The researchers found that patients with XDR-TB were significantly older than MDR-TB patients, were more likely to have a history of treatment with second-line TB drugs, and more likely to have a history of being treated for TB two or more times.
Among this population, treatment failure was, not surprisingly, much more common when compared to other patients with MDR-TB. While relapse rate among "cured" patients also tended to be higher among patients with XDR-TB, the difference was not statistically significant.
"[Having] XDR-TB was the strongest predictor of both all-cause and TB-related mortality, and survival curves showed higher cumulative mortality among patients with XDR-TB than in other patients with MDR-TB," wrote Dr. Shim. Over the three to seven years that the study's patient population was monitored, approximately 50 percent of those identified with XDR-TB died, which was a mortality rate similar to untreated TB patients in South India, and one that becomes even worse with HIV co-infection.
Perhaps the biggest public health threat associated with XDR-TB, however, is not its particular virulence, but the lack of information and treatment options that medical and public health officials have on which to draw. The collective dearth of knowledge was likened by Giovanni Battista Migliori, M.D., Morgan Richardson, R.N., P.H.N., and Christopher Lange, M.D., Ph.D., co-authors of the accompanying editorial, to the proverbial blind men trying to describe an elephanttoo big a task to accomplish with too little information.
The risks of this lack of information are clear. "Regrettably, a new drug [to treat TB] has no
|Contact: Keely Savoie|
American Thoracic Society