Phosphate is a potential biomarker of disease severity and predicts adverse outcomes in acute kidney injury patients undergoing continuous renal replacement therapy

Association of Geriatric Nutritional Risk Index with short-term mortality in patients with severe acute kidney injury: a retrospective cohort study

OBJECTIVES

Geriatric Nutritional Risk Index (GNRI) is a new and simple index recently introduced to assess nutritional status, and its predictive value for clinical outcomes has been demonstrated in patients with chronic kidney disease. However, the association between the GNRI and prognosis has not been evaluated so far in patients with acute kidney injury (AKI), especially in those receiving continuous renal replacement therapy (CRRT).

METHODS

A total of 1096 patients with severe AKI initiating CRRT were identified for inclusion in this retrospective observational study. Patients were divided into three groups according to GNRI tertiles, with tertile 1 as the reference. The outcomes of interest were the 28- and 90-days of all-cause mortality. The associations between GNRI and clinical outcomes were estimated using multivariate Cox proportional hazards model analysis.

RESULTS

The overall mortality rates at 28- and 90-days were 61.6% (675/1096) and 71.5% (784/1096), respectively. After adjusting for multiple confounding factors, GNRI was identified as an independent prognostic factor for 28-days all-cause mortality (HR, 0.582; 95% CI, 0.467-0.727; p < .001 for tertile 3 vs. tertile 1) as well as 90-days all-cause mortality (HR, 0.540; 95% CI, 0.440-0.661; p < .001 for tertile 3 vs. tertile 1). The observed inverse associations were robust across subgroup analysis, and were more pronounced in elderly patients over 65 years of age. Finally, incorporating GNRI in a model with established risk factors might significantly improve its predictive power for the short-term death.

CONCLUSIONS

GNRI is considered to be a useful prognostic factor in patients with severe AKI initiating CRRT, especially in elderly patients.

Using machine learning to predict the risk of short-term and long-term death in acute kidney injury patients after commencing CRRT

BACKGROUND

The mortality rate and prognosis of short-term and long-term acute kidney injury (AKI) patients who undergo continuous renal replacement therapy (CRRT) are different. Setting up risk stratification tools for both short-term and long-term deaths is highly important for clinicians.

METHOD

A total of 1535 AKI patients receiving CRRT were included in this study, with 1144 from the training set (the Dryad database) and 391 from the validation set (MIMIC IV database). A model for predicting mortality within 10 and 90 days was built using nine different machine learning (ML) algorithms. AUROC, F1-score, accuracy, sensitivity, specificity, precision, and calibration curves were used to assess the predictive performance of various ML models.

RESULTS

A total of 420 (31.1%) deaths occurred within 10 days, and 1080 (68.8%) deaths occurred within 90 days. The random forest (RF) model performed best in both predicting 10-day (AUROC: 0.80, 95% CI: 0.74-0.84; accuracy: 0.72, 95% CI: 0.67-0.76; F1-score: 0.59) and 90-day mortality (AUROC: 0.78, 95% CI: 0.73-0.83; accuracy: 0.73, 95% CI: 0.69-0.78; F1-score: 0.80). The importance of the feature shows that SOFA scores are rated as the most important risk factor for both 10-day and 90-day mortality.

CONCLUSION

Our study, utilizing multiple machine learning models, estimates the risk of short-term and long-term mortality among AKI patients who commence CRRT. The results demonstrated that the prognostic factors for short-term and long-term mortality are different. The RF model has the best prediction performance and has valuable potential for clinical application.

Multi-omics and imaging mass cytometry characterization of human kidneys to identify pathways and phenotypes associated with impaired kidney function

Despite the recent advances in our understanding of the role of lipids, metabolites, and related enzymes in mediating kidney injury, there is limited integrated multi-omics data identifying potential metabolic pathways driving impaired kidney function. The limited availability of kidney biopsies from living donors with acute kidney injury has remained a major constraint. Here, we validated the use of deceased transplant donor kidneys as a good model to study acute kidney injury in humans and characterized these kidneys using imaging and multi-omics approaches. We noted consistent changes in kidney injury and inflammatory markers in donors with reduced kidney function. Neighborhood and correlation analyses of imaging mass cytometry data showed that subsets of kidney cells (proximal tubular cells and fibroblasts) are associated with the expression profile of kidney immune cells, potentially linking these cells to kidney inflammation. Integrated transcriptomic and metabolomic analysis of human kidneys showed that kidney arachidonic acid metabolism and seven other metabolic pathways were upregulated following diminished kidney function. To validate the arachidonic acid pathway in impaired kidney function we demonstrated increased levels of cytosolic phospholipase A2 protein and related lipid mediators (prostaglandin E2) in the injured kidneys. Further, inhibition of cytosolic phospholipase A2 reduced injury and inflammation in human kidney proximal tubular epithelial cells in vitro. Thus, our study identified cell types and metabolic pathways that may be critical for controlling inflammation associated with impaired kidney function in humans.

Phosphate level predicts mortality in acute kidney injury patients undergoing continuous kidney replacement therapy and has a U-shaped association with mortality in patients with high disease severity: a multicenter retrospective study

BACKGROUND

This study investigated the association between serum phosphate level and mortality in acute kidney injury (AKI) patients undergoing continuous kidney replacement therapy (CKRT) and evaluated whether this association differed according to disease severity.

METHODS

Data from eight tertiary hospitals in Korea were retrospectively analyzed. The patients were classified into four groups (low, normal, high, and very high) based on their serum phosphate level at baseline. The association between serum phosphate level and mortality was then analyzed, with further subgroup analysis being conducted according to disease severity.

RESULTS

Among the 3,290 patients identified, 166, 955, 1,307, and 862 were in the low, normal, high, and very high phosphate groups, respectively. The 90-day mortality rate was 63.9% and was highest in the very high group (76.3%). Both the high and very high groups showed a significantly higher 90-day mortality rate than did the normal phosphate group (high: hazard ratio [HR], 1.35, 95% confidence interval [CI], 1.21-1.51, p < 0.001; very high: HR, 2.01, 95% CI, 1.78-2.27, p < 0.001). The low group also exhibited a higher 90-day mortality rate than did the normal group among those with high disease severity (HR, 1.47; 95% CI, 1.09-1.99; p = 0.01) but not among those with low disease severity.

CONCLUSION

High serum phosphate level predicted increased mortality in AKI patients undergoing CKRT, and low phosphate level was associated with increased mortality in patients with high disease severity. Therefore, serum phosphate levels should be carefully considered in critically ill patients with AKI.

A nomogram for predicting 28-day mortality in elderly patients with acute kidney injury receiving continuous renal replacement therapy: a secondary analysis based on a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is a common and serious condition, particularly among elderly patients. It is associated with high morbidity and mortality rates, further compounded by the need for continuous renal replacement therapy in severe cases. To improve clinical decision-making and patient management, there is a need for accurate prediction models that can identify patients at a high risk of mortality.

METHODS

Data were extracted from the Dryad Digital Repository. Multivariate analysis was performed using least absolute shrinkage and selection operator (LASSO) logistic regression analysis to identify independent risk factors and construct a predictive nomogram for mortality within 28 days after continuous renal replacement therapy in elderly patients with acute kidney injury. The discrimination of the model was evaluated in the validation cohort using the area under the receiver operating characteristic curve (AUC), and calibration was evaluated using a calibration curve. The clinical utility of the model was assessed using decision curve analysis (DCA).

RESULTS

A total of 606 participants were enrolled and randomly divided into two groups: a training cohort (n = 424) and a validation cohort (n = 182) in a 7:3 proportion. A risk prediction model was developed to identify independent predictors of 28-day mortality in elderly patients with AKI. The predictors included age, systolic blood pressure, creatinine, albumin, phosphorus, age-adjusted Charlson Comorbidity Index (CCI), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and sequential organ failure assessment (SOFA) score. These predictors were incorporated into a logistic model and presented in a user-friendly nomogram. In the validation cohort, the model demonstrated good predictive performance with an AUC of 0.799. The calibration curve showed that the model was well calibrated. Additionally, DCA revealed significant net benefits of the nomogram for clinical application.

CONCLUSION

The development of a nomogram for predicting 28-day mortality in elderly patients with AKI receiving continuous renal replacement therapy has the potential to improve prognostic accuracy and assist in clinical decision-making.

An integrated metabo-lipidomics profile of induced sputum for the identification of novel biomarkers in the differential diagnosis of asthma and COPD

BACKGROUND

Due to their complexity and to the presence of common clinical features, differentiation between asthma and chronic obstructive pulmonary disease (COPD) can be a challenging task, complicated in such cases also by asthma-COPD overlap syndrome. The distinct immune/inflammatory and structural substrates of COPD and asthma are responsible for significant differences in the responses to standard pharmacologic treatments. Therefore, an accurate diagnosis is of central relevance to assure the appropriate therapeutic intervention in order to achieve safe and effective patient care. Induced sputum (IS) accurately mirrors inflammation in the airways, providing a more direct picture of lung cell metabolism in comparison to those specimen that reflect analytes in the systemic circulation.

METHODS

An integrated untargeted metabolomics and lipidomics analysis was performed in IS of asthmatic (n = 15) and COPD (n = 22) patients based on Ultra-High-Pressure Liquid Chromatography-Mass Spectrometry (UHPLC-MS) and UHPLC-tandem MS (UHPLC-MS/MS). Partial Least Squares-Discriminant Analysis (PLS-DA) was applied to resulting dataset. The analysis of main enriched metabolic pathways and the association of the preliminary metabolites/lipids pattern identified to clinical parameters of asthma/COPD differentiation were explored. Multivariate ROC analysis was performed in order to determine the discriminatory power and the reliability of the putative biomarkers for diagnosis between COPD and asthma.

RESULTS

PLS-DA indicated a clear separation between COPD and asthmatic patients. Among the 15 selected candidate biomarkers based on Variable Importance in Projection scores, putrescine showed the highest score. A differential IS bio-signature of 22 metabolites and lipids was found, which showed statistically significant variations between asthma and COPD. Of these 22 compounds, 18 were decreased and 4 increased in COPD compared to asthmatic patients. The IS levels of Phosphatidylethanolamine (PE) (34:1), Phosphatidylglycerol (PG) (18:1;18:2) and spermine were significantly higher in asthmatic subjects compared to COPD.

CONCLUSIONS

This is the first pilot study to analyse the IS metabolomics/lipidomics signatures relevant in discriminating asthma vs COPD. The role of polyamines, of 6-Hydroxykynurenic acid and of D-rhamnose as well as of other important players related to the alteration of glycerophospholipid, aminoacid/biotin and energy metabolism provided the construction of a diagnostic model that, if validated on a larger prospective cohort, might be used to rapidly and accurately discriminate asthma from COPD.

Phosphate Restriction Prevents Metabolic Acidosis and Curbs Rise in FGF23 and Mortality in Murine Folic Acid-Induced AKI

SIGNIFICANCE STATEMENT

Patients with AKI suffer a staggering mortality rate of approximately 30%. Fibroblast growth factor 23 (FGF23) and phosphate (P i ) rise rapidly after the onset of AKI and have both been independently associated with ensuing morbidity and mortality. This study demonstrates that dietary P i restriction markedly diminished the early rise in plasma FGF23 and prevented the rise in plasma P i , parathyroid hormone, and calcitriol in mice with folic acid-induced AKI (FA-AKI). Furthermore, the study provides evidence for P i -sensitive osseous Fgf23 mRNA expression and reveals that P i restriction mitigated calciprotein particles (CPPs) formation, inflammation, acidosis, cardiac electrical disturbances, and mortality in mice with FA-AKI. These findings suggest that P i restriction may have a prophylactic potential in patients at risk for AKI.

BACKGROUND

In AKI, plasma FGF23 and P i rise rapidly and are independently associated with disease severity and outcome.

METHODS

The effects of normal (NP) and low (LP) dietary P i were investigated in mice with FA-AKI after 3, 24, and 48 hours and 14 days.

RESULTS

After 24 hours of AKI, the LP diet curbed the rise in plasma FGF23 and prevented that of parathyroid hormone and calcitriol as well as of osseous but not splenic or thymic Fgf23 mRNA expression. The absence of Pth prevented the rise in calcitriol and reduced the elevation of FGF23 in FA-AKI with the NP diet. Furthermore, the LP diet attenuated the rise in renal and plasma IL-6 and mitigated the decline in renal α -Klotho. After 48 hours, the LP diet further dampened renal IL-6 expression and resulted in lower urinary neutrophil gelatinase-associated lipocalin. In addition, the LP diet prevented the increased formation of CPPs. Fourteen days after AKI induction, the LP diet group maintained less elevated plasma FGF23 levels and had greater survival than the NP diet group. This was associated with prevention of metabolic acidosis, hypocalcemia, hyperkalemia, and cardiac electrical disturbances.

CONCLUSIONS

This study reveals P i -sensitive FGF23 expression in the bone but not in the thymus or spleen in FA-AKI and demonstrates that P i restriction mitigates CPP formation, inflammation, acidosis, and mortality in this model. These results suggest that dietary P i restriction could have prophylactic potential in patients at risk for AKI.

A novel method for automated crystal visualization and quantification in murine folic acid-induced acute kidney injury

Folic acid (FA)-induced acute kidney injury (FA-AKI) is an increasingly prevalent rodent disease model involving the injection of a high dose of FA that culminates in renal FA crystal deposition and injury. However, the literature characterizing the FA-AKI model is sparse and dated in part due to the absence of a well-described methodology for the visualization and quantification of renal FA crystals. Using widely available materials and tools, we developed a straightforward and crystal-preserving histological protocol that can be coupled with automated imaging for renal FA crystal visualization and generated an automated macro for downstream crystal content quantification. The applicability of the method was demonstrated by characterizing the model in male and female C57BL6/JRj mice after 3 and 30 h of FA treatment. Kidneys from both sexes and timepoints showed a bimodal distribution of FA crystal deposition in the cortical and medullary regions while, compared with males, females exhibited higher renal FA crystal content at the 30-h timepoint accompanied by greater kidney weight and higher plasma urea. Despite comparable plasma phosphate concentrations, FA-AKI resulted in a substantially more elevated plasma intact fibroblast growth factor 23 (FGF23) in females, reflected by a similar pattern in osseous Fgf23 mRNA expression. Therefore, the presented method constitutes a valuable tool for the quantification of renal FA crystals, which can aid the mechanistic characterization of the FA-AKI model and serves as a means to control for confounding changes in FA crystallization when using the model for investigating early and prophylactic AKI therapeutic interventions.NEW & NOTEWORTHY Here, we describe a novel method for the visualization and quantification of renal folic acid (FA) crystals in the rodent FA-induced acute kidney injury (FA-AKI) model. The protocol involves a straightforward histological approach followed by fully automated imaging and quantification steps. Applicability was confirmed by showing that the FA-AKI model is sex-dependent. The method can serve as a tool to aid in characterizing FA-AKI and to control for studies investigating prophylactic therapeutic avenues using FA-AKI.

Colistin treatment in older adults: why should we know more?

OBJECTIVES

We aimed to investigate the risk factors of colistin-associated nephrotoxicity in patients older than 65 years treated in the palliative care unit.

METHODS

119 palliative care patients who received intravenous colistimethate for at least 7 days were included in the study. The estimated glomerular filtration rate (GFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation. Data were obtained from the hospital information system.

RESULTS

The mean age of the participants was 76.7 ± 9.9 years and 49.4% were female. Of the 119 patients, 57 had colistin-induced nephropathy (CIN) according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The rate of CIN was higher in women than in men. The baseline phosphate level was higher in the CIN (+) group than in the CIN (-) group. The lower GFR values in patients with pneumonia persisted at days 14 and 30, whereas the lower GFR in patients without pneumonia did not. According to multivariate logistic regression, female gender and baseline phosphate level ≥ 4.5 mg/dl were found as independent variables for the development of nephropathy.

CONCLUSIONS

The creatinine levels of the patients with pneumonia and CIN did not improve after nephrotoxicity, whereas the creatinine levels of the other patients without pneumonia and CIN did. Female gender and baseline phosphate were independent risk factors for CIN. Prolonged kidney failure may lead to a more difficult clinical follow-up process for clinicians. Therefore, clinicians should be aware of persistent renal insufficiency in older patients with pneumonia receiving colistimethate.

Association between serum phosphate and in-hospital mortality of patients with AECOPD: A retrospective analysis on eICU database

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is an important adverse event in the development of chronic obstructive pulmonary disease (COPD). Hyperphosphatemia is associated with higher mortality in patients with multiple diseases. In this study, we aimed to determine the relationship between serum phosphate and the risk of in-hospital mortality in patients with AECOPD. Methods: In the present study, patients with AECOPD were enrolled in the electronic Intensive Care Unit Collaborative Research Database (eICU-CRD), and divided into three groups according to the tertiles of serum phosphate level. The primary outcome measure was all-cause in-hospital mortality. The association between serum phosphate level and in-hospital mortality was investigated using multivariate logistic regression analysis. Moreover, subgroup analysis was performed to explore whether the relationship was consistent among different subgroups. Results: A total of 1199 AECOPD patients were included in this study. Non-survivors had higher serum phosphate levels than survivors. All patients were classified into lowest tertile, median tertile, and highest tertile, respectively. Multivariate logistic regression analysis indicated that serum phosphate was positively associated with in-hospital mortality after adjusting for confounders. Moreover, there was a significant trend across tertiles when serum phosphate level was diverted as a categorical variable. In addition, subgroup analysis demonstrated that serum phosphate was consistently associated with a higher risk of in-hospital mortality in different subgroups. Conclusion: Higher serum phosphate was positively associated with the increased in-hospital mortality in patients with AECOPD. Hyperphosphatemia may be an underlying high-risk factor for in-hospital mortality owing to AECOPD.

Relationship between serum phosphate and mortality in critically ill children receiving continuous renal replacement therapy

Purpose

We aimed to explore the relationship between serum phosphate concentration and 90-day mortality in critically ill children receiving continuous renal replacement therapy (CRRT).

Methods

Data from the medical records of children aged <13 years who received CRRT at the Pediatric Intensive Care Unit of Hunan Children's Hospital, China from January 2015 to June 2020 were retrospectively collected. Children were grouped into four categories according to the baseline phosphate concentration before CRRT and mean serum phosphate concentration during CRRT: <0.81 mmol/L (hypophosphatemia), 0.81-1.19 mmol/L, 1.2-2.4 mmol/L (normal phosphate concentration), and >2.4 mmol/L (hyperphosphatemia), with the normal phosphate group serving as the comparator group. The correlation of the serum phosphate concentration before and during CRRT with the 90-day mortality after CRRT initiation was analyzed using logistic regression.

Results

A total of 177 children were included in our study. The mean serum phosphate concentration before CRRT was 1.46 mmol/L (quartiles: 1.04, 2.20). The 90-day mortality rate was increased in children with a serum phosphate concentration >2.4 mmol/L before CRRT (adjusted odds ratio [aOR] 3.74, 95% confidence interval [CI] 1.42-9.86, P = 0.008). The mean serum phosphate concentration during CRRT was 1.2 mmol/L (quartiles: 0.91, 1.49). The 90-day mortality rate was increased in children with a mean serum phosphate concentration >2.4 mmol/L during CRRT (aOR 7.34, 95% CI 1.59-33.88, P = 0.011).

Conclusion

Hyperphosphatemia before and during CRRT predicts a higher 90-day mortality rate.

Management for Electrolytes Disturbances during Continuous Renal Replacement Therapy

Despite the lack of proven superiority in mortality compared to intermittent hemodialysis, continuous renal replacement therapy (CRRT) is the preferred renal replacement therapy modality for critically ill patients with acute kidney injury (AKI) due to better hemodynamic stability and steady correction of electrolytes disturbances and volume overload. Multiple and complex electrolyte disorders in patients with AKI can be managed effectively with CRRT because controlled and predictable correction is feasible. Thus, CRRT has an advantage with safety over conventional hemodialysis, especially in patients with both renal dysfunction and electrolyte disorder that require a sophisticated treatment with avoidance of rapid correction. On the contrary, CRRT can potentially lead to paradoxical disturbance of electrolytes such as hypokalemia or hypophosphatemia, especially in patients under high dose or prolonged duration of CRRT treatment. These electrolytes related complications can be prevented with close monitoring followed by the appropriate use of CRRT fluids. Although there is a lack of solid evidence and standardized guideline for CRRT prescriptions, optimal management of various electrolyte disturbances can be achieved with individualized and tailored dialysate and replacement fluid prescriptions. Several commercially available CRRT solutions with varying compositions provide flexibility to manage electrolyte disorders and maintain the stability of electrolyte. In this review, we discuss various prescription methods to manage common electrolyte imbalances as well as preventative strategies to maintain electrolyte homeostasis during CRRT providing detailed protocols used in our center. This review may contribute to future research that can lead to the development of clinical practice guidelines.

Predicting mortality in acute kidney injury patients undergoing continuous renal replacement therapy using a visualization model: A retrospective study

Background: Patients with severe acute kidney injury (AKI) require continuous renal replacement therapy (CRRT) when hemodynamically unstable. We aimed to identify prognostic factors and develop a nomogram that could predict mortality in patients with AKI undergoing CRRT. Methods: Data were extracted from the Dryad Digital Repository. We enrolled 1,002 participants and grouped them randomly into training (n = 670) and verification (n = 332) datasets based on a 2:1 proportion. Based on Cox proportional modeling of the training set, we created a web-based dynamic nomogram to estimate all-cause mortality. Results: The model incorporated phosphate, Charlson comorbidity index, body mass index, mean arterial pressure, levels of creatinine and albumin, and sequential organ failure assessment scores as independent predictive indicators. Model calibration and discrimination were satisfactory. In the training dataset, the area under the curves (AUCs) for estimating the 28-, 56-, and 84-day all-cause mortality were 0.779, 0.780, and 0.787, respectively. The model exhibited excellent calibration and discrimination in the validation dataset, with AUC values of 0.791, 0.778, and 0.806 for estimating 28-, 56-, and 84-day all-cause mortality, respectively. The calibration curves exhibited the consistency of the model between the two cohorts. To visualize the results, we created a web-based calculator. Conclusion: We created a web-based calculator for assessing fatality risk in patients with AKI receiving CRRT, which may help rationalize clinical decision-making and personalized therapy.

Endogenous markers of kidney function and renal drug clearance processes of filtration, secretion, and reabsorption

The kidneys are responsible for maintaining physiologic homeostasis. The kidneys clear a variety of drugs and other substances through passive (filtration) and active processes that utilize transport proteins. Renal clearance is comprised of the processes of glomerular filtration, tubular secretion, and tubular reabsorption. Endogenous biomarkers, such as creatinine and cystatin C, are routinely used to estimate renal clearance. Understanding the contributing components of renal function and clearance, through the use of biomarkers, is necessary in elucidating the renal pharmacology of drugs and other substances. While exogenous markers of kidney function have been known for decades, several complexities have limited their usage. Several endogenous markers are being evaluated and hold promise to elucidate the individual components of kidney function that represent filtration, secretion, and reabsorption.

Development and validation of outcome prediction models for acute kidney injury patients undergoing continuous renal replacement therapy

Object

This study aimed to develop and validate a set of practical predictive tools that reliably estimate the 28-day prognosis of acute kidney injury patients undergoing continuous renal replacement therapy.

Methods

The clinical data of acute kidney injury patients undergoing continuous renal replacement therapy were extracted from the Medical Information Mart for Intensive Care IV database with structured query language and used as the development cohort. An all-subset regression was used for the model screening. Predictive models were constructed via a logistic regression, and external validation of the models was performed using independent external data.

Results

Clinical prediction models were developed with clinical data from 1,148 patients and validated with data from 121 patients. The predictive model based on seven predictors (age, vasopressor use, red cell volume distribution width, lactate, white blood cell count, platelet count, and phosphate) exhibited good predictive performance, as indicated by a C-index of 0.812 in the development cohort, 0.811 in the internal validation cohort and 0.768 in the external validation cohort.

Conclusions

The model reliably predicted the 28-day prognosis of acute kidney injury patients undergoing continuous renal replacement therapy. The predictive items are readily available, and the web-based prognostic calculator (https://libo220284.shinyapps.io/DynNomapp/) can be used as an adjunctive tool to support the management of patients.

Electrolyte, acid-base, and medication management with renal replacement therapy

Fluid and electrolyte homeostasis exhibited by the kidneys is a complex process that is challenging to regulate with artificial renal replacement therapy (RRT). RRT has been used as a treatment modality for electrolyte and acid-base disturbances in patients with acute kidney injury and chronic kidney disease. This review highlights the management of electrolyte shifts, acid-base disturbances, and medication considerations in RRT, with a focus on intermittent hemodialysis and continuous RTT in the inpatient setting.

Hyperphosphatemia and Outcomes in Critically Ill Patients: A Systematic Review and Meta-Analysis

Introduction

Serum phosphate level is often deranged during critical illness. Hyperphosphatemia, as a marker of disease severity, attracts more and more attention. This study aimed to evaluate the impact of hyperphosphatemia on clinical outcomes in critically ill patients.

Methods

We searched for relevant studies in PubMed, EMBASE, and the Cochrane database up to Jan 10, 2022. Two authors independently screened studies, extracted data, and assessed the study quality. Meta-analyses were performed to determine hyperphosphatemia prevalence and evaluate its relationship with prognosis and important clinical outcomes. We also conducted subgroup analysis and sensitivity analyses to explore the sources of heterogeneity.

Results

Ten studies with 60,358 patients met the inclusion criteria. These studies were moderate to high quality. The median prevalence of hyperphosphatemia was 30% (range from 5.6 to 45%). Patients with hyperphosphatemia had a significantly higher risk of all-cause mortality than those without (OR 2.85; 95% CI, 2.35 to 3.38, P < 0.0001). Subgroup analyses, sensitivity analyses, and regression analyses further confirmed these results. In addition, patients with hyperphosphatemia required more CRRT (OR 4.96; 95% CI, 2.43 to 10.2, P < 0.0001) but not significantly increased duration of mechanical ventilation (mean difference, MD 0.13, 95% CI −0.04 to 0.30; P = 0.138), length of stay in intensive care unit (ICU) (SMD 0.164 day, 95% CI −0.007 to 0.335; P = 0.06), and length of stay in hospital (SMD 0.005 day, 95% CI −0.74 to 0.75; P = 0.99).

Conclusions

Our results indicated that hyperphosphatemia was associated with all-cause mortality in critically ill patients. However, due to the retrospective design of the included studies, more prospective, well-designed research is required in the future.

Systematic Review Registration

[https://doi.org/10.37766/inplasy2021.12.0130], identifier [INPLASY2021120130].

Correlations between First 72 h Hypophosphatemia, Energy Deficit, Length of Ventilation, and Mortality-A Retrospective Cohort Study

INTRODUCTION

Hypophosphatemia may prolong ventilation and induce weaning failure. Some studies have associated hypophosphatemia with increased mortality. Starting or restarting nutrition in a critically ill patient may be associated with refeeding syndrome and hypophosphatemia. The correlation between nutrition, mechanical ventilation, and hypophosphatemia has not yet been fully elucidated.

METHODS

A retrospective cohort study of 825 admissions during two consecutive years was conducted. Using the electronic medical chart, demographic and clinical data were obtained. Hypophosphatemia was defined as a phosphate level below 2.5 mg/dL (0.81 mmol/L) in the first 72 h of ICU admission. Comparisons between baseline characteristics and outcomes and multivariate analysis were performed.

RESULTS

A total of 324 (39.27%) patients had hypophosphatemia during the first 72 h of ICU admission. Patients with hypophosphatemia tended to be younger, with lower APACHE-II, SOFA24, and ΔSOFA scores. They had a longer length of stay and length of ventilation, more prevalent prolonged ventilation, and decreased mortality. Their energy deficit was lower. There was no effect of hypophosphatemia severity on these results. In multivariate analysis, hypophosphatemia was not found to be statistically significant either with respect to mortality or survivor's length of ventilation, but lower average daily energy deficit and SOFA24 were found to be statistically significant with respect to survivor's length of ventilation.

CONCLUSION

Hypophosphatemia had no effect on mortality or length of ventilation. Lower average daily energy deficit is associated with a longer survivor's length of ventilation.

Admission electrolyte and osmotic pressure levels are associated with the incidence of contrast-associated acute kidney injury

This retrospective study aimed to explore the relationships between electrolytes and osmotic pressure homeostasis with contrast-associated acute kidney injury (CA-AKI) risk in patients with percutaneous coronary intervention or coronary angiography. We totally enrolled 4386 hospitalized patients, who were categorized into five groups based on the predetermined cutoff values of electrolytes and osmotic pressure. CA-AKI was defined as an increase in serum creatine by 0.5 mg/dL (44.2 mol/L) or a 25% increase of the highest level post-operation compared to baseline. Multivariable logistic analysis was used to examine the association of CA-AKI incidence with electrolytes and osmotic pressure levels. Piecewise linear regression models and restricted cubic spline analysis were further utilized to determine the nonlinear relationship. The results showed U-shaped relationships between sodium, chloride, magnesium, and osmotic pressure levels and CA-AKI incidence. The lowest incidence was observed in the categories of 139–141.9 mmol/L, 107.0–109.9 mmol/L, 0.91–1.07 mmol/L, and 290.0–299.9 mOsm/kg, respectively. J-shaped associations were observed for potassium and phosphate levels and CA-AKI incidence, with the lowest incidence in the categories of 3.50–4.09 mmol/L and 0.96–1.28 mmol/L, respectively. A negative correlation was observed between calcium level and CA-AKI incidence, with the lowest CA-AKI risk in the category of ≥ 2.58 mmol/L. In conclusion, abnormally higher or lower sodium, chloride, magnesium, phosphate, and osmotic pressure levels on admission were associated with increased risks of CA-AKI. While for potassium and calcium, the status of hyperkalemia and hypocalcemia on admission showed more susceptibility for CA-AKI.

Albumin levels predict mortality in sepsis patients with acute kidney injury undergoing continuous renal replacement therapy: a secondary analysis based on a retrospective cohort study

BACKGROUND

Albumin (ALB) levels are negatively associated with mortality in patients with sepsis. However, among sepsis patients with acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT), there has been no similar study on the correlation between ALB levels and mortality alone. This study tested the hypothesis that ALB levels are negatively associated with mortality among such patients.

METHODS

We conducted a secondary analysis of 794 septic patients who were diagnosed with AKI and underwent CRRT in South Korea. For the Kaplan-Meier survival analysis, Cox proportional hazards models were used to study the hypotheses, with adjustments for the pertinent covariables. We also explore the possible nonlinear relationship and conducted sensitivity analyses including subgroup analyses and tests for interactions to investigate the association further. Additionally, ALB was used to construct model and we then compared the performance of ALB with that of APACHE II and SOFA in predicting mortality.

RESULTS

The ALB level was an independent prognostic factor for death at 28 and 90 days after CRRT initiation (HR = 0.75, 95% CI: 0.62-0.90, P = 0.0024 for death at 28 days and HR = 0.73, 95% CI: 0.63-0.86, P < 0.0001 for death at 90 days). A nonlinear association was not identified between ALB levels and the endpoints. Subgroup analyses and tests for interactions indicated that HCO₃ and CRP played an interactive role in the association. ROC analysis indicated ALB, SOFA and APACHE-II were separately inadequate for clinical applications.

CONCLUSION

A 1 g/dL increase in ALB levels was independently associated with a 25 and 27% decrease in the risk of death at 28 and 90 days, respectively. However, this conclusion needs to be taken with caution as this study has several limitations.

Association of Serum Phosphate Derangement With Mortality in Patients on Continuous Renal Replacement Therapy

Background:

There is limited evidence on the association of serum phosphate with mortality in patients receiving continuous renal replacement therapy (CRRT).

Objective:

To assess the association of serum phosphate with mortality in critically ill patients requiring CRRT for acute kidney injury (AKI).

Design:

A cohort study.

Setting:

A tertiary referral hospital in the United States.

Patients:

Acute kidney injury patients receiving CRRT from 2006 through 2015 in intensive care units.

Measurements:

(1) Serum phosphate before CRRT and (2) mean serum phosphate during CRRT were categorized into 3 groups; ≤2.4 (hypophosphatemia), 2.5 to 4.5 (normal serum phosphate group), and ≥4.6 (hyperphosphatemia) mg/dL.

Methods:

Multivariable logistic regression was used to assess the association between serum phosphate and 90-day mortality.

Results:

A total of 1108 patients were included in this study. Of these, 55% died within 90 days after CRRT initiation. Before CRRT, 3%, 30%, and 66% had hypophosphatemia, normophosphatemia, and hyperphosphatemia, respectively. Before CRRT, both hypophosphatemia and hyperphosphatemia were significantly associated with higher 90-day mortality with the adjusted odds ratio (OR) of 2.22 (95% confidence interval [CI]: [1.03, 4.78]) and 1.62 (95% CI: [1.21, 2.18]), respectively. During CRRT, 3%, 85%, and 12% had mean serum phosphate in hypophosphatemia, normophosphatemia, and hyperphosphatemia range. During CRRT, hyperphosphatemia was significantly associated with higher 90-day mortality with adjusted OR of 2.22 (95% CI: [1.45, 3.38]).

Limitations:

Single center, observational design, lack of information regarding causes of serum phosphate derangement.

Conclusion:

Most CRRT patients had hyperphosphatemia before CRRT initiation but maintain normal serum phosphate during CRRT. Before CRRT, hypo- and hyperphosphatemia, and during CRRT, hyperphosphatemia predicted higher mortality.

Trial registration:

Not registered.

Fibroblast Growth Factor-23-Klotho Axis in Cardiorenal Syndrome: Mediators and Potential Therapeutic Targets

Cardiorenal syndrome (CRS) is a complex disorder that refers to the category of acute or chronic kidney diseases that induce cardiovascular disease, and inversely, acute or chronic heart diseases that provoke kidney dysfunction. There is a close relationship between renal and cardiovascular disease, possibly due to the presence of common risk factors for both diseases. Thus, it is well known that renal diseases are associated with increased risk of developing cardiovascular disease, suffering cardiac events and even mortality, which is aggravated in those patients with end-stage renal disease or who are undergoing dialysis. Recent works have proposed mineral bone disorders (MBD) as the possible link between kidney dysfunction and the development of cardiovascular outcomes. Traditionally, increased serum phosphate levels have been proposed as one of the main factors responsible for cardiovascular damage in kidney patients. However, recent studies have focused on other MBD components such as the elevation of fibroblast growth factor (FGF)-23, a phosphaturic bone-derived hormone, and the decreased expression of the anti-aging factor Klotho in renal patients. It has been shown that increased FGF-23 levels induce cardiac hypertrophy and dysfunction and are associated with increased cardiovascular mortality in renal patients. Decreased Klotho expression occurs as renal function declines. Despite its expression being absent in myocardial tissue, several studies have demonstrated that this antiaging factor plays a cardioprotective role, especially under elevated FGF-23 levels. The present review aims to collect the recent knowledge about the FGF-23-Klotho axis in the connection between kidney and heart, focusing on their specific role as new therapeutic targets in CRS.

Serum Albumin Before CRRT Was Associated With the 28- and 90-Day Mortality of Critically Ill Patients With Acute Kidney Injury and Treated With Continuous Renal Replacement Therapy

Introduction: Although low serum albumin (ALB) may worsen acute kidney injury (AKI), additional study is needed to establish the connection between ALB and the prognosis of critically ill patients with AKI and treated with continuous renal replacement therapy (CRRT). Methods:A secondary analysis of a bi-center, retrospective, and observational study, such as critically ill patients with AKI and treated with CRRT from January 2009 to September 2016. The univariate analysis, multi-factor regression analysis, sensitivity analysis, and curve-fitting analysis were applied to explore the association of ALB with the 28 and 90 days mortality of critically ill patients with AKI and treated with CRRT, and the removal efficiency of serum phosphorus. Results: From January 2009 to September 2016, 1,132 cases with AKI and treated with CRRT met the inclusion criteria and enrolled in this study. We found that the higher ALB before CRRT, the lower the 28- and 90-day mortality of patients with AKI and treated with CRRT, the higher removal efficiency of serum phosphorus, the adjusted hazard ratio (HR) value for 28-day mortality in the four models were separately 0.92 (0.90, 0.95), 0.91 (0.89, 0.94), 0.92 (0.89, 0.95), and 0.92 (0.89, 0.95); the adjusted HR value for 90 day mortality in the four models were 0.91 (0.89, 0.94), 0.92 (0.89, 0.95), 0.92 (0.89, 0.95), and 0.92 (0.89, 0.96); the adjusted OR value for the removal efficiency of serum phosphorus in the four models were separately -0.04 (-0.07, -0.01), -0.05 (-0.08, -0.01), -0.04 (-0.08, -0.01), and -0.04 (-0.08, -0.01). The sensitivity analysis and curve-fitting analysis also showed that ALB before CRRT was correlated with the 28 and 90 days mortality of critically ill patients with AKI and treated with CRRT and the removal efficiency of serum phosphorus. Conclusion: The higher the serum ALB before CRRT, the lower the mortality of critically ill patients with AKI and treated with CRRT, and the higher the clearance efficiency of serum phosphorus.

Reduced serum albumin as a risk factor for poor prognosis in critically ill patients receiving renal replacement therapy

Background

Albumin is the primary body protein, which can predict the poor prognosis of several critical diseases. However, there are a few scientific studies on the relationship between albumin and the prognosis of dialysis patients. This study aims to explore the impact of hypoalbuminemia on the prognosis of critically ill patients with acute kidney injury (AKI) receiving continuous renal replacement therapy (CRRT).

Methods

This was a secondary study. Clinical, biochemical, and 28-day and 90-day mortality rates for critical patients with AKI who received CRRT between 2009 and 2016 were searched from the database to determine the effect of hypoalbuminemia on poor outcomes by univariate, multivariate, smooth curve fitting, and subgroup analysis.

Results

A total of 837 participants were enrolled in this study. Multivariate Cox proportional hazard regression analysis showed that hypoalbuminemia was associated with both 28-day and 90-day mortality risks after full adjustment for confounding variables, with an adjusted hazard ratio (95% confidence interval) of 0.63 (0.50–0.80) and 0.63 (0.51–0.78), respectively for each 1 g/dL increase of albumin. Stratified analysis showed that hypoalbuminemia was not associated with poor prognosis in oliguria.

Conclusion

Hypoalbuminemia is associated with poor prognosis in critically ill AKI patients with CRRT; therefore, measuring albumin may be helpful for predicting the prognosis. However, in those with oliguria, this conclusion is not valid.

Hyperammonemia in azotemic cats

OBJECTIVES

Hyperammonemia occurs in cats with hepatobiliary and nutritional (cobalamin and arginine deficiency) disorders, and has also been documented in four cats with renal azotemia. We hypothesized that in cats with renal azotemia, fasting hyperammonemia would correlate with indices of worsening kidney function, and would be independent of cobalamin, potassium, systemic inflammation or urinary tract infection (UTI) with urease-producing bacteria.

METHODS

A fasted blood sample was prospectively collected for ammonia and cobalamin analysis from 18 client-owned cats with renal azotemia (creatinine [Cr] ⩾1.6 mg/dl, urine specific gravity <1.030 or documentation of historical chronic kidney disease [CKD]). Correlations between blood ammonia and selected biochemical parameters were analyzed using Pearson's correlation coefficient.

RESULTS

Seven castrated males and 11 spayed females with a median age of 12 years (range 4-19 years) were enrolled. Ten of 18 (56%) cats presented for acute kidney injury (AKI) or acute on chronic kidney disease (AoCKD), and 8/18 (44%) presented for progressive CKD. The median Cr was 5.9 mg/dl (range 1.9-24.7 mg/dl). Hyperammonemia was documented in 4/18 (22%) cats, with a median of 95 µmol/dl (range 85-98 µmol/dl), and all four of these cats were classified as AKI/AoCKD. Blood ammonia concentrations had a significant moderate positive correlation between blood urea nitrogen (BUN) (r = 0.645, P = 0.003), Cr (r = 0.578, P = 0.012) and serum phosphorus (r = 0.714, P = 0.0009) but not with cobalamin, potassium or white blood cell count. No cats had UTIs with urease-producing bacteria.

CONCLUSIONS AND RELEVANCE

A correlation exists between blood ammonia and BUN, Cr and phosphorus in cats with renal azotemia. Future studies are warranted in a larger population of cats to determine the true prevalence, etiology and potential therapeutic effect of medical management of hyperammonemia on long-term prognosis in cats with kidney disease.

Effect of Phoxilium on prognostic predictors in patients undergoing continuous venovenous hemodiafiltration

Background

Phosphorus-containing dialysis solution is used to prevent hypophosphatemia in patients undergoing continuous venovenous hemodiafiltration (CVVHDF). This study evaluated the effect of phosphorus-containing dialysis solution on mortality in patients undergoing CVVHDF based on changes in phosphorus and red cell distribution width-coefficient of variation (RDW-CV) levels.

Methods

We included 272 patients with acute kidney injury (AKI) who underwent CVVHDF at the medical intensive care unit from 2017 to 2019 and classified them according to Phoxilium (Baxter Healthcare Ltd.), as a phosphorus-containing dialysis solution, use within 48 hours after CVVHDF initiation. Clinical data were collected at baseline and 48 hours after CVVHDF initiation. The primary outcome was all-cause mortality during the follow-up period.

Results

The non-Phoxilium (NP) group had higher phosphorus and lower RDW-CV levels than the Phoxilium (P) group (phosphorus, 7.3 ± 4.3 vs. 5.0 ± 2.8 mg/dL; RDW-CV, 14.6 ± 1.9 vs. 15.7 ± 2.6%; all p < 0.001). In the multivariable Cox proportional hazard regression of the NP group, an increase in phosphorus and RDW-CV at 48 hours of CVVHDF was associated with mortality (delta phosphorus: median, >0 mg/dL vs. <-2.0 mg/dL; hazard ratio [HR], 8.62; 95% confidence interval [CI], 2.10-35.32; p = 0.003/delta RDW-CV: median, >0% vs. <-0.2%; HR, 4.34; 95% CI, 1.49-13.18; p = 0.008). Meanwhile, in the P group, an increase in delta RDW-CV was associated with mortality (delta RDW-CV: >0% vs. >-0.2% and <0%; HR, 2.65; 95% CI, 1.12-6.24; p = 0.03), while an increase in delta phosphorus was not.

Conclusion

In patients with AKI undergoing CVVHDF, the risk factors for all-cause mortality differed according to the initial phosphorus levels and use of Phoxilium.

Potentiometric Phosphate Ion Sensor Based on Electrochemical Modified Tungsten Electrode

Determination of phosphate ions in aqueous solutions attracts a great deal of interest in the areas of environment, medicine, and agriculture. As phosphoric acid is a poly basic acid, the different forms of existence at different pH result in direct determination facing a big challenge. Herein, we reported a potentiometric phosphate ion sensor based on a surface-modified tungsten electrode. Pure tungsten was electrodeposited at a constant potential of 0.2 V versus Ag|AgCl in Na2HPO4. WO3 and H3O40PW12·xH2O were electrodeposited on the surface of the tungsten electrode. The modified tungsten electrode was used as a working electrode in a two-electrode system to detect the concentration of phosphate ions in aqueous solutions. The detection limit of the modified tungsten electrode for phosphate ions is 10-6 M from pH 7 to pH 8 and 10-5 M from pH 9 to pH 10. It has good selectivity to other common anions. The long-term monitoring experiment showed that the potential fluctuation was less than ±3 mV in 24 h. Compared to conventional determination methods, the current phosphate ion sensor showed a close value in a real sample. The mechanism of phosphate ion response was investigated in detail. This sensor possesses advantages of simple manufacture, low cost, a wide pH range for detecting, and good selectivity.

SOFA score is superior to APACHE-II score in predicting the prognosis of critically ill patients with acute kidney injury undergoing continuous renal replacement therapy

Background

Acute kidney injury (AKI) is the most common cause of organ failure in multiple organ dysfunction syndrome (MODS) and is associated with increased mortality. This study aimed at determining the efficacy of sequential organ failure assessment (SOFA), and acute physiology and chronic health evaluation II (APACHE-II) scoring systems in assessing the prognosis of critically ill patients with AKI undergoing continuous renal replacement therapy (CRRT). At present, APACHE-II score and SOFA score were also used to evaluate and predict the prognosis of critically ill patients with AKI.

Methods

The predictive value of SOFA and APACHE-II scores for 28- and 90-d mortality in patients with AKI undergoing CRRT were determined by multivariate analysis, sensitivity analysis, and curve-fitting analysis.

Results

A total of 836 cases were included in this study. Multivariate Cox logistic regression analysis showed that SOFA scores were associated with 28- and 90-d mortality in patients with AKI undergoing CRRT. The adjusted HR of SOFA for 28-d mortality were 1.18 (1.14, 1.21), 1.24 (1.18, 1.31), and 1.19 (1.13, 1.24) in the three models, respectively, and the adjusted HR of SOFA for 90-d mortality was 1.12 (1.09, 1.16), 1.15 (1.10, 1.19), and 1.15 (1.10, 1.19), respectively. The subgroup analysis showed that the SOFA score was associated with 28-d and 90-d mortality in patients with AKI undergoing CRRT. APACHE-II score was not associated with 28- and 90-d mortality patients with AKI undergoing CRRT. Curve fitting analysis showed that SOFA scores increased had a higher prediction accuracy for 28- and 90-d than APACHE-II.

Conclusions

The SOFA score showed a higher accuracy of mortality prediction in critically ill patients with AKI undergoing CRRT than the APACHE-II score.

Renohepatic crosstalk: a review of the effects of acute kidney injury on the liver

Several theories regarding acute kidney injury (AKI)-related mortality have been entertained, although mounting evidence supports the paradigm that impaired kidney function directly and adversely affects the function of several remote organs. The kidneys and liver are fundamental to human metabolism and detoxification, and it is therefore hardly surprising that critical illness complicated by hepatorenal dysfunction portends a poor prognosis. Several diseases can simultaneously impact the proper functioning of the liver and kidneys, although this review will address the impact of AKI on liver function. While evidence for this relationship in humans remains sparse, we present supportive studies and then discuss the most likely mechanisms by which AKI can cause liver dysfunction. These include 'traditional' complications of AKI (uremia, volume overload and acute metabolic acidosis, among others) as well as systemic inflammation, hepatic leukocyte infiltration, cytokine-mediated liver injury and hepatic oxidative stress. We conclude by addressing the therapeutic implications of these findings to clinical medicine.

The Causes of Hypo- and Hyperphosphatemia in Humans

Phosphate homeostasis involves several major organs that are the skeleton, the intestine, the kidney, and parathyroid glands. Major regulators of phosphate homeostasis are parathormone, fibroblast growth factor 23, 1,25-dihydroxyvitamin D, which respond to variations of serum phosphate levels and act to increase or decrease intestinal absorption and renal tubular reabsorption, through the modulation of expression of transcellular transporters at the intestinal and/or renal tubular level. Any acquired or genetic dysfunction in these major organs or regulators may induce hypo- or hyperphosphatemia. The causes of hypo- and hyperphosphatemia are numerous. This review develops the main causes of acquired and genetic hypo- and hyperphosphatemia.

A Nomogram to Predict the 28-day Mortality of Critically Ill Patients With Acute Kidney Injury and Treated With Continuous Renal Replacement Therapy

BACKGROUND

Acute kidney injury (AKI) is a severe and common complication in critically ill patients and is associated with increased morbidity and mortality. At present, there is not a tool to predict the prognosis of critically ill patients with AKI and treated with continuous renal replacement therapy (CRRT).

METHODS

A retrospective cohort study was to construct a prediction model for the 28-day mortality of patients with AKI and treated with CRRT. From January 2009 to September 2016, A total of 846 cases were included in our study.

RESULTS

A total of five variables selected by multi-factor Cox regression analysis were used to constructed three predictive models and adopted bootstrapping for internal validation. Finally, we get five sets of models (three sets of construction models and two sets of internal verification models) with similar predictive value. The stepwise model, which including four variables (CCI score, Alb, Phosphate (24h) and SOFA score), was the simplest model, so we chose it as our final predictive model and constructed a nomogram based on it. The area under the ROC curve (AUC) of the stepwise model and the stepwise bootstrap model (BS stepwise) were respectively 0.78(0.75,0.82) and 0.78 (0.75,0.82). The AUC of the stepwise model and the BS stepwise in patients with sepsis were 0.77 (0.73,0.81) and 0.77 (0.73,0.81). The AUC of the stepwise model and the BS stepwise in patients without sepsis were 0.83 (0.78,0.89) and 0.83 (0.78,0.89).

CONCLUSIONS

We developed a four-marker-based prognostic tool that could effectively predict each individual's 28-day mortality for patients with AKI and treated with CRRT.

Risk factors for severe acute kidney injury among patients with rhabdomyolysis

BACKGROUND

Acute kidney injury (AKI) is a life-threatening complication of rhabdomyolysis (RM). The aim of the present study was to assess patients at high risk for the occurrence of severe AKI defined as stage II or III of KDIGO classification and in-hospital mortality of AKI following RM.

METHODS

We performed a retrospective study of patients with creatine kinase levels > 1000 U/L, who were admitted to the West China Hospital of Sichuan University between January 2011 and March 2019. The sociodemographic, clinical and laboratory data of these patients were obtained from an electronic medical records database, and univariate and multivariate regression analyses were subsequently conducted.

RESULTS

For the 329 patients included in our study, the incidence of AKI was 61.4% and the proportion of stage I, stage II, stage III were 18.8, 14.9 and 66.3%, respectively. The overall mortality rate was 19.8%; furthermore, patients with AKI tended to have higher mortality rates than those without AKI (24.8% vs. 11.8%; P < 0.01). The clinical conditions most frequently associated with RM were trauma (28.3%), sepsis (14.6%), bee sting (12.8%), thoracic and abdominal surgery (11.2%) and exercise (7.0%). Furthermore, patients with RM resulting from sepsis, bee sting and acute alcoholism were more susceptible to severe AKI. The risk factors for the occurrence of stage II-III AKI among RM patients included hypertension (OR = 2.702), high levels of white blood cell count (OR = 1.054), increased triglycerides (OR = 1.260), low level of high-density lipoprotein cholesterol (OR = 0.318), elevated serum phosphorus (OR = 5.727), 5000<CK ≤ 10,000 U/L (OR = 2.617) and CK>10,000 U/L (OR = 8.093). Age ≥ 60 years (OR = 2.946), sepsis (OR = 3.206) and elevated prothrombin time (OR = 1.079) were independent risk factors for in-hospital mortality in RM patients with AKI.

CONCLUSIONS

AKI is independently associated with mortality in patients with RM, and several risk factors were found to be associated with the occurrence of severe AKI and in-hospital mortality. These findings suggest that, to improve the quality of medical care, the early prevention of AKI should focus on high-risk patients and more effective management.

Contemporary Management of Severe Acute Kidney Injury and Refractory Cardiorenal Syndrome: JACC Council Perspectives

Acute kidney injury (AKI) and cardiorenal syndrome (CRS) are increasingly prevalent in hospitalized patients with cardiovascular disease and remain associated with poor short- and long-term outcomes. There are no specific therapies to reduce mortality related to either AKI or CRS, apart from supportive care and volume status management. Acute renal replacement therapies (RRTs), including ultrafiltration, intermittent hemodialysis, and continuous RRT are used to manage complications of medically refractory AKI and CRS and may restore normal electrolyte, acid-base, and fluid balance before renal recovery. Patients who require acute RRT have a significant risk of mortality and long-term dialysis dependence, emphasizing the importance of appropriate patient selection. Despite the growing use of RRT in the cardiac intensive care unit, there are few resources for the cardiovascular specialist that integrate the epidemiology, diagnostic workup, and medical management of AKI and CRS with an overview of indications, multidisciplinary team management, and transition off of RRT.

Higher body mass index is not a protective risk factor for 28-days mortality in critically ill patients with acute kidney injury undergoing continuous renal replacement therapy

Background: Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) is a fatal and common clinical disorder in critically ill patients. Recent studies have shown that the relationship between BMI and the outcome of patients with AKI undergoing CRRT is conflicting.

Methods: A retrospective cohort study based on data reuse. Univariate analysis, multi-factor regression analysis and subgroup analyses were used to explore the association of the BMI with the 28-days mortality risk in patients with AKI undergoing CRRT.

Results: From January 2009 to September 2016, a total of 1120 cases met the inclusion criteria and were enrolled in this study. The univariate analysis showed that BMI was associated with 28-days mortality of patients with AKI undergoing CRRT, its HR value was 0.98 (0.96, 0.99). The multi-factor regression analysis showed that BMI was not associated with 28-days mortality of patients with AKI undergoing CRRT in the four models, the adjusted HR value of four models were 1.00 (0.96, 1.04), 1.01 (0.97, 1.04), 1.00 (0.96, 1.04) and 1.00 (0.96, 1.04), respectively. The subgroups analyses showed that the BMI was a risk factor of the 28-days mortality in patients with AKI undergoing CRRT when GFR ≥30 mL/min, its HR value was 1.04 (1.01, 1.09).

Conclusion: Higher BMI was not a protective risk of 28-day mortality in patients with AKI undergoing CRRT. Especially, when GFR ≥30 mL/min, higher BMI increased the risk of the 28-day mortality rate in patients with AKI undergoing CRRT.

Hyperphosphatemia and risks of acute kidney injury, end-stage renal disease, and mortality in hospitalized patients

BACKGROUND

Hyperphosphatemia is associated with vascular calcification and bone mineral disorders and is a major concern among patients with chronic kidney disease (CKD). However, the relationship between hyperphosphatemia and renal outcome in non-CKD patients has not been studied. Furthermore, the clinical implications of hyperphosphatemia in relation to the risks of acute kidney injury (AKI), end-stage renal disease (ESRD), and mortality after hospitalization remain unresolved.

METHODS

A total of 20,686 patients (aged ≥18 years) admitted to Seoul National University Bundang Hospital from January 2013 to December 2013 were retrospectively reviewed. Patients were divided into quartiles according to serum phosphorus level at the time of admission. The odds ratios (ORs) for AKI and hazard ratios (HRs) for ESRD and all-cause mortality were calculated after adjustment of multiple covariates.

RESULTS

AKI developed in 2319 patients (11.2%), with higher ORs for patients in the third and fourth quartiles (1.4 [1.24-1.68] and 2.8 [2.44-3.22], respectively) compared with the first quartile group. During a median follow-up period of 4.0 years, 183 patients (0.88%) developed ESRD and 3675 patients (17.8%) died. Patients in the fourth quartile had higher risks of ESRD and mortality than patients in the first quartile (HRs, 2.3 [1.46-3.75] and 1.4 [1.22-1.49], respectively). These trends remained consistent in patients with an estimated glomerular filtration rate > 60 ml/min/1.73 m².

CONCLUSIONS

Hyperphosphatemia is related to the risks of AKI, ESRD, and mortality, and it may therefore be necessary to monitor serum phosphorus level in hospitalized patients, irrespective of kidney function.

Short-term outcome associated with disease severity and electrolyte abnormalities among critically ill children with acute kidney injury

Background

Acute kidney injury (AKI) in critically ill children is associated with increased mortality and morbidity. In this study we evaluated the effect of AKI severity on the incidence of short-term mortality and morbidity.

Methods

Multicenter prospective cohort study was conducted over two years period. We used the Kidney Disease Improving Global Outcomes (KDIGO) to diagnose and stage AKI.

Results

A total of 511 out of 1367 included children (37.4%; 95% CI: 34.8–40.0) were diagnosed with AKI. They were categorized into three KDIGO stages: stage I (mild) in 47.5% (95% CI: 43.2–52.0), stage II (moderate) in 32.8% (95% CI: 28.8–37.1) and stage III (severe) in 19.7% (95% CI: 16.4–23.5). Stage II and III AKI had higher risk of mortality and longer length of stay (LOS) in hospital.

Children with stage III AKI were more likely to require mechanical ventilation, referral to pediatric nephrology and discharge with abnormal creatinine level (above 100 uml\L).

Hypervolemia, hypocalcemia, anemia, and acidosis were found to be independent risk factors of mortality.

Conclusion

The extent of severity of AKI is directly associated with increased mortality, LOS and short-term morbidity.

The relationship and threshold of serum phosphate with regard to the 28-day mortality risk in sepsis patients undergoing continuous renal replacement therapy

Objective

To investigate the association between serum phosphate levels and the risk of 28-day mortality in critically-ill patients with septic acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT).

Methods

This retrospective cohort study analysed data from critically-ill patients with septic AKI who underwent CRRT between January 2009 and September 2016. Demographic, clinical and routine biochemical data were retrieved from a database and analysed to identify risk factors for 28-day mortality.

Results

A total of 796 patients were included in the analyses. Multivariate regression analyses showed that phosphate (0 h), phosphate (24 h) and delta phosphate were associated with the 28-day mortality in patients with septic AKI undergoing CRRT. The adjusted odds ratios (95% confidence interval) were 1.12 (1.03, 1.22), 1.22 (1.14, 1.30) and 1.12 (1.04, 1.20) for phosphate (0 h), phosphate (24 h) and delta phosphate, respectively. Curve fitting and threshold analyses showed that when phosphate (0 h) was between 5.6 mg/dl and 8.7 mg/dl, phosphate (24 h) was >3.8 mg/dl and delta phosphate was >–1, the 28-day mortality risk increased significantly.

Conclusion

In patients with septic AKI undergoing CRRT, serum phosphate level was associated with the prognosis of patients in terms of 28-day mortality.

Renal ischemia-reperfusion injury impairs renal calcium, magnesium, and phosphate handling in mice

Fibroblast growth factor 23 (FGF23) levels are elevated in patients with acute kidney injury (AKI). The consequences on renal Ca²⁺, Mg²⁺, and P_i regulatory mechanisms are unknown. We hypothesized that renal ischemia-reperfusion (I/R) injury alters the expression of important renal Ca²⁺, Mg²⁺, and P_i transport proteins. I/R injury was induced in male C57BL/6 mice by clamping both renal arteries for 27 min. Mice were investigated 18 h later. The mRNA and protein levels of renal Ca²⁺, Mg²⁺, and P_i transport proteins were measured by RT-qPCR and western blot analysis. I/R injury-induced hyperphosphatemia and hypermagnesemia were paralleled by a decrease in glomerular filtration rate and an increase in the fractional excretion of Ca²⁺, Mg²⁺, and P_i. I/R injury affected the fibroblast growth factor 23 (FGF23)-klotho-vitamin D axis by increasing plasma levels of FGF23 and downregulation of renal klotho expression. Plasma levels of PTH and 1,25-dihydroxyvitamin D₃ were unchanged. Further, downregulation of key genes for paracellular reabsorption of Ca²⁺ and Mg²⁺ (claudin (Cldn)2, Cldn10b, Cldn16, Cldn19) and for active transcellular transport of Ca²⁺, Mg²⁺, and P_i (calbindin-D_28K, Ncx1, Pmca4, Cnnm2, Trpm7, NaP_i-2a, and NaP_i-2c) was observed. However, renal expression of Trpv5 and Trpv6 was increased. In vitro studies support a direct effect of proinflammatory cytokines on the mRNA expression of Cldn16, Cldn19, and Trpv6. Our findings indicate that renal I/R injury increases FGF23 blood levels independent of PTH and 1,25-dihydroxyvitamin D₃. This increase is associated with hypermagnesemia, hyperphosphatemia, and increased or decreased expression of specific renal Ca²⁺, Mg²⁺, and P_i transporters, respectively.

Factors Associated with Early Mortality in Critically Ill Patients Following the Initiation of Continuous Renal Replacement Therapy

Continuous renal replacement therapy (CRRT) is an important modality to support critically ill patients, and the need for CRRT treatment has been increasing. However, CRRT management is costly, and the associated resources are limited. Thus, it remains challenging to identify patients that are likely to have a poor outcome, despite active treatment with CRRT. We sought to elucidate the factors associated with early mortality after CRRT initiation. We analyzed 240 patients who initiated CRRT at an academic medical center between September 2016 and January 2018. We compared baseline characteristics between patients who died within seven days of initiating CRRT (early mortality), and those that survived more than seven days beyond the initiation of CRRT. Of the patients assessed, 130 (54.2%) died within seven days of CRRT initiation. Multivariate logistic regression models revealed that low mean arterial pressure, low arterial pH, and high Sequential Organ Failure Assessment score before CRRT initiation were significantly associated with increased early mortality in patients requiring CRRT. In conclusion, the mortality within seven days following CRRT initiation was very high in this study. We identified several factors that are associated with early mortality in patients undergoing CRRT, which may be useful in predicting early outcomes, despite active treatment with CRRT.