Asthma treatment costs using inhaled corticosteroids

Asthma is a chronic inflammatory disorder of the airways that affects 10 to 17.5 million people and leads to more than $5 billion in treatment costs in the Unites States annually. This retrospective study is an initial step in understanding the beneficial economic outcomes of inhaled corticosteroid therapy by determining whether differences exist in healthcare utilization expenditures for three inhaled corticosteroids available for use in the United States: (1) beclomethasone dipropionate (Vanceril/Schering and Beclovent/Allan & Hanburys); (2) flunisolide (Aerobid/Forest); and (3) and triamcinolone acetonide (Azmacort/Rhône-Poulenc Rorer). This study was based on an analysis of 4,441 patients with at least one pharmaceutical claim for one of the study drugs, using inpatient, outpatient, and prescription drug claims data obtained from The MEDSTAT Group's MarketScan database for calendar years 1990 through 1993. We tested a null hypothesis for no differences in total asthma treatment costs, when drugs were excluded, using multivariate linear regression modeling controlling for patient demographic and clinical characteristics that might affect the study outcome. We found that, after excluding study drug payments and controlling for other contributing factors, total asthma healthcare expenditures to triamcinolone acetonide (Azmacort) users were higher than those for beclomethasone dipropionate (Vanceril and Beclovent) and flunisolide (Aerobid) users. When study drug costs were included in the expenditure measure, both triamcinolone acetonide (Azmacort) and flunisolide (Aerobid) users had higher expenditures than did beclomethasone dipropionate (Vanceril and Beclovent) users. No significant differences in expenditures were detected between Vanceril and Beclovent patients, a finding consistent with the fact that these drugs are the same type of inhaled corticosteroid. Other factors contributing to differences in total asthma healthcare costs included patient age, patterns of switching among and continuing with study drugs, prestudy asthma utilization or drug proxy severity, and comorbidities of precipitating illnesses.