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

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 .

Development and Validation of an In-Hospital Mortality Prediction Model for Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

“… 10 , 15 , 18 Similar to ALB, BUN is currently regarded as a predictive factor for in-hospital mortality in AECOPD patients. 6 , 23 In the study by Chen et al, 6 the optimal cut-off value for BUN was 7.63, which is very close to the median value of BUN in our death cohort (7.49).…”

Risk factors of in-hospital mortality and discriminating capacity of NIVO score in exacerbations of COPD requiring noninvasive ventilation

“…An association between BUN and increased mortality in AECOPD has been reported in several studies. 17 , 30 The probable reasons for this association were activation of the sympathetic nerve systems and renal dysfunction. 17 …”

“… 17 , 30 The probable reasons for this association were activation of the sympathetic nerve systems and renal dysfunction. 17 …”

“…The research results of the MAGNET AECOPD Registry study have been published previously. 14 – 17 In the present study, inclusion criteria: (1) AECOPD as primary diagnosis; (2) pre-admission spirometry evidence of airflow obstruction (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.7); (3) acute hypercapnic respiratory failure (pH < 7.35 or partial pressure of carbon dioxide (PaCO2) > 45 mmHg) treated with assisted NIV. Exclusion criteria were patients without acute hypercapnic respiratory failure and data missed.…”

Validation of the Rome Severity Classification of Chronic Obstructive Pulmonary Disease Exacerbation: A Multicenter Cohort Study

“… 31 Our research team previously discovered that blood urea nitrogen (BUN), a component of BAP-65, was linked to an increased risk of in-hospital death and other adverse outcomes in AECOPD inpatients. 6 , 32 Moreover, the baseline parameters, especially dyspnea in the stable stage, may have an impact on how this exacerbation may turn out. 33 , 34 Comorbidities like heart failure, arrhythmia, coronary heart disease, and diabetes, which are highly prevalent in COPD patients, also contribute to event severity in the real-life clinical setting.…”