USPSTF Recommends Obesity Screening for All Adults  CME


News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd
Authors and Disclosures

To earn CME credit, read the news brief, the paragraphs that follow, and answer the questions below.

Release Date: December 1, 2003; Valid for credit through December 1, 2004



Credits Available

 

Physicians - up to 0.25 AMA PRA category 1 credit(s)

Dec. 1, 2003 — The U.S. Preventive Services Task Force (USPSTF) recommends obesity screening for all adults and intensive weight loss counseling and behavioral interventions for obese patients, according to an update of 1996 guidelines published in the Dec. 2 issue of the Annals of Internal Medicine.

"A number of techniques...can measure body fat, but it is impractical to use them routinely," write Alfred O. Berg, MD, MPH, from the University of Washington in Seattle, and colleagues. "Body mass index (BMI), which is simply weight adjusted for height, is a more practical and widely used method to screen for obesity."

The USPSTF recommends using BMI to determine weight category, with overweight defined as BMI between 25 and 29.9 kg/m2, and obesity as BMI of 30 kg/m2 or higher. Obesity is a recognized risk factor for hypertension, diabetes, cardiovascular disease, reduced life span, and limited quality of life.

Central adiposity, with body shape resembling an apple rather than a pear, is an independent predictor of cardiovascular disease. According to the guidelines, waist measurement greater than 40 inches for men or 35 inches for women can indicate excessive abdominal fat, which increases cardiovascular risk. However, waist circumference thresholds are not reliable for BMI greater than 35 kg/m2.

"The most effective interventions combine nutrition education and diet and exercise counseling with behavioral strategies to help patients acquire the skills and supports needed to change eating patterns and to become physically active," the authors write, based on a literature review. Compared with the evidence for obese adults, the evidence for the effectiveness of counseling and behavioral interventions in overweight adults is limited.

Although surgical interventions such as gastric bypass or banding and gastroplasty can produce substantial weight loss in patients with class III obesity, clinical guidelines of the National Heart, Lung, and Blood Institute recommend reserving these procedures for patients with class III obesity, or for those with class II obesity and at least one other obesity-related illness.

Orlistat and sibutramine can produce modest but sustained weight loss if continued for at least two years, according to the guidelines, but there are no data on longer-term benefits or adverse effects of these drugs. In the short term, primary adverse drug effects include gastrointestinal distress with orlistat and hypertension with sibutramine.

"Experts recommend that pharmacological treatment of obesity be used only as part of a program that also includes lifestyle modification interventions," the authors conclude. "In selected patients, surgery promotes large amounts of weight loss with rare but sometimes severe complications."

Ann Intern Med. 2003;139:930-932, 933-949

Learning Objectives

Upon completion of this activity, participants will be able to:

  • Describe the USPSTF suggested guidelines for obesity screening.
  • List evidence-based strategies for managing obese and overweight patients.

Clinical Context

The prevalence of obesity in the U.S. has increased from 13% to 31%, and overweight has increased from 31% to 34% over the past 40 years in the U.S. Obesity is more common in women, African Americans, Native Americans, and Hispanics, while overweight is more common in men. Obesity is a known risk factor for cardiovascular disease, cancer (breast, colon, uterine, and ovarian), gallstones, osteoarthritis, sleep apnea, and social stigmatization, and is linked to markedly diminished life expectancy. Visceral fat (central obesity) vs. subcutaneous fat is particularly linked to adverse cardiovascular profiles and diabetes. Lifetime costs for cardiovascular disease increase by 20% with mild obesity, 50% with moderate obesity, and 200% with severe obesity. Estimated direct costs in the U.S. are 5.7% of total health expenditures.

The USPSTF examined its own 1996 review, searched MEDLINE, the Cochrane Library, the National Institutes of Health (NIH), the Canadian Task Force on Preventive Health Care (CTFPHC), the U.K. National Health Service (NHS), and BMJ Clinical Evidence as resources for publications and reports dating from 1994 to 2003. Two authors independently reviewed studies and calculated 95% CIs for treatment efficacy to summarize the evidence for screening and treating obesity in adults. The data are derived primarily from studies in white women, and generalizability to other populations including the elderly is uncertain.

The guidelines are available online at http://www.preventiveservices.ahrq.gov.

Study Highlights

  • BMI is closely correlated with adult body fat (г = 0.7-0.8) and is recommended for primary screening, while waist circumference (greater than 40 inches for men and 35 inches for women) is associated with central obesity and predicts increased cardiovascular risk, even in nonobese individuals. Waist circumference thresholds are unreliable for BMI greater than 35 kg/m2.
  • Overweight is defined as a BMI of 25 to 29.9 kg/m2, obesity class I as BMI of 30 to 34.9 kg/m2, obesity class II as BMI of 35 to 39.9 kg/m2, and obesity class III as BMI equal to 40 kg/m2, with a linear increase in morbidity associated with increasing BMI.
  • The USPSTF concluded that the benefits of screening outweigh the potential harm, but the CTFPHC found insufficient evidence to recommend for or against BMI measurements annually or community-based obesity prevention programs. The American Academy of Family Practice and the American College of Obstetricians and Gynecologists recommend periodic weight and height measurements, while the American College of Preventive Medicine recommends periodic BMI measurements of all adults along with diet and exercise counseling.
  • The most effective strategies combine nutrition, diet and exercise counseling, and behavioral modification, using the 5 As of Assess, Advise, Agree, Assist, and Arrange.
  • There is fair to good evidence that high-intensity counseling, defined as a minimum of 3 monthly one-on-one visits, combined with behavioral interventions produces sustained weight loss of typically 3 to 5 kg for 1 year in obese adults. The evidence is insufficient to apply this recommendation to overweight adults.
  • The evidence is insufficient to recommend for or against moderate or low-intensity counseling with behavioral interventions for sustained weight loss in obese or overweight adults.
  • Pharmacologic interventions with sibutramine and orlistat may result in modest mean weight loss of 3 to 5 kg compared with control patients, and prolonged drug therapy can sustain this loss for up to 2 years. Both are Food and Drug Administration–approved for persons with BMI higher than 30 kg/m2 or greater than 27 kg/m2 with other medical risks such as hypertension. Phentermine and mazindol have similar short-term efficacy but are not approved for long-term use. Metformin, diethylpropion, and fluoxetine showed mixed efficacy.
  • Pharmacotherapy should be used in conjunction with lifestyle modification, including intensive diet and exercise counseling and behavioral interventions.
  • Intermediate health outcomes such as improved glucose metabolism, lipid levels, and blood pressure, are demonstrated with modest weight loss and provide indirect evidence of health benefits of weight loss.
  • Surgical interventions should be limited to patients with BMI equal to 40 kg/m2 (ie, obesity class III) or with BMI higher than 35 kg/m2 (ie, obesity class II) who have severe health complications and have failed other interventions. Such patients should receive psychological counseling before surgery.
  • Bariatric surgery, gastric bypass, and gastric banding (open or laparoscopic) have been associated with weight loss of 10 to 159 kg over 12 to 48 months in reviews by the NIH, and weight loss of 17 to 46 kg after 2 to 5 years in reviews by the CTFPHC. After 8 years, subset analysis showed average loss of 20 kg.
  • Primary adverse effects of obesity management include hypertension with sibutramine (mean increase of 0 to 3.5 mm Hg), gastrointestinal distress with orlistat (1%-37% of patients), up to 1% mortality in surgical patients, and 25% need for repeat surgery within 5 years. Surgery is also associated with wound infection, diarrhea, and hemorrhage. No study evaluated the potential harm of behavioral interventions.

Pearls for Practice

  • The benefits of screening and behavioral interventions for obesity outweigh the potential harms.
  • Intentional weight loss in obese persons can reduce mortality and prevent diabetes and other morbidities.

Post Test

Az ûrlap teteje

1.

A 40-year-old white woman with BMI of 32 kg/m2 and no other risk factors wishes to reduce weight to achieve normal BMI. All of the following interventions are appropriate except:

 

a.

Dietary and exercise counseling

 

b.

Orlistat or sibutramine

 

c.

Gastric banding

 

d.

Behavior modification

 

 

 

 

2.

Obesity class II is defined as a BMI of

 

a.

Greater than 30 kg/m2

 

b.

25 to 29.9 kg/m2

 

c.

35 to 39.9 kg/m2

 

d.

40 to 44.9 kg/m2

 

e.

Greater than 35 kg/m2

Az ûrlap alja