ABSTRACT More than 500,000 persons require maintenance hemodialysis (pMHD) per year in the United States, disproportionately affecting persons who are Black or Hispanic. pMHD are an Agency of Healthcare Research and Quality priority population. Infections are the second most common cause of mortality among pMHD due to a uremia-induced immunocompromised state and multiple co-morbidities. pMHD are also at substantial risk of hospital-acquired infections (HAI) as they are admitted to the hospital on average twice per year. Compared to the general hospitalized population, pMHD have a 2.4-fold higher risk of developing an HAI. There is a tremendous paucity of data pertaining to the epidemiology of HAI among pMHD, including potential racial and ethnic disparities. In this proposal, entitled “The INFECTADO study: INFECTions Acquired by persons on maintenance hemoDialysis during hOspitalizations”, we will quantify and characterize the epidemiology of HAI among pMHD. This proposal will therefore generate important information as how to best improve current prevention strategies aimed at reducing HAI in pMHD. Under aims 1 and 2, we will use the Unites States Renal Data System (USRDS), a nationwide-Medicare database, to analyze prevalence, risk factors and outcomes of HAI over an 8-year study period (~360,000 pMHD per year). Analyses will also focus on MHD modality type, race/ethnicity and social determinants of health. Under aim 3, we will use the Centers for Disease Control and Prevention’s National Healthcare Safety Network-based active surveillance data from 31 hospitals within the University of Pittsburgh Medical Center hospital network over an 8-year period (~4,777 pMHD per year), to further characterize HAI epidemiology, including causative pathogens and antimicrobial resistance profiles. By using two different data sources, a complete characterization of HAI epidemiology among pMHD will be obtained, since each data source provides supplementary data, as outlined in the proposal. The interdisciplinary team is comprised of investigators who have produced an abundance of scholarly end-stage renal disease research efforts over the last 2-decades and have expertise in infections among pMHD, data analyses using the USRDS and HAI active surveillance methodologies. A summary of specific aims are 1] Aims 1 and 2: To quantify and characterize HAI prevalence, risk factors and outcomes among all pMHD with and without HAI, and between: a] in-center vs home MHD, b] Black persons vs persons of other races on MHD and c] Hispanic vs non-Hispanic persons on MHD, using the USRDS database and 2] Aim 3: To quantify and characterize HAI epidemiology among pMHD with an HAI compared to hospitalized persons with an HAI, including causative pathogens and antimicrobial resistance profiles, using active infection surveillance. This proposal will result in an increased understanding of HAI epidemiology among the high-risk group of pMHD and health disparities within this populat...