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Improved diagnosis of treatment of multidrug-resistant tuberculosis should be highly prioritized

Patients with multidrug-resistant tuberculosis are more likely to have developed the disease through incidence transmission, rather than a new treatment-related acquisition, according to recent research published in The Lancet.

“This mechanistic model of tuberculosis treatment and drug resistance suggests that existing notifications are most consistent with today’s [multidrug-resistant (MDR)] tuberculosis epidemic being predominantly (>80%) an epidemic of MDR transmission. A preponderance of transmission is consistent with both reported MDR tuberculosis epidemiology and historical successes in MDR tuberculosis control,” Emily A. Kendall, MD, from the division of infectious diseases at Johns Hopkins School of Medicine, Baltimore, and colleagues wrote. “If, as our model suggests, only a small proportion of MDR tuberculosis incidence results directly from previous treatment, then incremental improvements in drug-susceptible tuberculosis treatment are unlikely to bend the epidemic curve of MDR tuberculosis in most settings. By contrast, expansion of MDR tuberculosis treatment availability, along with improvement in MDR tuberculosis treatment outcomes, has tremendous potential to limit the spread of MDR tuberculosis in the future.”

Kendall and colleagues evaluated national tuberculosis data from several countries to estimate the incidence of MDR in 2013 related to MDR transmission instead of treatment-related acquisition, according to the abstract. They found that 3.5% of MDR tuberculosis was developed through new tuberculosis notifications, while 20.5% of MDR tuberculosis was developed through re-treatment notifications. Further, they estimated that resistance transmission accounted for 95.9% of incident tuberculosis cases (95% UR; 68% - 99.6%) and 61.3% of incidence MDR tuberculosis cases (95% UR; 16.5% - 95.2%) in previously treated patients, according to the abstract.

Bangladesh had the lowest notification data at 48% (95% UR; 30% - 75%), and Uzbekistan had the highest notification data at 99% (95% UR; 91% - 100%), according to the abstract.

“If the current MDR tuberculosis epidemic is to be controlled, expanding effective MDR tuberculosis treatment while developing novel rapid drug susceptibility tests and more tolerable, less resource-intensive drug regimens should be prioritized by the global public health community,” Kendall and colleagues wrote. – by Jeff Craven

Disclosure: One researcher reports ownership in GlaxoSmithKline.