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

Abstract

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.

Conflict of interest statement

Conflicts of Interest: No conflicts of interest to declare.

Figures

Figure 1

Percentage of patients with baseline (BL) and monthly cumulative optimal treatment adherence to ARV, TB medications. Numbers reporting adherence data for antiretroviral therapy (ARV), TB medications (TB), or both (Dual) at each monthly visit in the table below. Intensive treatment phase includes injectable agents. Data censored at time of death. (N=19/104).