Brazilian cohort study of risk factors associated with unsuccessful outcomes of drug resistant tuberculosis

Abstract

Background

Treatment outcomes were evaluated of a cohort of new pulmonary tuberculosis (TB) cases that were rifampicin resistant, multidrug-resistant, or extensively resistant during 2013 and 2014 in Brazil. The objective of this study is to identify factors associated with unfavorable treatment outcomes for drug-resistant TB cases.

Methods

The Brazilian Special Tuberculosis Treatment Information System (SITE-TB) was the main data source. The independent variables were classified into four blocks (block I: individual characteristics; block II: clinical characteristics and proposed treatment; block III: treatment follow-up characteristics; and block IV: TB history). The category of successful therapeutic outcome was compared with lost to follow-up, failure, and death. Considering the multiple outcomes as the dependent variable, the odds ratios (OR) and its respective 95% confidence interval (95% CI) were estimated by multinomial logistic regression.

Results

After applying the exclusion criteria, 980 (98.8%) individuals were included in the study. Of these, 621 (63.4%) had successful treatment, 163 (16.6%) lost to follow-up, 76 (7.8%) failed, and 120 (12.2%) died. Important factors associated with lost to follow-up in the final model included use of illicit drugs (OR = 2.5 95% CI: 1.57–3.82). Outcome failure was associated with having disease in both lungs (OR = 2.0; 95% CI: 1.09–3.62) and using more than one or not using injectable medication (OR = 2.8; 95% CI: 1.05–7.69). Major factors for the death outcome were at least 60 years old (OR = 3.4; 95% CI: 1.90–6.03) and HIV positive (OR = 2.7; 95% CI: 1.45–4.83).

Conclusions

The factors associated with unfavorable treatment outcomes were different. Some of these factors are specific to each outcome, which reflects the complexity of providing care to these individuals.