Background: Human immune deficiency virus is a significant cause of morbidity and mortality, especially in developing countries. Globally, about 37.9 million people had HIV/ AIDS in 2018 and 36.2 million people were adults, Moreover, about 770,000 AIDS-related mortality occurred in adult infected people. Appropriate antiretroviral therapy adherence is important to minimize drug resistance, improve virological response, and decrease morbidity and mortality. Researches done in Ethiopia reported knowledge on antiretroviral therapy adherence and determinant factors were limited and the literature was scared. Moreover, the eastern zone of Tigray was inhabited with a highly rural population and this may be a significant facilitator and barrier to ART adherence. According to a census conducted by the central agency of Ethiopia in 2013, the eastern zone of Tigray has a population of 755,343, of whom 395,705 are women and 609,279 (80.66%) are rural inhabitants. Objective: This study aimed to assess antiretroviral therapy adherence and determinant factors among Adult HIV infected people in eastern Tigray, 2019. Methods: A cross-sectional study design was conducted from January 1 to June 30 2019 on 339 adults attending the antiretroviral clinic at eastern Tigray. A systematic random sampling method was used to pick the study samples. Data were collected by a structured question-naire using face to face interview. P-value < 0.05 in multivariate analysis was used as a cut-point for the statistical significance of the association. Results: About 74.6% of participants were adhering to antiretroviral therapy. Place of residence (AOR= 5.13 (1.63–13.44), social support (AOR=2.71 (1.37–9.74), HIV disclosure (AOR=3.32 (1.43–9.24), free from depression (AOR=2.54 (1.36–9.43) and free from substance use (AOR=3.42 (1.67–10.87) were the factors associated with adherence to antiretroviral therapy. Conclusion and Recommendation: Drug adherence in eastern Tigray was low and place of residence, social support, HIV disclosure, free from depression and free substance use were the factors associated with ART. So, awareness creation for rural residence, social support, avoidance of depression, and substance use should be strengthened to increase drug adherence.
