Among tuberculosis (TB) patients who were underweight when diagnosed, those who subsequently regained less than five percent of their weight during the first two months of treatment had a significantly increased risk of disease relapse, according to results from a large study.

The research appears in the first issue for August 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.

Awal D. Khan, Ph.D., of the TB Trials Consortium Study Data and Coordinating Center at the Centers for Disease Control and Prevention in Atlanta, and four associates monitored 857 TB patients for two years. Of this group, 61 (7.1 percent) relapsed.

"In a model adjusted for other relapse risk factors, a weight gain of 5 percent or less between diagnosis and completion of a two-month intensive phase therapy among persons underweight at diagnosis was significantly associated with relapse risk," said Dr. Khan.

(For the study, persons were classified as underweight if they were 10 percent below their ideal body weight.)

The authors pointed to an 18.5 percent relapse rate in persons with greater than 5 percent body weight gain and a 50.5 percent relapse rate in persons who gained less than 5 percent in weight.

The researchers said that the association between weight and disease relapse still held among underweight persons who had abnormal chest x-rays and positive sputum cultures after 2 months of anti-tuberculosis treatment.

"Less than 5 percent weight gain could be a marker of increased tuberculosis disease activity and/or poor response to therapy," said Dr. Khan.

TB is a contagious, potentially fatal infection usually caused by the airborne bacterium Mycobacterium tuberculosis. About 85 percent of TB infections are caused by re-activation of dormant bacteria that have been healed and sealed off at the site of the original infection. TB that affects o
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Contact: Suzy Martin
smartin@thoracic.org
212-315-8631
American Thoracic Society
1-Aug-2006