Low BMI, presence of diabetes affect TB treatment outcomes
Low BMI was significantly associated with an increased risk for adverse treatment outcomes in patients with tuberculosis, although comorbid diabetes resulted in “unexpectedly” better outcomes for these patients, according to a study in a South Indian cohort.
“The study was initiated in response to a request for proposals to create the RePORT India consortium,” Hardy Kornfeld, MD, professor in the department of medicine at the University of Massachusetts, told Healio. “The rationale was that nearly all the studies of TB-diabetes comorbidity at the time — approximately 7 years ago — were retrospective in nature, had imprecise clinical definitions for diabetes mellitus, such as reported history, and were not conducted in India, which has the highest number of people living with the combined diseases.”
Patients in the study were newly diagnosed with culture-positive pulmonary TB and had either diabetes mellitus or normal glucose tolerance. Kornfeld and colleagues measured baseline TB severity, sputum conversion and treatment outcomes, including cure, failure, death or lost to followup, and compared these results between groups, with respect to glycemic status and BMI. Patients were followed over 6 months of TB treatment.
The cohort included 389 participants — 256 with diabetes and 133 with normal glucose tolerance.
Low BMI (<18.5 kg/m2) was more common in participants without diabetes (n = 99; 74.4%) than in those with diabetes (n = 85; 33.2%). Patients with low BMI had the highest radiographic severity of disease, the longest time to sputum culture conversion and the highest rates of treatment failure and death. However, poorly controlled diabetes “unexpectedly” correlated with better TB treatment outcomes in patients with low BMI.
“The mechanism of the protective effect associated with diabetes mellitus in individuals with a low BMI is presently unknown,” Kornfeld said. “However, it might fit with a previously described medical hypothesis that states that the tendency to develop diabetes mellitus in the South Asian population was an evolutionary response to maintain an energy reserve to fight chronic infectious diseases in the pre-antibiotic era.”
Rates of cure, treatment failure or death did not vary by glycemic status for participants with a normal or high BMI.
“It is reasonable to suggest that monitoring during and after TB treatment should be intensified in individuals with a low BMI in an effort to ensure successful treatment and the avoidance, or at least early detection, of recurrent TB,” Kornfeld concluded. “Given the evidence that TB drives diabetes mellitus complication pathways, it would be prudent to implement measures that reduce cardiovascular disease risk.” – by Caitlyn Stulpin
Disclosure: Kornfeld reports no relevant financial disclosures.