Association between serum osmolality and risk of in-hospital mortality in patients with intracerebral hemorrhage.

Aim: This study aimed to analyze the association between serum osmolality and the risk of in-hospital mortality in intracerebral hemorrhage (ICH) patients. Methods: In this retrospective cohort study, data of a total of 1,837 ICH patients aged ≥18 years were extracted from the Medical Information Mart for Intensive Care-IV (MIMIC-IV). Serum osmolality and blood urea nitrogen (BUN)-to-creatinine (Cr) ratio (BCR) were used as the main variables to assess their association with the risk of in-hospital mortality in ICH patients after first intensive care unit (ICU) admission using a univariable Cox model. Univariable and multivariable Cox regression analyses were applied to explore the associations between serum osmolality, BCR, and in-hospital mortality of ICH patients. Hazard ratio (HR) and 95% confidence intervals (CIs) were calculated. Results: The median survival duration of all participants was 8.29 (4.61-15.24) days. Serum osmolality of ≥295 mmol/L was correlated with an increased risk of in-hospital mortality in patients with ICH (HR = 1.43, 95%CI: 1.14-1.78). BCR of >20 was not significantly associated with the risk of in-hospital mortality in ICH patients. A subgroup analysis indicated an increased risk of in-hospital mortality among ICH patients who were women, belonged to white or Black race, or had complications with acute kidney injury (AKI). Conclusion: High serum osmolality was associated with an increased risk of in-hospital mortality among ICH patients.

Blood urea nitrogen to creatinine ratio is associated with in-hospital mortality in critically ill patients with venous thromboembolism: a retrospective cohort study.

Background: The relationship between the blood urea nitrogen to creatinine ratio (BCR) and the risk of in-hospital mortality among intensive care unit (ICU) patients diagnosed with venous thromboembolism (VTE) remains unclear. This study aimed to assess the relationship between BCR upon admission to the ICU and in-hospital mortality in critically ill patients with VTE. Methods: This retrospective cohort study included patients diagnosed with VTE from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The primary endpoint was in-hospital mortality. Univariate and multivariate logistic regression analyses were conducted to evaluate the prognostic significance of the BCR. Receiver operating characteristic (ROC) curve analysis was utilized to determine the optimal cut-off value of BCR. Additionally, survival analysis using a Kaplan-Meier curve was performed. Results: A total of 2,560 patients were included, with a median age of 64.5 years, and 55.5% were male. Overall, the in-hospital mortality rate was 14.6%. The optimal cut-off value of the BCR for predicting in-hospital mortality in critically ill VTE patients was 26.84. The rate of in-hospital mortality among patients categorized in the high BCR group was significantly higher compared to those in the low BCR group (22.6% vs. 12.2%, P < 0.001). The multivariable logistic regression analysis results indicated that, even after accounting for potential confounding factors, patients with elevated BCR demonstrated a notably increased in-hospital mortality rate compared to those with lower BCR levels (all P < 0.05), regardless of the model used. Patients in the high BCR group exhibited a 77.77% higher risk of in-hospital mortality than those in the low BCR group [hazard ratio (HR): 1.7777; 95% CI: 1.4016-2.2547]. Conclusion: An elevated BCR level was independently linked with an increased risk of in-hospital mortality among critically ill patients diagnosed with VTE. Given its widespread availability and ease of measurement, BCR could be a valuable tool for risk stratification and prognostic prediction in VTE patients.

Association between blood urea nitrogen to creatinine ratio and neurologically favourable outcomes in out-of-hospital cardiac arrest in adults: A multicentre cohort study.

BACKGROUND: We aimed to investigate the association between blood urea nitrogen to creatinine ratio (BCR) and survival with favourable neurological outcomes in patients with out-of-hospital cardiac arrest (OHCA). METHODS: This prospective, multicentre, observational study conducted in Osaka, Japan enrolled consecutive OHCA patients transported to 16 participating institutions from 2012 through 2019. We included adult patients with non-traumatic OHCA who achieved a return of spontaneous circulation and whose blood urea nitrogen and creatinine levels on hospital arrival were available. Based on BCR values, they were divided into: 'low BCR' (BCR <10), 'normal BCR' (10 ≤ BCR < 20), 'high BCR' (20 ≤ BCR < 30), and 'very high BCR' (BCR ≥ 30). We evaluated the association between BCR values and neurologically favourable outcomes, defined as cerebral performance category score of 1 or 2 at one month after OHCA. RESULTS: Among 4415 eligible patients, the 'normal BCR' group had the highest favourable neurological outcome [19.4 % (461/2372)], followed by 'high BCR' [12.5 % (141/1127)], 'low BCR' [11.2 % (50/445)], and 'very high BCR' groups [6.6 % (31/471)]. In the multivariable analysis, adjusted odds ratios for 'low BCR', 'high BCR', and 'very high BCR' compared with 'normal BCR' for favourable neurological outcomes were 0.58 [95 % confidence interval (CI 0.37-0.91)], 0.70 (95 % CI 0.49-0.99), and 0.40 (95 % CI 0.21-0.76), respectively. Cubic spline analysis indicated that the association between BCR and favourable neurological outcomes was non-linear (p for non-linearity = 0.003). In subgroup analysis, there was an interaction between the aetiology of arrest and BCR in neurological outcome (p for interaction <0.001); favourable neurological outcome of cardiogenic OHCA patients was lower when the BCR was higher or lower, but not in non-cardiogenic OHCA patients. CONCLUSIONS: Both higher and lower BCR were associated with poor neurological outcomes compared to normal BCR, especially in cardiogenic OHCA patients.

Relationship between the Blood Urea Nitrogen to Creatinine Ratio and In-Hospital Mortality in Non-Traumatic Subarachnoid Hemorrhage Patients: Based on Propensity Score Matching Method.

(1) Background: To explore the correlation between the blood urea nitrogen to creatinine ratio (UCR) and in-hospital mortality in non-traumatic subarachnoid hemorrhage patients. (2) Methods: Specific clinical information was collected from the Medical Information Mart for Intensive Ⅳ (MIMIC-Ⅳ) database. The optimal cut-off value of the UCR was calculated with ROC curve analysis conducted using the maximum Youden index for the prediction of survival status. Univariable and multivariable logistic regression analyses were also carried out to assess the prognostic significance of UCR, and the Kaplan−Meier (K−M) analysis was conducted to draw the survival curves. Then, the 1:1 propensity score matching (PSM) method was applied to improve the reliability of the research results while balancing the unintended influence of underlying confounders. (3) Results: This retrospective cohort study included 961 patients. The optimal cut-off value of the UCR for in-hospital mortality was 27.208. The PSM was performed to identify 92 pairs of score-matched patients, with balanced differences exhibited for nearly all variables. According to the K−M analysis, those patients with a UCR of more than 27.208 showed a significantly higher level of in-hospital mortality compared to the patients with a UCR of less than 27.208 (p < 0.05). After the adjustment for possible confounders, those patients whose UCR was more than 27.208 still had a significantly higher level of in-hospital mortality than the patients whose UCR was less than 27.208, as revealed by the multivariable logistic regression analysis (OR = 3.783, 95% CI: 1.959~7.305, p < 0.001). Similarly, the in-hospital mortality remained substantially higher for those patients in the higher UCR group than for the patients in the lower UCR group after PSM. (4) Conclusion: A higher level of the UCR was evidently associated with an increased risk of in-hospital mortality, which made the ratio useful as a prognostic predictor of clinical outcomes for those patients with non-traumatic subarachnoid hemorrhage.

Potential Usefulness of Blood Urea Nitrogen to Creatinine Ratio in the Prediction and Early Detection of Delirium Motor Subtype in the Intensive Care Unit.

Prediction and early detection of delirium can improve patient outcomes. A high blood urea nitrogen to creatinine ratio (BCR), which reflects dehydration, has been reported as a risk factor for delirium. Additionally, BCR represents skeletal muscle loss in intensive care unit (ICU) patients, which can have critical implications for clinical outcomes. We investigated whether BCR could be used to predict the occurrence and motor subtype of delirium in ICU patients through a retrospective cohort study that included 7167 patients (50 years or older) admitted to the ICU. Patients were assessed daily using the Richmond Agitation-Sedation Scale and the Confusion Assessment Method for ICU and categorized according to the delirium subtype. Participants were split into 10 groups according to BCR at ICU admission and the prevalence of each delirium subtype was compared. Multivariable logistic regression was then used for analysis. A higher BCR at ICU admission was associated with the development of hypoactive delirium. Moreover, BCR > 24.9 was associated with higher rates of hypoactive delirium. Our findings showed that a high BCR at ICU admission was associated with the development of hypoactive delirium, which suggested that BCR could be a potential biomarker for hypoactive delirium in ICU patients.

[Value of Blood Urea Nitrogen-to-Creatinine Ratio for Differentiating the Site of Gastrointestinal Bleeding and Assessing the Prognosis of Patients with Acute Nonvariceal Upper Gastrointestinal Bleeding].

Objective: To explore the diagnostic performance of blood urea nitrogen-to-creatinine (BUN/Cr) ratio in differentiating the site of gastrointestinal bleeding, and to assess the predictive value of early elevated BUN/Cr ratio for clinical outcomes in patients with acute nonvariceal upper gastrointestinal bleeding (ANVUGIB). Methods: The adult patients diagnosed with gastrointestinal bleeding who were hospitalized in the Department of Gastroenterology, Zhongshan Hospital, Xiamen University between May 2020 and May 2021 were retrospectively enrolled. According to the site of gastrointestinal bleeding, the patients were divided into the upper gastrointestinal tract group, the proximal small intestinal bleeding group, and the distal small intestinal and colonic bleeding group. According to the early dynamic changes of BUN/Cr ratio within 6-48 hours after admission, patients with ANVUGIB were divided into early dynamic elevated BUN/Cr ratio group and non-early dynamic elevated BUN/Cr ratio group. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic performance of BUN/Cr ratio in differentiating the site of gastrointestinal bleeding and examine the predictive efficacy of early dynamic elevated BUN/Cr ratio after admission, Rockall scoring system, and the combined indicator of the two for estimating the primary clinical outcomes in ANVUGIB patients. Results: A total of 266 patients were enrolled. Among them, 204 cases were in the upper gastrointestinal bleeding group, 15 cases were in the proximal small intestinal bleeding group, and 47 cases were in the distal small intestinal and colonic bleeding group. In the ANVUGIB patients, 16 were in the group with early dynamic elevated BUN/Cr ratio after admission, and 146 were in the group with non-early dynamic elevated BUN/Cr ratio after admission. The area under the ROC curve of the BUN/Cr ratio was 0.831 (95% CI: 0.780-0.874), the optimal cut-off value being 34.59 mg/g for differentiation between upper and lower gastrointestinal bleeding. The area under the ROC curve of the BUN/Cr ratio was 0.901 (95% CI: 0.798-0.963) and the optimal cut-off value was 19.27 mg/g for differentiation between proximal small intestinal bleeding and the distal small intestinal and colonic bleeding. The area under the ROC curve of the early dynamic elevated BUN/Cr ratio after admission was 0.806 (95% CI: 0.737-0.864) for predicting the primary clinical outcome in patients with ANVUGIB. The area under the ROC curve of the combined indicator included the early dynamic elevated BUN/Cr ratio after admission and the Rockall scoring system was 0.909 (95% CI: 0.854-0.949) for predicting the primary clinical outcome in patients with ANVUGIB. Conclusion: The BUN/Cr ratio shows rather reliable diagnostic performance for identifying the site of gastrointestinal bleeding, and the early dynamic elevated BUN/Cr ratio after admission is a reliable indicator for predicting clinical outcomes in patients with ANVUGIB.

Body mass index and blood urea nitrogen to creatinine ratio predicts refeeding hypophosphatemia of anorexia nervosa patients with severe malnutrition.

AIM: To investigate development of refeeding hypophosphatemia during the refeeding period and the extent of the decrease in the serum phosphorus level among anorexia nervosa patients with severe malnutrition. OBJECTIVE: The accurate prediction of the severity of refeeding hypophosphatemia in patients with anorexia nervosa during acute treatment is of great importance. Although some predictors were found in previous reports, these studies used binominal data-the presence or absence of hypophosphatemia-as an outcome indicator but not the extent of serum phosphorus level decrease. It is crucial in clinical settings to predict the extent of the serum phosphorus level decrease as well as development of refeeding hypophosphatemia, in particular, for patients with severe malnutrition, who has a higher risk of death. METHODS: We investigated 63 admissions from 37 patients with anorexia nervosa who had severe malnutrition (admission body mass index 11.5 ± 1.6) and carried out a linear discriminant regression analysis for the development of refeeding hypophosphatemia. The extent of the decrease in the serum phosphorus level were investigated using multiple linear regression analysis. Explanatory variables included data upon admission (age, sex, body mass index, blood urea nitrogen to creatinine ratio, albumin, initial serum phosphorus level, anorexia nervosa type, i.e., restrictive or binge-purge) as well as treatment-related indicators (calorie intake, amount of phosphate administered, and rate of weight gain). RESULTS: Development of refeeding hypophosphatemia and a change in serum phosphorus levels were predicted by body mass index and elevated blood urea nitrogen to creatinine ratio. CONCLUSIONS: Our study found that refeeding hypophosphatemia among patients with severe malnutrition was predicted by a lower body mass index and elevated blood urea nitrogen to creatinine ratio.

Blood Urea Nitrogen to Creatinine Ratio and Long-Term Mortality in Patients with Acute Heart Failure: A Prospective Cohort Study and Meta-Analysis.

OBJECTIVE: To further explore the relationship between the blood urea nitrogen to creatinine (BUN/Cr) ratio and the prognosis of patients with acute heart failure (AHF), a two-part study consisting of a prospective cohort study and meta-analysis were conducted. METHODS: A total of 509 hospitalized patients with AHF were enrolled and followed up. Cox proportional hazards regression was used to analyze the relationship between the BUN/Cr ratio and the long-term prognosis of patients with AHF. Meta-analysis was also conducted regarding the topic by searching PubMed and Embase for relevant studies published up to October 2019. RESULTS: During a median follow-up of 2.8 years, 197 (42.6%) deaths occurred. The cumulative survival rate of patients with a BUN/Cr ratio in the bottom quartile was significantly lower than in the other 3 groups (log-rank test: p = 0.003). In multivariate Cox regression models, the mortality rate of AHF patients with a BUN/Cr ratio in the bottom quartile was significantly higher than in the top quartile (adjusted HR 1.52; 95% CI 1.03-2.24). For the meta-analysis, we included 8 studies with 4,700 patients, consisting of 7 studies from the database and our cohort study. The pooled analysis showed that the highest BUN/Cr ratio category was associated with an 77% higher all-cause mortality than the lowest category (pooled HR 1.77; 95% CI 1.52-2.07). CONCLUSIONS: Elevated BUN/Cr ratio is associated with poor prognosis in patients with AFH and is an independent predictor of all-cause mortality.

Blood Urea Nitrogen Levels to Verify Estimated Glomerular Filtration Rate, as Derived from 2 Commonly Used Equations.

BACKGROUND: A blood urea nitrogen to creatinine ratio (BCR) of 20 or greater indicates various physiological conditions. Whether glomerular filtration rate (GFR) estimates obtained using the Modification of Diet in Renal Disease (MDRD) study equation and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) study equations are affected by a high BCR remains unknown. METHODS: Patients who underwent urine creatinine clearance (CrCl) and serum blood urea nitrogen (BUN) and creatinine assessments on the same day were enrolled in our study. Those with BCR of 20 or greater and less than 20 were categorized into high- and low-BCR groups. The concordance on diagnosing chronic kidney disease (CKD) stages by using urine CrCl level and serum GFR estimates was assessed. RESULTS: More disagreement in CKD stage diagnosis was observed in the high-BCR group (weighted κ = 0.600 and 0.541 for the MDRD and CKD-EPI study equations, respectively) than in the low-BCR group (weighted κ = 0.816 and 0.758, respectively). CONCLUSIONS: A BCR of 20 or greater caused misestimation of the CKD stage. GFR estimates for patients with high BCR should be interpreted cautiously.

The association between blood urea nitrogen to creatinine ratio and mortality in patients with upper gastrointestinal bleeding.

BACKGROUND AND STUDY AIMS: Azotaemia is commonly identified among patients with upper gastrointestinal bleeding (UGIB) due to absorption of blood products in the small bowel. Previous studies have found blood urea nitrogen-to-creatinine (BUN/Cr) ratio to be significantly elevated among patients UGIB bleeding compared to patients with lower GI bleeding. However, no studies have explored the relationship between BUN/Cr ratio and mortality. This study is aimed at investigating how BUN/Cr ratio relates to outcomes for UGIB patients. PATIENTS AND METHODS: This study was conducted prospectively at a university-affiliated teaching hospital with approximate 70,000 annual emergency department (ED) visits. Data from a total of 258 adult UGIB patients were collected between March 1, 2011 and March 1, 2012. Cox regression analysis was used to identify risk factors for 30-day mortality. RESULTS: Malignancy and Rockall score were associated with increased risk of 30-day mortality (Unadjusted hazard ratio (HR): 3.87, 95% CI: 1.59-9.41, p = 0.0029; HR: 1.31, 95% CI: 1.02-1.71, p = 0.0476, respectively). However, BUN/Cr > 30 was associated with lower risk of 30-day mortality (HR: 0.32, 95% CI: 0.11-0.97, p = 0.0441). CONCLUSIONS: A BUN/Cr ratio of >30 was found to be an independent risk factor for mortality and may be useful for pre-endoscopic assessment. Development of future risk scoring systems might warrant consideration of including BUN/Cr ratio as a parameter for estimating risk.

Influence of renal dysfunction phenotype on mortality in decompensated heart failure with preserved and mid-range ejection fraction.

BACKGROUND: Natriuretic peptides or the blood urea nitrogen to creatinine ratio (BUN/creat) can identify high- vs low-risk renal impairment (RI) in patients with heart failure and reduced ejection fraction (HF-REF). However, the situation in HF patients with preserved ejection fraction (HF-PEF) and mid-range ejection fraction (HF-MREF) remains unclear. METHODS: We evaluated patients from the Spanish National Registry of Heart Failure (RICA) that were admitted to Internal Medicine units with acute decompensated HF. Median admission values were used to define elevated NT-proBNP and BUN/creat. RESULTS: A total of 935 patients were evaluated, 743 with HF-PEF and 192 with HF-MREF). In patients with both NT-proBNP and BUN/creat below median admission values, RI was not associated with mortality (HR 1.15; 95% CI 0.7-1.87, p=0.581 in HF-PEF and HR 1.27; 95% CI 0.58-2.81, p=0.548 in HF-MREF). However, in patients with both elevated NT-proBNP and BUN/creat, those with RI had worse survival than those without RI (HR 2.01, 95% CI 1.33-3.06, p<0.001 in HF-PEF and HR 2.79, 95% CI 1.37-5.67, p=0.005 in HF-MREF). In HF-PEF even patients with RI with only 1 of the 2 parameters elevated, had a substantially higher risk of death compared to patients without RI (HR 1.53; 95% CI 1.04 to 2.26; p=0.031). CONCLUSIONS: In this clinical cohort of acute decompensated HF-PEF and HF-MREF patients, the combined use of NT-proBNP and BUN/creat stratifies patients with RI into groups with significantly different prognoses.

The risk of death associated with proteinuria in heart failure is restricted to patients with an elevated blood urea nitrogen to creatinine ratio.

BACKGROUND: Renal dysfunction (RD) is associated with reduced survival in HF; however, not all RD is mechanistically or prognostically equivalent. Notably, RD associated with "pre-renal" physiology, as identified by an elevated blood urea nitrogen to creatinine ratio (BUN/Cr), identifies a particularly high risk RD phenotype. Proteinuria, another domain of renal dysfunction, has also been associated with adverse events. Given that several different mechanisms can cause proteinuria, we sought to investigate whether the mechanism underlying proteinuria also affects survival in HF. METHODS AND RESULTS: Subjects in the Studies of Left Ventricular Dysfunction (SOLVD) trial with proteinuria assessed at baseline were studied (n=6439). All survival models were adjusted for baseline characteristics and estimated glomerular filtration rate (eGFR). Proteinuria (trace or 1+) was present in 26% and associated with increased mortality (HR=1.2; 95% CI, 1.1-1.3, p=0.006). Proteinuria >1+ was less common (2.5%) but demonstrated a stronger relationship with mortality (HR=1.9; 95% CI, 1.5-2.5, p<0.001). In patients with BUN/Cr in the top tertile (≥17.3), any proteinuria (HR=1.3; 95% CI, 1.1-1.5, p=0.008) and >1+ proteinuria (HR=2.3; 95% CI, 1.7-3.3, p<0.001) both remained associated with mortality. However, in patients with BUN/Cr in the bottom tertile (≤13.3), any proteinuria (HR=0.95; 95% CI, 0.77-1.2, p=0.63, p interaction=0.015) and >1+ proteinuria (HR=1.3; 95% CI, 0.79-2.2, p=0.29, p interaction=0.036) were not associated with worsened survival. CONCLUSION: Analogous to a reduced eGFR, the mechanism underlying proteinuria in HF may be important in determining the associated survival disadvantage.

Utility of fractional excretion of urea in the differential diagnosis of acute kidney injury in children.

INTRODUCTION: The fractional excretion of sodium (FENa) has been used as an index for the differential diagnosis of acute tubular necrosis (ATN) and prerenal acute kidney injury (AKI). The reliability of this index, however, decreases with the use of the diuretic agent furosemide. The fractional excretion of urea nitrogen (FEUN) has been shown to be useful in such settings in adults. The objective of this study was to examine whether FEUN is also useful in these settings in children. METHODS: We assessed 102 episodes of AKI in 74 children, classifying these into three groups based on history, physical examination, urine examination and subsequent clinical course: (1) prerenal AKI without furosemide (N = 37), (2) prerenal AKI with furosemide (N = 32) and (3) ATN (N = 33). RESULTS: Of the 37 prerenal AKI episodes without furosemide, 35 showed low FENa of <1 %, with an overall average of 0.35 ± 0.11 %, whereas prerenal AKI with furosemide (1.63 ± 0.37 %) and ATN (8.76 ± 2.11 %) were associated with a higher FENa. FEUN in the clinical setting of prerenal AKI was lower than that in ATN (27.9 ± 2.1 vs. 51.6 ± 3.8 %, respectively) and, in contrast to FENa, not significantly different between the categories of prerenal AKI with and without furosemide (29.2 ± 3.1 vs. 25.1 ± 2.9, respectively). The sensitivity of FEUN <35 % was 75 % in prerenal AKI with furosemide, whereas that of FENa was 53 %. CONCLUSIONS: FEUN is useful in detecting prerenal AKI in children administered furosemide.

A combined-biomarker approach to clinical phenotyping renal dysfunction in heart failure.

BACKGROUND: Differentiating heart failure (HF) induced renal dysfunction (RD) from intrinsic kidney disease is challenging. It has been demonstrated that biomarkers such as B-type natriuretic peptide (BNP) or the blood urea nitrogen to creatinine ratio (BUN/creat) can identify high- vs low-risk RD. Our objective was to determine if combining these biomarkers could further improve risk stratification and clinical phenotyping of patients with RD and HF. METHODS AND RESULTS: A total of 908 patients with a discharge diagnosis of HF were included. Median values were used to define elevated BNP (>1296 pg/mL) and BUN/creat (>17). In the group without RD, survival was similar regardless of BNP and BUN/creat (n = 430, adjusted P = .52). Similarly, in patients with both a low BNP and BUN/creat, RD was not associated with mortality (n = 250, adjusted hazard ratio [HR] = 1.0, 95% confidence interval [CI] 0.6-1.6, P = .99). However, in patients with both an elevated BNP and BUN/creat those with RD had a cardiorenal profile characterized by venous congestion, diuretic resistance, hypotension, hyponatremia, longer length of stay, greater inotrope use, and substantially worse survival compared with patients without RD (n = 249, adjusted HR = 1.8, 95% CI 1.2-2.7, P = .008, P interaction = .005). CONCLUSIONS: In the setting of decompensated HF, the combined use of BNP and BUN/creat stratifies patients with RD into groups with significantly different clinical phenotypes and prognosis.