HIV
Prevalence Dramatically Impacts the Number of New Tuberculosis Cases and Deaths
The
increased risk for tuberculosis
(TB) in HIV-infected people has fueled a worldwide resurgence of the disease.
A major hindrance to controlling tuberculosis is the long treatment duration,
leading to non-adherence, generating drug resistance and jeopardizing the potential
for being cured.
In a study published in the current issue of AIDS
(May 11, 2008), researchers evaluated how tuberculosis is impacted by reducing
treatment duration alone or combined with enhanced case detection and/or cure
under different HIV prevalence levels.
The authors stated that their model
included HIV stages I-IV and was calibrated to long-term tuberculosis and HIV
data from Kenya. Benefits were assessed in terms of absolute and relative reductions
in new tuberculosis cases and deaths.
Results
•
Compared with
present-day strategies, at 3%-20% HIV prevalence, a 6%-20% decrease in TB incidence
and mortality in 25 years was attained when reducing TB treatment duration alone.
•
Benefits exceeded
300% when combined with increased detection and cure.
•
Benefits varied
substantially according to HIV status and prevalence.
•
Challenges
arise because, in absolute terms, the number of TB-infected people and deaths
increase dramatically with increasing HIV prevalence.
•
The relative
efficacy of TB control policies displays a nonlinear pattern whereby they become
less effective on a per capita basis at HIV prevalence levels greater than 15%.
•
Benefits of
reducing TB treatment duration may even be reversed at extreme HIV prevalence
levels.
•
Benefits of
increasing cure versus detection increase as HIV prevalence increases.
Conclusion
"Reducing
tuberculosis treatment duration, alone or in combination with other control strategies,
can provide enormous benefits at high HIV prevalence," the investigators
concluded. "Tuberculosis control policies need to account for HIV levels
because the efficacy of different interventions varies substantially with HIV
prevalence."
Department of Environmental Science, Policy and Management,
University of California, Berkeley, CA; Center for Infectious Disease Dynamics,
Pennsylvania State University, University Park, PA; Department of Epidemiology
and Biostatistics, University of California, San Francisco, CA; ; Department of
International Health, Harvard School of Public Health, Boston, MA; Harvard University
Initiative for Global Health, Cambridge, MA; World Health Organization, Stop TB
Department, Geneva, Switzerland; KNCV Tuberculosis Foundation, The Hague, Netherlands;
Department of Infectious Diseases, Tropical Medicine and AIDS, University of Amsterdam,
Amsterdam, Netherlands; National TB Programme, Nairobi, Kenya.
5/08/06
Reference MS
Sanchez, J Lloyd-Smith, TC Porco, and others. Impact of HIV on novel therapies
for tuberculosis control. AIDS 22(8): 963-972, May 11, 2008.
The
increased risk for 
Results
