[Incidence and prevalence of adverse drug reactions]

FUNDAMENTAL DATA: Estimation of incidence and prevalence rates of adverse drug reactions are necessary to assess the consequences and impact of these effects in a population. HOSPITAL STUDIES: During the last 20 years, several studies conducted in one or more departments of a single hospital have found incidence of hospitalizations induced by adverse drug reactions between 2 and 8%. Three meta-analyses confirm these reports with incidence varying from 4.4 to 5.8% in different countries and from 5.2 to 8.2% and from 2.37 to 3.6% in the United States and Australia respectively. Two recent studies conducted by the French pharmacovigilance regional centers on a representative sample of medical departments in public hospitals found a prevalence of adverse drug reactions between 4.2 and 22.1% (according to the type of department and hospital) and a hospitalization incidence due to adverse drug reaction between 2.37 and 4.01%. COMMUNITY STUDIES: In community medicine, few data are available. In general medicine, the incidence would be 1.99 adverse effects per general practitioner per day. The number of serious adverse drug reactions has been estimated at 0.01 per general practitioner per day. These numbers show the magnitude of adverse drug reactions in terms of morbidity and mortality.