Objective: This retrospective cohort study compared exacerbations, health services utilization, and costs among chronic obstructive pulmonary disease (COPD) patients who received nebulized arformoterol or nebulized formoterol therapy.
Methods: Using PharMetrics Plus health plan claims, 417 nebulized long-acting β2-agonist (LABA) users meeting the study inclusion criteria were identified: had ≥2 fills of nebulized arformoterol or nebulized formoterol from January 1, 2009, to December 31, 2011, adhered to using their index drug ≥60% of the days during 1 year post-index, were ≥35 years old and continuously enrolled 180 days pre- and 1 year post-index, and did not use a nebulized LABA or have an asthma diagnosis during the pre-index period. Descriptive and multivariate analyses were performed.
Results: A total of 274 nebulized arformoterol users and 143 nebulized formoterol users were identified with comparable demographic characteristics. However, significant differences were observed between the two groups in some clinical characteristics at index including comorbidities and use of antibiotics. At 1 year post-index, a lower proportion of nebulized arformoterol users had ≥1 exacerbation compared to nebulized formoterol users (70.4% vs 80.4%; p = 0.028). Among patients with ≥1 hospital admission, COPD-related costs per inpatient stay were significantly lower for nebulized arformoterol users than nebulized formoterol users (median = $9542 vs $14,025; p = 0.009). After controlling for confounders, nebulized arformoterol users had 19% marginally lower risk of exacerbations than nebulized formoterol users (hazard ratio = 0.81, 95% confidence interval = 0.64-1.03; p < 0.084) and 14.4% marginally lower COPD-related total costs at 1 year post-index (p = 0.062), primarily related to fewer hospital readmissions (7.6% vs 12.2%) and lower average costs per readmission stay (median = $7392 vs $18 081; p = 0.006).
Conclusions: This study suggests that the choice of nebulized LABA may influence COPD-related exacerbation occurrence and costs. Future studies with larger and more closely matched nebulized arformoterol and nebulized formoterol users are needed to confirm these findings.
Keywords: Arformoterol; COPD exacerbations; Formoterol; Health services utilization; Hospitalizations; Nebulized LABA; Nebulized long-acting beta2-agonist.