To the Editor.
—In the 3 articles on ADEs,1-3 the estimated annual additional costs associated with preventable ADEs occurring during hospitalization were substantial and justify investing in efforts to reduce these events to the lowest possible incidence. We would like to point out, from a global "systemic" point of view, the impact of hospitalization due to preventable ADEs.In a prospective study we estimated incidence, causes, and severity of all drug-related visits to an emergency department of a 900-bed multidisciplinary public hospital in Milan (northern Italy). Visits for any cause were recorded daily during the first week of each month from October 1994 to September 1995. Age, sex, and diagnosis of patients were collected for each visit. Events related to drug consumption were identified and described through a structured form. Clinical records were retrieved for drug-related hospital admissions. Adverse drug reactions were defined according to the World Health Organization definition.4 Other