Prevalence and risk factors of drug‐resistant extrapulmonary tuberculosis. (6th March 2018) - Boonsarngsuk, Viboon
Abstract: Background: Physicians are usually aware of the occurrence of drug‐resistant (DR) pulmonary tuberculosis (PTB), but lack concern about DR‐extrapulmonary TB (EPTB). Data regarding the prevalence and risk factors of DR‐EPTB remain limited. Objectives: To determine the prevalence and risk factors of DR‐EPTB. Methods: A retrospective study was performed in patients who had culture‐proven Mycobacterium tuberculosis (MTB) from various specimens between January 2013 and December 2015. Patients were classified into three groups: PTB, EPTB and concomitant PTB and EPTB (PTB + EPTB). Clinical data, chest radiographic extent of disease and patterns of DR were collected. Results: There were 1014 culture‐proven MTB specimens (716 pulmonary specimens and 298 extrapulmonary specimens) from 986 patients (648 PTB, 218 EPTB and 120 PTB + EPTB). The prevalences of isoniazid‐, rifampicin‐ and multidrug‐resistant EPTB were 7.8%, .5% and .5%, respectively, which were lower than those of PTB. When PTB and EPTB coexisted, a higher rate of DR‐TB was observed than for PTB alone. Of 338 EPTB patients, the extent of radiographic disease was associated with isoniazid‐, rifampicin‐ and multidrug‐resistant TB. Previous history of TB and use of steroids/immunosuppressive drugs were also associated with rifampicin‐ and multidrug‐resistant TB in multivariate analysis. Conclusions: The prevalence of DR‐EPTB was high in patients who had concomitant PTB. Although the prevalences of rifampicin‐ and multidrug‐resistant TB were low in isolated EPTB, the prevalence of isoniazid‐resistant TB remained high. Therefore, drug susceptibility testing should be performed in EPTB patients, especially those who carry the aforementioned risk factors.