Double trouble: impact of inappropriate use of asthma medication on the use of health care resources

Background: There is considerable controversy about the regular use of shor t-acting beta -agonists for the treatment of asthma. Although case-control studies have suggested that excessive use of these drugs may worsen asthma control and increase the risk of fatal or near-fatal asthma, the controvers y remains unresolved because of the confounding that exists among disease c ontrol, disease severity and the use of short-acting beta -agonists. Whatev er the cause-and-effect relation between the use of short-acting beta -agon ists and disease severity, we hypothesized that their excessive use,:in con junction with underuse of inhaled corticosteroids, would be a marker for po orly controlled asthma and excessive use of health care resources. Methods: To characterize the pattern of health services utilization among a sthmatic patients taking various doses of inhaled beta -agonists and cortic osteroids in British Columbia, we linked the relevant health administrative databases. All patients between 5 and 50 years of age for whom a prescript ion for a short-acting beta -agonist was filled in 1995 and whose prescript ion data were captured through the provincial drug plan were included in a retrospective analysis of prescriptions for asthma drugs, physician prescri bing patterns and health services utilization. Patients' use of asthma medi cation was classified as appropriate (low doses of short-acting beta -agoni st and high doses of inhaled corticosteroid) or inappropriate thigh doses o f short-acting beta -agonist and low doses of inhaled corticosteroid), and the 2 resulting groups were compared, by means of logistic, Poisson and gam ma regression, for differences in prescribing patterns, physician visits an d use of hospital resources. Results: A total of 23 986 patients were identified as having filled a pres cription for a short-acting beta -agonist (for inhalation) in 1995. Of thes e, 3069 (12.8%) filled prescriptions for 9 or more canisters of beta -agoni st, and of this group of high-dose beta -agonist users, 763 (24.9%) used no more than 100 mug-day of inhaled beclomethasone. On average, those with in appropriate use of beta -agonists visited significantly more physicians for their prescriptions (1.8 v. 1.4), and each of these physicians on average wrote significantly more prescriptions for asthma medications per patient t han the physicians who prescribed to appropriate users (5.2 v. 2.5 prescrip tions). Patients with inappropriate use were more likely to be admitted to hospital (adjusted relative risk [RR] 1.68, 95% confidence interval [CI] 1. 25-2.26), were admitted to hospital more frequently (adjusted RR 1.81, 95% CI 1.41-2.32) and were more likely to require emergency admission (adjusted RR 1.93, 95% CI 1.35-2.77). Interpretation: Despite the widespread distribution of guidelines for asthm a pharmacotherapy, inappropriate use of asthma medications persists (specif ically excessive use of inhaled short-acting beta -agonists combined with u nderuse of inhaled corticosteroids). Not only are patients who use medicati on inappropriately at higher risk for fatal or near-fatal asthma attacks, b ut, as shown in this study, they use significantly more health care resourc es than patients with appropriate medication use.