Abstract

Introduction: Drug resistance is one of the critical aspects had to be considered in the tuberculosis control program. Factors related to drug resistance are different in geographic regions and vary during the time. The present study aims to determine the risk factors of drug resistance among TB patients in northern of Iran. Methods: In this case control study, 22 cases (drug resistant TB patients) and 88 controls (TB patients selected out of those with successive treatment) were randomly selected from a cohort of TB patients in Northern of Iran. The required information was collected from TB registration software in Mazandaran University of Medical Sciences. Results: Of 22 drug resistant TB patients, resistance to isoniazid, rifampin and also multidrug resistance were observed in 10(9.1), 3(2.7) and 9(8.2) respectively. Moreover, 22.2 of MDR cases, 66.7 of rifampin resistant cases and 40 of isoniazid resistant patients had experienced previous TB treatment (p = 0.363). Logistic regression models showed that the history of previous treatment was significantly associated with drug resistance (OR = 16.55, 95 CI = 2.83-96.89). Conclusion: History of previous anti-TB treatment can be a determinant factor for TB drug resistance.