Multidrug-Resistant Tuberculosis in Patients for Whom First-Line Treatment Failed, Mongolia, 2010–2011

In Ulaanbaatar, Mongolia, multidrug-resistant tuberculosis (MDR TB) was diagnosed for more than a third of new sputum smear–positive tuberculosis patients for whom treatment had failed. This finding suggests a significant risk for community-acquired MDR TB and a need to make rapid molecular drug susceptibility testing available to more people.

The implementation of DOTS is supported by the provision of community-DOT by a network of over 300 community volunteers coordinated by the Mongolian Anti-Tuberculosis Association (MATA) in addition to conventional clinic-based DOT.

Definitions
Cured was defined as a pulmonary TB patient with bacteriologically confirmed TB at the beginning of treatment who was smear-or culture-negative in the last month of treatment and on at least one previous occasion. Treatment completed was defined as a TB patient who completed treatment without evidence of failure, but with no record to show that sputum smear or culture results in the last month of treatment and on at least one previous occasion were negative, either because tests were not done or because results are unavailable.

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Treatment failed was defined as a TB patient whose sputum smear or culture is positive at month five or later during treatment. Died was defined as a TB patient who dies for any reason before starting or during the course of treatment. Lost to follow-up was defined as a TB patient who did not start treatment or whose treatment was interrupted for two consecutive months or more. Not evaluated was defined as a TB patient for whom no treatment outcome is assigned. This includes cases "transferred out" to another treatment unit as well as cases for which the treatment outcome is unknown to the reporting unit. Treatment success was defined as the sum of cured and treatment completed. "Occupation" was defined based on categories included in the Mongolian routine TB data surveillance, which were employed (including self-employed), unemployed, retired, schoolchild (primary and secondary education), student (higher education and vocational training), people on disability pension, prisoner, homeless.

Cultures and Drug Susceptibility Testing
DST procedures passed an external quality assessment by the Japanese Research Institute of Tuberculosis (RIT), which acts as the supranational reference laboratory (SRL) for the Mongolian National Reference Laboratory (NRL).
DST to pyrazinamide was not performed during the study period (despite the use of pyrazinamide as part of the standard Category I treatment).

Analysis
Associations between demographic and clinical characteristics were assessed using logistic regression and odds ratios (ORs) with 95% confidence intervals (95% CIs). The independent effect of potential predictors of MDR-TB among patients in whom Category I treatment failed, was estimated using multivariate logistic regression. Only categorical variables were used in logistic regression; the continuous variable age was converted into a categorical variable by creating age groups. Multivariate analysis included adjustment for age, sex and occupation. Districts/treatment facilities were excluded from multivariate analysis to prevent overcorrection, as they had markedly different populations in terms of gender and age distribution as well as level of unemployment. Additionally, the study was

Ethical Considerations
As data were collected as part of routine TB surveillance, this analysis was not considered research involving human subjects, and ethics approval was not required.
MDR-TB was subsequently confirmed in one while in the other treatment failed despite completing a full 6-months course of standard Category I treatment; no DST was performed.