Examining Disease Characteristics and Patterns of Weight Gain in Tuberculosis Treatment

Tuberculosis (TB), in addition to causing symptoms such as coughing and fever, often results in significant weight loss and lack of appetite. In one study, more than 40% of Los Angeles residents with TB experienced a lack of appetite and more than 44% lost weight. This weight loss—also known as wasting—leads to malnutrition and subsequent impairment of the immune system, and puts the TB sufferer at a much higher risk of dying from the disease. Indeed, TB remains a top cause of death around the globe.

A Baylor College of Medicine study of 134 patients being treated for active TB at a Houston hospital looked at the results of treatment, specifically with regard to whether patients regained some or all of the weight they had initially lost. The researchers hoped to discern patterns of weight gain in the patients and whether certain characteristics of the disease could predict whether a patient would gain weight.

Weight gain during disease treatment is an important marker of the restoration of health, according to researchers. “Systemic illnesses such as TB frequently cause weight loss—both in fat and lean body mass—as noted in the [study] introduction,” said Elizabeth Guy, MD, an assistant professor at Baylor College of Medicine and an author of the study. “Recovery from illness is frequently accompanied by recovery of the lost body mass and additional gain for some. It is viewed as an indicator of response to treatment (patient goes from catabolic phase—where they have more tissue breakdown—to anabolic phase, during which protein breakdown decreases and synthesis predominates). Some studies indicate that failure to gain weight was associated with poorer outcomes of treatment, including relapse of tuberculosis.”

Overall, the patients in the Baylor study did gain weight, but it often took some time for them to achieve a healthy body-mass index. In the intensive two-month initial phase of treatment, only 31.9% of patients had gained at least 5% of their body weight. By the end of treatment, which often lasted nine months or longer, 62.4% of patients had gained 5% or more of their body weight. The weight was gained in a steady, linear manner during treatment.

The study’s authors found that it was those patients who had the most severe burden of disease who tended to gain weight. These patients had positive sputum smears, positive sputum cultures, cavitary (a condition in which progressive lung damage causes enlarged air pockets), and more extensive lesions, but proper treatment and nutrition did, in time, lead to a replenishment of the body mass lost. Those participants who didn’t gain weight were more likely to have a malignancy of some sort, be coinfected with hepatitis B or C, be older than 60 years of age, or have multidrug-resistant TB. Scientists admitted that the exact reasons why certain TB patients gain weight and others do not, remain murky.

Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.