Incidence of Reye's syndrome in France: a hospital-based survey.

At the time of the study no information was available in France about the incidence of Reye's Syndrome (RS) and no warnings about RS and aspirin. The objective was to evaluate the incidence of RS in France by a hospital-based study. For a period of 1 year from November 1995 to November 1996, all French paediatric departments were required to report any child under 15 years with unexplained noninflammatory encephalopathy (i.e., CDC consciousness level stage I or deeper with normal CSF) and a threefold (or greater) increase in serum aminotransferase and/or ammonia. All suspected cases were classified by a panel of experts as probable RS or excluded RS. In 10% of randomly selected paediatric departments we checked that every suspected case had been reported. Forty-six suspected cases were reported during the year of the survey, of which 14 were classified as RS. Five of these 14 cases had a metabolic disorder. Nine children were definitively diagnosed as having RS (i.e., an estimated incidence of RS of 0.79/1,000,000 children, i.e., below 15/year). Eight children had been exposed to aspirin, four to aspirin alone and four to aspirin and acetaminophen. On the basis of these results the incidence of RS in France in 1996-1997 was not substantially different from that of countries where warning labels were already in use, but it was higher than in the US after 1994. This was probably due to the reduction in aspirin prescription in France because of warnings in Europe and the US and also because many cases of RS are now identified as metabolic disease. On the basis of these results and because the relationship between aspirin and RS has already been proved, public and professional warnings concerning RS on aspirin-containing products in cases of varicella and viral febrile illness have been adopted by the French Drugs Agency.