Elevated BUN Upon Admission as a Predictor of in-Hospital Mortality Among Patients with Acute Exacerbation of COPD: A Secondary Analysis of Multicenter Cohort Study

Jiarui Zhang; Yichun Qin; Chen Zhou; Yuanming Luo; Hailong Wei; Huiqing Ge; Hui-Guo Liu; Jianchu Zhang; Xianhua Li; Pinhua Pan; Mengqiu Yi; Lina Cheng; Liang Liu; Adila Aili; Lige Peng; Yu Liu; Jiaqi Pu; Qun Yi; Haixia Zhou

doi:10.2147/COPD.S412106

Elevated BUN Upon Admission as a Predictor of in-Hospital Mortality Among Patients with Acute Exacerbation of COPD: A Secondary Analysis of Multicenter Cohort Study

Int J Chron Obstruct Pulmon Dis. 2023 Jul 13:18:1445-1455. doi: 10.2147/COPD.S412106. eCollection 2023.

Authors

Jiarui Zhang^#¹, Yichun Qin^#², Chen Zhou³, Yuanming Luo⁴, Hailong Wei⁵, Huiqing Ge⁶, Hui-Guo Liu⁷, Jianchu Zhang⁸, Xianhua Li⁹, Pinhua Pan¹⁰, Mengqiu Yi¹¹, Lina Cheng¹¹, Liang Liu¹², Adila Aili¹, Lige Peng¹, Yu Liu¹, Jiaqi Pu¹, Qun Yi^#^{1

13}, Haixia Zhou^#¹

Affiliations

¹ Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People's Republic of China.
² State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
³ West China School of Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People's Republic of China.
⁴ State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, Guangdong Province, People's Republic of China.
⁵ Department of Respiratory and Critical Care Medicine, People's Hospital of Leshan, Leshan, Sichuan Province, People's Republic of China.
⁶ Department of Respiratory and Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, People's Republic of China.
⁷ Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, People's Republic of China.
⁸ Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, People's Republic of China.
⁹ Department of Respiratory and Critical Care Medicine, The First People's Hospital of Neijiang City, Neijiang, Sichuan Province, People's Republic of China.
¹⁰ Department of Respiratory and Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan Province, People's Republic of China.
¹¹ Department of Emergency, First People's Hospital of Jiujiang, Jiujiang, Jiangxi Province, People's Republic of China.
¹² Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Chengdu University, Chengdu, Sichuan Province, People's Republic of China.
¹³ Sichuan Cancer Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, People's Republic of China.

^# Contributed equally.

Abstract

Background: High blood urea nitrogen (BUN) is observed in a subset of patients with acute exacerbation of COPD (AECOPD) and may be linked to clinical outcome, but findings from previous studies have been inconsistent.

Methods: We performed a retrospective analysis of patients prospectively enrolled in the MAGNET AECOPD Registry study (ChiCTR2100044625). Receiver operating characteristic (ROC) was used to determine the level of BUN that discriminated survivors and non-survivors. Univariate and multivariate Cox proportional hazards regression analyses were performed to assess the impact of BUN on adverse outcomes.

Results: Overall, 13,431 consecutive inpatients with AECOPD were included in this study, of whom 173 died, with the mortality of 1.29%. The non-survivors had higher levels of BUN compared with the survivors [9.5 (6.8-15.3) vs 5.6 (4.3-7.5) mmol/L, P < 0.001]. ROC curve analysis showed that the optimal cutoff of BUN level was 7.30 mmol/L for in-hospital mortality (AUC: 0.782; 95% CI: 0.748-0.816; P < 0.001). After multivariate analysis, BUN level ≥7.3 mmol/L was an independent risk factor for in-hospital mortality (HR = 2.099; 95% CI: 1.378-3.197, P = 0.001), also for invasive mechanical ventilation (HR = 1.540; 95% CI: 1.199-1.977, P = 0.001) and intensive care unit admission (HR = 1.344; 95% CI: 1.117-1.617, P = 0.002). Other independent prognostic factors for in-hospital mortality including age, renal dysfunction, heart failure, diastolic blood pressure, pulse rate, PaCO2 and D-dimer.

Conclusion: BUN is an independent risk factor for in-hospital mortality in inpatients with AECOPD and may be used to identify serious (or severe) patients and guide the management of AECOPD.

Clinical trial registration: MAGNET AECOPD; Chinese Clinical Trail Registry NO.: ChiCTR2100044625; Registered March 2021, URL: http://www.chictr.org.cn/showproj.aspx?proj=121626.

Keywords: AECOPD; adverse outcomes; blood urea nitrogen; inpatients; mortality.

Publication types

Multicenter Study

MeSH terms

Blood Urea Nitrogen
Hospital Mortality
Hospitalization
Humans
Prognosis
Pulmonary Disease, Chronic Obstructive*
Retrospective Studies

Grants and funding

This study was supported by the National Natural Science Foundation of China (82170013), the Sichuan Science and Technology Program (2022YFS0262) and the National Key Research Program of China (2016YFC1304202).