Risk factors for extensively drug-resistant tuberculosis: a review

IntroductionExtensively drug-resistant tuberculosis (XDR-TB) is emerging as a global public health problem. Its treatment is more expensive and difficult, and the outcomes much severe. The identification of risk factors for XDR-TB is of paramount importance to design effective TB control strategies. ObjectiveTo review published articles on risk factors for XDR-TB. MethodsWe identified 249 English articles on PubMed, and 182 were excluded by the abstract. The remaining articles were retrieved for full-text detailed evaluation by authors, and 27 relevant articles were selected for final review. ResultsSome risk factors were consistently present, mainly previous TB treatment and its length. Other conditions often associated were immigration, alcoholism and HIV coinfection. Pre-XDR-TB points to an increased risk of XDR-TB. ConclusionThe information regarding determinants of XDR-TB is relatively weak. However, special emphasis should be given to minimize the risks of TB retreatment to prevent the emergence of highly resistant TB.