Clinical and economic impact of adverse drug reactions in hospitalized patients

OBJECTIVE: To identify the classes of drugs that most commonly cause adverse drug reactions (ADRs) and the characteristics of these ADRs and to determine the economic impact of ADRs on patients' length of stay and hospitalization costs. METHODS: Data on ADRs from patients admitted to a hospital in New Jersey were collected, studied, and analyzed over a five-month period. To determine the economic impact of ADRs, patients who experienced ADRs during hospitalization were matched to controls. Each ADR was rated with regard to is severity, the patients' outcomes were determined, and specific classes of medications 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 their diagnosis-related group code. The leading causal drugs according to therapeutic class were antiinfective (17%), cardiovascular (17%), antineoplastic (15%), and analgesics/antiinflammatory agents (15%). The organ systems most often affected were gastrointestinal (24%), dermatologic (19%), and immune systems (15%). The mean length of stay per patient differed significantly 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 significantly higher for patients experiencing ADRs than those who did not experience ADRs. ADR reporting systems in hospitals need to be changed and strengthened to decrease the incidence of avoidable reactions.