Objective: To compare risk of hospitalization or emergency department (ED) visit and healthcare costs in patients with chronic bronchitis initiating inhaled maintenance therapy with fluticasone propionate/salmeterol 250/50 mcg combination (FSC) versus other inhaled maintenance therapies.
Design and methods: This retrospective cohort study assessed 9,217 patients from the PharMetrics administrative claims database enrolled from July 1997 to January 2005. Study subjects were persons with medical claims with diagnoses of chronic bronchitis (ICD-9-CM 491.xx) who also had pharmacy claims for FSC, salmeterol (SAL), inhaled corticosteroid (ICS), ipratropium (IPR), or ipratropium/albuterol combination (IAC). Persons with <12 months of continuous eligibility after the first prescription for initial maintenance therapy ("index date") were excluded as were those receiving fluticasone propionate/salmeterol 100/50 mcg or 500/50 mcg (not indicated for patients with chronic bronchitis). For remaining persons, time to first hospitalization or ED visit during follow-up was compared for those receiving FSC versus other therapies using Cox proportional hazards regression. Healthcare costs during the first 12 months of follow-up were analyzed using generalized linear model regression.
Results: Receipt of FSC as initial inhaled maintenance therapy for chronic bronchitis (n = 1361) was associated with 41% lower risk of COPD-related hospitalization or ED visit compared with IPR (n < 1316) (p < 0.001). Adjusted costs of COPD-related hospitalization/ED visit were $507 (95% CI $218-$1083) less with FSC than IPR. However, patients receiving FSC had $261 (95% CI $205-$322) higher COPD-related pharmacy costs than those receiving IPR. Total COPD-related costs were $90 lower with FSC than IPR although this difference was not significant (95% CI $330-$443). Compliance, as measured by medication possession ratio, was 12% greater with FSC compared with IPR (p < 0.05). Comparisons of FSC with IAC yielded generally similar results. The limitations of the study are similar to those of other observational studies of secondary data regarding potential misclassification and omitted variable bias and residual confounding.
Conclusions: In persons with chronic bronchitis, initial maintenance therapy with FSC 250/50 mcg was associated with improved outcomes versus ipratropium-based therapy and although FSC was associated with greater pharmacy costs, it did not significantly increase total costs of COPD-related care.