Use of hydrofluoroalkane propellant delivery system for inhaled albuterol in patients receiving asthma medications

Objective: This study was undertaken to assess drug-use patterns associated with albuterol delivery via a new propellant device compared with conventi onal chlorofluorocarbon (CFC) metered-dose inhalers (MDIs) in patients taki ng asthma medications in a population with pharmacy benefits. Background: In addition to their ozone-depleting properties, conventional C FC inhalers often deliver inconsistent doses because of loss of prime and t emperature instability. A new propellant, hydrofluoroalkane (HFA), incorpor ates a re-engineered delivery system associated with dosing reproducibility throughout the life of the canister. Methods: Drug markers associated with management of asthma were used to ide ntify a study cohort of new users of inhaled albuterol from a geographicall y diverse pharmacy-claims database from July 1, 1997, through December 31, 1997. A population of 282,879 members was identified over the 20-month foll ow-up period. In addition, a subset of chronic albuterol inhaler users (gre ater than or equal to 12 months; n = 96,879) was also identified to support a longitudinal analysis. Disease severity was controlled for by use of inh aled corticosteroids (ICS). To control for canisters received via physician office samples, HFA patient use was corrected by a physician-based caniste r adjustment based on HFA sample data. Results: A total of 53.1% of participants were women and 46.1% were men; mo st of the population (72.5%) was <65 years of age. Canister use for HFA pat ients was consistently lower (2.7 +/- 3.2 vs 5.4 +/- 6.7) than for CFC MDIs for the entire cohort over the 20-month assessment period. This difference was consistently observed for albuterol canister use in patients with and without concomitant ICS use (3.3 +/- 3.8 HFA vs 7.2 +/- 7.5 CFC for ICS use rs and 2.1 +/- 2.1 HFA vs 4.1 +/- 5.7 CFC for non-ICS users). Time to next prescription also was longer for HFA patients than for CFC patients (61.6 /- 50.9 days HFA vs 47.3 +/- 40.8 days CFC). When duration of therapy and p hysician samples associated with product launch were controlled for, simila r differences were consistently observed. CFC patients used, on average, 1. 3 more canisters per year than did HFA patients (P < 0.001), averaging 10.7 canisters (95% CI, 10.6 to 10.7), compared with 9.4 canisters used by HFA patients (95% CI, 8.9 to 9.9). Further analyses indicated that this finding was consistent when ICS use was controlled for (CFC plus ICS mean, 11.9 ca nisters vs HFA plus ICS mean, 10.4 canisters; P < 0.001). Conclusion: This study provides useful information about the effect of use of a new albuterol delivery system on asthma inhaler management. These data suggest that CFC patients use an average of 1.3 more canisters per year co mpared with HFA patients independent of asthma severity as measured by ICS use. This improvement in dosing characteristics has the potential to transl ate into enhanced economic outcomes.