It remains unclear whether extreme levels of blood urea nitrogen (BUN) and BUN to creatinine ratio (BUN/Cr) can increase future risk of stroke. We conducted this study to investigate the associations of BUN and BUN/Cr with incident stroke and its subtypes.

Background: Primary pulmonary hypertension (PPH) is a life-threatening disease associated with increased mortality. The urea cycle pathway plays a major role in PPH severity and treatment response. Little is known about the association of the blood urea nitrogen (BUN) and PPH prognosis. Methods: Clinical data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. Adult patients (≥18 years) patients with primary pulmonary hypertension (PPH) in the database were enrolled. Spearman correlation was used to analyze the association of BUN with length of hospital and intensive care unit (ICU) stays. The chi-square test was used to analyze the association of BUN with mortality rate. Survival curves were estimated using the Kaplan-Meier method and compared by the log-rank test. Multivariable logistic regression was used to identify the BUN as an independent prognostic factor of mortality. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used to analyze the sensitivity and specificity for mortality. Results: In total, 263 patients who met the selection criteria were enrolled. BUN was significantly positively associated with length of hospital stay and ICU stay (hospital stay: ρ = 0.282, ICU stay: ρ = 0.276; all P < 0.001). Higher hospital, 90-day and 4-year mortality rates were observed in the higher BUN quartile of PPH patients (hospital: P = 0.002; 90-day: P = 0.025; 4-year: P < 0.001). The Kaplan-Meier survival curves showed that patients in higher BUN quartile tended to have lower 4-year survival (Q1:7.65%, Q2: 10.71%; Q3: 14.80%, Q4: 16.84%; P < 0.0001). Logistic regression analyses found a significant association of BUN and mortality (hospital: OR = 1.05, 95% CI = 1.02-1.08, P = 0.001; 90-day: OR = 1.02, 95% CI = 1.00-1.05, P = 0.027; 4-year: OR = 1.05, 95% CI = 1.02-1.08, P = 0.001). Results of ROC and AUC showed that the diagnostic performance of BUN for mortality was moderately good. Conclusion: BUN was positively correlated with the length of hospital stay and ICU stay of PPH patients. Higher BUN was associated with higher hospital, 90-day and 4-year mortality and lower 4-year survival of PPH patients. These findings indicate that BUN can be a novel potential prognostic predictor for PPH.

Heart failure (HF) is one of the leading causes for hospitalization and mortality. After first admission with acute decompensated HF, some patients are in high risk for short-term and long-term mortality. These patients should be identified, closely followed up, and treated. It has been observed that blood urea nitrogen (BUN) on admission is a predictive marker for short-term mortality. Recently, it has been shown that higher BUN levels on discharge are also a bad prognostic predictor. However, the prognostic value of BUN alteration during hospital stay was not investigated; therefore, we aimed to investigate the effect of BUN variation during hospitalization on mortality.

Chronic subdural hematoma (CSDH) is fundamentally treatable with about a 2-31% recurrence rate. Recently, there has been renewed interest in the association between Blood Urea Nitrogen (BUN) and intracranial lesion. Therefore, this paper attempts to show the relationship between BUN and CSDH recurrence.

The aim of this study was to estimate the association between blood urea nitrogen (BUN) and clinical prognosis in patients with COVID-19. A multicenter, retrospective study was conducted in adult patients with COVID-19 in 3 hospitals in Zhenjiang from January 2023 to May 2023. Patients were divided into survival and death group based on whether they survived at day 28. The demographic, comorbidities, and laboratory data were independently collected and analyzed, as well as clinical outcomes. Total 141 patients were enrolled and 23 (16.3%) died within 28 days. Patients who died within 28 days had a higher level of BUN compared with survivors. Bivariate logistic regression analysis showed that BUN was a risk factor for 28-day mortality in patients with COVID-19. ROC curve showed that BUN could predict 28-day mortality of COVID-19 patients (AUC = 0.796, 95%CI: 0.654-0.938, P < .001). When the cutoff value of BUN was 7.37 mmol/L, the sensitivity and specificity were 84.62% and 70.31%. Subgroup analysis demonstrated that hyper-BUN (≥7.37 mmol/L) was associated with increased 28-day mortality among COVID-19 patients. Patients with COVID-19 who died within 28 days had a higher level of BUN, and hyper-BUN (≥7.37 mmol/L) was associated with increased 28-day mortality.

Colonic urea-nitrogen metabolites have been implicated in the pathogenesis of certain diseases which can be affected by environmental factors.

Blood urea nitrogen (BUN) is a metabolic product validated to be an independent risk factor in the prognosis of several diseases. However, the prognostic value of BUN in patients with infective endocarditis (IE) remains unevaluated.

To explore the correlation between Blood urea nitrogen to creatinine ratio (BUN/Scr ratio) and prognosis of patients with chronic heart failure complicated with renal injury.

To investigate the ability of the ratio of blood urea nitrogen (BUN) to serum albumin ratio (BAR) in patients with sepsis in intensive care units (ICUs) to predict the prognosis of short-and long-term death. Data are from the Marketplace for Intensive Care Medical Information IV (MIMIC-IV v2.0) database for patients with sepsis as defined by SEPSIS-3. The primary outcome was 30-day mortality and the secondary outcome was 360-day mortality. Kaplan-Meier (KM) survival curves were plotted to describe differences in BAR mortality in different subgroups and area under the curve (AUC) analysis was performed to compare the predictive value of sequential organ failure assessment (SOFA), BAR, blood urea nitrogen (BUN) and albumin. Multivariate Cox regression models and subgroup analysis were used to determine the correlation between BAR and 30-day mortality and 360-day mortality. A total of 7656 eligible patients were enrolled in the study with a median BAR of 8.0 mg/g, including 3837 in the ≤ 8.0 group and 3819 in the BAR > 8.0 group, with 30-day mortality rates of 19.1% and 38.2% (P < 0.001) and 360-day mortality rates of 31.1% and 55.6% (P < 0.001). Multivariate Cox regression models showed an increased risk of death for 30-day mortality (HR = 1.219, 95% CI 1.095-1.357; P < 0.001) and 360-day mortality (HR = 1.263, 95% CI 1.159-1.376; P < 0.001) in the high BAR group compared to the low BAR group. For the 30-day outcome, the area under the curve (AUC) was 0.661 for BAR and 0.668 for 360-day BAR. In the subgroup analysis, BAR remained an isolated risk factor for patient death. As a clinically inexpensive and readily available parameter, BAR can be a valuable forecaster of prognosis in patients with sepsis in the intensive care unit.

Finding easily accessible and non-invasive methods for differentiating various sources of gastrointestinal (GI) bleeding before performing endoscopy and colonoscopy is of great interest. The present study was designed with the aim of evaluating the screening performance characteristics of blood urea nitrogen (BUN) to Creatinine (Cr) ratio in this regard.

The effect of the blood urea nitrogen (BUN) to creatinine (Cr) ratio (henceforth BUN/Cr) on haemorrhagic transformation (HT) of acute ischaemic stroke (AIS) patients is unclear.

Background: High blood urea nitrogen (BUN) is associated with adverse outcomes in patients with cardiac disease risks. However, no study has explored whether BUN can predict the risk of cardiovascular disease (CVD) in the healthy older population. This study aims to explore the incidence and risk factors of CVD among a healthy older population community in China. Design and Methods: This study was designed as a cohort study with a 4-year follow-up. We recruited 5,000 older people among 137,625 residents of the Gaohang community. In the baseline, subjects were asked to participate in medical screening and biological tests, and answered survey questions. During the follow-up period (2014-2017), the researchers regularly tested the subjects' indicators and assessment scales. We monitored the occurrence of CVD and explored the relationship between BUN and CVD via a Cox regression analysis. Results: During the follow-up, subjects were newly diagnosed with CVD including heart failure (HF), heart disease events, atrial fibrillation, diabetes, hypertension, metabolic syndrome, and kidney disease. The Cox regression analysis found an association between baseline BUN and incident CVD in female subjects, with higher BUN associated with increased risk of AF in females and kidney disease in both male and females. No association was found between BUN and CVD in male subjects. Conclusions: Current results indicate that BUN is a valuable predictive biomarker of CVD. A higher BUN level (>13.51 mg/dL) is associated with an increased occurrence of HF but a decreased occurrence of diabetes and metabolic symptoms in normal older females.

Blood urea nitrogen (BUN) is a surrogate marker for neurohormonal activation, but the association between BUN and the post-discharge prognosis in elderly patients with acute decompensated heart failure (ADHF) is not well defined. We explored the association between BUN and post-discharge all-cause mortality in 652 elderly patients (73.9 ± 7.8 yr) with ADHF. All patients were followed for a mean duration of 32 months (12-69 months). BUN was analyzed both as a continuous variable and according to two categories: low BUN group (BUN < 15.35 mmol/L, N = 361) and high BUN group (BUN ≥ 15.35 mmol/L, N = 291). The risk of all-cause mortality increased by 1.6% per 1 mmol/L increase in BUN concentration when BUN was used as a continuous variable [hazard ratio (HR): 1.016, 95% confidence interval (CI): 1.006-1.026, p = 0.002]. BUN maintained an independent and significant positive correlation with all-cause mortality as a categorical variable (HR: 1.355, 95% CI: 1.023-1.794, p = 0.034 for the high BUN group). The BUN C-statistic for predicting all-cause mortality was 0.624 (95% CI: 0.585-0.661). The cut-off value for BUN was 15.35 mmol/L with sensitivity of 0.58 and specificity of 0.63. The prognostic performance of BUN was similar to brain natriuretic peptide (BNP) for predicting all-cause mortality (C-statistic: z = 0.044, p = 0.965). These results suggest that BUN is an independent predictor of post-discharge all-cause mortality in elderly patients with ADHF and its prognostic performance was similar to that of BNP.

Research has previously been done into the risk factors for mortality in septic shock patients. However, there has been no epidemiological study investigating the effect of the blood urea nitrogen/creatinine ratio (BCR) on the prognosis of critically ill septic shock patients. This study is aimed at determining the relationship between BCR and all-cause mortality in adult septic shock patients.

Chronic heart failure (CHF) is often a common comorbidity in critically ill patients admitted to the intensive care unit (ICU) and carries an extremely poor prognosis. The study aimed to investigate the relationship between the blood urea nitrogen to serum albumin ratio (BAR) and the prognosis of patients with CHF admitted to the ICU.

The association between blood urea nitrogen to creatinine ratio (UCR) and survival is uncertain in hemodialysis patients. We examined the influence of UCR on mortality and morbidity in hemodialysis patients. A total of 3,401 hemodialysis patients were prospectively followed for 4 years. The association between UCR with overall survival was analyzed using a Cox regression model. During a 4-year follow-up period, 545 patients died from any cause and 582 experienced MACE, 392 with coronary heart disease (CHD), 114 with infection-related death, 77 with hemorrhagic stroke, 141 with ischemic stroke, and 107 with cancer death. Every 1 increase in UCR level was significantly associated with an increased risk for all-cause mortality (hazard ratio [HR] 1.07; 95% confidence interval [CI] 1.03-1.12), CHD (HR 1.08; 95% CI 1.02-1.14), and infection-related death (HR 1.11; 95% CI 1.02-1.21). There was no evidence of a significant association between UCR and death from cancer, and incidence of stroke. A high UCR was significantly associated with an increased risk for all-cause mortality, infection-related death and incidence of CHD in hemodialysis patients.

The association between blood urea nitrogen (BUN) and prognosis has been the focus of recent research. Therefore, the objective of this study was to investigate the association between BUN and hospital mortality in critically ill patients with cardiogenic shock (CS). This was a retrospective cohort study, in which data were obtained from the Medical Information Mart for Intensive Care III V1.4 database. Data from 697 patients with CS were analyzed. Logistic regression and subgroup analyses were used to assess the association between BUN and hospital mortality in patients with CS. The average age of the 697 participants was 71.14 years, and approximately 42.18% were men. In the multivariate logistic regression model, after adjusting for age, sex, diabetes, cardiac arrhythmias, urine output, simplified acute physiology score II, sequential organ failure assessment, creatinine, anion gap, and heart rate, high BUN demonstrated strong associations with increased in-hospital mortality (per standard deviation increase: odds ratio [OR] 1.47, 95% confidence interval [CI] 1.13-1.92). A similar result was observed in BUN tertile groups (BUN 23-37 mg/dL versus 6-22 mg/dL: OR [95% CI], 1.42 [0.86-2.34]; BUN 38-165 mg/dL versus 6-22 mg/dL: OR [95% CI], 1.99 [1.10-3.62]; P trend 0.0272). Subgroup analysis did not reveal any significant interactions among various subgroups, and higher BUN was associated with adverse clinical outcomes in patients with CS.

The associations between blood urea nitrogen (BUN)/albumin ratio and poor prognosis in patients with diagnosis of coronavirus disease 2019 (COVID-19) remain to be clarified.

Nitrogen utilization efficiency (NUE) and lysine utilization efficiency (LUE) are key indicators of sustainable pork production and vary depending on nutritional and non-nutritional factors. The objective was to study NUE and LUE together with concentrations of blood urea nitrogen (BUN) and other metabolites in growing pigs fed diets with marginal Lys concentrations at 11-13 wk (40.5 kg mean BW) and 14 to 16 wk (60.2 kg mean BW). The cereal grain-soybean meal-based diets contained 10.6 and 7.9 g Lys/kg DM in periods 1 and 2, respectively. Feed intake and BW were measured for 508 individually penned pigs, and blood samples were collected 5 h after morning feeding at weeks 13 and 16. A subgroup of 48 barrows was used in a nitrogen (N) metabolism trial at weeks 13 and 16. In this subgroup, the mean N retention of pigs (27.3 g N/d) and mean LUE (70%) were not different between the periods, but NUE was higher in period 1 (47%) than in period 2 (43%) (P < 0.001). After administration of a single dose of 15N labeled glycine and measurement of 15N recovery in urine, the calculated whole-body protein turnover did not differ between the periods. The rate of protein synthesis was positively correlated with NUE (P < 0.001), but protein degradation was not. Excretion of urea-N in urine accounted for 80% of the total urinary N and was positively correlated with BUN. The N retention of all 508 pigs was estimated using an equation that was derived from the N metabolism data. N retention was on average 31.4 g/d, equal in both periods, and higher in barrows than in gilts in period 2, but not in period 1 (P = 0.003). The calculated NUE was, on average, 47% and was lower in barrows than in gilts (P < 0.001) and higher in period 1 than in period 2 (P < 0.001). The calculated LUE was, on average, 71%, and was lower in barrows than in gilts in period 2, but not in period 1 (P < 0.001). The BUN concentration was higher in barrows than in gilts (P < 0.001) and higher in period 1 than in period 2 (P < 0.001). BUN concentration was negatively correlated with NUE in Periods 1 (r = -0.50) and 2 (r = -0.15) (P < 0.05). We concluded that the maximum LUE was in the range of 70-72% under the conditions of this study, and only small differences between the periods and sexes existed. Protein synthesis, rather than degradation, appears to affect NUE. BUN concentration may be useful for estimating NUE in a large group of animals fed a diet with a marginal Lys concentration.

Estimated glomerular filtration rate (eGFR) has been reported to be associated with risk of incident coronary heart disease (CHD), and blood urea nitrogen (BUN) has been shown to be a strong predictor of mortality in patients with heart failure (HF). However, such epidemiological evidence from Chinese population was still limited. We used Cox proportional-hazards regression models to investigate the associations of eGFR and BUN with risk of incident CHD in the prospective Dongfeng-Tongji (DFTJ) cohort. After fully adjusted for potential confounders, a 10-unit decline in eGFR was associated with higher risk for CHD (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.01-1.09); compared with individuals with normal eGFR levels (eGFR ≥ 90 ml/min per 1.73 m2), individuals with a mild-to-severe eGFR decline (15 to 60 ml/min per 1.73 m2) were at significantly greater risk for CHD (HR 1.25, 95% CI 1.05-1.48; P = 0.011). Compared with individuals in the lowest tertile of BUN, those in the highest tertile were at significantly greater risk for CHD (HR 1.17, 95% CI 1.03-1.33; P = 0.014). In conclusion, a mild-to-severe decline in eGFR or a raised level of BUN might be associated with increased risk of incident CHD in middle-aged and elderly Chinese populations.