title: The cost-effectiveness of routine tuberculosis screening with Xpert MTB/RIF prior to initiation of antiretroviral therapy:  a model-based analysis.
abstract: BACKGROUND
  In settings with high tuberculosis (TB) prevalence, 15-30% of HIV-infected individuals initiating antiretroviral therapy (ART) have undiagnosed TB. Such patients are usually screened by symptoms and sputum smear, which have poor sensitivity.
  
  
  OBJECTIVE
  To project the clinical and economic outcomes of using Xpert MTB/RIF(Xpert), a rapid TB/rifampicin-resistance diagnostic, to screen individuals initiating ART.
  
  
  METHODS
  We used a microsimulation model to evaluate the clinical impact and cost-effectiveness of alternative TB screening modalities - in all patients or only symptomatic patients - for hypothetical cohorts of individuals initiating ART in South Africa (mean CD4 cell count = 171 cells/μl; TB prevalence 22%). We simulated no active screening and four diagnostic strategies, smear microscopy (sensitivity 23%); smear and culture (sensitivity, 100%); one Xpert sample (sensitivity in smear-negative TB: 43%); two Xpert samples (sensitivity in smear-negative TB: 62%). Outcomes included projected life expectancy, lifetime costs (2010 US$), and incremental cost-effectiveness ratios (ICERs). Strategies with ICERs less than $7100 (South African gross domestic product per capita) were considered very cost-effective.
  
  
  RESULTS
  Compared with no screening, life expectancy in TB-infected patients increased by 1.6 months using smear in symptomatic patients and by 6.6 months with two Xpert samples in all patients. At 22% TB prevalence, the ICER of smear for all patients was $2800 per year of life saved (YLS), and of Xpert (two samples) for all patients was $5100/YLS. Strategies involving one Xpert sample or symptom screening were less efficient.
  
  
  CONCLUSIONS
  Model-based analysis suggests that screening all individuals initiating ART in South Africa with two Xpert samples is very cost-effective.
authors.affiliation: Division of Infectious Diseases, Massachusetts General Hospital, Boston, 02114, USA. jasonandr@gmail.com
authors.forename: Jason R
authors.initials: JR
authors.lastname: Andrews
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lawn
authors.forename: Corina
authors.initials: C
authors.lastname: Rusu
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
authors.forename: Farzad
authors.initials: F
authors.lastname: Noubary
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Bender
authors.forename: C Robert
authors.initials: CR
authors.lastname: Horsburgh
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Freedberg
authors.forename: Rochelle P
authors.initials: RP
authors.lastname: Walensky
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D003362:Cost-Benefit Analysis; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000188:drug therapy; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000191:economics* / Q000379:methods; D008826:Microbial Sensitivity Tests / Q000191:economics / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013019:South Africa; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000150:complications / Q000175:diagnosis* / Q000191:economics
chemical_list: D044966:Anti-Retroviral Agents