Risk factors for mortality among MDR- and XDR-TB patients in a high HIV prevalence setting

Abstract

Setting: Recent studies suggest that the prevalence of drug-resistant tuberculosis (TB) in sub-Saharan Africa may be rising. This is of concern, as human immunodeficiency virus (HIV) co-infection in multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB has been associated with exceedingly high mortality rates.

Objective: To identify risk factors associated with mortality in MDR- and XDR-TB patients co-infected with HIV in South Africa.

Design: Case-control study of patients who died of all causes within 2 years of diagnosis with MDR- or XDR-TB.

Results: Among 123 MDR-TB patients, 78 (63%) died following diagnosis. CD4 count ≤ 50 (HR 4.64, P = 0.01) and 51-200 cells/mm(3) (HR 4.17, P = 0.008) were the strongest independent risk factors for mortality. Among 139 XDR-TB patients, 111 (80%) died. CD4 count ≤ 50 cells/mm(3) (HR 4.46, P = 0.01) and resistance to all six drugs tested (HR 2.54, P = 0.04) were the principal risk factors. Use of antiretroviral therapy (ART) was protective (HR 0.34, P = 0.009).

Conclusions: Mortality due to MDR- and XDR-TB was associated with greater degree of immunosuppression and drug resistance. Efforts to reduce mortality must focus on preventing the amplification of resistance by strengthening TB treatment programs, as well as reducing the pool of immunosuppressed HIV-infected patients through aggressive HIV testing and ART initiation.

Figure 1

Survival among patients with multidrug-resistant tuberculosis from the time of sputum collection.

Figure 2

Survival among patients with extensively drug-resistant tuberculosis from the time of sputum collection.