title: Reducing tuberculosis incidence by tuberculin skin testing, preventive treatment, and antiretroviral therapy in an area of low tuberculosis transmission.
abstract: BACKGROUND
  Tuberculin skin testing (TST) and preventive treatment of tuberculosis (TB) are recommended for all persons with human immunodeficiency virus (HIV) infection. We aimed to assess the effect of TST and preventive treatment of TB on the incidence of TB in the era of combination antiretroviral therapy in an area with low rates of TB transmission.
  
  
  METHODS
  We calculated the incidence of TB among participants who entered the Swiss HIV Cohort Study after 1995, and we studied the associations of TST results, epidemiological and laboratory markers, preventive TB treatment, and combination antiretroviral therapy with TB incidence.
  
  
  RESULTS
  Of 6160 participants, 142 (2.3%) had a history of TB at study entry, and 56 (0.91%) developed TB during a total follow-up period of 25,462 person-years, corresponding to an incidence of 0.22 cases per 100 person-years. TST was performed for 69% of patients; 9.4% of patients tested had positive results (induration > or = 5 mm in diameter). Among patients with positive TST results, TB incidence was 1.6 cases per 100 person-years if preventive treatment was withheld, but none of the 193 patients who received preventive treatment developed TB. Positive TST results (adjusted hazard ratio [HR], 25; 95% confidence interval [CI], 11-57), missing TST results (HR, 12; 95% CI, 4.8-20), origin from sub-Saharan Africa (HR, 5.8; 95% CI, 2.7-12.5), low CD4+ cell counts, and high plasma HIV RNA levels were associated with an increased risk of TB, whereas the risk was reduced among persons receiving combination antiretroviral therapy (HR, 0.44; 95% CI, 0.2-0.8).
  
  
  CONCLUSIONS
  Screening for latent TB using TST and administering preventive treatment for patients with positive TST results is an efficacious strategy to reduce TB incidence in areas with low rates of TB transmission. Combination antiretroviral therapy reduces the incidence of TB.
authors.affiliation: University Hospital Basel, Switzerland.
authors.forename: Luigia
authors.initials: L
authors.lastname: Elzi
authors.forename: Matthias
authors.initials: M
authors.lastname: Schlegel
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
authors.forename: Bernard
authors.initials: B
authors.lastname: Hirschel
authors.forename: Matthias
authors.initials: M
authors.lastname: Cavassini
authors.forename: Patrick
authors.initials: P
authors.lastname: Schmid
authors.forename: Enos
authors.initials: E
authors.lastname: Bernasconi
authors.forename: Martin
authors.initials: M
authors.lastname: Rickenbach
authors.forename: Hansjakob
authors.initials: H
authors.lastname: Furrer
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D015995:Prevalence; D012367:RNA, Viral / Q000097:blood; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors