In the United States, injection drug use is a serious public health concern associated with an array of negative health outcomes and substantial financial consequences for systems of care. The purpose of this study was to characterize a statewide sample of Medicaid insured persons who inject drugs in terms of health outcomes, service utilization and cost. A cross-sectional, retrospective analysis of West Virginia Medicaid claims data between 2014 and 2016 was conducted. Between 2014 and 2016, 5,082 West Virginia Medicaid beneficiaries amassed 14,414 service visits, among which inpatient, emergency room, and mental health and substance abuse were the most common. Drug poisonings (n=5,077), soft-tissue infections (n=4,127) and other infectious diseases (n=2,141) were the most common clinical conditions within this sample. Medicaid claims data were not a suitable proxy for state surveillance data as it pertains to new cases of Hepatitis B, Hepatitis C, HIV and heroin overdoses. Ordinal logistic regression results indicate that infectious diseases like endocarditis and soft-tissue infections are associated with increased service utilization. Similarly, multiple regression models show increased cost among individuals with HIV, endocarditis, and Hepatitis B. Preventative services, e.g. syringe exchange programs, are important tools to reducing the spread of infectious diseases, and thereby decrease frequent service utilization and cost among injection drug users. iii DEDICATION To my parents, Karl and Cathy, for their unwavering love and support that have propelled me forward my entire life. To my brother, Dom, for being my best friend and keeping me laughing. To all the Cima's and Gavin's here and gone, I miss and love you all. To my friends for the memories and good times to come. To my beautiful, thoughtful, patient, and inspiring fiancée (by the time this gets published), Laura, who stole my heart on a Miami beach and has brought me nothing but love, happiness, and fulfillment since. iv ACKNOWLEDGMENTS My adviser, boss, mentor, committee chair, confidant, and friend David Parker, without whom these past four years would not be nearly as fun nor memorable. Thank you for being you, for challenging me, for believing in me, and for making my success your success. Michael Regier for his support not only on this project but everything else over these past few years. Thank you for being a great teacher and friend. My committee, Michael Brumage, Sijin Wen, and Tony Atkins, for their genuine interest and guidance throughout this project. v