Blood Urea Nitrogen (BUN) is independently associated with mortality in critically ill patients admitted to ICU.
Arihan Okan,Wernly Bernhard,Lichtenauer Michael,Franz Marcus,Kabisch Bjoern,Muessig Johanna,Masyuk Maryna,Lauten Alexander,Schulze Paul Christian,Hoppe Uta C,Kelm Malte,Jung Christian
PURPOSE:Blood urea nitrogen (BUN) was reported to be associated with mortality in heart failure patients. We aimed to evaluate admission BUN concentration in a heterogeneous critically ill patient collective admitted to an intensive care unit (ICU) for prognostic relevance. METHODS:A total of 4176 medical patients (67±13 years) admitted to a German ICU between 2004 and 2009 were included. Follow-up of patients was performed retrospectively between May 2013 and November 2013. Association of admission BUN and both intra-hospital and long-term mortality were investigated by Cox regression. An optimal cut-off was calculated by means of the Youden-Index. RESULTS:Patients with higher admission BUN concentration were older, clinically sicker and had more pronounced laboratory signs of multi-organ failure including kidney failure. Admission BUN was associated with adverse long-term mortality (HR 1.013; 95%CI 1.012-1.014; p<0.001). An optimal cut-off was calculated at 28 mg/dL which was associated with adverse outcome even after correction for APACHE2 (HR 1.89; 95%CI 1.59-2.26; p<0.001), SAPS2 (HR 1.85; 95%CI 1.55-2.21; p<0.001) and several parameters including creatinine in an integrative model (HR 3.34; 95%CI 2.89-3.86; p<0.001). We matched 614 patients with admission BUN >28 mg/dL to case-controls ≤ 28mg/dL corrected for APACHE2 scores: BUN above 28 mg/dL remained associated with adverse outcome in a paired analysis with the difference being 5.85% (95%CI 1.23-10.47%; p = 0.02). CONCLUSIONS:High BUN concentration at admission was robustly associated with adverse outcome in critically ill patients admitted to an ICU, even after correction for co-founders including renal failure. BUN might constitute an independent, easily available and important parameter for risk stratification in the critically ill.
Does Baseline BUN Have an Additive Effect on the Prediction of Mortality in Patients with Acute Pulmonary Embolism?
Jenab Yaser,Haji-Zeinali Ali-Mohammad,Alemzadeh-Ansari Mohammad Javad,Shirani Shapour,Salarifar Mojtaba,Alidoosti Mohammad,Vahidi Hamed,Pourjafari Marzieh,Jalali Arash
The journal of Tehran Heart Center
In patients with heart failure, elevated levels of blood urea nitrogen (BUN) is a prognostic factor. In this study, we investigated the prognostic value of elevated baseline BUN in short-term mortality among patients with acute pulmonary embolism (PE). : Between 2007 and 2014, cardiac biomarkers and BUN levels were measured in patients with acute PE. The primary endpoint was 30-day mortality, evaluated based on the baseline BUN (≥14 ng/L) level in 4 groups of patients according to the European Society of Cardiology's risk stratification (low-risk, intermediate low-risk, intermediate high-risk, and high-risk). Our study recruited 492 patients with a diagnosis of acute PE (mean age=60.58±16.81 y). The overall 1-month mortality rate was 6.9% (34 patients). Elevated BUN levels were reported in 316 (64.2%) patients. A high simplified pulmonary embolism severity index (sPESI) score (OR: 5.23, 95% CI: 1.43-19.11; P=0.012), thrombolytic or thrombectomy therapy (OR: 2.42, 95% CI: 1.01-5.13; P=0.021), and elevated baseline BUN levels (OR: 1.04, 95% CI: 1.01-1.03; P=0.029) were the independent predictors of 30-day mortality. According to our receiver-operating characteristics analysis for 30-day mortality, a baseline BUN level of greater than 14.8 mg/dL was considered elevated. In the intermediate-low-risk patients, mortality occurred only in those with elevated baseline BUN levels (7.2% vs. 0; P=0.008). An elevated baseline BUN level in our patients with PE was an independent predictor of short-term mortality, especially among those in the intermediate-risk group.
Blood urea nitrogen (BUN) independently predicts mortality in critically ill patients admitted to ICU: A multicenter study.
Wernly Bernhard,Lichtenauer Michael,Vellinga Namkje A R,Boerma E Christiaan,Ince Can,Kelm Malte,Jung Christian
Clinical hemorheology and microcirculation
BACKGROUND AND PURPOSE:The Microcirculatory Shock Occurrence in Acutely Ill Patients (micro-SOAP) study investigated associations of microcirculation and mortality. Risk stratification in critically ill patients is of utmost interest. Established score such as APACHE2 (Acute Physiology And Chronic Health Evaluation 2) are relatively complex and might therefore be of limited use. Blood urea nitrogen (BUN) was described to be associated with mortality in various diseases. We therefore aimed (i) to evaluate BUN for prediction of mortality in a cohort of critically ill patients and (ii) to investigate associations of BUN with microcirculation. METHODS:412 patients were included in our post-hoc analysis of the prospective multicenter microSOAP study. Assesment of the sublingual microcirculation (Sidestream Dark Field (SDF) imaging) and collection of laboratory values were performed on the same day in this point prevalence study. Evaluation of associations with mortality was done by logistic regression analysis. An optimal BUN cut-off was calculated by means of the Youden Index. RESULTS:Median BUN was 9.0 mmol/L. BUN was associated with in-hospital-mortality in a logistic regression analysis (HR 1.03; 95% CI 1.01-1.05; p < 0.001). Per quartile (BUN 0-5.4 mmol/L, 5.4-9.0 mmol/L, 9.0-15.9 mmol/L and above 15.9 mmol/L) in-hospital mortality increased by as much as 51% (HR 1.51; 95% CI 1.23-1.85; p < 0.001). ROC analysis was done (AUC 0.63 95% CI 0.58-0.67) and the statistically optimal cut-off calculated by means of the Youden Index: 9.7 mmol/L. This cut-off was associated with a significant 3-fold increase in mortality (HR 2.97 95% CI 1.88-4.70; p < 0.001) and remained robustly associated with adverse outcome after correction for APACHE2 (HR 2.71 95% CI 1.61-4.59; p < 0.001), renal function as expressed by creatinine (HR 2.63 95% CI 1.59-4.33; p = 0.001), as well in an integrative model (MAP<60 mmHg, tachycardia (heart rate >90/min), lactate above 1.5 mmol/L, age above 80 years; HR 2.43 95% CI 1.50-3.92; p < 0.001). Parameters of microvascular perfusion were associated neither with BUN nor mortality. CONCLUSIONS:BUN is associated with hospital mortality and a combination of BUN and clinical signs might constitute a powerful but easy-to-use tool for risk stratification in critically ill patients and help improve their outcome. BUN was not associated with parameters of microcirculation which were not associated with mortality.