Economic impact of adverse drug events--a retrospective population-based cohort study of 4970 adults

• Published in: PloS one 2014-03, Vol.9 (3), p.e92061
• Main Authors: Gyllensten, Hanna, Hakkarainen, Katja M, Hägg, Staffan, Carlsten, Anders, Petzold, Max, Rehnberg, Clas, Jönsson, Anna K
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adults; adverse drug event; Aged; Analysis; Cohort analysis; Cohort Studies; cost-of-illness; Councils; County councils; Data Collection; Data warehouses; Drug abuse; Drug therapy; Drug-Related Side Effects and Adverse Reactions - economics; Drugs; Economic aspects; Economic impact; Ethics; Farmakologi och toxikologi; Female; Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi; Health Care Costs; Health care expenditures; Health Care Service and Management, Health Policy and Services and Health Economy; Health sciences; Hospitals; Humans; Hälso- och sjukvårdsorganisation, hälsopolitik och hälsoekonomi; Identity; Impact analysis; Inhabitants; Male; Medical records; Medical research; MEDICIN; Medicin och hälsovetenskap; MEDICINE; Medicine and Health Sciences; Middle Aged; Morbidity; Patient care; Patients; Pharmaceutical Preparations - economics; Pharmacology; Pharmacology and Toxicology; Physicians; Population; Population studies; Population-based studies; Primary care; Public health; Public Health, Global Health, Social Medicine and Epidemiology; Research and Analysis Methods; Retrospective Studies; Samhällsfarmaci och klinisk farmaci; Social and Clinical Pharmacy; Studies; Sweden; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092061

The aim was to estimate the direct costs caused by ADEs, including costs for dispensed drugs, primary care, other outpatient care, and inpatient care, and to relate the direct costs caused by ADEs to the societal COI (direct and indirect costs), for patients with ADEs and for the entire study population. We conducted a population-based observational retrospective cohort study of ADEs identified from medical records. From a random sample of 5025 adults in a Swedish county council, 4970 were included in the analyses. During a three-month study period in 2008, direct and indirect costs were estimated from resource use identified in the medical records and from register data on costs for resource use. Among 596 patients with ADEs, the average direct costs per patient caused by ADEs were USD 444.9 [95% CI: 264.4 to 625.3], corresponding to USD 21 million per 100 000 adult inhabitants per year. Inpatient care accounted for 53.9% of all direct costs caused by ADEs. For patients with ADEs, the average societal cost of illness was USD 6235.0 [5442.8 to 7027.2], of which direct costs were USD 2830.1 [2260.7 to 3399.4] (45%), and indirect costs USD 3404.9 [2899.3 to 3910.4] (55%). The societal cost of illness was higher for patients with ADEs compared to other patients. ADEs caused 9.5% of all direct healthcare costs in the study population. Healthcare costs for patients with ADEs are substantial across different settings; in primary care, other outpatient care and inpatient care. Hence the economic impact of ADEs will be underestimated in studies focusing on inpatient ADEs alone. Moreover, the high proportion of indirect costs in the societal COI for patients with ADEs suggests that the observed costs caused by ADEs would be even higher if including indirect costs. Additional studies are needed to identify interventions to prevent and manage ADEs.