title: Factors associated with time to sputum smear conversion in active pulmonary tuberculosis.
abstract: OBJECTIVE
  To ascertain the factors affecting the time between the initiation of treatment and obtaining three negative sputum smears.
  
  
  METHODS
  In a study of 109 patients with pulmonary tuberculosis, the main variable was the period during which the patients had sputum smears once treatment was initiated. Multivariate analysis (multiple linear regression) was performed to document those variables independently associated with time to conversion.
  
  
  RESULTS
  The patients had positive smears for a mean of 28.63 days. The most frequent radiographic pattern was cavitary disease (36.7%). HIV co-infection was present in 38.5% of the patients. HIV-infected patients showed a cavitation pattern in only 9.6% vs 52.2% of patients without HIV infection (P < 0.001). The variables that showed a statistically significant and independent relationship with the time to sputum smear conversion were pulmonary radiographic pattern, age and erythrocyte sedimentation rate (ESR).
  
  
  CONCLUSIONS
  ESR, age and the presence of cavitary disease seem to be factors associated with a longer time to sputum smear conversion in patients with active pulmonary tuberculosis. However, HIV co-infection is associated with a shorter time to sputum conversion. A key factor is therefore the presence or not of cavitation, independently of HIV infection.
authors.affiliation: Infectious Diseases Unit, Internal Medicine Service, Virgen Macarena Hospital, Seville, Spain. adomin@saludalia.com
authors.forename: A
authors.initials: A
authors.lastname: Domínguez-Castellano
authors.forename: M A
authors.initials: MA
authors.lastname: Muniain
authors.forename: J
authors.initials: J
authors.lastname: Rodriguez-Baño
authors.forename: M
authors.initials: M
authors.lastname: Garcia
authors.forename: M J
authors.initials: MJ
authors.lastname: Rios
authors.forename: J
authors.initials: J
authors.lastname: Galvez
authors.forename: R
authors.initials: R
authors.lastname: Perez-Cano
mesh_terms: D000328:Adult; D001799:Blood Sedimentation; D015897:Comorbidity; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000453:epidemiology