Seasonal patterns in health care use and pharmaceutical claims for asthma prescriptions for preschool- and school-aged children

Background: In children, hospitalization for asthma is reported to have a distinct seasonal pattern with peaks coincident with the start of school. Although guidelines indicate that asthma controller medications should be used daily, there is limited information on actual seasonal patterns of medication use. Objective: To describe seasonal patterns of asthma-related health care use and asthma controller and reliever medication claims in children. Methods: An ecological analysis was conducted of data collected from records for children aged 2 to 12 years from 2002 through 2004 from an automated research database of insurance claims from a large US health care plan. Seasonal patterns for health care use and estimates of prescription asthma controller and reliever use were determined for preschool-aged children (aged 2-5 years) and school-aged children (aged 6-12 years). Rates were constructed by week; deviations from annual mean rates were used to determine peaks in use. Results were confirmed using Poisson regression models, modeling for rates within age group, with factors for week, year, and regions. Results: Emergency department and outpatient visits and hospitalizations were lowest during summer; rates increased beginning in September, peaking in October or November. Asthma controller and reliever medication claims increased beginning in September, peaking in December. Rates also were elevated in February. Conclusions: The data suggest that children who reduce their asthma medications during the summer do not resume taking medications until signs or symptoms of asthma worsen. The summer hiatus and other factors may contribute to seasonal increases in health care use and in asthma medication prescriptions, particularly in the fall.