Association between adherence with fixed dose combination fluticasone propionate/salmeterol on asthma outcomes and costs

ABSTRACT

Objective: To assess the association between adherence with fluticasone propionate/salmeterol combination (FSC) product in a single inhaler and asthma care utilization and costs in asthma patients in typical US clinical practice.

Methods: Retrospective longitudinal analysis using linked medical and pharmacy claims from a managed care database representing >70 US health plans. Subjects included those with two prescriptions for FSC after January 1, 2000 (first prescription = ‘index date’) and diagnosis of asthma. Follow-up was defined as time from index date to disenrollment or discontinuation of FSC (180 days without supply), receipt of different controller, or 24 months post-index. Patients were excluded if: <12 months continuous enrollment pre-index, <12 months of follow-up, diagnoses of COPD or respiratory cancer, use of ipratropium, or age <12 years. Effect of FSC adherence on asthma-related outcomes (short-acting beta-agonist use (SABA), corticosteroid use (CS), emergency department (ED) visit/hospitalizations) and asthma-related health plan costs during each quarter post-index and FSC adherence in prior quarter controlling for demographics, time since index, season, comorbidities, pre-index medications, utilization, and cost.

Results: 12 907 patients were identified: mean age, 40 years; mean follow-up, 20 months; mean quarterly FSC adherence, 54%; mean quarterly incidence of asthma-related ED visit/hospitalization, 1.12%. After adjusting for baseline characteristics, each 25% improvement in adherence was associated with a 10% reduction in the odds of asthma-related ED visit or hospitalization (p < 0.001), a 10% reduction in the odds of receiving SABA (p < 0.001), a 3% reduction in the odds of receiving a CS (p = 0.027). However, total asthma-related costs also increased 23% for each 25% increase in the use of FSC.

Conclusions: Despite the limitations of the study, this analysis shows that improving compliance with an asthma controller medication such as FSC may help reduce the burden of asthma.

Key words: :

• Adherence
• Asthma
• Fluticasone propionate
• Inhaled corticosteroids
• Salmeterol

Acknowledgements

Declaration of interest: This study was sponsored by GlaxoSmithKline. T.E.D. and M.H. are employed by Policy Analysis, Inc. which received grant support from GlaxoSmithKline for this study. R.H.S. and D.A.S. are employees of GlaxoSmithKline.

The authors acknowledge Cynthia Toso PharmD, a freelance medical writer, for assistance in preparing this manuscript.

Notes

* Preliminary results of this study were presented at 101st Annual Meeting of the American Thoracic Society, San Francisco, CA, USA, May 19–24 2007