Association of mild chronic obstructive pulmonary disease with all-cause mortality: A systematic review and meta-analysis

Weifeng Zou; Jie Ou; Fan Wu; Huanuan Fan; Yuyan Hou; Haiqing Li; Zhishan Deng; Shuling Liu; Jinxing Hu; Pixin Ran

doi:10.1016/j.pulmoe.2023.09.002

Association of mild chronic obstructive pulmonary disease with all-cause mortality: A systematic review and meta-analysis

Pulmonology. 2023 Oct 27:S2531-0437(23)00165-4. doi: 10.1016/j.pulmoe.2023.09.002. Online ahead of print.

Authors

Weifeng Zou¹, Jie Ou¹, Fan Wu², Huanuan Fan³, Yuyan Hou⁴, Haiqing Li⁵, Zhishan Deng⁵, Shuling Liu¹, Jinxing Hu¹, Pixin Ran⁶

Affiliations

¹ State Key Laboratory of Respiratory Disease, Guangzhou Chest Hospital, Guangzhou, China.
² State Key Laboratory of Respiratory Disease & Guangzhou Institute of Respiratory Health & National Clinical Research Center for Respiratory Disease & National Center for Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Guangzhou National Laboratory, Bio-land, Guangzhou, China.
³ Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
⁴ Medical school of Jiaying University, Meizhou, China.
⁵ State Key Laboratory of Respiratory Disease & Guangzhou Institute of Respiratory Health & National Clinical Research Center for Respiratory Disease & National Center for Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
⁶ State Key Laboratory of Respiratory Disease & Guangzhou Institute of Respiratory Health & National Clinical Research Center for Respiratory Disease & National Center for Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Guangzhou National Laboratory, Bio-land, Guangzhou, China. Electronic address: pxran@gzhmu.edu.cn.

PMID: 38093693
DOI: 10.1016/j.pulmoe.2023.09.002

Abstract

Background: It is unclear whether patients with Global Initiative for Chronic Obstructive Lung Disease stage 1 (mild) chronic obstructive pulmonary disease (COPD) have worse respiratory outcomes than individuals with normal spirometry.

Methods: For this systematic review and meta-analysis, we conducted a search of PubMed, Embase, and Web of Science for all literature published up to 1 March 2023. Studies comparing mortality between mild COPD and normal spirometry were included. A random-effects model was used to estimate the combined effect size and its 95% confidence interval (CI). The primary outcome was all-cause mortality. Respiratory disease-related mortality were examined as secondary outcomes.

Results: Of 5242 titles identified, 12 publications were included. Patients with mild COPD had a higher risk of all-cause mortality than individuals with normal spirometry (pre-bronchodilator: hazard ratio [HR] = 1.21, 95% CI: 1.11-1.32, I² = 47.1%; post-bronchodilator: HR = 1.19, 95% CI: 1.02-1.39, I² = 0.0%). Funnel plots showed a symmetrical distribution of studies and did not suggest publication bias. In jackknife sensitivity analyses, the increased risk of all-cause mortality remained consistent for mild COPD. When the meta-analysis was repeated and one study was omitted each time, the HR and corresponding 95% CI were >1. Patients with mild COPD also had a higher risk of respiratory disease-related mortality (HR = 1.71, 95% CI: 1.03-2.82, I² = 0.0%).

Conclusions: Our results suggest that mild COPD is associated with increased all-cause mortality and respiratory disease-related mortality compared with normal spirometry. Further research is required to determine whether early intervention and treatment are beneficial in mild COPD.

Keywords: All-cause mortality; COPD; GOLD stage I; Meta-analysis; Systematic review; mild.