Association Between Extracellular Superoxide Dismutase Activity and 1-Year All-Cause Mortality in Patients With Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Prospective Cohort Study

Haiqing Li; Wei Hong; Zixiong Zeng; Shan Gong; Fan Wu; Zihui Wang; Heshen Tian; Juan Cheng; Ruiting Sun; Mi Gao; Chunxiao Liang; Weitao Cao; Guoping Hu; Yuqun Li; Liping Wei; Yumin Zhou; Pixin Ran

doi:10.3389/fmed.2022.811975

Association Between Extracellular Superoxide Dismutase Activity and 1-Year All-Cause Mortality in Patients With Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Prospective Cohort Study

Front Med (Lausanne). 2022 Mar 14:9:811975. doi: 10.3389/fmed.2022.811975. eCollection 2022.

Authors

Haiqing Li^{1

2}, Wei Hong³, Zixiong Zeng¹, Shan Gong¹, Fan Wu², Zihui Wang², Heshen Tian², Juan Cheng¹, Ruiting Sun², Mi Gao³, Chunxiao Liang², Weitao Cao², Guoping Hu¹, Yuqun Li¹, Liping Wei¹, Yumin Zhou², Pixin Ran²

Affiliations

¹ Department of Respiratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
² State Key Laboratory of Respiratory Disease, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
³ GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China.

Abstract

Background and objectives: Accumulating evidence suggests that oxidative stress is involved in the development of chronic obstructive pulmonary disease (COPD) and its progression. Activity of extracellular superoxide dismutase (ecSOD), the only extracellular enzyme eliminating superoxide radicals, has been reported to decline in acute exacerbations of COPD (AECOPD). However, the association between serum ecSOD activity and 1-year all-cause mortality in AECOPD patients remains unclear. The objective of our study was to explore the usefulness of ecSOD activity on admission in AECOPD as an objective predictor for 1-year all-cause mortality.

Methods: We measured serum ecSOD activity in AECOPD patients on admission in a prospective cohort study. We also recorded their laboratory and clinical data. Multivariate Cox regression was used to analyze the association between ecSOD activity and the risk of 1-year all-cause mortality. Restricted cubic spline curves were used to visualize the relationship between ecSOD activity and the hazard ratio of 1-year all-cause mortality.

Results: A total of 367 patients were followed up for 1 year, and 29 patients died during a 1-year follow-up period. Compared with survivors, the non-survivors were older (79.52 ± 8.39 vs. 74.38 ± 9.34 years old, p = 0.004) and had increased levels of tobacco consumption (47.07 ± 41.67 vs. 33.83 ± 31.79 pack-years, p = 0.037). Having an ecSOD activity ≤ 98.8 U/ml was an independent risk factor of 1-year all-cause mortality after adjustment for baseline differences, clinical variables and comorbidities [hazard ratio = 5.51, 95% confidence interval (CI): 2.35-12.95, p < 0.001].

Conclusion: Lower serum ecSOD activity was a strong and independent predictor of 1-year all-cause mortality in AECOPD patients.

Keywords: AECOPD; SOD3; extracellular superoxide dismutase (ecSOD); mortality; prognosis.