[Iatrogenic medication: estimation of its prevalence in French public hospitals. Regional Centers of Pharmacovigilance].

The French network of Regional Centres of Pharmacovigilance has made an estimation of the occurrence of adverse drug reactions in a representative sample of patients in French public hospitals (departments of medicine, of surgery and of geriatrics). The study looked at one specific day in the spring of 1997. Each observed case of adverse drug reaction was validated. The total sample comprised 2132 patients of whom 969 were in a university hospital and 1163 in a general hospital. The hospitals and units concerned are representative of the country as a whole. One adverse drug reaction at least was present for 221 patients on the day of the investigation. This means a prevalence rate of 10.3 per cent (95 per cent CI: 8.7 to 11.9 per cent). In 33 per cent of cases (95 per cent CI: 26 to 42 per cent), the observed effects were rated as serious. From an incidence rate of 1.8 per cent (95 per cent CI: 1.0 to 25 per cent) on one specified day it can be estimated that in France an adverse drug reaction will occur in about 1,300,000 patients per year during a stay in hospital.