Adverse Drug Events in Hospitalized PatientsExcess Length of Stay, Extra Costs, and Attributable Mortality

Objective. —To determine the excess length of stay, extra costs, and mortality attributable to adverse drug events (ADEs) in hospitalized patients. Design. —Matched case-control study. Setting. —The LDS Hospital, a tertiary care health care institution. Patients. —All patients admitted to LDS Hospital from January 1, 1990, to December 31,1993, were eligible. Cases were defined as patients with ADEs that occurred during hospitalization; controls were selected according to matching variables in a stepwise fashion. Methods. —Controls were matched to cases on primary discharge diagnosis related group (DRG), age, sex, acuity, and year of admission; varying numbers of controls were matched to each case. Matching was successful for 71% of the cases, leading to 1580 cases and 20197 controls. Main Outcome Measures. —Crude and attributable mortality, crude and attributable length of stay, and cost of hospitalization. Results. —ADEs complicated 2.43 per 100 admissions to the LDS Hospital during the study period. The crude mortality rates for the cases and matched controls were 3.5% and 1.05%, respectively (PPPPPPPConclusion. —The attributable lengths of stay and costs of hospitalization for ADEs are substantial. An ADE is associated with a significantly prolonged length of stay, increased economic burden, and an almost 2-fold increased risk of death.