Hypoalbuminemia: a risk factor for acute kidney injury development and progression to chronic kidney disease in critically ill patients

Prognostic nutritional index as a predictive marker for acute kidney injury in adult critical illness population: a systematic review and diagnostic test accuracy meta-analysis

BACKGROUND

The prognostic nutritional index (PNI), integrating nutrition and inflammation markers, has been increasingly recognized as a prognostic predictor in diverse patient cohorts. Recently, its effectiveness as a predictive marker for acute kidney injury (AKI) in various clinical settings has gained attention. This study aims to assess the predictive accuracy of the PNI for AKI in critically ill populations through systematic review and meta-analysis.

METHODS

A systematic review was conducted using the databases MEDLINE, EMBASE, PubMed, and China National Knowledge Infrastructure up to August 2023. The included trials reported the PNI assessment in adult population with critical illness and its predictive capacity for AKI. Data on study characteristics, subgroup covariates, and diagnostic performance of PNI, including sensitivity, specificity, and event rates, were extracted. A diagnostic test accuracy meta-analysis was performed. Subgroup analyses and meta-regression were utilized to investigate the sources of heterogeneity. The GRADE framework evaluated the confidence in the meta-analysis's evidence.

RESULTS

The analysis encompassed 16 studies with 17 separate cohorts, totaling 21,239 patients. The pooled sensitivity and specificity of PNI for AKI prediction were 0.67 (95% CI 0.58-0.74) and 0.74 (95% CI 0.67-0.80), respectively. The pooled positive likelihood ratio was 2.49 (95% CI 1.99-3.11; low certainty), and the negative likelihood ratio was 0.46 (95% CI 0.37-0.56; low certainty). The pooled diagnostic odds ratio was 5.54 (95% CI 3.80-8.07), with an area under curve of summary receiver operating characteristics of 0.76. Subgroup analysis showed that PNI's sensitivity was higher in medical populations than in surgical populations (0.72 vs. 0.55; p < 0.05) and in studies excluding patients with chronic kidney disease (CKD) than in those including them (0.75 vs. 0.56; p < 0.01). Overall, diagnostic performance was superior in the non-chronic kidney disease group.

CONCLUSION

Our study demonstrated that PNI has practical accuracy for predicting the development of AKI in critically ill populations, with superior diagnostic performance observed in medical and non-CKD populations. However, the diagnostic efficacy of the PNI has significant heterogeneity with different cutoff value, indicating the need for further research.

High Serum Albumin Levels were Associated with Acute Kidney Injury in Pediatric Surgical Intensive Care Units

INTRODUCTION

There are limited studies revealing the association between serum albumin concentrations and acute kidney injury (AKI) in critically ill children.

METHODS

This was a multicenter retrospective study. Children consecutively admitted to four pediatric surgical intensive care units (PSICUs) between January 2016 and December 2020 were screened for analysis. Patients without recorded albumin values during the PSICU stay were excluded. Data were extracted from the electronic medical records systems of the hospitals. AKI was defined according to the Kidney Disease Improving Global Outcome (KDIGO) guidelines. The associations between serum albumin levels and AKI were assessed by using logistic regression models.

RESULTS

A total of 7802 children were included in the analysis. The median age of the children was 1.0 (interquartile range (IQR), 0.0-4.0) years. There were 3214 (41.2 %) children who developed AKI. In the univariate logistic regression model, serum albumin levels were associated with AKI (odds ratio (OR) = 1.04, 95 % confidence interval (CI) 1.04-1.05). After adjusting for covariates, serum albumin showed an independent association with AKI (OR = 1.04, 95 % CI 1.03-1.05). Albumin levels above 39.43 g/L (OR = 1.036, 95 % CI 1.002-1.070) were associated with AKI in the unadjusted cubic spline. In the adjusted cubic spline, albumin levels above 40.41 g/L (OR = 1.061, 95 % CI 1.003-1.122) were associated with AKI.

CONCLUSION

High serum albumin was associated with AKI in critically ill children in the PSICU. Further studies are needed to validate our findings.

TYPE OF STUDY

Prognostic Study.

LEVEL OF EVIDENCE

LEVEL II.

Acute Kidney Injury and Chronic Kidney Disease and Their Impacts on Prognosis among Patients with Severe COVID-19 Pneumonia: An Expert Center Case-Cohort Study

Background: Acute kidney injury (AKI) is associated with substantial mortality. In this case-control study, we analyzed the impacts of AKI and chronic kidney disease (CKD) on outcomes in a group of 323 patients with severe COVID-19. The correlation of clinical and laboratory data with AKI and CKD was also analyzed. Methods: A retrospective case-control study was conducted among AKI, CKD, and normal kidney function (NKF) groups hospitalized in a COVID-19 center in 2021. Results: AKI patients had higher in-hospital mortality (55.2 vs. 18.8%, p < 0.001), more frequent transfers from the HDU to ICU (57.5 vs. 12.9%, p < 0.001), and prolonged hospital stays (15.4 ± 10.7 vs. 10.7 ± 6.7 days, p < 0.001) compared to the NKF group. AKI was a predictor of death (OR 4.794, 95%CI: 2.906-7.906, p < 0.001). AKI patients also had broader lung parenchymal involvement and higher inflammatory markers compared to the NKF group. Patients with prior CKD had higher in-hospital mortality compared to the NKF group (64.0 vs. 18.8%, p < 0.001, OR 4.044, 95%CI: 1.723-9.490, p = 0.013); however, transfers from the HDU to ICU were not more frequent (16.0 vs. 12.9%, p = 0.753). Conclusions: AKI among COVID-19 patients was correlated with more ICU transfers, higher morbidity, and greater markers of severe disease. Patients with CKD had a higher mortality; however, the rate of ICU transfer was not substantially higher due to their poor prognosis.

Navigating Multiple Challenges: Malnutrition and Nephrotoxic Drug Effects in a Non-verbal Child With Autism Spectrum Disorder Requiring Dialysis

Acute kidney injury (AKI) is a common medication adverse event, particularly in patients with pre-existing medical conditions taking nephrotoxic medications. However, little is known about the differences in the risk of nephrotoxic medication-related complications in children with autism spectrum disorder (ASD) compared to the general pediatric population. A nine-year-old non-verbal boy with ASD was hospitalized for scrotal cellulitis requiring vancomycin and piperacillin/tazobactam due to a lack of clinical response to cephalosporins. His history is significant for being an extremely selective eater, and his appetite decreased over four months prior to presentation. Poorly controlled scrotal pain, despite acetaminophen use, was suspected based on his facial expressions and maternal assessment, especially considering his non-verbal status. Consequently, a non-steroidal anti-inflammatory drug was initiated. The hospital course was complicated by the development of a scrotal abscess, minimal enteral intake, hypoalbuminemia-induced intravascular dehydration, oliguria, and generalized edema. His creatinine increased to 5.11 mg/dL from 0.51 mg/dL despite early discontinuation of nephrotoxic medications and fluid resuscitation, which led to hemodialysis due to worsening AKI. Subsequently, urinary output and edema improved. Creatinine improved to <1 mg/dL with careful creatinine monitoring and concomitant furosemide and albumin infusion in the pediatric intensive care unit. Children with comorbidities, such as malnutrition, who require nephrotoxic medications, need extra attention. Implementing clinical decision support tools or quality improvement programs can promote the prevention of nephrotoxic medication exposure and decrease the incidence of AKI. An alert within an electronic health record system for multiple nephrotoxic drugs and daily multidisciplinary huddles during patient-centered rounds could help reduce and eliminate adverse events. In particular, for non-verbal patients or those with limited communication skills, such as children with ASD, rigorous and close monitoring of vital signs, physical condition, pain, medication intake, and lab results, in addition to a nephrotoxic medication screening and notification system, should be key to optimizing patient care.

A single-center clinical study of acute kidney injury associated with acute myocardial infarction

OBJECTIVE

To investigate the risk factors of acute kidney injury (AKI) patients with acute myocardial infarction (AMI) and establish potential microRNA (miRNA) biomarkers in the peripheral blood of AMI-AKI patients.

METHODS

Patients hospitalized from 2016 to 2020 and diagnosed with AMI (with AKI or without AKI groups) were recruited. The data of the two groups were compared and the risk factors of AMI-AKI were analyzed by logistic regression. The receiver operator characteristics (ROC) curve was drawn and the predictive value of risk factors in AMI-AKI was evaluated. Six AMI-AKI patients were selected and six healthy subjects were enrolled as the control. The peripheral blood samples of the two groups were collected for miRNA high-throughput sequencing.

RESULTS

A total of 300 AMI patients were collected, including 190 patients with AKI and 110 patients without AKI. Multivariate logistic regression analysis indicated that diastolic pressure (68-80 mmHg), urea nitrogen, creatinine, serum uric acid (SUA), aspartate aminotransferase (AST), and left ventricular ejection fraction were the dependent risk factors of AMI-AKI patients (P < 0.05). ROC curve showed that the incidence of AMI-AKI patients was most correlated with urea nitrogen, creatinine, and SUA. In addition, 60 differentially expressed miRNAs were identified between AMI-AKI and controls. Then, hsa-miR-2278, hsa-miR-1827, and hsa-miR-149-5p were more corrected with predictors. Twelve of them targeted 71 genes involved in phagosome, oxytocin signaling pathway, and microRNAs in cancer pathways.

CONCLUSION

Urea nitrogen, creatinine, and SUA were the dependent risk factors and important predictors for AMI-AKI patients. Three miRNAs may be considered as biomarkers for AMI-AKI.

Association between total bilirubin/Albumin ratio and all-cause mortality in acute kidney injury patients: A retrospective cohort study

BACKGROUND

The association between the total bilirubin/albumin (B/A) and the all-cause mortality of critically ill patients with acute kidney injury (AKI) remains unclear. This retrospective study aimed to investigate the relationship between B/A ratio and mortality in patients with AKI.

METHODS

The clinical data of AKI patients in the Medical Information Mart for Intensive Care III (MIMIC-III) database were retrospectively analyzed. Patients were divided into the low and high B/A groups (B/A ≤ 0.25 and B/A > 0.25, respectively). The primary outcome was 28-day all-cause mortality, and the secondary outcomes were 60-day, 1-year and 4-year all-cause mortality. Kaplan-Meier survival curves and Cox proportional risk models were constructed to evaluate the effect of B/A on survival outcomes.

RESULTS

The 28-day mortality rates were 18.00% and 25.10% in the low and high B/A groups, respectively (P < 0.001). The Kaplan-Meier analysis showed that patients with higher B/A values had higher all-cause mortality risk (log-rank P < 0.0001). The multivariate Cox proportional risk analysis showed that B/A was an independent risk predictor for death at 28 days, 60 days, 1 year, and 4 years.

CONCLUSION

B/A is an independent risk factor for increased mortality in patients with AKI and may be used as a predictor of clinical outcomes in AKI.

Association between red cell distribution width to albumin ratio and acute kidney injury in patients with sepsis: a MIMIC population-based study

PURPOSE

To investigate the association between red cell distribution width (RDW) to albumin (ALB) ratio and acute kidney injury (AKI) in sepsis.

METHODS

This was a retrospective cohort study. Data were collected from the Medical Information Mart for Intensive Care Database IV (MIMIC-IV) from 2008 to 2019. The incidence of AKI was the primary outcome, which was defined based on the improving Global Outcomes (KDIGO). The association of RDW/ALB ratio with AKI in sepsis was assessed by multivariate logistic regression analysis using relative risk (RR) and a 95% confidence interval (CI). Subgroup group analyses were applied according to age, use of ventilation, and use of vasopressor, SAPS II, and SOFA.

RESULTS

Of 1810 sepsis patients involved in this study, 563 (31.10%) sepsis patients developed AKI after ICU admission. The results suggested an increase in RDW/ALB was associated with a rise in the risk of AKI in sepsis (RR 1.09, 95% CI 1.02 to 1.16, P = 0.013).Based on the subgroup analysis, RDW/ALB ratio was significantly associated with the risk of AKI in sepsis patients using the treatment of ventilation (RR: 1.07, 95% CI 1.01 to 1.14, P = 0.041)) and in patients with SAPS II < 43 (RR: 1.16, 95% CI 1.04 to 1.29, P = 0.007).

CONCLUSION

RDW/ALB ratio was independently associated with the risk of AKI in sepsis patients.

Continuous and early prediction of future moderate and severe Acute Kidney Injury in critically ill patients: Development and multi-centric, multi-national external validation of a machine-learning model

BACKGROUND

Acute Kidney Injury (AKI) is a major complication in patients admitted to Intensive Care Units (ICU), causing both clinical and economic burden on the healthcare system. This study develops a novel machine-learning (ML) model to predict, with several hours in advance, the AKI episodes of stage 2 and 3 (according to KDIGO definition) acquired in ICU.

METHODS

A total of 16'760 ICU adult patients from 145 different ICU centers and 3 different countries (US, Netherland, Italy) are retrospectively enrolled for the study. Every hour the model continuously analyzes the routinely-collected clinical data to generate a new probability of developing AKI stage 2 and 3, according to KDIGO definition, during the ICU stay.

RESULTS

The predictive model obtains an auROC of 0.884 for AKI (stage 2/3 KDIGO) prediction, when evaluated on the internal test set composed by 1'749 ICU stays from US and EU centers. When externally tested on a multi-centric US dataset of 6'985 ICU stays and multi-centric Italian dataset of 1'025 ICU stays, the model achieves an auROC of 0.877 and of 0.911, respectively. In all datasets, the time between model prediction and AKI (stage 2/3 KDIGO) onset is at least of 14 hours after the first day of ICU hospitalization.

CONCLUSIONS

In this study, a novel ML model for continuous and early AKI (stage 2/3 KDIGO) prediction is successfully developed, leveraging only routinely-available data. It continuously predicts AKI episodes during ICU stay, at least 14 hours in advance when the AKI episode happens after the first 24 hours of ICU admission. Its performances are validated in an extensive, multi-national and multi-centric cohort of ICU adult patients. This ML model overcomes the main limitations of currently available predictive models. The benefits of its real-world implementation enable an early proactive clinical management and the prevention of AKI episodes in ICU patients. Furthermore, the software could be directly integrated with IT system of the ICU.

Ensemble machine learning algorithm for predicting acute kidney injury in patients admitted to the neurointensive care unit following brain surgery

Acute kidney injury (AKI) is a common postoperative complication among patients in the neurological intensive care unit (NICU), often resulting in poor prognosis and high mortality. In this retrospective cohort study, we established a model for predicting AKI following brain surgery based on an ensemble machine learning algorithm using data from 582 postoperative patients admitted to the NICU at the Dongyang People's Hospital from March 1, 2017, to January 31, 2020. Demographic, clinical, and intraoperative data were collected. Four machine learning algorithms (C5.0, support vector machine, Bayes, and XGBoost) were used to develop the ensemble algorithm. The AKI incidence in critically ill patients after brain surgery was 20.8%. Intraoperative blood pressure; postoperative oxygenation index; oxygen saturation; and creatinine, albumin, urea, and calcium levels were associated with the postoperative AKI occurrence. The area under the curve value for the ensembled model was 0.85. The accuracy, precision, specificity, recall, and balanced accuracy values were 0.81, 0.86, 0.44, 0.91, and 0.68, respectively, indicating good predictive ability. Ultimately, the models using perioperative variables exhibited good discriminatory ability for early prediction of postoperative AKI risk in patients admitted to the NICU. Thus, the ensemble machine learning algorithm may be a valuable tool for forecasting AKI.

Association and prediction of red blood cell distribution width to albumin ratio in all-cause mortality of acute kidney injury in critically ill patients

Aim

The progression of acute kidney injury (AKI) might be associated with systemic inflammation. Our study aims to explore the association and predictive value of the red blood cell distribution width (RDW) to human serum albumin (ALB) ratio (RDW/ALB ratio), an inflammation-related indicator, in the risk of all-cause mortality and renal replacement therapy (RRT) in AKI patients admitted in intensive care units (ICU).

Methods

A retrospective cohort study was designed, and data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III). The primary outcome was the risk of all-cause mortality (1-month, 3-month, and 12-month), and the secondary outcome was the risk of RRT. The association between the RDW/ALB ratio and the risk of all-cause mortality and RRT was assessed using the Cox regression analysis, with results shown as hazard ratio (HR) and 95% confidence intervals (CIs). The relationship between the RDW/ALB ratio and crude probability of all-cause mortality or RRT was assessed using restricted cubic splines (RCS). The concordance index (C-index) was used to assess the discrimination of the prediction model.

Results

A total of 13,856 patients were included in our study. In the fully adjusted Cox regression model, we found that a high RDW/ALB ratio was associated with an increased risk of 1-month, 3-month, and 12-month all-cause mortality and RRT (all p &lt; 0.05). Moreover, RCS curves showed the linear relationship between the RDW/ALB ratio and the probability of all-cause mortality and RRT, and the probability was elevated with the increase of the ratio. In addition, the RDW/ALB ratio showed a good predictive performance in the risk of 1-month all-cause mortality, 3-month all-cause mortality, 12-month all-cause mortality, and RRT, with a C-index of 0.728 (95%CI: 0.719–0.737), 0.728 (95%CI: 0.721–0.735), 0.719 (95%CI: 0.713–0.725), and 0.883 (95%CI: 0.876–0.890), respectively.

Conclusion

The RDW/ALB ratio performed well to predict the risk of all-cause mortality and RRT in critically ill patients with AKI, indicating that this combined inflammatory indicator might be effective in clinical practice.

Low albumin levels are independently associated with neonatal acute kidney injury: a report from AWAKEN Study Group

BACKGROUND

Data from adult and pediatric literature have shown an association between albumin levels and AKI. Whether hypoalbuminemia and neonatal AKI are associated has not been studied.

METHODS

We evaluated the association of albumin with early (during the first postnatal week) and late (after the first postnatal week) AKI for 531 neonates from the Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN) database and for 3 gestational age (GA) subgroups: < 29, 29 to < 36, and ≥ 36 weeks GA.

RESULTS

Low albumin levels were associated with increased odds of neonatal AKI; for every 0.1 g/dL decrease in albumin, the odds of late AKI increased by 12% on continuous analysis. After adjustment for potential confounders, neonates with albumin values in the lowest quartiles (< 2.2 g/dL) had an increased odds of early [Adjusted Odd Ratio (AdjOR) 2.5, 95% CI = 1.1-5.3, p < 0.03] and late AKI [AdjOR 13.4, 95% CI = 3.6-49.9, p < 0.0001] compared to those with albumin in the highest quartile (> 3.1 g/dL). This held true for albumin levels 2.3 to 2.6 g/dL for early [AdjOR 2.5, 95% CI = 1.2-5.5, p < 0.02] and late AKI [AdjOR 6.4, 95% CI = 1.9-21.6, p < 0.01]. Albumin quartiles of (2.7 to 3.0 g/dL) were associated with increased odds of late AKI. Albumin levels of 2.6 g/dL and 2.4 g/dL best predicted early (AUC = 0.59) and late AKI (AUC = 0.64), respectively. Analysis of albumin association with AKI by GA is described.

CONCLUSIONS

Low albumin levels are independently associated with early and late neonatal AKI. Albumin could be a potential modifiable risk factor for neonatal AKI.

Acute kidney injury secondary to urinary tract infection in kidney transplant recipients

Acute kidney injury (AKI) in kidney transplant recipients (KTRs) is a common, yet poorly investigated, complication of urinary tract infections (UTI) and urosepsis. A retrospective comparative analysis was performed, recruiting 101 KTRs with urosepsis, 100 KTRs with UTI, and 100 KTRs without history of UTI or sepsis. The incidences of AKI in the urosepsis and UTI groups were 75.2% and 41%, respectively. The urosepsis group has also presented with a significantly higher prevalence of AKI stage 2 and 3 than the UTI group. The rates of recovery from AKI stages 1, 2 and 3, were 75,6%, 55% and 26.1%, respectively. Factors independently associated with renal recovery from AKI were: AKI severity grade (AKI stage 2 with OR = 0.25 and AKI stage 3 with OR = 0.1), transfusion of red blood cells (RBC) (OR = 0.22), and the use of steroid bolus in the acute phase of treatment (OR = 4). The septic status (urosepsis vs UTI) did not influence the rates of renal recovery from AKI after adjustment for the remaining variables. The dominant cause of RBC transfusions in the whole population was upper GI-bleeding. In multivariable analyses, the occurrence of AKI was also independently associated with a greater decline of eGFR at 1-year post-discharge and with a greater risk of graft loss. In KTRs with both urosepsis and UTI, the occurrence of AKI portends poor transplantation outcomes. The local transfusion policy, modulation of immunosuppression and stress ulcer prophylaxis (which is not routinely administered in KTRs) in the acute setting may be modifiable factors that significantly impact long-term transplantation outcomes.

Association of the serum albumin level with prognosis in chronic kidney disease patients

PURPOSE

Chronic kidney disease (CKD) is an important contributor to the overall morbidity and mortality due to noncommunicable diseases. We investigated the relationship between serum albumin and the clinical prognosis in patients with stage G2-G5 CKD who were not undergoing dialysis.

METHODS

This was a post hoc analysis of 1138 patients enrolled from 2010 to 2011 in the Chronic Kidney Disease Research of Outcomes in Treatment and Epidemiology (CKD-ROUTE) study. The primary endpoints were CKD progression, cardiovascular disease (CVD) development, and all-cause mortality. Cox proportional hazards models were used.

RESULTS

During a median follow-up time of 35 months, the number of patients who experienced CKD progression, CVD development, and all-cause mortality was 278 (24.7%), 116 (10.3%), and 78 (6.9%), respectively. In multivariable-adjusted Cox proportional hazards models, the adjusted hazard ratios (HRs) for CKD progression, CVD development, and all-cause mortality in patients with the highest quartile of serum albumin concentrations compared to those with the lowest quartile of serum albumin concentrations were 0.13 (P < 0.0001), 0.29 (P = 0.0002), and 0.27 (P = 0.0009), respectively, in the model adjusted for demographic factors, hypertension, diabetes, and a history of CVD. After further adjustment for the estimated glomerular filtration rate (eGFR), urinary protein/creatinine ratio (UPCR), and systolic blood pressure (SBP), the results remained significant (HR for CKD progression 0.37, P < 0.0001; HR for CVD development 0.41, P = 0.0120; HR for all-cause mortality 0.37, P = 0.0158).

CONCLUSION

Serum albumin levels were inversely associated with the risks of CKD progression, CVD development, and all-cause mortality among patients with stage G2-G5 CKD who were not undergoing dialysis.

Acute Kidney Disease and Mortality in Acute Kidney Injury Patients with COVID-19

BACKGROUND

The incidence of AKI in coronavirus disease 2019 (COVID-19) patients is variable and has been associated with worse prognosis. A significant number of patients develop persistent kidney damage defined as Acute Kidney Disease (AKD). There is a lack of evidence on the real impact of AKD on COVID-19 patients. We aim to identify risk factors for the development of AKD and its impact on mortality in COVID-19 patients.

METHODS

Retrospective analysis of COVID-19 patients with AKI admitted at the Centro Hospitalar Universitário Lisboa Norte between March and August of 2020. The Kidney Disease Improving Global Outcomes (KDIGO) classification was used to define AKI. AKD was defined by presenting at least KDIGO Stage 1 criteria for >7 days after an AKI initiating event.

RESULTS

In 339 COVID-19 patients with AKI, 25.7% patients developed AKD (n = 87). The mean age was 71.7 ± 17.0 years, baseline SCr was 1.03 ± 0.44 mg/dL, and the majority of patients were classified as KDIGO stage 3 AKI (54.3%). The in-hospital mortality was 18.0% (n = 61). Presence of hypertension (p = 0.006), CKD (p < 0.001), lower hemoglobin (p = 0.034) and lower CRP (p = 0.004) at the hospital admission and nephrotoxin exposure (p < 0.001) were independent risk factors for the development of AKD. Older age (p = 0.003), higher serum ferritin at admission (p = 0.008) and development of AKD (p = 0.029) were independent predictors of in-hospital mortality in COVID-19-AKI patients.

CONCLUSIONS

AKD was significantly associated with in-hospital mortality in this population of COVID-19-AKI patients. Considering the significant risk of mortality in AKI patients, it is of paramount importance to identify the subset of higher risk patients.

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.

Hypoalbuminemia: a risk factor in patients with STEC-associated hemolytic uremic syndrome

BACKGROUND

We aimed to determine the prevalence of hypoalbuminemia in STEC-HUS patients with hemorrhagic colitis (HC) and whether serum albumin level (SAL), leukocyte count, hematocrit and serum sodium level (SSL) are prognostic markers of HC, central nervous system disease (CNSd) and/or dialysis requirement and evaluate if hypoalbuminemia is associated with fecal protein losses.

METHODS

We prospectively evaluated STEC-HUS patients treated at our institution from 9/2011 to 2/2019, analyzing the presence of HC, CNSd and dialysis requirement and SAL, SSL, leukocytes, hematocrit and α1-antitrypsin clearance.

RESULTS

We evaluated 98 patients, with mean age of 33.3 months. SAL ≤ 29.5 g/l, > 24,600 leukocytes/mm³ and hematocrit > 30% behave as independent prognostic markers for HC. SAL ≤ 28 g/l, > 25,200 leukocytes/mm³ and hematocrit > 30% behave as prognostic markers for CNSd. SAL ≤ 31.6 g/l, > 13,800 leukocytes/mm³, hematocrit > 18.9% and hyponatremia (≤ 132 mEq/l) behave as prognostic markers for dialysis requirement. However, in multivariate logistic regression models, only hypoalbuminemia behaved as a risk factor for HC, CNSd and dialysis. α1-antitrypsin clearance was performed in 69 patients and was high in 9/69 (13%), only 4 with HC. No significant association was observed between α1-antitrypsin clearance and albuminemia (χ² = 0.1076, p = 0.7429) as well as α1-antitrypsin clearance and HC (χ² = 1.7892, p = 0.1810).

CONCLUSIONS

Almost all patients with HC had hypoalbuminemia, which behaves as a risk factor for HC, CNSd and dialysis requirement. No significant association was observed between elevated α1-antitrypsin clearance and hypoalbuminemia nor between elevated α1-antitrypsin clearance and HC. These findings could be related to the small number of evaluated patients.

Uric acid albumin ratio as a predictive marker of short-term mortality in patients with acute kidney injury

OBJECTIVE

We aimed to investigate uric acid and albumin ratio (UA/A) as a marker of short-term mortality in acute kidney injury (AKI). Both uric acid and albumin are strongly correlated with the development and mortality of AKI.

METHODS

The patients hospitalized from May 2019 to September 2019 for AKI were included in this study. The diagnostic odds ratio (DOR), Youden index (J), and the area under a receiver operating characteristic curve (AUROC) determined a cut-off UA/A ratio for mortality. Cox-regression analysis was performed to identify UA/A as a prognostic marker of the 30-day mortality rate.

RESULTS

A total of 171 patients with an average age of 69.20±13.0 (45.6% women) were included in the study. The average UA/A ratio was 3.3±1.5 mg/g and 2.5±1.0 mg/g in the non-survivor and survivor groups, respectively (P=0.001). The best cut-off UA/A ratio associated with mortality was determined as 2.4 mg/g with a specificity of 52% and a sensitivity of 77% (DOR, 3.6; J, 28.8; AUROC, 0.644). Thirty-day cumulative survival rates of the low and high UA/A ratio groups were 85.9±4.0% and 63.7±5.0%, respectively. The estimated survival times of the low and high UA/A ratio groups were 27.7 days (95% confidence interval [CI], 26.2-29.3) and 23.9 days (95% Cl, 22.0-25.9), respectively.

CONCLUSION

We found a direct correlation between 30-day mortality and UA/A ratio at initial presentation in AKI patients regardless of age, comorbidities, and clinical and laboratory findings, including albuminuria.

Predictive Value of Hypoalbuminemia for Contrast-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis

Contrast-associated acute kidney injury (CA-AKI) is a major adverse complication of intravascular administration of contrast medium. Current studies have shown that hypoalbuminemia might be a novel risk factor of CA-AKI. This systematic review and meta-analysis was performed to evaluate the predictive value of hypoalbuminemia for CA-AKI. Relevant studies were identified in Ovid-Medline, PubMed, Embase, and Cochrane Library up to December 31, 2019. Two authors independently screened studies, consulting with a third author when necessary to resolve discrepancies. The pooled odds ratio (OR) was calculated to assess the association between hypoalbuminemia and CA-AKI using a random-effects model or fixed-effects model. Eight relevant studies involving a total of 18 687 patients met our inclusion criteria. The presence of hypoalbuminemia was associated with an increased risk of CA-AKI development (pooled OR: 2.59, 95% CI: 1.80-3.73). Hypoalbuminemia is independently associated with the occurrence of CA-AKI and may be a potentially modifiable factor for clinical intervention. This systematic review and meta-analysis was registered in PROSPERO (CRD42020168104).

Hydrogen Sulfide and Carnosine: Modulation of Oxidative Stress and Inflammation in Kidney and Brain Axis

Emerging evidence indicates that the dysregulation of cellular redox homeostasis and chronic inflammatory processes are implicated in the pathogenesis of kidney and brain disorders. In this light, endogenous dipeptide carnosine (β-alanyl-L-histidine) and hydrogen sulfide (H₂S) exert cytoprotective actions through the modulation of redox-dependent resilience pathways during oxidative stress and inflammation. Several recent studies have elucidated a functional crosstalk occurring between kidney and the brain. The pathophysiological link of this crosstalk is represented by oxidative stress and inflammatory processes which contribute to the high prevalence of neuropsychiatric disorders, cognitive impairment, and dementia during the natural history of chronic kidney disease. Herein, we provide an overview of the main pathophysiological mechanisms related to high levels of pro-inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and neurotoxins, which play a critical role in the kidney–brain crosstalk. The present paper also explores the respective role of H₂S and carnosine in the modulation of oxidative stress and inflammation in the kidney–brain axis. It suggests that these activities are likely mediated, at least in part, via hormetic processes, involving Nrf2 (Nuclear factor-like 2), Hsp 70 (heat shock protein 70), SIRT-1 (Sirtuin-1), Trx (Thioredoxin), and the glutathione system. Metabolic interactions at the kidney and brain axis level operate in controlling and reducing oxidant-induced inflammatory damage and therefore, can be a promising potential therapeutic target to reduce the severity of renal and brain injuries in humans.

Association of diabetes, education level, and care dependency with use of temporary vascular access in patients with chronic kidney disease

OBJECTIVE

Temporary vascular access (TVA) is frequently used during the first dialysis in patients with chronic kidney disease (CKD), and it is associated with an increased risk of infection, central vein stenosis, and mortality. Here, factors associated with TVA in patients with CKD were explored.

METHODS

This study included patients in a single-center CKD care program who initiated long-term renal replacement therapy. The primary outcome was TVA use at first dialysis. Factors possibly associated with TVA use were analyzed using Cox regression.

RESULTS

Temporary vascular access was used in 53.2% of the patients at first dialysis. In total, 73.2% (n = 865) and 26.8% (n = 317) of the patients were on hemodialysis and peritoneal dialysis, respectively. Multivariate Cox regression analysis showed that TVA use in patients with CKD was associated with diabetes (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.28-1.81, p < 0.001), lower albumin (HR 0.82, 95% CI 0.75-0.91, p < 0.001), lower education level (HR 0.75, 95% CI 0.56-1.00, p = 0.055), and total care dependency (HR 1.92, CI 1.44-3.43, p = 0.003).

CONCLUSION

Diabetes, education level, and care dependency are associated with TVA at dialysis initiation in patients with CKD.

Association Between Albumin Level and Mortality Among Cardiac Intensive Care Unit Patients

PURPOSE

To study the effect of hypoalbuminemia on short- and long-term mortality in Cardiac Intensive Care Unit (CICU) patients.

METHODS

We reviewed 12,418 unique CICU patients from 2007 to 2018. Hypoalbuminemia was defined as an admission albumin level <3.5 g/dL. Predictors of hospital mortality were identified using multivariable logistic regression.

RESULTS

We included 2,680 patients (22%) with a measured admission albumin level. The median age was 68 (39% females). Admission diagnoses included acute coronary syndrome, heart failure, cardiac arrest, and cardiogenic shock. The median albumin level was 3.4 g/dL and 55% of patients had hypoalbuminemia. Hospital mortality occurred in 16%, and patients with hypoalbuminemia had higher hospital mortality (21% vs. 9%, adjusted OR 2.64, 95% CI 2.09-3.34, p < 0.001). Albumin level was inversely associated with hospital mortality (adjusted OR 0.60 per 1 g/dL higher albumin level, 95% CI 0.47-0.75, p <0.001), with a stepwise increase in the hospital mortality at lower albumin levels. Post-discharge mortality was higher in hospital survivors with hypoalbuminemia, and increased as a function of lower albumin levels.

CONCLUSION

Hypoalbuminemia is common in CICU patients and associated with higher short- and long-term mortality. Progressively lower serum albumin was incrementally associated with higher hospital and post-discharge mortality.

Hypoalbuminemia and Obesity in Orthopaedic Trauma Patients: Body Mass Index a Significant Predictor of Surgical Site Complications

The purpose of this investigation was to identify the prevalence of hypoalbuminemia and obesity in orthopaedic trauma patients with high-energy injuries and to investigate their impact on the incidence of surgical site complications. Patients 18 years of age and older undergoing intramedullary nail fixation of their femoral shaft fractures at a university-based level-1 trauma centre were assessed. Malnutrition was measured using serum markers (albumin <3.5 g/dL) as well as body mass index (BMI) as a marker of obesity (BMI > 30 kg/m²). The primary outcome measure was surgical wound complications. A total of 249 patients were included in this study. Ninety-eight patients (39.4%) presented with hypoalbuminaemia and 80 patients (32.1%) were obese. The overall incidence of wound complications in our study population was 9.65% (n = 25/259). A logistic regression model showed that non-obese patients (BMI < 30 kg/m²) were at significantly reduced risk for perioperative wound complications (Odds Ratio 0.400 [95% confidence interval 0.168, 0.954], p = 0.039). This study demonstrated a substantial prevalence of hypoalbuminemia and obesity among orthopaedic trauma patients with high-energy injuries. Obesity may increase the risk of surgical site complications. Future studies are required to further define malnutrition and its correlation with surgical site complications in orthopaedic trauma patients.

Can Serum Nutritional Related Biomarkers Predict Mortality Of Critically Ill Older Patients With Acute Kidney Injury?

Background

Critically ill older patients with acute kidney injury (AKI), also referred to as acute renal failure, are associated with high in-hospital mortalities. Preexisting malnutrition is highly prevalent among AKI patients and increases in-hospital mortality rate. This study is to evaluate the predictive power of some serum nutritional related biomarkers predicting the 90 days in-hospital mortality of critically ill older patients with AKI.

Methods

A prospective, observational study was conducted in a university teaching hospital. One hundred and five critically ill older patients with AKI aged 60-95 were enrolled and were divided into survival group (n=44) and non-survival group (n=61) in the light of their final outcomes. Receiver operating characteristic analyses (ROC) were performed to calculate the area under ROC curve (AUC). Sensitivity and specificity of in-hospital mortality prediction were calculated.

Results

Significant differences were found between the survival group and non-survival group of critically ill older patients with AKI. AUC of low density lipoprotein (LDL) and albumin were 0.686 and 0.595, respectively. The asymptotic 95% confidence intervals of LDL and albumin were 0.524-0.820 and 0.488-0.696, respectively. Sensitivity of the 90 days in-hospital mortality prediction of LDL and albumin were 68.71% and 69.09%, respectively. Specificity of 90 days in-hospital mortality prediction of LDL and albumin were 69.23% and 50.0%, respectively.

Conclusion

LDL and albumin did not have sufficient power to predict the 90 days in-hospital mortality of critically ill older patients with AKI. Further research on the association between malnutrition and poor prognosis of critically ill older patients with AKI is needed in the future.Trial registration: ClinicalTrials.gov identifier: NCT00953992.

Acute kidney injury in hospitalized patients who underwent percutaneous kidney biopsy for histological diagnosis of their renal disease

BACKGROUND

Performing a kidney biopsy is necessary to accurately diagnose diseases such as glomerulonephritis and tubulointerstitial nephritis, among other such conditions. These conditions predispose patients to chronic kidney disease, as well as acute kidney injury (AKI). Notably, most epidemiological studies describing AKI have not investigated this patient population.

METHODS

Included patients admitted to the nephrology ward of a tertiary hospital who underwent percutaneous kidney biopsy. AKI was diagnosed based on the Kidney Disease: Improving Global Outcomes criteria.

RESULTS

Of the 223 patients investigated, 140 (62.8%) showed AKI. Of these, 91 (65%), 19 (13.6%), and 30 (21.4%) presented with AKI classified as stages 1, 2, and 3, respectively. The primary indication for performing biopsy was nephrotic syndrome or nephrotic proteinuria (73 [52.1%] in the AKI vs. 51 [61.4%] in the non-AKI group, p = 0.048). Focal segmental glomerulosclerosis was the most prevalent primary disease (24 [17.1%] in the AKI vs. 15 [18.0%] in the non-AKI group, p = 0.150). Multivariate analysis of risk factors associated with AKI showed hemoglobin levels (odds ratio [OR] 0.805, 95% confidence interval [CI] 0.681-0.951, p = 0.011), serum high-density lipoprotein cholesterol levels (HDL-c, OR 0.970, 95% CI 0.949-0.992, p = 0.008), and baseline serum creatinine levels (OR 2.703, 95% CI 1.471-4.968, p = 0.001) were significantly associated with AKI.

CONCLUSIONS

We observed a high prevalence of AKI in hospitalized patients who underwent kidney biopsy to investigate their renal disease, particularly glomerulonephritis. Higher levels of hemoglobin and serum HDL-c were associated with a lower risk of AKI.

Mild to moderate proteinuria is a heralding sign for acute kidney injury and mortality for intensive care unit patients

Background/aim

Lack of early predictors of acute kidney injury is currently delaying timely diagnosis.This study was done to evaluate the relationship between mild to moderate proteinuria and incidence of acute kidney injury (AKI) and 28-day mortality in intensive care unit (ICU) patients.

Materials and methods

This observational, retrospective study was conducted in the internal medicine ICU. A total of 796 patients were screened and 525 patients were used for this analysis. Proteinuria was measured by urine dipstick test. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines.

Results

Patients with dipstick urine protein positivity on admission had higher proportion of AKI and 28-day mortality compared to dipstick urine protein negative group [164 (59.6%) vs. 111 (44.4%) and 101 (36.7%) vs. 54 (21.6%), P = 0.01 and P < 0.01, respectively]. Urine dipstick protein positivity was also a significant predictor of 28-day mortality in patients with GFR > 60 mL/min (hazard ratio: 1.988, 95% confidence interval 1.380–2.862).

Conclusion

Proteinuria before ICU admission is a risk factor for development of AKI within seven days of ICU stay and also is a risk factor for 28-day mortality, even in patients with GFR > 60 mL/min.

Early post-operative serum albumin level predicts survival after curative nephrectomy for kidney cancer: a retrospective study

BACKGROUND

Previous studies have shown that albumin-related systemic inflammation is associated with the long-term prognosis of cancer, but the clinical significance of an early (≤ 7 days) post-operative serum albumin level has not been well-documented as a prognostic factor in patients with renal cell cancer.

METHODS

We retrospectively included patients hospitalized for kidney cancer from January 2009 to May 2014. First, the receiver operating characteristic analysis was used to define the best cut-off of an early post-operative serum albumin level in determining the prognosis, from which survival analysis was performed.

RESULTS

A total of 329 patients were included. The median duration of follow-up was 54.8 months. Patients with an early post-operative serum albumin level < 32 g/L had a significantly shorter median recurrence-free survival (RFS; 49.1 versus 56.5 months, P = 0.001) and median overall survival (OS; 52.2 versus 57.0 months, P = 0.049) than patients with an early post-operative serum albumin level ≥ 32 g/L. After adjusting for age, BMI, tumor stage, post-operative hemoglobin concentration, and pre-operative albumin, globulin, and hemoglobin levels, multivariate Cox regression showed that an early post-operative serum albumin level < 32 g/L was an independent prognostic factor associated with a decreased RFS (HR = 3.60; 95% CI,1.05-12.42 [months], P = 0.042) and decreased OS (HR = 9.95; 95% CI, 1.81-54.80 [months], P = 0.008).

CONCLUSION

An early post-operative serum albumin level < 32 g/L is an independent prognostic factor leading to an unfavorable RFS and OS. Prospective trials and further studies involving additional patients are warranted.

Single Graft Utilization From Donors With Severe Acute Kidney Injury After Circulatory Death

Chronic shortages of organs for transplantation have led to the use of marginal kidneys from donors after circulatory death with acute kidney injury (AKI), but the utilization of kidneys with severe AKI is not well established. We retrospectively analyzed eight kidney transplantation (KTx) cases from donation after circulatory death (DCD) with terminal creatinine (t-Cr) concentrations higher than 10.0 mg/dL and/or oliguria for more than 5 days (AKI network criteria: stage III). Although all patients showed delayed graft function, no cases of primary nonfunction (PNF) were found. Five patients maintained stable renal function for approximately 15.5, 10, 10, 5, and 0.5 years after KTx. Only 1 patient showed biopsy-proven acute rejection. Also, 2 patients developed graft failure: one attributable to chronic antibody mediated rejection at 11.3 years after KTx, and one attributable to recurrence of IgA nephropathy at 4.6 years after KTx. Kidneys with AKI stage III yielded great outcomes without the risk of primary nonfunction and rejection. Although the AKI kidneys were associated with delayed graft function, these results suggest that even the most severe kidneys with AKI stage III from DCD donors can be considered a valid alternative for recipients on a waiting list for KTx.

Long-term clinical impact of serum albumin in coronary artery disease patients with preserved renal function

BACKGROUND AND AIMS

Low serum albumin level is reportedly associated with worse clinical outcomes in patients with chronic kidney disease (CKD). However, associations between decreased serum albumin level and outcomes in non-CKD patients with coronary artery disease (CAD) remain unclear. Therefore, we aimed to evaluate the prognostic value of serum albumin concentrations in stable CAD patients with preserved renal function.

METHODS AND RESULTS

We studied 1316 patients with CAD and preserved renal function (estimated glomerular filtration rate ≥60 mL/min/1.73 m²) who underwent their first PCI between 2000 and 2011 and had data available for pre-procedural serum albumin. Patients were assigned to quartiles based on pre-procedural albumin concentrations. The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated. Mean albumin concentration was 4.1 ± 0.4 g/dL. During the median follow-up of 7.5 years, 181 events occurred (13.8%). Kaplan-Meier curves revealed that patients with decreased serum albumin concentrations showed a higher event rate for MACE (log-rank, p < 0.0001). Using the highest tertiles (>4.3 g/dL) as reference, adjusted hazard ratios were 1.97 (95% CI, 1.12-3.55), 1.77 (95% CI, 0.99-3.25), and 1.19 (95% CI, 0.68-2.15) for serum albumin concentrations of <3.9, 3.9-4.0, and 4.1-4.3 g/dL, respectively. Decreased serum albumin concentration was associated with MACE even after adjusting for other independent variables (HR, 2.21 per 1-g/dL decrease; 95% CI, 1.37-3.56, p = 0.001).

CONCLUSION

Decreased serum albumin concentration independently predicted worse long-term prognosis in non-CKD patients after PCI. Pre-procedural serum albumin concentration could offer a useful predictor for patients with CAD and preserved renal function.

Low caloric and protein intake is associated with mortality in patients with acute kidney injury

BACKGROUND

Acute renal injury (AKI) interferes greatly with nutritional status, affecting the metabolism of all macronutrients and increased mortality rates in hospitalized patients. Our objective was to evaluate the association of nutritional parameters (albumin, cholesterol, caloric and protein intake and nitrogen balance (NB)) with mortality in patients with AKI.

METHODS

This is a prospective observational study that evaluated 595 consecutive patients over the age of 18 years with AKI, requiring enteral or parenteral feeding. At the time of the patient's enrollment, demographic and laboratorial data, caloric and protein supply and NB were recorded on the first day of referral to the nephrologist. All patients were followed throughout the hospital stay and mortality rate was also recorded.

RESULTS

The medium age of patients with AKI was 64 (54-75) years, 64.5% male, 62% admitted to intensive care unit (ICU), 52% on dialysis and the majority (48%) were at stage 3 by AKIN. Length of stay and hospital mortality were 18 (10-31) days and 46%, respectively. Superior age, AKI severity, lower body weight and body mass index (BMI), higher need for dialysis, ICU admission and shorter hospital stay were associated with higher mortality. At logistic regression, caloric (OR: 0.946; CI:95%: 0.901-0.994; p:0.029) and protein intake (OR: 0.947; CI:95%: 0.988-0.992; p = 0.028) and serum albumin (OR: 0.545; CI:95%: 0.401-0741; p < 0.001) were associated with hospital mortality. Cholesterol (OR: 0.995; CI:95%: 0.991-1.000; p = 0.052) was not associated with increased mortality in the adjusted analysis. Analysis of the receiver operating characteristic (ROC) curve showed that calorie intake < 12 kcal/kg (AUC: 0.745; CI:95%: 0.684-0.765; p < 0.001) and protein intake < 0.5 g/kg (AUC: 0.726; CI:95%: 0.686-0.767; p < 0.001) were predictors of hospital mortality, as well as a negative NB < -6.47 g N/day (AUC: 0.745; CI:95%: 0.704-0.786; p < 0.001).

CONCLUSIONS

In conclusion, low caloric and protein intake, negative NB and low albumin value are conditions associated with higher hospital mortality in patients with AKI.