Barriers to successful tuberculosis treatment in Tomsk, Russian Federation: non-adherence, default and the acquisition of multidrug resistance

Objective To identify barriers to successful tuberculosis (TB) treatment in Tomsk, Siberia, by analysing individual and programmatic risk factors for non-adherence, default and the acquisition of multidrug resistance in a TB treatment cohort in the Russian Federation. Methods We conducted a retrospective cohort study of consecutively enrolled, newly detected, smear and/or culture-positive adult TB patients initiating therapy in a DOTS programme in Tomsk between 1 January and 31 December 2001. Findings Substance abuse was strongly associated with non-adherence [adjusted odds ratio (OR): 7.3; 95% confidence interval (0): 2.89-18.46] and with default (adjusted OR: 11.2; 95% CI: 2.55-49.17). Although non-adherence was associated with poor treatment outcomes (OR: 2.4; 95% CI: 1.1-5.5), it was not associated with the acquisition of multi-drug resistance during the course of therapy. Patients who began treatment in the hospital setting or who were hospitalized later during their treatment course had a substantially higher risk of developing multidrug-resistant TB than those who were treated as outpatients (adjusted HRs: 6.34; 95% Cl: 1.35-29.72 and 6.26; 95% CI: 1.02-38.35 respectively). Conclusion In this cohort of Russian TB patients, substance abuse was a strong predictor of non-adherence and default. DOTS programmes may benefit from incorporating measures to diagnose and treat alcohol misuse within the medical management of patients undergoing TB therapy. Multidrug-resistant TB occurred among adherent patients who had been hospitalized in-the course of their therapy. This raises the possibility that treatment for drug-sensitive disease unmasked a pre-existing population of drug-resistant organisms, or that these patients were reinfected with a drug-resistant strain of TB.