Projected health and economic outcomes in people who inject drugs in the United States, 2025-2034: A modeling study

Abstract Background People who inject drugs (PWID) face complications from injection drug use (IDU), including drug overdoses and infections (HIV, hepatitis C virus [HCV], and other serious injection-related infections). Decision makers need estimates of clinical outcomes and costs to plan health service programs and allocate resources. Methods We developed a microsimulation model, the Multimorbidity model to Reduce Infections Associated with Drug use (MYRIAD), with inputs derived from published data. We projected key clinical outcomes and costs in PWID in the US from 2025-2034: new HIV and HCV cases; hospitalizations for severe injection-related infections (e.g., endocarditis); and deaths from drug overdose and injection-related infections. We varied multiple parameters in deterministic sensitivity analyses and varied overdose death risk in scenario analyses. Results For 3.3 million PWID over 10 years, we estimate that 29,715 new HIV infections, 218,186 new HCV infections or reinfections, and 1,714,773 hospitalizations from severe injection-related infections will occur. We project 487,249 deaths from IDU: 348,650 from drug overdose, 37,658 from severe injection-related infections, 90,486 from HCV, and 10,455 from HIV. Healthcare costs from IDU are projected to exceed $565 billion with $431 billion from drug use and $135 billion from injection-related infections. Conclusions The US will face increasing IDU-related deaths and healthcare costs over the next decade with current levels of care. Although deaths are driven primarily by drug overdose, many are from injection-related infections. Interventions that concurrently prevent and treat drug overdose and injection-related infections are urgently needed to curb morbidity and mortality among PWID.