Risk Factors Associated with Multidrug-Resistant Tuberculosis.

Background: Multi-drug resistant tuberculosis (MDR-TB), a form of TB resistant to isoniazid and rifampin , is considered as a major threat to TB control worldwide. Moreover, the infectivity of MDR-TB is similar to that of non-MDR TB. This study aims to find the risk factors associated with the development of MDR-TB among TB patients admitted to Masih Daneshvari Hospital, the national referral center for tuberculosis and lung diseases. Materials and Methods: The national referral institute for tuberculosis and lung diseases in Tehran (NRITLD) receives all the MDR-TB cases from all over the country. Based on this criterion alone, forty-eight pulmonary MDR-TB patients who were referred to this center between 2002 and 2005 were included in this study. For the purpose of comparison, 234 patients diagnosed with pulmonary TB were also selected randomly as the control group. The two groups were compared based on 102 demographic and clinical variables. These variables included age, sex, nationality, drug and opium use, method of referral, symptoms and etc. Results: Immigration and refugee status as well as history of anti-TB medication were found to be the most significant among the risk factors associated with MDR-TB. Also, 95.8% of the MDR-TB cases reported a previous history of anti-TB medication. This number was 23.1% in the non-MDR group. MDR-TB was more prevalent among the Afghan patients; out of a total of 78 Afghan patients, 22 (46.8%) composed the MDR-TB category, whereas, 56 (23.9%) Afghan patients belonged to the non-TB category. All MDR-TB patients had positive smears whereas 13.2% of non-MDR-TB patients had negative smears. Dyspnea and weight loss were among other significant variables. History of close contact, diabetes, smoking, drug use, fever, and BCG scar in both MDR TB and non-MDR-TB groups were among the insignificant variables found in this study. Conclusion: The limited sample size and location of the study may have resulted in insignificant variables. However, based on the obtained data, patient’s status as an immigrant or a refugee is an important risk factor for both MDR and non-MDR TB and is of particular concern in the growing trend of MDR-TB.