Compared with HIV-negative people, those with HIV had a higher risk of recurrent tuberculosis in a prospective study in Malawi. Among people with HIV, taking antiretroviral therapy (ART) lowered the risk of recurrent TB.
Recurrent TB and TB reinfection pose threats in areas with high TB prevalence, particularly to people with HIV. To gauge the impact of HIV infection with or without ART on TB recurrence and reinfection, researchers conducted this prospective study in a long-term population cohort in Karonga District, Malawi. Karonga lies in northern Malawi on the western shore of Lake Nyasa. Malawi has an HIV prevalence of 11% in people 15 and older, according to UNAIDS.
The study involved 1133 adults who completed treatment for laboratory-confirmed TB diagnosed since 1996. Health workers visited each person once a year to record vital status and ART use, and to screen them for TB.
Through 4353 person-years of follow-up, 307 people died and 103 had lab-confirmed recurrent TB for a recurrence rate of 4.6 per 100 person-years. Half of all recurrences occurred in the first year after completion of TB therapy.
Statistical analysis adjusted for age, sex, period, and type of TB determined that HIV infection nearly tripled the TB recurrence rate (adjusted rate ratio [aRR] 2.69, 95% confidence interval [CI] 1.69 to 4.26). HIV had a lower impact on recurrence in the first year after completion of TB therapy (aRR 1.71, 95% CI 0.87 to 3.35) than later (aRR 4.2, 95% CI 2.16 to 8.15).
Compared with HIV-positive people not taking ART, those taking ART had about a 25% lower recurrence rate in the first year after TB therapy (aRR 0.74, 95% CI 0.27 to 2.06) and more than a 55% lower recurrence rate after that (aRR 0.43, 95% CI 0.11 to 1.73).
“The increased incidence of TB recurrence observed in HIV-positive patients appeared to be reduced by ART,” the researchers conclude.
They suggest that the effects of ART “are mostly on later (likely reinfection) disease so the impact of ART on reducing recurrence will be highest in high TB incidence settings.”
Source: Rein M.G.J. Houben, Judith R. Glynn, Sebastian Mboma, Themba Mzemba, Nimrod J. Mwaungulu, Lorren Mwaungulu, Michael Mwenibabu, James Mpunga, Neil French, Amelia C. Crampin. The impact of HIV and ART on recurrent tuberculosis in a sub-Saharan setting. AIDS. 2012; 26: 2233-2239.
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Source: IAS