title: Predictors of sputum culture conversion among patients treated for multidrug-resistant tuberculosis.
abstract: OBJECTIVE
  To identify predictors of initial sputum culture conversion, estimate the usefulness of persistent positive cultures at different time points in predicting treatment failure, and evaluate different definitions of culture conversion for predicting failure among patients with  multidrug-resistant tuberculosis (MDR-TB) in five countries, 2000-2004.
  
  
  METHODS
  Predictors of time to conversion were identified using multivariate Cox proportional hazards regression modeling. Receiver operating characteristic curves were plotted to visualize the effect of using  different definitions of 'culture conversion' on the balance between sensitivity and specificity.
  
  
  RESULTS
  Overall, 1209/1416 (85%) of patients with baseline positive cultures converted in a median of 3.0 months (interquartile range 2.0-5.0). Independent predictors of  less likely conversion included baseline positive smear (hazard ratio [HR] 0.60, 95%CI 0.53-0.68), resistance to pyrazinamide (HR 0.82, 95%CI 0.70-0.96), fluoroquinolones (FQs; HR 0.65, 95%CI 0.51-0.83) or thioamide (HR 0.83, 95%CI 0.71-0.96), previous use of FQs (HR  0.71, 95%CI 0.60-0.83), poor outcome of previous anti-tuberculosis treatment (HR 0.69, 95%CI 0.54-0.88) and alcoholism (HR 0.74, 95%CI 0.63-0.87). The maximum combined sensitivity (84%) and specificity (94%) in predicting treatment failure was based on lack of culture conversion  at month 9 of treatment, assuming conversion is defined as five consecutive negative cultures.
  
  
  CONCLUSIONS
  Patients with identified risk factors were less likely to achieve sputum culture conversion during MDR-TB treatment.
authors.affiliation: US Centers for Disease Control and Prevention, Atlanta, GA, USA. ekurbatova@cdc.gov
authors.forename: E V
authors.initials: EV
authors.lastname: Kurbatova
authors.forename: V M
authors.initials: VM
authors.lastname: Gammino
authors.forename: J
authors.initials: J
authors.lastname: Bayona
authors.forename: M C
authors.initials: MC
authors.lastname: Becerra
authors.forename: M
authors.initials: M
authors.lastname: Danilovitz
authors.forename: D
authors.initials: D
authors.lastname: Falzon
authors.forename: I
authors.initials: I
authors.lastname: Gelmanova
authors.forename: S
authors.initials: S
authors.lastname: Keshavjee
authors.forename: V
authors.initials: V
authors.lastname: Leimane
authors.forename: C D
authors.initials: CD
authors.lastname: Mitnick
authors.forename: M I
authors.initials: MI
authors.lastname: Quelapio
authors.forename: V
authors.initials: V
authors.lastname: Riekstina
authors.forename: A
authors.initials: A
authors.lastname: Taylor
authors.forename: P
authors.initials: P
authors.lastname: Viiklepp
authors.forename: M
authors.initials: M
authors.lastname: Zignol
authors.forename: J P
authors.initials: JP
authors.lastname: Cegielski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents