9CEP COST-EFFECTIVE STRATEGIES FOR ISONIAZID-BASED TUBERCULOSIS (TB) PREVENTIVE THERAPY FOR HIV-INFECTED ART-NAÏVE PATIENTS IN SOUTHERN INDIA

Tuesday, October 20, 2009
Grand Ballroom, Salons 1 & 2 (Renaissance Hollywood Hotel)
Mai T. Pho, MD1, Soumya Swaminathan, MD2, N. Kumarasamy, MBBS, PhD3, Elena Losina, PhD4, Chinnaiyan Ponnuraja, PhD2, Lauren M. Uhler, BA5, Callie A. Scott, MSc5, Kenneth H. Mayer, MD6, Kenneth A. Freedberg, MD, MSc5 and Rochelle P. Walensky, MD, MPH7, (1)Beth Israel Deaconess Medical Center, Boston, MA, (2)Tuberculosis Research Centre, Chennai, India, (3)YRG Centre for AIDS Research and Education, Chennai, India, (4)Brigham and Women's Hospital, Boston, MA, (5)Massachusetts General Hospital, Boston, MA, (6)The Miriam Hospital, Providence, RI, (7)Harvard Medical School, Boston, MA

Purpose: Treatment of latent TB infection (tLTBI) is not currently recommended in India, despite TB being the most common opportunistic infection in HIV-infected patients.  We examine the clinical and economic impact of alternative strategies for tLTBI with isoniazid-based therapy in ART-naive HIV-infected patients in India.

Method: We used a state-transition model (the CEPAC-International model) simulating HIV/TB coinfection to investigate 4 tLTBI strategies: 1) no tLTBI, 2) tuberculin skin testing (TST) with tLTBI for TST+ patients, 3) tLTBI if TST+ or CD4 <200/µl, and 4) tLTBI for all HIV-infected patients.  Input data from India included a mean CD4 390/µl, TB incidence 9.55/100PY without and 2.11/100PY with tLTBI (tLTBI efficacy=78% reduction in TB incidence), and tLTBI cost $6.90/month (2008 US$ for a 6-month regimen of Ethambutol and Isoniazid daily); a single “line” of ART was available.  We incrementally compared the cost per life year saved (US$/YLS) among the strategies.  We examined the impact of less efficacious prophylaxis and availability of a second-line ART in sensitivity analyses.

Result: tLTBI for all HIV-infected patients maximized life expectancy (LE, 97.4 months), and lifetime costs ($2,490), and prevented the most acute TB cases.  The cost-effectiveness ratio for the tLTBI for all strategy was $620/YLS, very cost-effective by WHO criteria for India.

Strategy

Mean LE/person (months)

Mean cost/person (2008 US$)

$/YLS

TB cases /100 patients

1) No tLTBI

96.4

2460

--

66

2) tLTBI by TST status

96.9

2470

Dominated*

57

3) tLTBI by TST or CD4<200/µl

97.3

2480

350

48

4) tLTBI for all

97.4

2490

620

42

YLS = Year of life saved, *More costly and/or less effective compared to next least costly strategy
Decreasing the absolute efficacy of tLTBI by 20-60% increased the number of acute TB cases by 10-21/100 patients, decreased overall LE from 0.1-0.6 months, and altered the incremental cost-effectiveness of tLTBI for all from $660/YLS to $1,560/YLS.  The provision of second-line ART increased LE in the tLTBI for all strategy by 26.3 months but also increased lifetime acute TB cases by 1.7/100 patients; the incremental cost-effectiveness of tLTBI for all was $820/YLS.

Conclusion: Treatment of LTBI will improve clinical outcomes and be cost-effective when provided to ART-naïve HIV-infected patients in India, regardless of TST status or CD4 count.  Expansion of tLTBI is encouraged.

Candidate for the Lee B. Lusted Student Prize Competition