Study objective: To examine trends in asthma prevalence in the Province of Saskatchewan using the Medical Claim Insurance Branch (MCIB) database.
Design: For each calendar year from 1981 to 1990, first visits to physicians for asthma were identified from the MCIB database. Age- and sex-specific prevalence rates were obtained for each calendar year by dividing the number of first asthma visits by the number of subjects in the age- and sex-specific group insured by the Provincial Government of Saskatchewan in that calendar year.
Results: Asthma prevalence increased in children and adults from 1981 to 1990. In the calendar year 1990, the prevalence of asthma was 5.1% in children < or = 4 years old, 4.4% in children 5 to 14 years old, 2.2% in young adults 15 to 34 years old, and 1.9% in adults 35 to 64 years old. Boys had higher asthma prevalence than girls in the age groups 0 to 4 years and 5 to 14 years, but it was reversed in older age groups, with women having greater asthma prevalence than men. Asthma diagnoses were verified by checking for asthma-related drug purchase in the Prescription Drug Plan database. Among the 0- to 4-year-old children with physician-diagnosed asthma, 57.3% purchased at least one asthma-related drug in 1981 and 72.3% purchased that in 1990. Among adults, asthma-related drug purchase was >73% in 1990.
Conclusions: Asthma prevalence increased in children and adults in the province of Saskatchewan. Reasons for the increase are not clear and further studies are required to determine factors related to the increase.