Abstract
BackgroundDespite inhaled medications that decrease exacerbation risk, some COPD patients experience frequent exacerbations. We determined prospective risk factors for exacerbations among subjects in the COPDGene Study taking inhaled medications.Methods2113 COPD subjects were categorized into four medication use patterns: triple therapy with tiotropium (TIO) plus long-acting beta-agonist/inhaled-corticosteroid (ICS ± LABA), tiotropium alone, ICS ± LABA, and short-acting bronchodilators. Self-reported exacerbations were recorded in telephone and web-based longitudinal follow-up surveys. Associations with exacerbations were determined within each medication group using four separate logistic regression models. A head-to-head analysis compared exacerbation risk among subjects using tiotropium vs. ICS ± LABA.ResultsIn separate logistic regression models, the presence of gastroesophageal reflux, female gender, and higher scores on the St. George’s Respiratory Questionnaire were significant predictors of exacerbator status within multiple medication groups (reflux: OR 1.62–2.75; female gender: OR 1.53 - OR 1.90; SGRQ: OR 1.02–1.03). Subjects taking either ICS ± LABA or tiotropium had similar baseline characteristics, allowing comparison between these two groups. In the head-to-head comparison, tiotropium users showed a trend towards lower rates of exacerbations (OR = 0.69 [95 % CI 0.45, 1.06], p = 0.09) compared with ICS ± LABA users, especially in subjects without comorbid asthma (OR = 0.56 [95 % CI 0.31, 1.00], p = 0.05).ConclusionsEach common COPD medication usage group showed unique risk factor patterns associated with increased risk of exacerbations, which may help clinicians identify subjects at risk. Compared to similar subjects using ICS ± LABA, those taking tiotropium showed a trend towards reduced exacerbation risk, especially in subjects without asthma.Trial registrationClinicalTrials.gov NCT00608764, first received 1/28/2008.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-016-0191-7) contains supplementary material, which is available to authorized users.
Highlights
Despite inhaled medications that decrease exacerbation risk, some chronic obstructive pulmonary disease (COPD) patients experience frequent exacerbations
We examined the differences between COPD subjects with and without exacerbations stratified by common medication use patterns using four separate logistic regression models, analyzing risk factors within each medication usage group to minimize confounding by indication
Head-to-head analysis We examined the effect of tiotropium vs long-acting betaagonist/inhaled corticosteroid on exacerbator phenotype in a logistic regression model using a combined subject pool of the TIO and ICS ± long-acting beta-agonist/inhaled corticosteroid (LABA) medication groups, who were shown to have similar baseline characteristics
Summary
Despite inhaled medications that decrease exacerbation risk, some COPD patients experience frequent exacerbations. The relative merits of these two therapies have been compared through a meta-analysis [12] as well as a randomized trial [13] These studies have provided evidence regarding COPD treatment, there still remains a subset of patients who experience frequent exacerbations despite appropriate therapy. It is unclear what factors separate medication non-responders from those who respond more favorably to inhaled medications such as short-acting bronchodilators (SAB), ICS ± LABA, longacting muscarinic antagonists, or combinations of these medications
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