U.S. health care spending reached $3.5 trillion in 2017, of which hospital care was $1.1 trillion and physician and clinical services was $694 billion. Retail prescription drugs cost $333.4 billion . The cost of drug-related patient injury, referred to adverse drug events (ADEs) in the U.S. is estimated at $528 billion in 2016 . Costs associated with ADEs include new hospital admissions, readmissions, prolonged length of inpatient stay and additional therapeutic interventions. According to a decade old research published by the Institute of Medicine, the number of preventable ADE’s in U.S. hospitals ranged between 380,000 to 450,000 every year .
The first comprehensive study on the impact of ADEs “To Err Is Human” published in 1998 became the first and most comprehensive research on topic . The latest developments and trends are difficult to quantify since the research on economic impact of ADEs is limited and methodologically heterogenous and there are no published studies on the cost of preventable adverse drug reactions. The estimates of the true prevalence and incidence of ADEs vary depending on the definition as well as the methodology used. The cost assigned to an ADE depends on type of the event and expenses included in the calculation. In 1997, the incremental cost of an ADE was estimated to be $5857. With the estimated number of 400,000 preventable ADEs a year, the price tag was placed at $3.5 billion a year .
According to the Association for Healthcare Research and Quality (AHRQ), ADEs account for about a third of all hospital AEs. ADEs affect about 2 million hospital stays a year and prolong the length of hospitalization by 1.7 to 4.6 days on average. In addition, ADEs lead to more than 3.5 million outpatient physician visits a year, an estimated 1 million emergency department visits a year, and approximately 125,000 hospital admissions a year . Becker’s Hospital Review estimates the reported cost of ADEs in 2013 to be around $4.7 billion, inflicting $25 billion in true costs if unreported ADRs are considered .
Reducing the numbers of adverse drug events is the focus of the National ADE Action Plan: the high priority targets include bleeding associated with anticoagulant treatment, hypoglycemia associated with diabetes agents, and accidental overdoses, over-sedation and/or respiratory depression linked to prescription opioids [8,9]. The cost of drug-related morbidity and mortality inflicted on the system is enormous, especially since significant portion of this harm is avoidable and preventable. Understanding the reasons why, how and in what contexts they occur is essential to bringing the costs of the U.S. healthcare system down.
 Centers for Medicare and Medicaid Services. National Health Expenditures 2017 Highlights. CMS 2018; https://www.cms.gov/research-statistics-data-and-systems/statistics-trends-and-reports/nationalhealthexpenddata/nationalhealthaccountshistorical.html
 Watanabe JH, McInnis T, Hirsch JD. Cost of prescription drug-related morbidity and mortality. Ann Pharmacother 2018;1060028018765159.
 Aspden P, Wolcott JA, Bootman JL, Cronenwett LR. Preventing Medication Errors: Quality Chasm Series, The Institute of Medicine, The National Academic Press, Washington, DC 2007.
 Institute of Medicine (US) Committee on Quality of Health Care in America; Kohn LT, Corrigan JM, Donaldson MS, editors. To Err is Human: Building a Safer Health System. Washington (DC): National Academies Press (US); 2000.
 Bates DW, Spell N, Cullen DJ, et al. The costs of adverse drug events in hospitalized patients. Adverse Drug Events Prevention Study Group. JAMA 1997; 277:307.
 Overview of Adverse Drug Events (ADEs). https://health.gov/hcq/ade.asp (2018)
 Becker’s Hospital Review. May 5, 2015. https://www.beckershospitalreview.com/hospital-management-administration/a-new-era-of-drug-safety-using-adverse-events-big-data-to-improve-outcomes-and-decrease-healthcare-costs.html
 U.S. DHHS: National Action Plan for ADE Prevention (2014)
 Data source: Medicare Patient Safety Monitoring System (MPSMS) and Quality and Safety Review System (QSRS), ARHQ