Objectives To determine the incidence of adverse drug events (ADEs) and assess their severity and preventability in four Saudi hospitals.
Design Prospective cohort study.
Setting The study included patients admitted to medical, surgical and intensive care units (ICUs) of four hospitals in Saudi Arabia. These hospitals include a 900-bed tertiary teaching hospital, a 400-bed private hospital, a 1400-bed large government hospital and a 350-bed small government hospital.