Use of anti-asthmatic medications as a proxy for prevalence of asthma in children and adolescents in Norway: a nationwide prescription database analysis.

BACKGROUND AND OBJECTIVE: The validity of using self-reported or parental reported asthma symptoms and/or doctor-diagnosed asthma in the estimation of asthma prevalence among children has been questioned. The aim of this study was to assess the prevalence of dispensed anti-asthmatic medications as a proxy of asthma among children and adolescents aged 0-19 years in Norway.

METHODS: Prescription data on subjects aged 0-19 years receiving at least one prescription for an anti-asthmatic during 2004 were retrieved from the nationwide Norwegian Prescription Database.

RESULTS: Overall, 108,719 (9.1% of the Norwegian population aged 0-19 years) individuals received at least one prescription for medication(s) for obstructive airway diseases. The application of criteria that restricted the study population to those receiving inhaled anti-asthmatic medications and those receiving medications reimbursed by the Norwegian health care system for asthma resulted in the identification of 64,458 (5.4%) individuals (4.6% of girls and 6.2% of boys). The prevalence varied by age, with a maximum in both genders at about 2 years of age (7.0% of girls and 10.1% of boys) and a minimum in girls at about 10 years of age (3.3%) and in boys at about 19 years of age (3.5%). Anti-asthmatic inhalants were more frequently prescribed among boys than among girls during the first 15 years of life. Of the children treated, 75% received inhaled glucocorticoids (ICS) in combination with beta2-agonists, of whom 38% received a fixed combination in one inhaler.

CONCLUSIONS: In 2004, about 1 in 20 Norwegians aged 0-19 years were in need of medical treatment for asthma for at least 3 months, reflecting ongoing and clinically important asthma. A rather high proportion of children received fixed combinations of ICS and long-acting beta2-agonists, which may indicate moderate to severe asthma.