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Multicenter Study
. 2023 Jul 13:18:1445-1455.
doi: 10.2147/COPD.S412106. eCollection 2023.

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 #  1 , Yichun Qin #  2 , Chen Zhou  3 , Yuanming Luo  4 , Hailong Wei  5 , Huiqing Ge  6 , Hui-Guo Liu  7 , Jianchu Zhang  8 , Xianhua Li  9 , Pinhua Pan  10 , Mengqiu Yi  11 , Lina Cheng  11 , Liang Liu  12 , Adila Aili  1 , Lige Peng  1 , Yu Liu  1 , Jiaqi Pu  1 , Qun Yi #  1   13 , Haixia Zhou #  1
Affiliations
Multicenter Study

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 et al. Int J Chron Obstruct Pulmon Dis. .

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.

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Conflict of interest statement

The authors declare that the research had no conflicts of interest.

Figures

Figure 1
Figure 1
Flow chart of the study.
Figure 2
Figure 2
The ROC curve of BUN as a predictor of mortality in patients with AECOPD.
Figure 3
Figure 3
Kaplan–Meier curves of overall survival in patients with AECOPD with BUN level above (≥) and below (<)7.30 mmol/L.
See this image and copyright information in PMC

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