Effect of Antiretroviral Therapy on Treatment Outcomes in a Prospective Study of Extensively Drug-Resistant Tuberculosis (XDR-TB) HIV Coinfection Treatment in KwaZulu-Natal, South Africa.

BACKGROUND: Extensively drug-resistant tuberculosis (XDR-TB)/HIV coinfection has been associated with high mortality and poor TB outcomes. We performed a prospective study to comprehensively characterize a cohort of patients with XDR-TB. METHODS: Adult patients with XDR-TB were enrolled at treatment initiation at a TB referral hospital in KwaZulu-Natal Province, South Africa, and followed through the end of treatment. Clinical data, questionnaires, adherence data, and sputum were collected monthly. Whole genome sequencing was performed on baseline Mycobacterium tuberculosis (MTB) isolates. Treatment outcomes were defined using standard definitions. RESULTS: One hundred five patients with XDR-TB (76.1% HIV-infected) were enrolled from August 2009 to July 2011. Among HIV-coinfected patients, 82.5% were on antiretroviral therapy initially and 93.8% cumulatively over the study period. At 24 months, 31.4% had a successful outcome and 68.6% had an unsuccessful outcome with 41% mortality. Antiretroviral therapy was associated with improved mortality in HIV-coinfected patients (P = 0.05), as was TB culture conversion (P < 0.0001). On whole genome sequencing, most strains were LAM4/KZN lineage (68%), with few single nucleotide polymorphism differences. CONCLUSIONS: Despite improved HIV care, treatment outcomes and mortality were only modestly improved compared with previous South African XDR-TB/HIV treatment cohorts. Of note, this study was completed before the introduction of new antimycobacterial agents (eg, bedaquiline and delamanid). As new TB drugs and regimens become available, it is important to monitor treatment to ensure that benefits seen in clinical trials are reproduced in high-burden, low-resource settings.

Primary Capreomycin Resistance Is Common and Associated With Early Mortality in Patients With Extensively Drug-Resistant Tuberculosis in KwaZulu-Natal, South Africa.

BACKGROUND: Capreomycin is a key antimycobacterial drug in treatment of extensively drug-resistant tuberculosis (XDR-TB). Drug-susceptibility testing (DST) for capreomycin is not routinely performed in newly diagnosed XDR-TB in South Africa. We performed this study to assess the prevalence, clinical significance, and molecular epidemiology of capreomycin resistance in newly diagnosed patients with XDR-TB in KwaZulu-Natal, South Africa. METHODS: Retrospective cohort study of consecutive patients with XDR-TB admitted to a TB referral hospital without previous XDR-TB treatment. A subset of isolates had extended DST (including capreomycin), mutational analysis, and IS6110 restriction fragment length polymorphism assays. RESULTS: A total of 216 eligible patients with XDR-TB were identified. The majority were treated with capreomycin (72%), were young (median age: 35.5 years), and were female (56%). One hundred five (76%) were HIV+, and 109 (66%) were on antiretroviral therapy. A subset of 52 patients had full DST. A total of 47/52 (90.4%) patients with XDR-TB were capreomycin resistant. Capreomycin-resistant patients experienced worse mortality and culture conversion than capreomycin susceptible, although this difference was not statistically significant. The A1401G mutation in the rrs gene was associated with capreomycin resistance. The majority of capreomycin-resistant strains were F15/LAM4/KZN lineage (80%), and clustering was common in these isolates (92.5%). CONCLUSIONS: Capreomycin resistance is common in patients with XDR-TB in KwaZulu-Natal, is predominantly because of ongoing province-wide transmission of a highly resistant strain, and is associated with high mortality. Capreomycin should be included in routine DST in all patients with XDR-TB. New drug regimens that do not include injectable agents should be operationally tested as empiric treatment in XDR-TB.

Adherence in the treatment of patients with extensively drug-resistant tuberculosis and HIV in South Africa: a prospective cohort study.

OBJECTIVE: Extensively drug-resistant tuberculosis (XDR-TB)/HIV coinfection is difficult to treat with frequent adverse drug reactions and associated with high mortality. Adherence to antiretroviral therapy (ARV) and second-line TB medications may reduce mortality, prevent amplification of drug resistance, and improve outcomes. METHODS: Prospective cohort study of XDR-TB patients on treatment in KwaZulu-Natal, South Africa. Adherence to ARV and TB medications was assessed separately at baseline and monthly. Knowledge, attitudes, and beliefs were assessed at baseline. Optimal adherence was defined as self-report of taking all pills in the previous 7 days; missing any pills was defined as suboptimal adherence. Primary outcome was optimal adherence 6 months after initiation of XDR-TB treatment to TB medications, ARV, and both ("dual adherence"). RESULTS: One hundred four XDR-TB patients (79.8% HIV coinfected, 84.3% on ARV at enrollment) were enrolled and followed monthly (median 8 visits; interquartile range: 4-12). Six-month optimal adherence was higher for ARV (88.2%) than TB medications (67.7%) (P < 0.001). Low educational attainment, male gender, and year of enrollment were independently associated with dual suboptimal adherence. At baseline, participants indicated that XDR-TB was curable (76.0%), HIV and TB were linked (81.7%), and ARV improves TB outcomes (72.1%). Baseline knowledge, attitudes, and beliefs did not predict subsequent adherence. CONCLUSIONS: Medication adherence was significantly higher for ARV than for TB medications in this cohort. Short-course treatment regimens for drug-resistant TB with lower pill burden may increase adherence and improve outcomes in XDR-TB/HIV. Programmatic support for dual adherence is critical in the treatment of drug-resistant TB and HIV.