Chronic Obstructive Pulmonary Disease (COPD)-Related Outcomes and Costs for Patients on Combination Fluticasone Propionate-Salmeterol Xinafoate 250/50mcg Versus Anticholinergics in a COPD-Comorbid Depression/Anxiety Population

The objective of this study was to examine COPD-related outcomes for patients with comorbid depression/anxiety who are on combination fluticasone propionate/salmeterol xinafoate compared to those receiving anticholinergics.

The prevalence of comorbid depression/anxiety in patients with chronic obstructive pulmonary disease (COPD) is estimated to be high and range from 10-40%, given that the risk of depression/anxiety symptoms is almost 3 times higher in patients with versus without COPD. Additionally, patients with comorbid COPD and depression/anxiety have higher COPD-related healthcare utilization and costs compared to those without depression/anxiety. Therapy with maintenance medications for COPD has been recommended to prevent future adverse COPD outcomes, but the impact of initiating these interventions has not yet been evaluated in a higher-risk population with comorbid COPD-depression/anxiety. The present study compares the risk of COPD exacerbations and COPD-related costs in patients initiating maintenance medications for treatment of COPD in a comorbid COPD/depression-anxiety population. Maintenance medications include inhaled corticosteroid (ICS), long-acting beta agonist (LABA), combination drug product of ICS+LABA, and anti-cholinergics (AC) including tiotropium (TIO) and ipratropium or combination ipratropium-albuterol (collectively abbreviated as IPR).

This was a retrospective cohort study using a large administrative database (study period: 1/1/2003 through 6/30/2009). Date of first FSC or ACs (tiotropium; ipratropium alone or in combination with albuterol) was defined as the index date. Managed care enrollees (aged \>40 years) having at least one medical claim with a primary diagnosis of COPD (ICD code 491.xx, 492.xx and 496.xx) and a diagnosis of depression (at least one claim with depression/anxiety or at least one prescription claim for depression/anxiety) in one-year pre-index and within 60-days post-index were defined in the comorbid population. Patients were continuously eligible throughout the one-year pre and post-index periods. Negative binomial models were used to analyze number of COPD-related events \[hospitalization (IP), emergency department (ED), office visits with oral steroid and/or antibiotic prescription within 5 days (OV+Rx)\] and logistic regression was used to examine risk of COPD events between the two cohorts. COPD-related costs were compared between the two cohorts using - generalized linear model with log-link/gamma distribution after adjusting for baseline differences.

Specifically the study hypothesis for the primary outcome being tested was:

Ho: There is no difference in risk of any COPD-related exacerbation between FSC and AC cohorts Ha: There is a difference in risk of any COPD-related exacerbation between FSC and AC cohorts

Hypothesis for the key secondary outcome of COPD-related costs that was tested was:

Ho: There is no difference in COPD-related costs between FSC and AC cohorts Ha: There is a difference in COPD-related costs between FSC and AC cohorts

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of COPD in any field in the pre-index period and 60 days after the index date
* Diagnosis of depression/anxiety in any field and a medication for treating depression/anxiety in the pre-index period and 60 days after the index date
* Index date occurs during identification period
* Patients must be continuously eligible during 1-year pre and 1-year post-index date and be of at least 40 years of age

Exclusion Criteria:

* comorbid conditions (respiratory cancer, cystic fibrosis, fibrosis due to tuberculosis, and bronchiectasis, pneumonociosis, pulmonary fibrosis, pulmonary tuberculosis, sarcoidosis) during the 1 year pre or post-index periods
* No other maintenance medications other than the index medication on or 60 days after the index date