Inhaled corticosteroid use and asthma hospitalization rates in Japan.

This epidemiological study assessed whether the use of anti-inflammatory drugs, in particular inhaled corticosteroids, affected hospitalization rates for asthma in Japan between 1990 and 2002. Asthma hospitalization rates were calculated from the number of asthma in-patients recorded in governmental surveys. Information concerning use of anti-inflammatory drugs was extracted from the IMS prescription database. Patients were stratified into four age groups: < or = 4 years, 5 - 19 years, 20 - 39 years and 40 - 64 years. Over the study period, the number of prescriptions for inhaled corticosteroids per year increased dramatically and hospitalizations for asthma decreased in all groups except those < or = 4 years of age. Increased use of leukotriene receptor antagonists was also noted in all age groups. The use of anti-inflammatory drugs may have contributed to the observed decrease in asthma hospitalizations. Increased use of inhaled corticosteroids in infants and very young children may help prevent hospitalization in this age group.