This continued inflammation and airspace destruction in ex-smokers with GOLD stage IIb COPD-E could likely be more extensive if these subjects continued to smoke, and thus it remains important that smokers with COPD should quit smoking. However, this study provides further evidence that once tobacco smoke initiates and causes progression as far as GOLD stage IIb COPD-E, discontinuing smoking may slow but not necessarily halt the persistent inflammation and progression of this severity of COPD-E. These studies underscore the need to identify novel therapies to prevent the progression of moderate to severe COPD-E even in ex-smokers.

Author contributions: Dr Miller: contributed to processing and analyzing sputum samples, performing statistical analysis of results, and editing the manuscript.

Dr Cho: contributed to processing and analyzing sputum samples, performing statistical analysis of results, and editing the manuscript.

Ms Pham: contributed to processing and analyzing sputum samples, performing statistical analysis of results, and editing the manuscript.

Dr Friedman: contributed to interpreting and scoring of chest CT scans, analyzing the results, and editing the manuscript.

Dr Ramsdell: contributed to clinical characterization of study subjects, analyzing the results, and editing the manuscript.

Dr Broide: contributed to study design, supervising the measurements made, analysis of results, and writing the manuscript. Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Friedman interprets chest CT scans for COPDGene, a National Institutes of Health-supported research project, and consults for Broncus Technologies on CT scans in emphysema. Drs Miller, Cho, Ramsdell, and Broide, and Ms Pham have reported that no potential conflict of interest exist with any companies/organizations whose products or services may be discussed in this article.

Role of sponsors: The sponsor had no role in the design of the study, the collection and analysis of the data, or in the preparation of the manuscript.

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