PURPOSE: To assess the effect of adherence to fluticasone propionate/salmeterol administered in a single device (FSC) on asthma-related exacerbations (emergency department visits [ED] or hospitalizations [IP]), use of rescue medications (short-acting beta-agonists [SABAs]), and costs.
METHODS: This was a retrospective observational analysis of the association between FSC adherence and risk of asthma-related exacerbations, use of rescue medications, and costs using a healthcare claims database representing >70 US health plans. Study subjects included those with diagnosis of asthma (ICD-9 493.xx), age ≥12 yrs, and ≥2 dispensings of FSC from January 2000 to September 2006 (first prescription = “index date”). Patients with <12 months continuous enrollment pre-index a COPD diagnosis or dispensing of ipratropium were excluded. Follow-up was defined as time from index date to disenrollment, discontinuation of FSC (180 days w/o supply), receipt of different controller medication, or 24 months post-index. Repeated measures regression was used to estimate the association between FSC adherence (medication possession ratio [MPR] = days of FSC supplied χ days of follow-up) during each 90-day interval post-index and risk of ED/IP, use of rescue medications, and asthma-related exacerbation costs in subsequent intervals controlling for demographics, time since index, comorbidities, pre-index medications, healthcare utilization, and costs.
RESULTS: 12,930 patients were identified: mean age 40 yrs, mean follow up 20 months. After adjusting for baseline characteristics, each 10% increase in MPR of FSC was associated with a 4.4% reduction in odds of ED/IP (95% CI 1.9% - 6.8%), a 2.0% reduction in SABA use (95% CI 1.5% - 2.4%) and a 8.8% decrease in asthma-related exacerbation costs (95% CI 8.1% - 9.6%).
CONCLUSION: Improved adherence with FSC is associated with reduced asthma-related ED/IP risk, reduced use of SABAs and reduced asthma exacerbation costs.
CLINICAL IMPLICATIONS: Clinicians may be able to improve asthma control reduce the risk and costs of asthma-related exacerbations by stressing adherence to FSC.
DISCLOSURE: Richard Stanford, No Product/Research Disclosure Information; Shareholder RS and DS hold shares in the sponsor, GSK; Employee RS and DS are employees of the sponsor, GSK; Consultant fee, speaker bureau, advisory committee, etc. MH and TD are were paid consultants on this study