Risk factors for multidrug-resistant tuberculosis in Hong Kong

SETTING: Previous anti-tuberculosis treatment is a widely reported risk factor for multidrug-resistant tuberculosis (MDR-TB), whereas other risk factors are less well described. In Hong Kong, the clinical characteristics of MDR-TB have not been systematically evaluated.OBJECTIVE: To explore the risk factors for MDR-TB in Hong Kong.DESIGN: MDR-TB patients treated between 1999 and 2003 were compared with non-MDR-TB patients by stratification of previous anti-tuberculosis treatment.RESULTS: One hundred and fifty-six MDR-TB patients, including 93 with and 63 without a previous history of anti-tuberculosis treatment, were identified. Among the 322 non-MDR-TB controls, respectively 192 and 130 patients did and did not have a previous history of anti-tuberculosis treatment. Using logistic regression analysis, non-permanent residents (OR 6.85, 95%CI 1.38-34.09), frequent travel (OR 2.48, 95%CI 1.07-5.74) and younger age were found to be independent predictors of MDR-TB in previously treated patients, whereas living on financial assistance just failed to reach statistical significance (OR 2.75, 95%CI 0.98-7.68, P = 0.05). In the treatment-naïve group, despite significant differences in baseline characteristics among MDR-TB and non-MDR-TB patients, no independent predictor variables could be identified.CONCLUSION: In Hong Kong, non-permanent residents, frequent travel and young age were independent predictors of MDR-TB among previously treated patients.