title: The cost-effectiveness of tuberculosis preventive therapy for HIV-infected individuals in southern India: a trial-based analysis.
abstract: BACKGROUND
  Regimens for isoniazid-based preventive therapy (IPT) for tuberculosis (TB) in HIV-infected individuals have not been widely adopted given concerns regarding efficacy, adherence and drug resistance. Further, the cost-effectiveness of IPT has not been studied in India.
  
  
  METHODS
  We used an HIV/TB model to project TB incidence, life expectancy, cost and incremental cost-effectiveness of six months of isoniazid plus ethambutol (6EH), thirty-six months of isoniazid (36H) and no IPT for HIV-infected patients in India. Model input parameters included a median CD4 count of 324 cells/mm(3), and a rate ratio of developing TB of 0.35 for 6EH and 0.22 for 36H at three years as compared to no IPT. Results of 6EH and 36H were also compared to six months of isoniazid (6H), three months of isoniazid plus rifampin (3RH) and three months of isoniazid plus rifapentine (3RPTH).
  
  
  RESULTS
  Projected TB incidence decreased in the 6EH and 36H regimens by 51% and 62% respectively at three-year follow-up compared to no IPT. Without IPT, projected life expectancy was 136.1 months at a lifetime per person cost of $5,630. 6EH increased life expectancy by 0.8 months at an additional per person cost of $100 (incremental cost-effectiveness ratio (ICER) of $1,490/year of life saved (YLS)). 36H further increased life expectancy by 0.2 months with an additional per person cost of $55 (ICER of $3,120/YLS). The projected clinical impact of 6EH was comparable to 6H and 3RH; however when compared to these other options, 6EH was no longer cost-effective given the high cost of ethambutol. Results were sensitive to baseline CD4 count and adherence.
  
  
  CONCLUSIONS
  Three, six and thirty-six-month regimens of isoniazid-based therapy are effective in preventing TB. Three months of isoniazid plus rifampin and six-months of isoniazid are similarly cost-effective in India, and should be considered part of HIV care.
authors.affiliation: Section of Hospital Medicine, Department of Medicine, University of Chicago Medical Center, Chicago, Illinois, USA. mpho@medicine.bsd.uchicago.edu
authors.forename: Mai T
authors.initials: MT
authors.lastname: Pho
authors.forename: Soumya
authors.initials: S
authors.lastname: Swaminathan
authors.forename: Nagalingeswaran
authors.initials: N
authors.lastname: Kumarasamy
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: C
authors.initials: C
authors.lastname: Ponnuraja
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Uhler
authors.forename: Callie A
authors.initials: CA
authors.lastname: Scott
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Mayer
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Freedberg
authors.forename: Rochelle P
authors.initials: RP
authors.lastname: Walensky
mesh_terms: D000328:Adult; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D003362:Cost-Benefit Analysis; D004977:Ethambutol / Q000191:economics / Q000627:therapeutic use; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000191:economics / Q000628:therapy; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007538:Isoniazid / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use; D008297:Male; D018803:Models, Economic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D016896:Treatment Outcome; D014376:Tuberculosis / Q000188:drug therapy / Q000191:economics* / Q000453:epidemiology / Q000517:prevention & control*
chemical_list: D004977:Ethambutol; D007538:Isoniazid