Clinical and economic impact of adverse drug reactions in hospitalized patients

OBJECTIVE: To identify the classes of drugs that most commonly cause advers e drug reactions (ADRs) and the characteristics of these ADRs and to determ ine the economic impact of ADRs on patients' length of stay and hospitaliza tion costs. METHODS: Data on ADRs from patients admitted to a hospital in New Jersey we re collected, studied, and analyzed over a five-month period. To determine the economic impact of ADRs, patients who experienced ADRs during hospitali zation were matched to controls. Each ADR was rated with regard to is sever ity, the patients' outcomes were determined, and specific classes of medica tions were identified as particularly causative of ADRs. RESULTS: A total of 196 patients experienced ADRs; 131 of these individuals were matched with 1338 patients who did not experience an ADR, based on th eir diagnosis-related group code. The leading causal drugs according to the rapeutic class were antiinfective (17%), cardiovascular (17%), antineoplast ic (15%), and analgesics/antiinflammatory agents (15%). The organ systems m ost often affected were gastrointestinal (24%), dermatologic (19%), and imm une systems (15%). The mean length of stay per patient differed significant ly between the ADR case group and matched control group (10.6 vs. 6.8 d; p = 0.003), as did the total hospitalization cost ($22 775 vs. $17 292; p = 0 .025). CONCLUSIONS: Length of hospital stay and total hospitalization costs were s ignificantly higher for patients experiencing ADRs than those who did not e xperience ADRs. ADR reporting systems in hospitals need to be changed and s trengthened to decrease the incidence of avoidable reactions.