Background: Many adverse drug events (ADEs) are the result of known pharmacologic properties, and some result from medication errors. However, some are the result of patient-specific risk factors.
Objective: To identify inpatient risk factors for ADEs.
Methods: Conditional logistic regression was used to analyze all pharmacist-verified ADEs by therapeutic class of drugs and severity during a 10-year study period. All inpatients > or = 18 years of age from a 520-bed tertiary teaching hospital were included. Each case patient was matched with up to 16 control patients. Odds ratios for patient factors associated with ADEs were calculated from different therapeutic classes of drugs.
Results: Odds ratios for numerous risk factors were identified for 4376 ADEs and were found to vary depending on therapeutic classification. The risk factors for the different classifications were grouped by (1) patient characteristics--female (OR 1.5-1.7), age (0.7-0.9), weight (1.2-1.4), creatinine clearance (0.8-4.7), and number of comorbidities (1.1-12.6); (2) drug administration--dosage (1.2-3.7), administration route (1.4-149.9), and number of concomitant drugs (1.2-2.4); and (3) patient type--service (1.2-4.9), nursing division (1.5-3.8), and diagnosis-related group (1.5-5.7).
Conclusions: Some risk factors are consistent for all ADEs and across multiple therapeutic classes of drugs, while others are class specific. High-risk agents should be closely monitored based on patient characteristics (gender, age, weight, creatinine clearance, number of comorbidities) and drug administration (dosage, administration route, number of concomitant drugs).