Prescribing trends in asthma: a longitudinal observational study.

BACKGROUND Inhaled corticosteroids (ICS) are effective treatment for childhood asthma. Cross-sectional studies indicate that some asthmatic children are treated with excessively high doses of ICS and are at risk of serious adverse effects. OBJECTIVE To describe longitudinal trends in asthma prescribing for children, with particular reference to very-high-dose (unlicensed) ICS prescribing. DESIGN Retrospective, cross-sectional, observational study of general practitioner prescribing for asthma drugs in children aged under 12 years with a recorded asthma diagnosis between 1992 and 2004 using the General Practice Research Database (GPRD). RESULTS Data were available for an average of 357,956 children per year. The percentage of children prescribed ICS increased from 2.7 in 1992 to 7.0 in 1997 and 1998 and then fell to 3.3 in 2004. In children under 5 years with asthma, very-high-dose ICS prescriptions (>400 microg/day) fell from 10.6% of all ICS prescriptions in 1992 to 4.5% by 2004. In contrast, very-high-dose ICS prescriptions (>800 microg/day) for asthmatic children aged 5-11 years rose from 1.1% in 1992 to 4.6% in 2004. Oral corticosteroid prescribing in under 5-year-olds who had been prescribed ICS fell from 37.1% in 1992 to 21.7% 1999 and remained constant thereafter; the respective percentages for those aged 5-11 years olds were 20.1 and 12.4. CONCLUSIONS Trends for corticosteroid prescribing in childhood asthma changed dramatically between 1992 and 2004. There are several plausible reasons for this.