Winter 1999

Clinical Trial to Study Health Effects of Weight Loss

Plans are under way to study the health effects of intentional weight loss in obese patients with type 2 diabetes. Six Government organizations have jointly issued a Request for Applications (RFA) for a clinical trial, called the Study of Health Outcomes of Weight Loss (SHOW).

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); the National Heart, Lung, and Blood Institute; the National Institute of Nursing Research; the Office of Research on Women's Health; the National Institute of Environmental Health Sciences; and the Centers for Disease Control and Prevention are inviting cooperative agreement applications from investigators to design and implement the clinical trial. This type of funding mechanism will allow NIDDK to support and stimulate investigators' activities by working with them in a partnership--not a directive--role.

The randomized, controlled, multicenter trial will study two primary research questions:

1. Do interventions designed to produce sustained weight loss in obese individuals with type 2 diabetes improve health?
   
2. How do the benefits and risks of these interventions compare with the benefits and risks associated with treatment of comorbid conditions in the absence of weight-loss intervention?

The primary outcome of the study is anticipated to be the effects of the interventions on progression of atherosclerosis. The study will also examine these intervention effects on the following: cardiovascular and cerebrovascular event rates, cardiovascular and noncardiovascular mortality, cardiovascular risk factors, glycemic control, and other outcomes. Numerous studies have shown that short-term weight loss improves obesity-related risk factors, but little information exists on the health effects of long-term intentional weight loss in obese individuals.

Barbara Harrison, special project officer in NIDDK's Division of Digestive Diseases and Nutrition and coordinator of the SHOW trial, emphasized the importance of the study findings. "This study will provide clinical information crucial to treating patients with obesity and diabetes. In addition, SHOW will serve as a valuable resource for basic research into the causes that underlie these diseases."

NIDDK anticipates recruitment of approximately 6,000 patients (including a significant number of minority individuals) over a 3-year period with 4 additional years of treatment and followup. Midway through recruitment, an independent assessment will be made to determine the feasibility of continuing the trial.

About two-thirds of the patients are expected to be enrolled in intensive, long-term behavioral treatment programs to improve diet, increase physical exercise, and enhance weight loss and maintenance. They will also be treated by their primary care physicians for obesity-related comorbid conditions. Some may be placed on weight-loss medications. The remaining one-third of patients will receive treatment for their medical conditions from their primary care physicians, but will not receive intensive weight-loss treatment.

Additional information pertaining to the SHOW trial and the RFA is posted on the website at www.niddk.nih.gov/patient/SHOW/showhmpg.htm.

Application and Review Schedule

Letter of Intent Receipt Date: February 10,1999

Application Receipt Date: March 24, 1999

Peer Review Date: June-July, 1999

Review by National Diabetes and Digestive
and Kidney Diseases Advisory Council: September 8-9, 1999

Expected Award Date: September 30, 1999