Impact of extensive drug resistance on treatment outcomes in non-HIV-infected patients with multidrug-resistant tuberculosis

Abstract

Background: Recently, serious concerns about extensively drug-resistant tuberculosis (XDR-TB), which shows resistance to second-line anti-TB drugs in addition to isoniazid and rifampicin, have been raised. The aim of this study was to elucidate the impact of extensive drug resistance on treatment outcomes in non-human immunodeficiency virus (HIV)-infected patients with multidrug-resistant tuberculosis (MDR-TB).

Methods: Patients who received the diagnosis of and treatment as having MDR-TB at Seoul National University Hospital (Seoul, Republic of Korea) between January 1996 and December 2005 were included. The definition of XDR-TB was TB caused by bacilli showing resistance to both isoniazid and rifampicin and also showing resistance to any fluoroquinolone and to at least 1 of the following 3 injectable anti-TB drugs: capreomycin, kanamycin, and amikacin. To identify the impact of extensive drug resistance on treatment outcomes, univariate comparison and multiple logistic regression were performed.

Results: A total of 211 non-HIV-infected patients with MDR-TB were included in the final analysis. Among them, 43 patients (20.4%) had XDR-TB. Treatment failure was observed in 19 patients (44.2%) with XDR-TB, whereas treatment of 46 patients (27.4%) with non-XDR-TB failed (P=.057). The presence of extensive drug resistance (adjusted odds ratio [OR], 4.46; 95% confidence interval [CI], 1.35-14.74) and underlying comorbidity (adjusted OR, 2.62; 95% CI, 1.00-6.87) were independent risk factors for treatment failure. However, a higher level of albumin was inversely associated with treatment failure (adjusted OR, 0.87; 95% CI, 0.77-0.97).

Conclusion: The presence of extensive drug resistance, the presence of comorbidity, and hypoalbuminemia were independent poor prognostic factors in non-HIV-infected patients with MDR-TB.