High Relapse Rate Seen After "Successful" Drug-Resistant TB Treatment

Researchers warn that the long-term success of treatment for drug-resistant tuberculosis may be lower than previously believed.

G.B. Migliori and colleagues at the World Health Organization in Geneva; the WHO Collaborating Center for Tuberculosis and Lung Diseases in Tradate, Italy; the Ivanovo TB Dispensary in Ivanovo, Russia; and the Central Tuberculosis Research Institute in Moscow investigated the "frequency of TB recurrence among MDR [multidrug-resistant] patients who achieved treatment 'success' on standard short-course chemotherapy."

Migliori and colleagues found that treatment success, especially for patients given Category I drug regimens, was often short-lived. Data from 18 TB patients with infections resistant to isoniazid and rifampicin, at least, showed roughly 28 percent suffering relapses, with 2.46 cases of recurrent disease per 100 person-months. Category I patients considered cured after directly observed treatment of isoniazid, ethambutol, rifampicin and pyrazinamide had a relapse rate of 40 percent. Patients treated with a Category II regimen, which adds streptomycin to the Category I regimen, had a relapse rate of 12.5 percent. The median time to relapse was 8 months.

The full report, "Frequency of Recurrence Among MDR-TB Cases 'Successfully' Treated with Standardized Short-Course Chemotherapy," was published in the International Journal of Tuberculosis and Lung Disease (2002;6(120):858-864).

"The frequency of TB recurrence among MDR-TB patients declared 'cured' after short-course chemotherapy is high," Migliori and colleagues concluded. "Culture-based bacteriological confirmation at the end of treatment is recommended."

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