A systematic review on associated risk factors for the development of multidrug resistant tuberculosis

Background: Drug resistant tuberculosis continues to be a public health threat. According to the most recent data published by the World Health Organization in 2019, there were about half million new cases of rifampicin resistant tuberculosis in 2018, of which 78% had multidrug resistant tuberculosis (MDR-TB). Globally, 3.4% of new tuberculosis (TB) cases and 18% of previously treated cases had MDR-TB or rifampicin resistant TB. MDR-TB is defined as disease caused by Mycobacterium tuberculosis with resistance to at least two anti-tuberculosis isoniazid and rifampicin. The mechanism of drug resistance can be caused by genetic factors, factors related to previous treatment and other factors such as comorbidity with diabetes mellitus. Several studies revealed that history of treatment of TB is the most powerful predictor of the presence of MDR-TB. The aim of this review is to identify and summarize, through included studies from different regions, the associated risk factors for the development of MDR-TB. Methods: The review was conducted on associated risk factors for MDR-TB, PubMed database was searched from 1993 to July 17th, 2020 using combination of specific key terms, and without using any filters or language restrictions. Studies were assessed and selected according to a defined inclusion criteria and data from this studies were collected. Result: Twenty two studies met the inclusion criteria among which several risk factors were identified, previous tuberculosis treatment was the most significant risk factor associated with multidrug resistant tuberculosis. Some studies were discordant about the association of MDR-TB with some chronic diseases such as diabetes mellitus and HIV, or with some social determinants such as age, gender or quality of life. Conclusion: The discordance between studies from different regions, regarding the association of different risk factors with MDR-TB, indicates that this epidemic is associated with region-specific risk factors and the study of this association should be undertaken regionally. Drug susceptibility tests for patients with high risk of MDR-TB could be the appropriate alternative for an optimal treatment of TB positive cases.