Prevalence of IGRA-positivity and risk factors for tuberculosis among injecting drug users in Estonia and Latvia

Abstract Background Illegal drug use and HIV are independent risk factors for tuberculosis (TB) among injecting drug users (IDU). Estonia and Latvia have experienced high rates of TB as well as IDU and HIV outbreaks. There is a lack of knowledge about TB among IDUs in these countries. The purpose of the current study was to estimate the prevalence and risk factors of Mycobacterium tuberculosis (MTB) infection among IDUs in Estonia and Latvia. Methods Participants for this cross-sectional study were recruited from syringe exchange programmes using respondent-driven sampling. For assessing infection with MTB interferon-gamma release assay (IGRA) was used. Results The study included 375 participants from Estonia and 313 from Latvia. The prevalence of IGRA-positivity among IDUs was 7.7% in Estonia and 25.6% in Latvia. HIV-prevalence was 62% in Estonia and 23% in Latvia. In both countries, IGRA-positivity rates did not differ between HIV-positive and HIV-negative participants. IGRA-positivity was independently associated with a prior diagnosis of TB in Estonia and with imprisonment (ever within a lifetime) and preceding contact with a TB patient in Latvia. Conclusion Our findings indicate there is an urgent need for a more vigorous approach in providing IDUs with TB screening services.