NIDDK

The first Federal clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults were released on June 17, 1998. The guidelines, which were developed for primary care practitioners, are cosponsored by the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health. "These guidelines are a comprehensive presentation of the most relevant data related to identifying, evaluating, and treating obesity," said Dr. Phillip Gorden, NIDDK director.

The guidelines establish principles of safe and effective weight loss and present an approach for the assessment of overweight and obesity. This approach involves the evaluation of three measures: body mass index (BMI), waist circumference, and a patient's risk factors for diseases and conditions associated with obesity. The guidelines identify overweight as a BMI of 25 to 29.9, and obesity as a BMI of 30 and above. The new definitions are consistent with those used in many other countries, and support the Dietary Guidelines for Americans issued in 1995. Under these definitions, 97 million American adults -- 55 percent of the population -- are overweight or obese.

The 24-member expert panel that developed the guidelines used an evidence-based approach to review published studies on which the guidelines are based. This approach follows the NHLBI directive issued in 1995 that requires guidelines to reflect an evidence-based process and consensus. Under this directive, guidelines must explicitly describe the methodology used in development, summarize appropriate literature, and establish recommendations based on specific data, clinical judgment, or both.

The panel developed an evidence model for the treatment of the overweight or obese patient, performed extensive MEDLINE literature searches, reviewed pertinent literature, and created databases to accommodate the literature searches and data abstraction. The MEDLINE search of records from 1980 to 1997 provided over 41,000 titles pertinent to overweight or obesity, of which 394 represented randomized controlled trials (RCTs) meeting the panel's criteria for review. After final review, the panel abstracted 236 RCT articles and the data were then compiled into individual evidence tables developed for each RCT.

You may access the guidelines through the NIDDK website at www.niddk.nih.gov/health/nutrit/related.htm. You can also access tip sheets on healthy eating and a calculator for computing your BMI at this site.

WIN's fact sheet, Prescription Medications for the Treatment of Obesity, has been revised to reflect the withdrawal of fenfluramine and dexfenfluramine from the market and covers types of medications currently used and the risks and benefits associated with their use. The fact sheet is available to download from the World Wide Web at http://www.niddk.nih.gov.