title: Extensively drug-resistant tuberculosis in South Korea: risk factors and treatment outcomes among patients at a tertiary referral hospital.
abstract: BACKGROUND
  Extensively drug-resistant (XDR) tuberculosis (TB) is a major public health threat in South Korea.
  
  
  METHODS
  We analyzed baseline epidemiological data for 250 patients enrolled in an ongoing prospective observational study of TB at a large tertiary referral hospital in South Korea.
  
  
  RESULTS
  Twenty-six subjects with XDR TB were identified; all were patients who had previously received TB therapy. Cumulative previous treatment duration (range, 18-34 months; odds ratio [OR], 5.6; 95% confidence interval [CI], 1.0-59), number of previously received second-line anti-TB drugs (OR, 1.3; 95% CI, 1.1-1.5), and female sex (OR, 3.2; 95% CI, 1.1-8.3) were significantly associated with XDR TB in crude analyses. After controlling for other factors in a multivariable model, cumulative previous treatment duration remained significantly associated with XDR TB (OR, 5.8; 95% CI, 1.0-61). Subjects with XDR TB were more likely to produce culture-positive sputum at 6 months, compared with patients with non-multidrug resistant TB (risk ratio, 13; 95% CI, 5.1-53). Kanamycin resistance was found to be predictive of 6-month culture positivity after adjustment for ofloxacin and streptomycin resistance (risk ratio, 3.9; 95% CI, 1.9-11).
  
  
  CONCLUSIONS
  XDR TB was found to be associated with the cumulative duration of previous treatment with second-line TB drugs among subjects in a tertiary care TB hospital. Patients with XDR TB were more likely to not respond to therapy, and successful conversion of sputum culture results to negative was correlated with initial susceptibility to both fluoroquinolones and kanamycin but not to streptomycin.
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Christie Y
authors.initials: CY
authors.lastname: Jeon
authors.forename: Soo Hee
authors.initials: SH
authors.lastname: Hwang
authors.forename: Jin Hong
authors.initials: JH
authors.lastname: Min
authors.forename: D Rebecca
authors.initials: DR
authors.lastname: Prevots
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Goldfeder
authors.forename: Hyeyoung
authors.initials: H
authors.lastname: Lee
authors.forename: Seok Yong
authors.initials: SY
authors.lastname: Eum
authors.forename: Doo Soo
authors.initials: DS
authors.lastname: Jeon
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Kang
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Byoung Ju
authors.initials: BJ
authors.lastname: Kim
authors.forename: Dae Yeon
authors.initials: DY
authors.lastname: Kim
authors.forename: Steven M
authors.initials: SM
authors.lastname: Holland
authors.forename: Seung Kyu
authors.initials: SK
authors.lastname: Park
authors.forename: Sang Nae
authors.initials: SN
authors.lastname: Cho
authors.forename: Clifton E
authors.initials: CE
authors.lastname: Barry
authors.forename: Laura E
authors.initials: LE
authors.lastname: Via
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D015331:Cohort Studies; D054908:Extensively Drug-Resistant Tuberculosis / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome
chemical_list: D000995:Antitubercular Agents; D024841:Fluoroquinolones