Incidence of adverse drug events in public and private hospitals in Riyadh, Saudi Arabia: the (ADESA) prospective cohort study.

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.