Ratio of blood urea nitrogen to serum creatinine at initiation of dialysis is associated with mortality: a multicenter prospective cohort study

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Dihydromyricetin protects against gentamicin-induced nephrotoxicity via upregulation of renal SIRT3 and PAX2

AIM

Gentamicin-induced nephrotoxicity limits its widespread use as an effective antibacterial agent. Oxidative stress, inflammatory cytokines and apoptotic cell death are major participants in gentamicin-induced nephrotoxicity. We therefore, investigated whether dihydromyricetin (DHM), the antioxidant and anti-inflammatory flavonoid, could protect against the nephrotoxic effects of gentamicin.

METHODS

Male Wistar rats administrated gentamicin (100 mg/kg/day, i.p.) for 8 days. DHM (400 mg/kg, p.o.) was concurrently given with gentamicin for 8 days. Control group received the vehicle of DHM and gentamicin. Histopathological examinations, biochemical measurements and immunohistochemical analyses were done at the end of the study.

KEY FINDINGS

Treatment with DHM improved the gentamicin induced deterioration of renal functions; serum levels of urea, creatinine and cystatin-C as well as urinary levels of Kim-1 and NGAL, the sensitive indicators for early renal damage, were declined. Additionally, DHM abrogated gentamicin-induced changes in kidney morphology. These nephroprotective effects were possibly mediated via decreasing renal gentamicin buildup, activating the antioxidant enzymes GSH, SOD and CAT and decreasing lipid peroxidation and nitric oxide levels. Further, DHM suppressed renal inflammation and apoptotic cell death by decreasing the expression of nuclear factor-kappa B (NF-κB), TNF-alpha and caspase-3. These effects were correlated to the upregulation of renal SIRT3 expression. Also, DHM activated the regeneration and replacement of injured tubular cells with new ones via enhancing PAX2 expression.

SIGNIFICANCE

DHM is a promising therapeutic target that could prevent acute renal injury induced by gentamicin and help renal tubular cells to recover through its antioxidant, anti-inflammatory and antiapoptotic properties.

Clinical significance of serum urea-to-creatinine ratio in patients undergoing peritoneal dialysis

INTRODUCTION

We aimed to determine the correlation between the serum urea-to-creatinine ratio and residual kidney function (RKF) in patients undergoing peritoneal dialysis (PD), as well as its predictive value for PD-related outcomes.

METHODS

This study included a cross-sectional study to assess the correlation between serum urea-to-creatinine ratio and RKF in 50 patients on PD and a retrospective cohort study to assess the association between serum urea-to-creatinine ratio and PD-related outcomes in 122 patients who initiated PD.

RESULTS

Serum urea-to-creatinine ratios had significant positive correlations with renal Kt/V and creatinine clearance values (r = 0.60, p < 0.001 and r = 0.61, p < 0.001, respectively). Additionally, serum urea-to-creatinine ratio was significantly associated with a lower risk of transfer to hemodialysis or PD/hemodialysis hybrid therapy (hazard ratio: 0.84, 95% confidence interval: 0.75-0.95).

CONCLUSION

The serum urea-to-creatinine ratio can be an indicator of RKF and a prognostic factor in patients undergoing PD.

Plasma urea:creatinine ratio as a biomarker of gastrointestinal bleeding in dogs with anaemia

BACKGROUND

Gastrointestinal bleeding is a cause of anaemia in dogs. A reliable, non-invasive biomarker to differentiate gastrointestinal bleeding from other causes of anaemia would be advantageous to direct clinical decisions in anaemic patients. Plasma urea:creatinine ratio is an accepted biomarker of upper gastrointestinal bleeding in human medicine.

OBJECTIVES

The objective of this study was to evaluate plasma urea:creatinine ratio as a biomarker of gastrointestinal bleeding in a population of dogs with anaemia.

METHODS

This was a prospective cross-sectional study of dogs with anaemia presenting to referral centres for the investigation of anaemia. Cases were categorised as having overt gastrointestinal bleeding (melena on presentation), occult gastrointestinal bleeding (historical and diagnostic findings consistent with gastrointestinal bleeding without melena at presentation) or anaemia of other cause (confident diagnosis other than gastrointestinal bleeding reached, normal diagnostic imaging of gastrointestinal tract). Urea:creatinine ratio at presentation was calculated by dividing urea (mg/dL) by creatinine (mg/dL).

RESULTS

Ninety-five dogs were included. Plasma urea:creatinine ratio was not significantly different between dogs with overt or occult gastrointestinal bleeding or those with anaemia of other cause (median urea:creatinine ratio 25.8, 20.7 and 22.5, respectively). No significant difference in urea:creatinine ratio was found between dogs with upper and lower gastrointestinal bleeding (median urea:creatinine ratio 19.4 and 24.6, respectively).

CONCLUSIONS

Plasma urea:creatinine ratio was not helpful in differentiating between dogs with anaemia resulting from gastrointestinal bleeding (overt or occult) and those with other causes of anaemia.

Analysis of patency rates and factors associated with arteriovenous fistula in maintenance hemodialysis patients followed for 10 years

OBJECTIVE

This study analyzed the long-term arteriovenous fistula (AVF) patency rate and its determinants in patients undergoing maintenance hemodialysis.

METHODS

General data and laboratory examinations of hemodialysis patients were collected retrospectively. The primary patency time, primary functional patency time, cumulative patency time, cumulative functional patency time, and temporary central venous catheterization (CVC) time were counted. Cox regression was used to analyze the relationships between different factors and AVF survival time. Kaplan-Meier survival analysis was used to analyze the primary patency, primary functional patency, cumulative patency, and cumulative functional patency rates between different groups.

RESULTS

A total of 174 patients were included (mean age 58.38 ± 15.35 years), 57 women (32.76%) and 68 diabetics (39.08%). Univariate and multivariate Cox regression showed a correlation between UCR and AVF primary patency time, primary functional patency time, cumulative patency time, and cumulative functional patency time (HR 1.127, 1.116, 1.127, 1.115, 1.088, 1.075, 1.087, 1.013; 95%CI 1.055-1.204, 1.043-1.194, 1.055-1.204, 1.042-1.194, 1.022-1.158, 1.006-1.149, 1.021-1.157, 1.004-1.147; p < 0.001, 0.001, <0.001, 0.002, 0.008, 0.033, 0.009, 0.039, respectively). Duration of temporary CVC was also correlated (HR 1.013, 1.013, 1.013, 1.014, 1.008, 1.008, 1.008, 1.008; 95%CI 1.007-1.018, 1.008-1.019, 1.008-1.019, 1.009-1.020, 1.004-1.012, 1.004-1.012, 1.004-1.012, 1.004-1.012; p < 0.001, <0.001, <0.001, <0.001, <0.001, <0.001, <0.001, <0.001, respectively). Female sex was correlated with the primary patency time and the primary functional patency time (HR 1.755, 1.765, 1.767; 95%CI 1.028-2.997, 1.034-3.014, 1.021-3.057; p = 0.039, 0.037, 0.042, respectively), but not with the cumulative patency time and the cumulative functional patency time, the primary patency rate and primary functional patency rate of AVF were higher in male than in female patients (χ2 = 4.439, 4.531; p = 0.035, 0.033, respectively). The primary patency rate, primary functional patency rate, cumulative patency rate, and cumulative functional patency rate of AVF with UCR > 10.11 group are lower than those with UCR ≤ 10.11 (χ2 = 10.745, 10.712, 4.605, 4.472; p = 0.001, 0.001, 0.032, 0.034, respectively). The group of DTCP ≤ 42 days is better than DTCP > 42 days (χ2 = 6.014, 6.055, 8.572, 8.461; p = 0.014, 0.014, 0.003, 0.004, respectively).

CONCLUSION

Women with high UCR values at the beginning of dialysis and a long duration of temporary CVC have a poor long-term survival rate of AVF. Therefore, UCR can be used as an indicator to predict the long-term survival rate of AVF. Simultaneously, clinicians should remove the temporary catheter as early as possible if conditions permit it.

Blood urea nitrogen to creatinine ratio and long-term survival in patients with chronic heart failure

OBJECTIVES

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.

METHODS

A retrospective analysis of 504 patients hospitalized in Guang 'anmen Hospital, Chinese Academy of Traditional Chinese Medicine from March 2006 to June 2014 was conducted. The baseline data were analyzed, and the cutoff value was obtained by receiver operator characteristic curve (ROC) analysis, according to the cutoff value, all the participants were divided into two groups, BUN/Scr < 19.37 group (280 cases) and BUN/Scr ≥ 19.37 group (224 cases). The main end point was defined as all-cause death. The long-term mortality of the two groups was evaluated, and Kaplan-Meier survival curve was drawn. Univariate analysis was performed on all the variables affecting the patient's prognosis, and the variables with P < 0.05 were put into Cox regression model, and subgroup analysis was performed on the variables that might affect the patient's prognosis.

RESULTS

The baseline data of 504 patients were analyzed and found that the median follow up was 683. Through ROC analysis of 504 subjects, the cutoff value of BUN/Scr was 19.37. The results of Kaplan-Meier survival curve showed that the mortality rate of patients with ratio ≥ 19.37 was higher than that of patients with ratio < 19.37. After multivariate analysis, COX regression model showed that the mortality of patients with BUN/Scr ≥ 19.37 was 1.885 times that of patients with BUN/Scr < 19.37 [HR = 1.885 (1.298-2.737), P = 0.001]. Subgroup analysis showed that the relationship between BUN/Scr and the prognosis of CHF was influenced by NYHA and eGRF (P < 0.05).

CONCLUSIONS

BUN/Scr ratio is related to the poor prognosis of patients with CHF, and is an independent predictor of all-cause death.

Relationship between BUN/Cr and Prognosis of HF Across the Full Spectrum of Ejection Fraction

BACKGROUND

In patients with heart failure (HF), due to the relative deficiency of blood volume, neurohormone system activation leads to renal vasoconstriction, which affects the content of blood urea nitrogen (BUN) and creatinine (Cr) in the body, while BUN and Cr are easily affected by other factors. Therefore, BUN/Cr can be used as another marker for the prognosis of HF.

OBJECTIVE

Explore the prognosis of adverse outcome of HF in the high BUN/Cr group compared with the low BUN/Cr group across the full spectrum of ejection fraction.

METHODS

From 2014 to 2016, symptomatic hospitalized HF patients were recruited and followed up to observe adverse cardiovascular outcomes. Logistic analysis and COX analysis were performed to determine significance. p-values <0.05 were considered statistically significant.

RESULTS

In the univariate logistic regression analysis, the high BUN/Cr group had a higher risk of adverse outcome in heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Multivariate logistic regression analysis showed that the risk of cardiac death in the HFrEF group was higher than that in the low BUN/Cr group, while the risk of all-cause death was significant only in 3 months (p<0.05) (Central Illustration). The risk of all-cause death in the high BUN/Cr in the HFpEF group was significantly higher than that in the low BUN/Cr group at two years.

CONCLUSION

The high BUN/Cr group is related to the risk of poor prognosis of HFpEF, and is not lower than the predictive value of left ventricular ejection fraction (LVEF).

Elevated serum urea-to-creatinine ratio is associated with adverse inpatient clinical outcomes in non-end stage chronic kidney disease

To better understand the role of the urea-to-creatinine ratio in chronic kidney disease patients, we assessed the epidemiology of the urea-to-creatinine ratio among hospitalised chronic kidney disease patients, and the association between the urea-to-creatinine ratio and inpatient clinical outcomes. This retrospective cohort study (n = 11,156) included patients with at least two eGFR values < 60 mL/min/1.73m² measured greater than 90-days apart and admitted to a tertiary hospital between 2014 and 2019. Dialysis and renal transplant patients were excluded. Adjusted odds ratios for factors associated with an elevated urea-to-creatinine ratio were calculated. Multivariate regression was conducted to identify the relationship between elevated UCR and inpatient mortality, intensive care admission, hospital readmission and hospital length-of-stay. Urea-to-creatinine ratio > 100 was present in 27.67% of hospital admissions. Age ≥ 65 years, female gender, gastrointestinal tract bleeding, heart failure, acute kidney injury and lower serum albumin were associated with elevated urea-to-creatinine ratio. Higher urea-to-creatinine ratio level was associated with greater rates of inpatient mortality, hospital readmission within 30-days and longer hospital length-of-stay. Despite this, there was no statistically significant association between higher urea-to-creatinine ratio and intensive care unit admission. Elevated urea-to-creatinine ratio is associated with poor clinical outcomes in chronic kidney disease inpatients. This warrants further investigation to understand the pathophysiological basis for this relationship and to identify effective interventions.

Low Serum Albumin Is Associated with Poor Prognosis in Patients Receiving Peritoneal Dialysis Treatment

Background

The number of patients receiving dialysis treatment is sustainably increasing, especially peritoneal dialysis.

Objectives

It is necessary to find out potential factors that may indicate the prognosis of patients receiving peritoneal dialysis treatment.

Methods

This study retrospectively involved 325 patients who received peritoneal dialysis treatment.

Results

Low serum albumin (HR = 2.254; 95% CI: 1.534-3.311; P < 0.001) and high FBG (Fasting blood glucose) (HR = 1.474; 95% CI: 1.025-2.120; P=0.037) were risk factors for death in patients receiving peritoneal dialysis treatment. Serum albumin (AUC = 0.683; P < 0.001) and creatinine (AUC = 0.625; P < 0.001) exhibited value of prognosis prediction. Both high FBG (P=0.005) and low albumin (P < 0.001) were associated with poor prognosis, and low albumin predicted poorer survival.

Conclusions

Low serum albumin and high fasting blood glucose were risk factors and associated with poor prognosis. Low albumin has a potential in predicting the prognosis of patients receiving peritoneal dialysis treatment.

Renal markers and risks of all cause and cardiovascular mortality from the Taichung community based cohort study

This study aimed to explore the associations between renal-related and arterial stiffness biomarkers with all-cause and expanded cardiovascular disease (CVD) mortality in a general Taiwanese population. This prospective community-based cohort study included 4883 subjects aged ≥ 20 years who were followed up until December 31, 2016. Renal-related biomarkers consisted of blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and urine albumin-to-creatinine ratio (UACR). Arterial stiffness biomarker consisted of brachial-ankle pulse wave velocity (baPWV). The death status of the subjects was ascertained by matching information from death records with the identification number and date of birth of the subjects. Cox proportional hazard models with restricted cubic splines estimated the hazard ratios and 95% confidence intervals for all-cause mortality and expanded CVD mortality. During a mean 8.3 years of follow up, 456 deaths were recorded, 146 of which were due to expanded CVD mortality. The multivariable-adjusted hazard ratios of all-cause mortality was 1.53 (95% CI 1.21-1.94) for BUN (≥ 20 mg/dL vs. < 20 mg/dL), 1.57 (1.15-2.14) for eGFR (< 90 mL/min/1.73 m² vs. ≥ 90 mL/min/1.73 m²), 1.55 (1.25-1.92) for UACR (≥ 30 mg/g vs. < 30 mg/g), and 1.75 (1.14-2.67) for baPWV (≥ 1400 cm/s vs. < 1400 cm/s). The expanded CVD mortality was 1.89 (95% CI 1.30-2.73) for BUN (≥ 20 mg/dL vs. < 20 mg/dL), 2.28 (1.13-4.57) for eGFR (< 90 mL/min/1.73 m² vs. ≥ 90 mL/min/1.73 m²), 2.13 (1.52-2.99) for UACR (≥ 25 mg/g vs. < 25 mg/g), and 15.73 (2.14-115.61) for baPWV (≥ 1400 cm/s vs. < 1400 cm/s). High levels of BUN, UACR, and baPWV and low levels of eGFR showed high risks with all-cause and expanded CVD mortality. Our study provides insights into screening tests to target populations at high risk of premature death due to CVD.

Protein intake and renal function in older patients

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is highly prevalent in elderly patients. There is growing recognition of the importance of attention to dietary protein intake (DPI) in this population given their predisposition to age-related changes in kidney function and coexisting comorbidities (i.e., hypertension). We reviewed the impact of DPI on kidney health and survival and the role of dietary protein management in older CKD patients.

RECENT FINDINGS

While kidney function parameters including glomerular filtration rate (GFR) and renal plasma flow are slightly lower in elderly patients irrespective of CKD status, the kidneys' ability to compensate for increased DPI by augmentation of GFR is preserved until 80 years of age or less. However, long-term consumption of high DPI in individuals of older age and/or with CKD may contribute to kidney function deterioration over time. Prescription of a plant-dominant low-protein diet of 0.6-0.8 g/kg/day with more than 50% from plant sources or very low protein diets less than 0.45 g/kg/day supplemented with essential amino acids or their keto-analogues may be effective in preserving kidney function in older patients and their younger counterparts, while also monitoring for development of protein-energy wasting (PEW).

SUMMARY

Using tailored precision nutrition approaches in prescribing plant-dominant low DPI that also maintains adequate energy and nitrogen balance may ameliorate kidney function decline while also preventing development of PEW in elderly patients with CKD.

A high urea-to-creatinine ratio predicts long-term mortality independent of acute kidney injury among patients hospitalized with an infection

Acute kidney injury (AKI) occurs frequently in patients with sepsis. Persistent AKI is, in contrast to transient AKI, associated with reduced long-term survival after sepsis, while the effect of AKI on survival after non-septic infections remains unknown. As prerenal azotaemia is a common cause of transient AKI that might be identified by an increased urea-to-creatinine ratio, we hypothesized that the urea-to-creatinine ratio may predict the course of AKI with relevance to long-term mortality risk. We studied the association between the urea-to-creatinine ratio, AKI and long-term mortality among 665 patients presented with an infection to the ED with known pre-existent renal function. Long-term survival was reduced in patients with persistent AKI. The urea-to-creatinine ratio was not associated with the incidence of either transient or non-recovered AKI. In contrast, stratification according to the urea-to-creatinine-ratio identifies a group of patients with a similar long-term mortality risk as patients with persistent AKI. Non-recovered AKI is strongly associated with all-cause long-term mortality after hospitalization for an infection. The urea-to-creatinine ratio should not be employed to predict prerenal azotaemia, but identifies a group of patients that is at increased risk for long-term mortality after infections, independent of AKI and sepsis.

Incidence rate of atrial fibrillation after dialysis initiation and its relationship with cardiovascular events

Aim: This study aimed to investigate the incidence of atrial fibrillation (AF) and its prognosis in the patients after dialysis initiation.Methods: A total of 1524 patients with chronic kidney disease who were initiated on dialysis were included. Dialysis was initiated between October 2011 and September 2013. Electrocardiogram was obtained at dialysis initiation, in March 2015, and September 2016. The mortality and cardiovascular disease (CVD) event rates of 1520 patients (1028 men and 492 women; mean age, 67.5 ± 13.1 years) who were followed up were compared, and they were divided into 2 groups: the AF group (with AF at least once) and N group (without AF).Results: The prevalence of AF was 6.2, 7.9, and 6.5% at dialysis initiation, in March 2015, and September 2016, respectively, and the incidence of new AF onset was 4.8% in March 2015 and 2.3% in September 2016. In total, 45 (28.0%) and 347 (25.5%) patients died in the AF and N groups, (p = .508), respectively. The incidence rates of CVD event were 91 (56.5%) and 413 (30.4%) in the AF and N groups (p < .001), respectively. In the multivariate analysis, mortality was not significant, but the incidence of CVD event was significantly higher in the AF group. Albumin level was associated with new-onset AF.Conclusions: After dialysis initiation, a high incidence of new-onset AF was observed. The lower albumin value at the time of dialysis initiation is more likely to be associated with AF development. Attention should be paid to the CVD events in the AF group.

Major reductions in unnecessary aspartate aminotransferase and blood urea nitrogen tests with a quality improvement initiative

BACKGROUND/CONTEXT

Unnecessary laboratory testing leads to considerable healthcare costs. Aspartate aminotransferase (AST), commonly ordered with alanine aminotransferase (ALT) and blood urea nitrogen (BUN), commonly ordered with creatinine (Cr), often add little value to patient management at significant cost. We undertook a choosing wisely based quality improvement initiative to reduce the frequency of testing.

OBJECTIVES

To reduce the ratio of AST/ALT and BUN/Cr to less than 5% for all inpatient and outpatient test orders.

MEASURES

Absolute number and ratio of AST/ALT and BUN/Cr; AST, ALT, BUN and Cr tests per 100 hospital days; projected annualised cost savings and monthly acute inpatient bed days.

IMPROVEMENTS

We created guidelines for appropriate indications of AST and BUN testing, provided education with audit and feedback and removed AST and BUN from institutional order sets.

IMPACT/RESULTS

The ratios of AST/ALT and BUN/Cr decreased significantly over the study period (0.37 to 0.14, 0.57 to 0.14, respectively), although the goal of 0.05 was not achieved due to a delay in adopting the choosing wisely strategies during the study time period by some inpatient units. The number of tests per 100 hospital days decreased from 20 to 7 AST (95% CI 19 to 20.5, 5.6 to 8.7, p<0.001) and from 72 to 17 BUN (95% CI 70 to 73.4, 16.6 to 22.9, p<0.001). The initiative resulted in a projected annualised cost savings of C$221 749.

DISCUSSION

A significant decrease in the AST/ALT and BUN/Cr ratios can be achieved with a multimodal approach and will result in substantial healthcare savings.