Predictors of poor treatment outcome in highly drug-resistant pulmonary tuberculosis

¹ Dept of Pulmonary Medicine, University of Tartu, Tartu, Estonia

^* To whom correspondence should be addressed. E-mail: kai.kliiman{at}kliinikum.ee.

	Abstract

Treatment outcome in multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) is often unsuccessful, but particular determinants of poor treatment outcome have remained obscure. We therefore analysed treatment effectiveness and predictors of poor treatment outcome of pulmonary MDR-TB and XDR-TB in Estonia, a European country with one of the highest MDR-TB and XDR-TB rates worldwide.

All culture-confirmed pulmonary MDR-TB and XDR-TB patients, who started TB treatment in 2003–2005, were included. Multivariate analysis was performed on two models of predictors: 1) patients' HIV-status, demographic and socio-economic characteristics and 2) TB-related data.

In the 235 MDR-TB patients, the proportion of overall successful treatment outcome was 60.4%, being 72.8% among adherent patients. Among the 54 XDR-TB patients, these proportions were 42.6% and 50.0%, respectively. Risk factors behind poor treatment outcome in MDR-TB were HIV-infection, previous TB treatment, resistance to ofloxacin and positive AFB smear at the start of treatment. Predictors of poor treatment outcome in XDR-TB were urban residence and positive AFB smear.

This country-wide study provides evidence that to improve treatment outcome in MDR-TB and XDR-TB, special care should be taken to treat HIV-infected patients and urban residents, as well as to make efforts to diminish re-treatment cases by increasing patient adherence.