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Aggressive Regimens Reduce Risk of Recurrence After Successful Treatment of MDR-TB.

BACKGROUND
We sought to determine whether treatment with a "long aggressive regimen" was associated with lower rates of relapse among patients successfully treated for pulmonary multidrug-resistant tuberculosis (MDR-TB) in Tomsk, Russia.


METHODS
We conducted a retrospective cohort study of adult patients that initiated MDR-TB treatment with individualized regimens between September 2000 and November 2004, and were successfully treated. Patients were classified as having received "aggressive regimens" if their intensive phase consisted of at least 5 likely effective drugs (including a second-line injectable and a fluoroquinolone) used for at least 6 months post culture conversion, and their continuation phase included at least 4 likely effective drugs. Patients that were treated with aggressive regimens for a minimum duration of 18 months post culture conversion were classified as having received "long aggressive regimens." We used recurrence as a proxy for relapse because genotyping was not performed. After treatment, patients were classified as having disease recurrence if cultures grew MDR-TB or they re-initiated MDR-TB therapy. Data were analyzed using Cox proportional hazard regression.


RESULTS
Of 408 successfully treated patients, 399 (97.5%) with at least 1 follow-up visit were included. Median duration of follow-up was 42.4 months (interquartile range: 20.5-59.5), and there were 27 recurrence episodes. In a multivariable complete case analysis (n = 371 [92.9%]) adjusting for potential confounders, long aggressive regimens were associated with a lower rate of recurrence (adjusted hazard ratio: 0.22, 95% confidence interval, .05-.92).


CONCLUSIONS
Long aggressive regimens for MDR-TB treatment are associated with lower risk of disease recurrence.