• Huajing Yang, Yuqiong Yang, Fengyan Wang, Chengyu Miao, Zizheng Chen, Shanshan Zha, Xueping Li, Jiawei Chen, Aiqi Song, Rongchang Chen, and Zhenyu Liang.
• State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China; Guangzhou National Lab, Guangzhou, Guangdong, China.
• Chest. 2024 Oct 23.

BackgroundThe clinical and prognostic characteristics of mild-to-moderate COPD with and without emphysema remain inadequately investigated.Research QuestionDo the clinical and prognostic characteristics differ between mild- to-moderate COPD with and without emphysema?Study Design And MethodsWe obtained clinical data of 989 participants with mild-to-moderate COPD from the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS). They were categorized into 2 groups based on their baseline low-attention lung voxels with a density < -950 Hounsfield units of < 5% on CT scans: mild-to-moderate COPD with emphysema (EC) group and mild-to-moderate COPD without emphysema (NEC) group. Linear mixed-effects models were used to assess the differences in the decline of lung function, health-related quality of life, and quantitative CT indexes between these 2 groups. Zero-inflated negative binomial regressions were used to evaluate the rates of acute respiratory exacerbations between the groups.ResultsAmong participants with mild-to-moderate COPD, 428 (43.3%) exhibited emphysema on CT scans. The annual decline in FEV1 was -56.1 mL/y for the EC group and -46.9 mL/y for the NEC group, with a nonsignificant between-group difference of 9.1 mL/ (95% CI, -24.0 to 5.7 mL/y). The rate of emphysema progression in the EC group was significantly lower than in the NEC group (-0.173%; 95% CI, -0.252 to -0.094). The EC group also showed a more pronounced annual increase in the St. George's Respiratory questionnaire score (0.9 points) compared with the NEC group. The EC group had a higher rate of acute respiratory exacerbations (0.36 per person-year) than the NEC group (0.25 per person-year), with a rate ratio of 1.42 (95% CI, 1.27-1.54).InterpretationThe EC group did not have accelerated rates of decline in FEV1, but they experienced significantly worse health-related quality of life and a higher rate of acute respiratory exacerbations. The nonemphysema subtype demonstrated increased emphysema progression.Clinical Trial RegistrationClinicalTrials.gov; No.: NCT0196934; URL: www.Clinicaltrialsgov.Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

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