title: Risk factors for tuberculosis in HIV-infected persons. A prospective cohort study. The Gruppo Italiano di Studio Tubercolosi e AIDS (GISTA).
abstract: OBJECTIVE
  To analyze how demographic, clinical, and laboratory characteristics influence the risk of tuberculosis in human immunodeficiency virus (HIV)-infected individuals; to examine the incidence of tuberculosis associated with change in skin test responsiveness in HIV-infected, tuberculin-negative, nonanergic individuals.
  
  
  METHODS
  Multicenter cohort study.
  
  
  METHODS
  Twenty-three infectious disease units in public hospitals in Italy.
  
  
  METHODS
  A consecutive sample of 3397 HIV-infected subjects were considered for entry in the study. Of these, 2695 who were followed up for at least 4 weeks were enrolled in the study; 739 subjects (27.4%) were unavailable for follow-up. The median duration of follow-up was 91 weeks.
  
  
  METHODS
  Culture-proven tuberculosis.
  
  
  RESULTS
  Eighty-three episodes of tuberculosis were observed. Incidence rates of tuberculosis were 5.42 per 100 person-years among tuberculin-positive subjects, 3.00 per 100 person-years among anergic subjects, and 0.45 per 100 person-years among tuberculin-negative nonanergic subjects. In multivariate analysis, being tuberculin-positive (hazard ratio [HR], 9.94; 95% confidence interval [CI], 3.84 to 25.72) or anergic (HR, 3.35; 95% CI, 1.40 to 8.00), or having a CD4+ lymphocyte count less than 0.20 x 10(9)/L (HR, 4.87; 95% CI, 2.35 to 10.11) or between 0.20 and 0.35 x 10(9)/L (HR, 2.35; 95% CI, 1.09 to 5.05) were statistically significantly associated with the risk of tuberculosis. Incidence of tuberculosis increased with decreasing levels of CD4+ lymphocytes in the three groups of subjects with different skin test responsiveness. Skin tests were repeated 1 year after enrollment in 604 tuberculin-negative nonanergic subjects; three case of tuberculosis were observed among the 13 subjects who converted to tuberculin reactivity.
  
  
  CONCLUSIONS
  Risk of tuberculosis in HIV-infected persons can be more precisely quantified by jointly considering skin test reactivity and CD4+ lymphocyte count. Periodic skin tests in tuberculin-negative nonanergic individuals can be useful in identifying individuals at high risk of active tuberculosis.
authors.affiliation: Centro di Riferimento AIDS, Ospedale L. Spallanzani, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Antonucci
authors.forename: E
authors.initials: E
authors.lastname: Girardi
authors.forename: M C
authors.initials: MC
authors.lastname: Raviglione
authors.forename: G
authors.initials: G
authors.lastname: Ippolito
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000453:epidemiology*; D000328:Adult; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000276:immunology* / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*