Analysis of risk factors for adverse drug events in critically ill patients*

OBJECTIVES: An evaluation of risk factors for adverse drug events in critically ill patients has not been previously studied. The purpose of this original study was to determine risk factors for adverse drug events in critically ill adult patients. DESIGN: This retrospective case-control study includes patients who were admitted to the intensive care unit during a 7.5-yr period. SETTING: Academic medical center with 647 beds that contains approximately 120 intensive care unit beds. PATIENTS: Patients in the case group experienced an adverse drug event as documented in the hospital's database. The control group comprised the next two patients admitted to the same intensive care unit by the same admitting service. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Twenty-nine suspected risk factors identified from the literature were evaluated, including patient characteristics, drug characteristics, and laboratory values using a multiple logistic regression. A sample of 1101 cases and controls (54% male), with a mean age of 59.4 ± 17.5 yrs, were identified. In 367 cases, there was a total of 499 documented adverse drug events. Patients with kidney injury, thrombocytopenia, and those admitted emergently were 16-times, 3-times, and 2-times more likely to have an adverse drug event, respectively. Patients who were administered intravenous medications had a 3% higher risk of having an adverse drug event for each drug dispensed. Overall, the case group received more drugs per intensive care unit day and more drugs per intensive care unit stay. CONCLUSIONS: Several patient and drug-related characteristics contribute to the risk of adverse drug events in critically ill patients. Diligent monitoring of factors that can influence the pharmacokinetic properties for existing drug therapies is necessary. Drug regimens should be evaluated daily for minimization. Based on previous studies, pharmacists as part of the interdisciplinary team could help to manage these risks.