/m² to 29.9 kg/m² are overweight, and people with BMIs of 30 kg/m² or above are obese. Unfortunately, doctors often do not address weight problems with their patients. Treatment options include counseling and behavioral therapy. Counseling educates patients to change diet and exercise. Behavioral therapies are specific strategies to help patients to make these changes. For some patients, weight loss medications or surgery may be appropriate. Recommending that doctors screen all adult patients for weight problems makes sense only if treatments are effective.

How did the USPSTF develop these recommendations?

The USPSTF reviewed the published literature for studies of weight loss interventions done in primary care doctors' offices that followed patients for at least 6 months for studies of weight loss drugs and at least 12 months for other types of treatments. The authors defined high-intensity counseling and behavioral therapy as more than 2 person-to-person contacts focused on weight loss per month for at least the first 3 months, medium intensity as monthly contact, and low intensity as less frequent contact. They evaluated the quality of each study.

What did the USPSTF find?

The authors found few high-quality studies of the effectiveness of obesity treatments. Counseling was most effective when it was combined with behavioral therapy and when it was high intensity (>1 session per month for at least the first 3 months). It resulted in modest amounts (3 to 5 kg) of weight loss by the end of at least 1 year. Weight loss drugs showed similar weight loss over 6 months, but long-term studies of effectiveness and safety are unavailable. Surgery can result in large amounts of weight loss (10 to 159 kg), but life-threatening complications can occur.

What does the USPSTF suggest that patients and doctors do?

Adult patients who see doctors for preventive care are likely to have their weight and height measured. Obese patients (BMI 30 kg/m²) should know that they may benefit from high-intensity counseling and behavioral interventions to promote weight loss. There is not strong evidence showing less intense interventions to be effective. Overweight patients (BMI 25 to 29.9 kg/m²) should know that health risk begins to increase with weight in this range, but that evidence for effective treatment of overweight is lacking. For some patients, medications or surgery may be helpful in addition to intensive counseling.

What are the cautions related to these recommendations?

As better studies become available, the USPSTF may modify these recommendations.