title: Determinants of drug-resistant tuberculosis: analysis of 11 countries.
abstract: METHODS
  Eleven countries/territories.
  
  
  OBJECTIVE
  Global information on the determinants of drug-resistant tuberculosis (TB) based on representative data is not available. We therefore studied the relationship between demographic characteristics, prior TB treatment, and human immunodeficiency virus (HIV) infection with anti-tuberculosis drug resistance.
  
  
  METHODS
  Population-based representative data on new and previously treated patients with TB collected within an international drug resistance surveillance network.
  
  
  RESULTS
  Of 9,615 patients, 8,222 (85.5%) were new cases of TB and 1,393 (14.5%) were previously treated cases. Compared with new cases, previously treated cases were significantly more likely to have resistance to one (OR = 2.5,95% CI 2.1-3.0; P < 0.001), two (OR = 4.6, 95%CI 3.7-5.6; P < 0.001), three (OR = 11.5, 95%CI 8.6-15.3; P < 0.001), and four (OR = 18.5, 95% CI 12.0-28.5; P < 0.001) drugs. An approximately linear increase in the likelihood of having multidrug-resistant tuberculosis (MDR-TB) was observed as the total time (measured in months) of prior anti-tuberculosis treatment increased (P < 0.001, chi2 for trend). In multivariate analysis, prior TB treatment for 6-11 months (OR = 7.6, 95% CI 2.6, 22.4; P < 0.001) and > or = 12 months (OR 13.7, 95% CI 4.5-41.6; P < 0.001), but not HIV positivity, was associated with MDR-TB.
  
  
  CONCLUSIONS
  This study shows that prior but ineffective treatment is a strong predictor of drug resistance, and that HIV is not an independent risk factor for MDR-TB. The association between length of treatment and drug resistance may reflect longer treatment as a result of treatment failure in patients with drug resistance; it may also reflect irregular prior treatment for TB, leading to drug resistance.
authors.affiliation: World Health Organization, Communicable Diseases, Geneva, Switzerland. espinalm@who.ch
authors.forename: M A
authors.initials: MA
authors.lastname: Espinal
authors.forename: K
authors.initials: K
authors.lastname: Laserson
authors.forename: M
authors.initials: M
authors.lastname: Camacho
authors.forename: Z
authors.initials: Z
authors.lastname: Fusheng
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: R E
authors.initials: RE
authors.lastname: Tlali
authors.forename: I
authors.initials: I
authors.lastname: Smith
authors.forename: P
authors.initials: P
authors.lastname: Suarez
authors.forename: M L
authors.initials: ML
authors.lastname: Antunes
authors.forename: A G
authors.initials: AG
authors.lastname: George
authors.forename: N
authors.initials: N
authors.lastname: Martin-Casabona
authors.forename: P
authors.initials: P
authors.lastname: Simelane
authors.forename: K
authors.initials: K
authors.lastname: Weyer
authors.forename: N
authors.initials: N
authors.lastname: Binkin
authors.forename: M C
authors.initials: MC
authors.lastname: Raviglione
mesh_terms: D000293:Adolescent; D000328:Adult; D000349:Africa / Q000453:epidemiology; D000367:Age Factors; D000569:Americas / Q000453:epidemiology; D000904:Antibiotics, Antitubercular / Q000627:therapeutic use; D001208:Asia / Q000453:epidemiology; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D018432:Drug Resistance, Multiple; D004977:Ethambutol / Q000627:therapeutic use; D005060:Europe / Q000453:epidemiology; D005260:Female; D006678:HIV / Q000187:drug effects; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011159:Population Surveillance; D015995:Prevalence; D012293:Rifampin / Q000627:therapeutic use; D018088:Tuberculosis, Multidrug-Resistant / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*
chemical_list: D000904:Antibiotics, Antitubercular; D004977:Ethambutol; D012293:Rifampin