PURPOSE: Retrospective studies suggest that use of inhaled corticosteroids (ICS) may improve survival in COPD, particularly when combined with a long-acting beta agonist (LABA). However, the methods used to conduct these studies have been questioned, and none have examined what effect the newer combination ICS/LABA inhalers may have on survival. The goal of this project was to further examine the relationship between ICS treatment, with or without LABA, and survival in COPD.
METHODS: COPD patients were identified from the GroupHealth, Henry Ford, Harvard Pilgram, and Lovelace HMO programs. All patients who were diagnosed with COPD between September 1, 2000 and August 31, 2001 and who had at least 3 months treatment with either a combined fluticasone/salmeterol inhaler (FSI, N=866), any ICS used with a LABA (ICS/LABA, N=525), ICS alone (N=742), LABA alone (N=531), or a short-acting bronchodilator alone (SABD, N=1832), were included. Analyses were conducted using three different approaches to help reduce potential biases.
RESULTS: In the main Cox proportional hazards models, use of FSI, ICS/LABA, and ICS alone had significant survival benefits as compared to SABD alone, after adjustment for differences in age, gender, comorbidities, asthma status, and disease severity (HRs 0.638, 0.603, and 0.784, respectively, p<0.05). Propensity score matching, which reduces the clinical differences between the treatment groups versus the SABD reference group, yielded very similar results. Nested case-control matching based on survival status, which is not subject to immortal time bias, continued to show a highly significant survival benefit for FSI, while the other treatments also had favorable RR but did not reach statistical significance.
CONCLUSION: In this retrospective cohort, treatment with ICS is associated with improved survival in COPD, and combination of an ICS with a LABA either in a combined inhaler or separately is associated with additional survival benefit.
CLINICAL IMPLICATIONS: The survival benefits observed in randomized clinical trials with FSI in severe COPD do appear to translate to a survival benefit for COPD patients treated in the general population.
DISCLOSURE: Douglas Mapel, Grant monies (from industry related sources) This study was funded by a grant from GlaxoSmithKline; Employee Dr. Davis is an employee of GlaxoSmithKline. Dr. Soriano is a former employee of GlaxoSmithKline; Consultant fee, speaker bureau, advisory committee, etc. Dr. Mapel is a speaker and consultant for GlaxoSmithKline, Pfizer, and Boehringer Ingelheim; Product/procedure/technique that is considered research and is NOT yet approved for any purpose, Use of inhaled corticosteroids for COPD.