Acute Kidney Injury in the Elderly

Predictive models of sepsis-associated acute kidney injury based on machine learning: a scoping review

BACKGROUND

With the development of artificial intelligence, the application of machine learning to develop predictive models for sepsis-associated acute kidney injury has made potential breakthroughs in early identification, grading, diagnosis, and prognosis determination.

METHODS

Here, we conducted a systematic search of the PubMed, Cochrane Library, Embase (Ovid), Web of Science, and Scopus databases on April 28, 2023, and screened relevant literature. Then, we comprehensively extracted relevant data related to machine learning algorithms, predictors, and predicted objectives. We subsequently performed a critical evaluation of research quality, data aggregation, and analyses.

RESULTS

We screened 25 studies on predictive models for sepsis-associated acute kidney injury from a total of originally identified 2898 studies. The most commonly used machine learning algorithm is traditional logistic regression, followed by eXtreme gradient boosting. We categorized these predictive models into early identification models (60%), prognostic prediction models (32%), and subtype identification models (8%) according to their predictive purpose. The five most commonly used predictors were serum creatinine levels, lactate levels, age, blood urea nitrogen concentration, and diabetes mellitus. In addition, a single data source, insufficient assessment of clinical utility, lack of model bias assessment, and hyperparameter adjustment may be the main reasons for the low quality of the current research.

CONCLUSIONS

However, studies on the nondeath prognostic outcomes, the long-term clinical outcomes, and the subtype identification models are insufficient. Additionally, the poor quality of the research and the insufficient practicality of the model are problems that need to be addressed urgently.

Development and validation of a model for predicting in-hospital mortality in patients with sepsis-associated kidney injury receiving renal replacement therapy: a retrospective cohort study based on the MIMIC-IV database

Background

SAKI is a common and serious complication of sepsis, contributing significantly to high morbidity and mortality, especially in patients requiring RRT. Early identification of high-risk patients enables timely interventions and improvement in clinical outcomes. The objective of this study was to develop and validate a predictive model for in-hospital mortality in patients with SAKI receiving RRT.

Methods

Patients with SAKI receiving RRT from the MIMIC-IV database were retrospectively enrolled and randomly assigned to either the training cohort or the testing cohort in a 7:3 ratio. LASSO regression and Boruta algorithm were utilized for feature selection. Subsequently, three machine learning models-CART, SVM and LR-were constructed, and their predictive efficacy was assessed using a comprehensive set of performance indicators. Feature importance analysis was performed to determine the contribution of each feature to a model's predictions. Finally, DCA was employed to evaluate the clinical utility of the prediction models. Additionally, a clinical nomogram was developed to facilitate the interpretation and visualization of the LR model.

Results

A total of 1663 adults were ultimately enrolled and randomly allocated into the training cohort (n = 1164) or the testing cohort (n = 499). Twenty-eight variables were evaluated for feature selection, with eight ultimately retained in the final model: age, MAP, RR, lactate, Cr, PT-INR, TBIL and CVP. The LR model demonstrated commendable performance, exhibiting robust discrimination in both the training cohort (AUROC: 0.73 (95% CI 0.70-0.76); AUPRC: 0.75 (95% CI 0.72-0.79); accuracy: 0.66 (95% CI 0.63-0.68)) and the testing cohort (AUROC: 0.72 (95% CI 0.68-0.76); AUPRC: 0.73 (95% CI 0.67-0.79); accuracy: 0.65 (95% CI 0.61-0.69)). Furthermore, there was good concordance between predicted and observed values in both the training cohort (χ2 = 4.41, p = 0.82) and the testing cohort (χ2 = 4.16, p = 0.84). The results of the DCA revealed that the LR model provided a greater net benefit compared to other prediction models.

Conclusions

The LR model exhibited superior performance in predicting in-hospital mortality in patients with SAKI receiving RRT, suggesting its potential utility in identifying high-risk patients and guiding clinical decision-making.

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.

Acute Kidney Injury and Subsequent Kidney Failure With Replacement Therapy Incidence in Older Adults With Advanced CKD: A Cohort Study of US Veterans

Rationale & Objective

Advanced age is a major risk factor for chronic kidney disease (CKD) development, which has high heterogeneity in disease progression. Acute kidney injury (AKI) hospitalization rates are increasing, especially among older adults. Previous AKI epidemiologic analyses have focused on hospitalized populations, which may bias results toward sicker populations. This study examined the association between AKI and incident kidney failure with replacement therapy (KFRT) while evaluating age as an effect modifier of this relationship.

Study Design

Retrospective cohort study.

Setting & Participants

24,133 Veterans at least 65 years old with incident CKD stage 4 from 2011 to 2013.

Exposures

AKI, AKI severity, and age.

Outcomes

KFRT and death.

Analytical Approach

The Fine-Gray competing risk regression was used to model AKI and incident KFRT with death as a competing risk. A Cox regression was used to model AKI severity and death.

Results

Despite a nonsignificant age interaction between AKI and KFRT, a clinically relevant combined effect of AKI and age on incident KFRT was observed. Compared with our oldest age group without AKI, those aged 65-74 years with AKI had the highest risk of KFRT (subdistribution HR [sHR], 14.9; 95% CI, 12.7-17.4), whereas those at least 85 years old with AKI had the lowest (sHR, 1.71; 95% CI, 1.22-2.39). Once Veterans underwent KFRT, their risk of death increased by 44%. A 2-fold increased risk of KFRT was observed across all AKI severity stages. However, the risk of death increased with worsening AKI severity.

Limitations

Our study lacked generalizability, was restricted to ever use of medications, and used inpatient serum creatinine laboratory results to define AKI and AKI severity.

Conclusions

In this national cohort, advanced age was protective against incident KFRT but not death. This is likely explained by the high frequency of deaths observed in this population (51.1%). Nonetheless, AKI and younger age are substantial risk factors for incident KFRT.

Development and validation of a nomogram for predicting in-hospital mortality of elderly patients with persistent sepsis-associated acute kidney injury in intensive care units: a retrospective cohort study using the MIMIC-IV database

OBJECTIVES

To identify the clinical risk factors that influence in-hospital mortality in elderly patients with persistent sepsis-associated acute kidney injury (S-AKI) and to establish and validate a nomogram to predict in-hospital mortality.

DESIGN

Retrospective cohort analysis.

SETTING

Data from critically ill patients at a US centre between 2008 and 2021 were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database (V.1.0).

PARTICIPANTS

Data from 1519 patients with persistent S-AKI were extracted from the MIMIC-IV database.

PRIMARY OUTCOME

All-cause in-hospital death from persistent S-AKI.

RESULTS

Multiple logistic regression revealed that gender (OR 0.63, 95% CI 0.45-0.88), cancer (2.5, 1.69-3.71), respiratory rate (1.06, 1.01-1.12), AKI stage (2.01, 1.24-3.24), blood urea nitrogen (1.01, 1.01-1.02), Glasgow Coma Scale score (0.75, 0.70-0.81), mechanical ventilation (1.57, 1.01-2.46) and continuous renal replacement therapy within 48 hours (9.97, 3.39-33.9) were independent risk factors for mortality from persistent S-AKI. The consistency indices of the prediction and the validation cohorts were 0.780 (95% CI: 0.75-0.82) and 0.80 (95% CI: 0.75-0.85), respectively. The model's calibration plot suggested excellent consistency between the predicted and actual probabilities.

CONCLUSIONS

This study's prediction model demonstrated good discrimination and calibration abilities to predict in-hospital mortality of elderly patients with persistent S-AKI, although it warrants further external validation to verify its accuracy and applicability.

Association of serum N-terminal pro-brain natriuretic peptide levels with survival and renal outcomes among elderly patients with acute kidney injury in chronic heart failure

Background

Elderly patients exhibit a higher incidence of chronic heart failure (CHF). Patients with CHF can develop acute kidney injury (AKI) during follow-up, which can result in poor prognosis. This relationship between kidney dysfunction and levels of N-terminal pro-brain natriuretic peptides (NT-proBNP), with regard to prognosis, is complicated and has rarely been analyzed in elderly patients with CHF.

Method

We conducted a retrospective cohort study involving patients with a CHF history aged ≥ 65 years, who experienced an episode of AKI. Kaplan-Meier curves and Cox or logistic proportional hazards regression models were used to evaluate the association between serum NT-proBNP concentrations and mortality or renal recovery by day 90.

Results

A total of 1,160 eligible patients with AKI were available for the study. Of this sample, 41.5% of patients died within 90 days of the onset of AKI. Patients with a decreased change in NT-proBNP accompanying the episode of AKI had a lower risk (adjusted OR = 0.56, 95% CI = 0.34-0.91) of more severe AKI (stage 2 and 3 vs. stage 1). The more severe AKI were associated with higher mortality and non-recovery of renal function in elderly patients with CHF, independent of NT-proBNP levels. Elevated levels of baseline lnNT-proBNP (adjusted HR = 1.27, 95% CI = 1.17-1.38) predicted mortality in elderly patients with CHF within 90 days of AKI onset. Patients with a decrease in NT-proBNP accompanying AKI had a lower risk of mortality (adjusted HR = 0.62, 95% CI = 0.48-0.79). However, a decrease in NT-proBNP is a risk factor (adjusted OR = 1.59, 95% CI = 1.02-2.48) for the non-recovery of renal function following AKI-especially in elderly survivors with low baseline NT-proBNP levels.

Conclusion

A decreased change in NT-proBNP maybe protective for elderly patients with CHF by improving survival outcomes and preventing severe AKI. However, an excessive decrease in NT-proBNP is a risk factor for the non-recovery of renal function following AKI. Avoiding excessive changes in NT-proBNP may be protective for survival and renal injury prognosis.

Risk factors for and characteristics of community‐ and hospital‐acquired drug‐induced acute kidney injuries

Drugs constitute one of the leading causes of acute kidney injuries (AKIs) and can appear in community (CA‐AKI) or hospital (HA‐AKI) population. The objectives of the present study of a cohort of hospitalized patients with AKI were to describe the characteristics of drug‐induced AKIs and the patients' short‐term outcomes and assess risk factors for drug‐induced AKIs overall, CA‐AKIs, and HA‐AKIs. Based on a cohort of 1557 hospitalized patients suffering from AKIs based on PMSI extraction and chart review (IRA‐PMSI), drug‐induced AKIs were identified by applying the Naranjo adverse drug reaction (ADR) probability scale. Multivariate logistic regression was used to identify factors associated with CA‐AKIs and/or HA‐AKIs. When considering the 1557 patients who experienced an AKI, 445 (28.6%) of the injuries were drug‐induced (180 CA‐AKIs (40.4%) and 265 HA‐AKIs (59.6%)). Antibiotics, diuretics, and contrast agents were significantly more likely to be involved in HA‐AKIs, whereas antineoplastic, lipid‐lowering drugs, antidiabetics, and immunosuppressive were significantly more likely to be involved in CA‐AKIs. Female sex (odds ratio [OR] [95%CI] = 1.3 [1.04–1.67]), chronic kidney disease (CKD) (OR = 1.8 [1.40–2.67]), and a history of ADRs of any type (OR = 1.3 [1.05–1.73]) were significant risk factors for drug‐induced AKIs. CKD was a risk factor for both CA‐AKI and HA‐AKI. In view of the long‐term impact of AKI on the kidneys and the differences between our CA‐AKI and HA‐AKI subgroups, our present results are interesting for optimizing treatments, limiting the occurrence of CA‐ and HA‐AKIs and (ultimately) reducing healthcare costs.

The incidence and risk factors analysis of acute kidney injury in hospitalized patients received diuretics: A single-center retrospective study

Diuretics have been one of the well-known nephrotoxic drugs which can lead to acute kidney injury (AKI). However, there are few real-world studies on the incidence of AKI in hospitalized patients received diuretics. In the present study, a single-center retrospective study was conducted in our center. The clinical data of hospitalized patients received diuretics from January 2018 to December 2020 was retrospectively analyzed. Among the 18,148 hospitalized patients included in the study, 2,589 patients (14.26%) were judged as incidence with AKI, while only 252 patients were diagnosed with AKI in the medical record. Among diuretics drugs in the study, the incidence rate of AKI with torasemide was the highest with 21.62%, and hydrochlorothiazide had the lowest incidence rate (6.80%). The multiple logistic regression analysis suggested that complicated with hypertension, anemia, pneumonia, shock, sepsis, heart failure, neoplastic diseases, combined use of proton pump inhibitors (PPI) were independent risk factors for AKI related to diuretics. The logic regression models for diuretics related AKI were developed based on the included data. The model for diuretics-AKI achieved the area under the receiver operating characteristic curves (AUC) with 0.79 on 10-fold cross validation. It is urgent to improve the understanding and attention of AKI in patients received diuretics for medical workers, and the assessment of risk factors before the use of diuretics should be contributed to the early prevention, diagnosis and treatment of AKI, and ultimately reducing morbidity and improving prognosis.

Divergent regulation of lncRNA expression by ischemia in adult and aging mice

Elderly patients have increased susceptibility to acute kidney injury (AKI). Long noncoding RNAs (lncRNA) are key regulators of cellular processes, and have been implicated in both aging and AKI. Our aim was to study the effects of aging and ischemia-reperfusion injury (IRI) on the renal expression of lncRNAs. Adult and old (10- and 26-30-month-old) C57BL/6 N mice were subjected to unilateral IRI followed by 7 days of reperfusion. Renal expression of 90 lncRNAs and mRNA expression of injury, regeneration, and fibrosis markers was measured by qPCR in the injured and contralateral control kidneys. Tubular injury, regeneration, and fibrosis were assessed by histology. Urinary lipocalin-2 excretion was increased in old mice prior to IRI, but plasma urea was similar. In the control kidneys of old mice tubular cell necrosis and apoptosis, mRNA expression of kidney injury molecule-1, fibronectin-1, p16, and p21 was elevated. IRI increased plasma urea concentration only in old mice, but injury, regeneration, and fibrosis scores and their mRNA markers were similar in both age groups. AK082072 and Y lncRNAs were upregulated, while H19 and RepA transcript were downregulated in the control kidneys of old mice. IRI upregulated Miat, Igf2as, SNHG5, SNHG6, RNCR3, Malat1, Air, Linc1633, and Neat1 v1, while downregulated Linc1242. LncRNAs H19, AK082072, RepA transcript, and Six3os were influenced by both aging and IRI. Our results indicate that both aging and IRI alter renal lncRNA expression suggesting that lncRNAs have a versatile and complex role in aging and kidney injury. An Ingenuity Pathway Analysis highlighted that the most downregulated H19 may be linked to aging/senescence through p53.

Acute kidney injury and aging

Our aging population is growing and developing treatments for age-related diseases such as Alzheimer's and Parkinson's disease has taken on an increasing urgency and is accompanied by high public awareness. The already high and rising incidence of acute kidney injury (AKI) in the elderly, however, has received relatively little attention despite the potentially fatal outcomes associated with an episode of AKI in this age group. When discussing AKI and aging, one should consider two aspects: first, elderly patients have an increased susceptibility to an AKI episode, and second, they have decreased kidney repair after AKI given the high incidence of progression to chronic kidney disease (CKD). It is unclear if the same factors that drive the increased susceptibility to AKI could be playing a role in the decreased repair capacity or if they are totally different and unrelated. This review will examine current knowledge on the risk factors for the increased susceptibility to AKI in the elderly and will also explore potential aspects that might contribute to a decreased kidney repair response in this age group.

Critical oxygen delivery threshold during cardiopulmonary bypass in older cardiac surgery patients with increased frailty risk

OBJECTIVES

Older patients have a higher cardiac surgery-associated acute kidney injury (CSA-AKI) related mortality. Low oxygen delivery (DO2) during cardiopulmonary bypass (CPB) is a risk factor for CSA-AKI, but critical DO2 thresholds for older patients are unknown. This study investigated critical DO2 thresholds for CSA-AKI in patients ≥70 years undergoing on-pump cardiac surgery.

METHODS

Patients were enrolled from July 2015 until August 2017. CPB data from 432 patients were collected, and DO2 values were calculated per minute. The primary outcome was CSA-AKI. The association between DO2 and CSA-AKI was analysed with multivariable regression analysis. Multiple DO2 thresholds were analysed. The association between CSA-AKI and the area below the DO2 thresholds (DO2 deficit) was evaluated, as was the association between frailty and CSA-AKI.

RESULTS

CSA-AKI occurred in 63 (14.6%) patients. Mean and nadir (lowest) DO2 values were lower in patients with CSA-AKI (283 vs 312 ml/min/m2; P-value <0.001 and 238 vs 270 ml/min/m2; P-value <0.001, respectively). The adjusted relative risk for CSA-AKI was 1.006 [99% confidence interval (CI) 1.001-1.012] per ml/min/m2 nadir DO2 decrease. The critical DO2 threshold was 270 ml/min/m2 [adjusted relative risk 2.06 (99% CI 1.33-2.80)]. The DO2 deficit below 270 ml/min/m2 was associated with CSA-AKI [adjusted relative risk 2.84 (99% CI 1.87-3.81)]. No association between frailty and CSA-AKI was found (P = 0.82).

CONCLUSIONS

Low DO2 increased the risk for CSA-AKI in older patients who had cardiac surgery. A critical DO2 threshold of 270 ml/min/m2 was applicable for frail and non-frail patients. The efficacy of a DO2 >270 ml/min/m2 to reduce CSA-AKI in older patients needs further evaluation.

Evaluation of acute and chronic nephrotoxicity in patients received cisplatin-based chemotherapy: has anything changed over time?

PURPOSE

The aim of this study was to determine the frequency and the risk factors of acute and chronic nephrotoxicity in patients who received cisplatin due to malignancy.

MATERIALS AND METHODS

Medical records of all patients who received cisplatin-based chemotherapy regimen between January 2013 and July 2019 were retrospectively evaluated. The data of 203 patients who met the study criteria were examined. The patients were evaluated for acute nephrotoxicity at 48 h and late nephrotoxicity at 3rd month after first course of cisplatin. Early and late nephrotoxicity were defined by NCI CTCAE Version 4.0 criteria.

RESULTS

The mean age of the study patients was 56.44 ± 12.69 years, 78.8% were males and 21.2% were females. It is revealed that the incidence of cisplatin-induced acute nephrotoxicity was 9.2% and chronic nephrotoxicity was 37.9%. While the development of acute nephrotoxicity was associated with female gender, history of diabetes mellitus, history of ischemic heart disease and use of antiplatelet drug, the development of chronic nephrotoxicity was associated with older age, female gender and using of diuretics. High serum creatinine, urea and low eGFR value before treatment were found to be associated with both early and late nephrotoxicity (p < 0.05). There was no statistically significant relationship between acute or chronic nephrotoxicity and cumulative dose of cisplatin, hydration or intravenous magnesium supplementation.

CONCLUSION

High initial serum creatinine value and low initial eGFR are the most important determinants of both early and late nephrotoxicity.

Exploration of the Relationship Among Key Risk Factors of Acute Kidney Injury for Elderly Patients Considering Covid-19

Background: Previous systematic reviews and meta-analyses supported the relationship between frailty and risk of acute kidney injury (AKI) in elderly patients. However, few studies evaluated proactive management to wear down AKI risk in such frail populations.

Purpose: To understand how AKI risk factors might influence each other and to identify the source factors for clinical decision aids.

Methods: This study uses the decision-making trial and evaluation laboratory (DEMATEL) method to establish influential network-relationship diagrams (INRDs) to form the AKI risk assessment model for the elderly.

Results: Based on the DEMATEL approach, the results of INRD identified the six key risk factors: comorbidity, malignancy, diabetes, creatinine, estimated glomerular filtration rate, and nutritional assessment. (The statistical significance confidence is 98.423%, which is higher than 95%; the gap error is 1.577%, which is lower than 5%). After considering COVID-19 as an additional risk factor in comorbidity, the INRD revealed a similar influential relationship among the essential aspects.

Conclusion: While evaluating the geriatric population, physicians need to pay attention to patients' comorbidities and nutritional assessment; also, they should note patients' creatinine values and glomerular filtration rate. Physicians could establish a preliminary observation index and then design a series of preventive guidelines to reduce the incidence of AKI risk for the elderly.

Vitamin D/VDR in Acute Kidney Injury: A Potential Therapeutic Target

Despite many strategies and parameters used in clinical practice, the incidence and mortality of acute kidney injury (AKI) are still high with poor prognosis. With the development of molecular biology, the role of vitamin D and vitamin D receptor (VDR) in AKI is drawing increasing attention. Accumulated researches have suggested that Vitamin D deficiency is a risk factor of both clinical and experimental AKI, and vitamin D/VDR could be a promising therapeutic target against AKI. However, more qualitative clinical researches are needed to provide stronger evidence for the clinical application of vitamin D and VDR agonists in the future. Issues like the route and dosage of administration also await more attention. The present review aims to summarize the current works on the role of vitamin D/VDR in AKI and provides some new insight on its therapeutic potential.

Acute Kidney Injury following Cardiopulmonary Bypass: A Challenging Picture

Recent studies have recognized several risk factors for cardiopulmonary bypass- (CPB-) associated acute kidney injury (AKI). However, the lack of early biomarkers for AKI prevents practitioners from intervening in a timely manner. We reviewed the literature with the aim of improving our understanding of the risk factors for CPB-associated AKI, which may increase our ability to prevent or improve this condition. Some novel early biomarkers for AKI have been introduced. In particular, a combinational use of these biomarkers would be helpful to improve clinical outcomes. Furthermore, we discuss several interventions that are aimed at managing CPB-associated AKI, may increase the effect of renal replacement therapy (RRT), and may contribute to preventing CPB-associated AKI. Collectively, the conclusions of this paper are limited by the availability of clinical trial evidence and conflicting definitions of AKI. A guideline is urgently needed for CPB-associated AKI.

Prevalence and risk factors of acute kidney injury in polytrauma patients at Muhimbili Orthopedic Institute, Tanzania

Background

Polytrauma can lead to multi-organ dysfunction in addition to the local injuries. Acute kidney injury (AKI) is one of the most common causes and contributors to the high morbidity and mortality. Prevalence of acute kidney injury in trauma patients is as reported to be as high as 40.3%. Early detection and management leads to better outcomes. The prevalence of AKI among polytrauma patients remains unknown in our setting.

Methodology

A cross-sectional study involving all adults with polytrauma who presented at the emergency department at Muhimbili Orthopedic Institute (MOI) was designed. A score of ≥18 on the New Injury Severity Score (NISS) screening tool was used to identify polytrauma patients. The Kidney Disease Improving Global Outcomes (KDIGO) criteria was used to identify patient with polytrauma who developed acute kidney injury. Descriptive statistics were then obtained followed by hypothesis testing between variables with the chi squared test. Logistic regression models were used to determine factors associated with acute kidney injury.

Results

More than half (56.4%) of the patients were between 26 and 40 years and 92.3% of the polytrauma patients were males. Almost 2/5th (38.5%) of the polytrauma patients had acute kidney injury – half of these had stage 1 AKI, 33.3% had stage 2 AKI and the remaining 16.7% had stage 3 AKI. On multivariate logistic regression, it was found that patients who were older than 45 years (OR 8.53, CI 1.65–43.89, p = 0.01) and those patients with Systemic Inflammatory Response Syndrome (SIRS) (OR 21.83, CI 1.66–286.2, p = 0.019) had higher risk of acute kidney injury.

Conclusion

There is high prevalence of AKI among polytrauma patients. Elderly patients and those with SIRS were seen to have higher likelihood of AKI.

Clinical features, risk factors, and clinical burden of acute kidney injury in older adults

Background: Few epidemiologic studies on acute kidney injury (AKI) have focused on the older adult population. This study investigated the clinical features, risk factors, and clinical burden in this population. Methods: A retrospective observational study was performed with the clinical data of inpatients at Guangdong Geriatrics Institute from 1 August 2012, to 31 December 2016. AKI was classified into community-acquired AKI (CA-AKI) and hospital-acquired AKI (HA-AKI), and the risk factors for AKI were ranked by weight. The relationships between AKI and adverse outcomes during hospitalization were analyzed using univariate and multivariate logistic regression. Results: In total, 6126 patients were enrolled, and 1704 patients developed AKI (27.8%): 6.3% had CA-AKI, and 21.5% had HA-AKI. In total, 1425 (23.3%), 202 (3.3%), and 77 (1.3%) patients had stage 1, 2 and 3 AKI, respectively. Age, dementia, moderate/severe renal disease, moderate/severe liver disease, metastatic solid tumor, female sex, congestive heart failure, chronic pulmonary disease, diabetes mellitus with chronic complications, non-metastatic tumor and lymphoma were independent risk factors for HA-AKI. The first five were also independent risk factors for CA-AKI. After multiple adjustment, AKI was associated with intensive care admission (CA-AKI: OR 5.688, 95% CI 3.122-10.361; HA-AKI: OR 4.704, 95% CI 3.023-7.298) and in-hospital mortality (CA-AKI: OR 5.073, 95% CI 2.447-10.517; HA-AKI: OR 13.198, 95% CI 8.133-21.419). Conclusion: AKI occurs in >25% of older adults in the geriatric ward. In addition to traditional risk factors, dementia and tumors were risk factors for AKI in older adults. AKI is closely related to a poor prognosis.

Resemblance and differences in dietary restriction nephroprotective mechanisms in young and old rats

Dietary restriction (DR) is the strategy ameliorating the morbidity of various pathologies, including age-associated diseases. Acute kidney injury (AKI) remains a problem for the elderly with DR being a promising approach for diminishing its consequences. We evaluated the possible nephroprotective potential of short-term DR in young and old rats. DR in young rats resulted in pronounced beneficial effects normalizing lipid metabolism (triglycerides concentration, adiponectin level) activating autophagic-lysosomal system evaluated by LC3II/LC3I ratio, LAMP1, p62/SQSTM1 levels, and LysoTracker Green staining. DR had a remarkable recovering effect on mitochondrial structure and functions including regaining of mitochondrial membrane potential, the elevation of SIRT-3, PGC-1α, _Bcl-XL levels and partial restoration of ultrastructure. The beneficial effects of DR resulted in the mitigation of oxidative stress including a decrease in levels of protein carbonylation and lipid peroxidation. Aging led to decreased activity of autophagy, elevated oxidative stress and impaired kidney regenerative capacity. Eventually, in old rats, even 8-week DR was not able to ameliorate AKI, but it caused some rejuvenating effects including elevation of mitochondrial membrane potential and Bcl-X_L levels, as well as lowered severity of the oxidative stress. Thus, the age-associated decline of protective signaling demands extended DR to achieve nephroprotective potential in old animals.

Clinical Characteristics of Hospitalized Patients with Drug-Induced Acute Kidney Injury and Associated Risk Factors: A Case-Control Study

Background

Drug-induced acute kidney injury (D-AKI) is increasingly common and can extend the hospital length of stay and increase mortality. This study is aimed at analyzing the clinical characteristics of hospitalized patients with D-AKI and the associated risk factors in a multidrug environment.

Methods

A retrospective study among hospitalized patients was conducted in July 2019 based on the Adverse Drug Events Active Surveillance and Assessment System-2 developed by the authors. Four controls were matched with each case according to the matching criteria. The risk factors for D-AKI were identified by binary multivariate logistic regression.

Results

A total of 23,073 patients were hospitalized in July 2019, 21,131 of whom satisfied the inclusion criteria. The independent risk factors for D-AKI consisted of alcohol abuse (odds ratio (OR), 2.05; 95% confidence interval (CI), 1.04-4.07), nonsteroidal anti-inflammatory drug (NSAID) use (OR, 2.39; 95% CI, 1.25-4.58), diuretic use (OR, 2.64; 95% CI, 1.42-4.92), prior anemia (OR, 4.10; 95% CI, 1.94-8.67), and prior chronic kidney disease (OR, 2.33; 95% CI, 1.07-5.08).

Conclusions

The occurrence of D-AKI in hospitalized patients had significant associations with alcohol abuse, combination therapy with NSAIDs or diuretics, and prior anemia or chronic kidney disease. Clinicians should meticulously follow patients with the above characteristics.

Exogenous biological renal support ameliorates renal pathology after ischemia reperfusion injury in elderly mice

We established an exogenous biological renal support model through the generation of parabiotic mice. At 72 hours after ischemia reperfusion injury (IRI), the aged mice that received exogenous biological renal support showed significantly higher levels of renal cell proliferation and dedifferentiation, lower levels of renal tubular injury, improved renal function, and a lower mortality than those that did not receive exogenous biological renal support. Using the Quantibody Mouse Cytokine Antibody Array, we found that aged IRI mice that received exogenous biological renal support had an up-regulation of multiple inflammatory related cytokines compared to the group that did not receive exogenous biological renal support. We suggest that the exogenous biological renal support might promote renal tubular epithelial cell proliferation and dedifferentiation and improve the prognosis of aged IRI mice. Exogenous biological renal support may play an important role in the amelioration of renal IRI by regulating the expression of multiple cytokines.

Association of acute kidney injury with frailty in elderly population: a systematic review and meta-analysis

Aim: The objective of this study was to assess whether an elderly patient's frailty was associated with acute kidney injury (AKI) and to examine whether severe frailty group had an increased risk of AKI than mild-moderate group.Methods: We searched The Cochrane Library, PubMed, and EMBASE for relevant studies without language limitations before 1 March 2019 with a priori defined inclusion and exclusion criteria. Five population-based cohort studies were included for systematic review and meta-analysis.Results: Compared with the control group, the frailty group is significantly associated AKI (Odds Ratio = 2.05; 95% CI: 1.23-3.43). The moderate-severe frailty group has an increased risk of AKI than mild frailty group (Hazard Ratio = 2.87; 95% CI: 1.60-5.17.Conclusion: In conclusion, the available best evidence support an association between frailty and AKI among elder patients, thus relevant interventions should be taken among elderly under potential risk of AKI.

Perioperative care of geriatric patients

The older population is expected to nearly double across the globe by 2050, and the baby boom cohort is expected to represent at least 20% of the US population by 2030. Geriatric patients will increasingly utilize the health-care system, and therefore surgical and perioperative care must be tailored to this sensitive group given the increased risk for perioperative complications. The literature was reviewed to highlight fundamental components of the preoperative evaluation as well as cardiac, pulmonary, and renal complications. Frailty is a multidimensional process that can lead to the physiologic effects of aging and estimates the risk of perioperative morbidity and mortality better than chronologic age alone. Health-care providers should assess a geriatric patient's cognitive status, decision-making capacity, frailty, advance care planning, medications, and anesthetic approach in a multidisciplinary fashion to ensure optimal care. The risks of postoperative cardiac, pulmonary, and renal complications should be evaluated and optimized preoperatively to reduce the potential for adverse outcomes.

Community-Acquired Acute Kidney Injury Induced By Drugs In Older Patients: A Multifactorial Event

Purpose

Community-acquired acute kidney injury (CA-AKI) is a frequent and severe adverse drug reaction (ADR) among older patients. The combination of drugs and other CA-AKI risk factors was barely evaluated. The objectives of our study were to both accurately identify CA-AKI induced by drugs in older patients, and to describe their combination with other risk factors.

Patients and methods

We conducted a retrospective, single-center study in a general hospital over a two-year period. An automated detection identified CA-AKI according to KDIGO criteria, amongst 4,767 eligible inpatient stays among patients aged 75 years or older. Two independent experts reviewed all CA-AKI events to adjudicate drug involvement (Naranjo scale), identify inappropriate prescriptions (STOPP criteria), evaluate avoidability (Hallas criteria) and identify combined risk factors.

Results

An expert review confirmed 713 CA-AKI (15.0% of inpatient stays) and determined that 419 (58.8%) CA-AKI were induced by drugs. A multifactorial cause (i.e., at least one drug with a precipitating factor) was found in 63.2% of drug-induced CA-AKI. Most of the drug-induced events were avoidable (66.8%), mainly in relation to a multifactorial cause.

Conclusion

Drug-induced CA-AKI were frequent, multifactorial events in hospitalized older patients and their prevention should focus on combinations with precipitating factors.

American Geriatrics Society-Beers Criteria and adverse drug reactions: a comparative cross-sectional study of Nigerian and South African older inpatients

Background

The Beers Criteria were developed with the aim of improving the safety of medicines among older persons. While the association between the Beers' list of potentially inappropriate medicines (PIMs) and adverse drug reactions (ADRs) among older Caucasians is contentious, the ability of the Criteria to predict ADRs among older persons in Africa remains unexplored.

Objectives

This study aimed to compare the prevalence of PIMs and ADRs among hospitalized older persons in Nigeria and South Africa, and to determine the association between the 2015 American Geriatrics Society-Beers (AGS-Beers) PIMs and ADRs.

Methods

The medical records of older persons aged ≥60 years who were hospitalized in teaching hospitals in Nigeria and South Africa were randomly selected, and retrospectively evaluated for ADRs by two clinical pharmacists using the Naranjo algorithm. The PIMs were assessed using the 2015 AGS-Beers Criteria. A multivariate logistic regression was used to determine the associated factors for ADRs among the hospitalized older persons, with P<0.05 being considered significant.

Results

The samples which comprised 268 and 339 hospitalized older persons (mean age 70.53±8.22; 95% CI -0.21 to 2.32 vs mean age 69.49±7.64; 95% CI -0.25 to 2.34, P=0.11) were evaluated in Nigeria and South Africa, respectively. The PIMs among the older persons in Nigeria were 32.1% (86/268) and 30.1% (102/339, OR=0.91, 95% CI 0.64-1.29, P=0.6) for South Africa; 13.8% (37/268) of the hospitalized older persons in Nigeria experienced 43 cases of ADRs compared to 9.1% (31/339) in South Africa (95% CI 0.38-1.04, P=0.07). The multivariate analysis showed no association between PIMs and ADRs among the hospitalized older persons in Nigeria (OR=1.48 95% CI 0.70-3.17, P=0.31) and South Africa (OR=1.09, 95% CI 0.48-2.49, P=0.83).

Conclusion

The 2015 AGS-Beers PIMs were not associated with ADRs among the hospitalized older persons in Nigeria and South Africa. However, physicians should be cautious when prescribing certain medications in the AGS-Beers list.

Mechanisms of Age-Dependent Loss of Dietary Restriction Protective Effects in Acute Kidney Injury

Dietary restriction (DR) is one of the most efficient approaches ameliorating the severity of different pathological conditions including aging. We investigated the protective potential of short-term DR in the model of acute kidney injury (AKI) in young and old rats. In kidney tissue, the levels of autophagy and mitophagy were examined, and proliferative properties of renal cells obtained from rats of different age were compared. DR afforded a significant nephroprotection to ischemic kidneys of young rats. However, in old rats, DR did not provide such beneficial effect. On the assessment of the autophagy marker, the LC3 II/LC3 I ratio, and after staining the tissue with LysoTracker Green, we concluded that in old rats activity of the autophagic-lysosomal system decreased. Mitophagy, as assessed by the levels of PINK-1, was also deteriorated in old animals. Renal cells from old rats showed impaired proliferative capacity, a worse rate of recovery after ischemic injury, increased levels of oxidative stress, accumulation of lipofuscin granules and lower mitochondria membrane potential. The results suggest that the loss of DR benefits in old animals could be due to deterioration in the autophagy/mitophagy flux.

Is Frailty a Predictor of Outcomes in Elderly Inpatients with Acute Kidney Injury? A Prospective Cohort Study

BACKGROUND

Frailty and acute kidney injury are independently associated with an increased risk of morbidity and mortality. The degree of frailty can be assessed by the Clinical Frailty Score (CFS). This study assessed whether an individual's CFS was associated with acute kidney injury in acute elderly medical admissions and recorded the short-term outcomes.

METHODS

This was a single-center prospective observational cohort study. All patients aged ≥65 years admitted under an acute medical take over 12 nonconsecutive days were included. Patient demographics, comorbidities, baseline CFS, and renal status on admission were recorded. Outcomes of death, length of stay, and hospital re-attendance were assessed 2 weeks following admission.

RESULTS

Of 164 patients (77 males), 19% had acute kidney injury on admission and 22% were considered severely frail. Severe frailty was associated with acute kidney injury (P = .01) and death within 2 weeks (P = .01). Two-week mortality was highest among patients with both (36%).

CONCLUSION

The incidence of acute kidney injury in "severely frail" acutely unwell elderly patients is significantly higher and associated with an increased short-term mortality. The CFS may be useful in acute illness to guide clinical decisions in elderly patients.

The characteristics and risk factors for cisplatin-induced acute kidney injury in the elderly

Objectives

The most serious adverse reaction of cisplatin is acute kidney injury (AKI). Cisplatin-induced acute kidney injury (CIA) has no specific preventive measures. This study aims to explore the characteristics and risk factors for CIA in the elderly and to identify potential methods to reduce CIA.

Materials and methods

Patients ≥18 years old, with primary tumors, who received initial cisplatin chemotherapy and whose serum creatinine (SCr) values were measured within 2 weeks pre- and postcisplatin treatment and who had complete medical records, were selected from a single center from January 1, 2013 to December 31, 2015. The exclusion criteria included radiotherapy or surgery, recurrent tumors, previous cisplatin treatment, lack of any SCr values before or after cisplatin therapy, and incomplete medical records.

Results

Out of a total of 527 patients, 349 were elderly. Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) use (9.2%) was more prevalent in the elderly than in younger patients (2.8%, p = 0.007). The dosage of cisplatin treatment was lower in the elderly, but the incidence of CIA (9.46%) was higher in the elderly than in younger patients (3.37%). There were significant differences in the SCr levels, estimated glomerular filtration rate, ACEI/ARB use, and whether a single application of cisplatin was administered, between the elderly AKI group and the non-AKI group. Multivariable analysis showed that administration of a single application of cisplatin (OR 2.853, 95% CI: 1.229, 6.621, p = 0.015) and ACEI/ARB use (OR 3.398, 95% CI: 1.352, 8.545, p = 0.009) were predictive factors for developing CIA in the elderly.

Conclusion

The incidence of CIA in the elderly was higher than in younger patients. ACEI/ ARB usage and administration of a single application of cisplatin were independent risk factors for CIA in the elderly.

Youthful systemic milieu alleviates renal ischemia-reperfusion injury in elderly mice

The incidence of acute kidney injury (AKI) is high in elderly people, and is difficult to prevent and treat. One of its major causes is renal ischemia-reperfusion injury (IRI). A young systemic environment may prevent the senescence of old organs. However, it is unknown whether a young milieu may reduce renal IRI in the elderly. To examine this question, bilateral renal IRI was induced in old (24 months) mice three weeks after parabiosis model establishment. At 24 hours after IRI, compared to old wild-type mice, the old mice with IRI had significantly damaged renal histology, decreased renal function, increased oxidative stress, inflammation, and apoptosis. However, there was no increase in autophagy. Compared to old mice with IRI, old-old parabiosis mice with IRI did not show differences in renal histological damage, oxidative stress, inflammation, apoptosis, or autophagy, but did exhibit improved renal function. Compared to the old-old parabiosis mice with IRI, the old mice with IRI in the young (12 week)-old parabiosis showed less renal histological injury and better renal function. Renal oxidative stress, inflammation, and apoptosis were significantly decreased, and autophagy was significantly increased. Thus, a youthful systemic milieu may decrease oxidative stress, inflammation, and apoptosis, and increase autophagy in old mice with IRI. These effects ameliorated IRI injuries in old mice. Our study provides new ideas for effectively preventing and treating AKI in the elderly.

Drug-Induced Kidney Injury in the Elderly

The incidence of acute kidney injury in the elderly has grown over the past decade. One of the primary drivers is drug-induced nephrotoxicity, which is the result of a combination of the unique susceptibilities to kidney injury and the increased use of medications in the elderly population. Specific drug classes are associated with increased rates of kidney injury including agents that block the renin angiotensin system, antimicrobials, and chemotherapeutic agents. Mechanistically, injury may be due to hemodynamic effects, tubular or glomerular toxicity, and interstitial nephritis. Early recognition of nephrotoxicity is critical, as are preventative steps when applicable. Unfortunately, treatment for established drug-induced kidney injury is limited and supportive care is required. Limiting exposure to nephrotoxic drugs is critical in decreasing the incidence of acute kidney injury in the elderly patient.

Acute Kidney Injury in Elderly Population: A Prospective Observational Study

BACKGROUND/AIMS

Acute kidney injury (AKI) has been reported as a recognized condition among the elderly population; however, its clinical epidemiology is still poorly evaluated. We propose to evaluate the epidemiological profile of AKI in hospitalized elderly patients and the variables associated with renal replacement therapy (RRT) dependency at discharge after an episode of AKI.

METHODS

This prospective observational study enrolled 286 elderly patients (aged ≥60 years), who had a diagnosis of AKI and were admitted to a tertiary care hospital. Clinical data were analyzed, which included RRT indication, referral time to nephrologist support, standby period in the emergency care units (ECU) before a transfer to an intensive care unit, staff criteria used to indicate palliative care, and the incidence of patients who stayed on chronic dialysis for at least 6 months after discharge.

RESULTS

The overall hospital mortality was 56.3%. Acute Kidney Injury Network (AKIN) 3 at the time of admission was significantly higher in patients who underwent RRT. Intrinsic AKI (p < 0.001), AKIN 3 (p < 0.001), RRT (p < 0.001), and increased length of stay in ECUs (p = 0.01) all had a significantly higher prevalence among non-survivors. On multivariate analysis, however, only renal aetiology (intrinsic AKI) was independently associated with mortality (OR 2.88; 95% CI [1.29-6.13]). Approximately 85% of the discharged patients (n = 125) were dialysis free and 36.4% of them who had a previous diagnosis of chronic kidney disease (CKD) upon admission had a worse renal function. Age, AKIN 3, RRT, prior history of CKD, diabetes mellitus, and the number of hemodialysis sessions showed to have an impact on dialysis dependence. Furthermore, 24 of 161 patients who had a dialysis indication were placed on palliative care.

CONCLUSIONS

The severity of AKI and the need for RRT were risk factors for mortality and dependence on dialysis. Antecedents of CKD seem to be associated with a poor renal outcome following an AKI episode. Starting RRT had an impact on the clinical decision to enroll these patients into palliative care.

Sav1 Loss Induces Senescence and Stat3 Activation Coinciding with Tubulointerstitial Fibrosis

Tubulointerstitial fibrosis (TIF) is recognized as a final phenotypic manifestation in the transition from chronic kidney disease (CKD) to end-stage renal disease (ESRD). Here we show that conditional inactivation of Sav1 in the mouse renal epithelium resulted in upregulated expression of profibrotic genes and TIF. Loss of Sav1 induced Stat3 activation and a senescence-associated secretory phenotype (SASP) that coincided with the development of tubulointerstitial fibrosis. Treatment of mice with the YAP inhibitor verteporfin (VP) inhibited activation of genes associated with senescence, SASPs, and activation of Stat3 as well as impeded the development of fibrosis. Collectively, our studies offer novel insights into molecular events that are linked to fibrosis development from Sav1 loss and implicate VP as a potential pharmacological inhibitor to treat patients at risk for developing CKD and TIF.

Factors associated with adverse drug reactions in older inpatients in teaching hospital

Background Adverse drug reactions (ADRs) occur frequently during hospital stays and are an important public health problem, particularly in the care of the older. Objectives This study aimed to determine the prevalence of ADRs among older inpatients and the factors associated with their occurrence. Setting Brazilian teaching hospital. Methods This was a cross-sectional study with older inpatients in the internal medicine ward of a teaching hospital. The dependent variable was the occurrence of an ADR during hospitalization. The independent variables were gender, age, length of hospitalization, number of health problems, medications, and potentially inappropriate medications for the older. Logistic regression was performed to analyze the association between an ADR and the independent variables. Main outcome measure Factors associated with ADR in older inpatients. Results Among the 237 inpatients investigated, 50 (21.1%) developed at least one ADR. The total number of ADRs observed was 62 and the most frequent were acute kidney injury, hypotension, and cutaneous adverse reactions A multivariate analysis demonstrated a positive and independent association between the occurrence of an ADR and the presence of heart failure [odds ratio (OR) 2.4; 95% confidence interval (CI) 1.2-4.6], and with hospitalization time exceeding 12 days (OR 2.3; 95% CI 1.2-4.4). Conclusions The study showed a high prevalence of ADRs among the older and a positive association with hospitalization time and heart failure. Understanding the factors associated with the occurrence of ADRs among older inpatients provides elements for improving the safety of care and optimization of pharmacotherapy.

Twist2 Is Upregulated in Early Stages of Repair Following Acute Kidney Injury

The aging kidney is a marked by a number of structural and functional changes, including an increased susceptibility to acute kidney injury (AKI). Previous studies from our laboratory have shown that aging male Fischer 344 rats (24 month) are more susceptible to apoptosis-mediated injury than young counterparts. In the current studies, we examined the initial injury and early recovery phases of mercuric chloride-induced AKI. Interestingly, the aging kidney had decreased serum creatinine compared to young controls 1 day following mercuric chloride injury, but by day 4, serum creatinine was significantly elevated, suggesting that the aging kidney did not recover from injury. This conclusion is supported by the findings that serum creatinine and kidney injury molecule-1 (Kim-1) gene expression remain elevated compared to young controls at 10 days post-injury. To begin to elucidate mechanism(s) underlying dysrepair in the aging kidney, we examined the expression of Twist2, a helix-loop-helix transcription factor that may mediate renal fibrosis. Interestingly, Twist2 gene expression was elevated following injury in both young and aged rats, and Twist2 protein expression is elevated by mercuric chloride in vitro.

Short- and Long-Term Mortality Rates of Elderly Acute Kidney Injury Patients Who Underwent Continuous Renal Replacement Therapy

Background

The world’s population is aging faster and the incidence of acute kidney injury (AKI) needing continuous renal replacement therapy (CRRT) is increasing in elderly population. The outcome of AKI needing CRRT in elderly patients is known to be poor. However, the definitions of elderly used in the previous literatures were diverse and, there were few data that compared the long-term mortality rates of these patients with middle aged patients. This study was aimed to evaluate this issue.

Methods

This study was a single-center, retrospective cohort study of patients who underwent CRRT from January 2013 to December 2015. The patients were divided into the following four age cohorts: middle-aged (55–64), young-old (65–74), middle-old (75–84), and old-old (≥85). The short- and long-term mortality rates for each age cohort were compared.

Results

A total of 562 patients met the inclusion criteria. The short-term mortality rate was 57.3% in the entire cohort. Compared with the middle-aged cohort, the middle-old cohort (HR 1.48 (1.09–2.02), p = 0.012) and the old-old cohort (HR 2.33 (1.30–4.19), p = 0.005) showed an increased short-term mortality rate along with an increased SOFA score, acidemia and a prolonged prothrombin time. When we analyzed the long-term mortality rate of the 238 survived patients, the middle-old cohort (HR 3.76 (1.84–7.68), p<0.001), the old-old cohort (HR 4.40(1.20–16.10), p = 0.025), a lower BMI, the presence of liver cirrhosis, the presence of congestive heart failure and a history of sepsis were independent risk factors for the prediction of long-term mortality.

Conclusion

Compared with the middle-aged cohort, the middle-old and the old-old cohort showed an increased short-term and long-term mortality rate. However, in the young-old cohort, neither the short-term nor the long-term mortality rate was increased.

Biopsy-proven kidney diseases in the elderly: clinical characteristics, renal histopathological spectrum and prognostic factors

Objective

To explore the clinical characteristics, renal histopathological spectrum and prognostic factors of biopsy-proven kidney diseases in the elderly.

Methods

A retrospective observational study was conducted in elderly patients who had received renal biopsies. Demographic, clinical and pathological data at the time of the biopsy were collected from the medical records. Follow-up records and prognostic factors were studied.

Results

The elderly (≥60 years) accounted for 74 of 434 (17.1%) native renal biopsies that were performed in a 9-year period. In the cohort of included elderly patients (n = 72), the prevalence of nephrotic syndrome and acute kidney injury was 62.5% (45 of 72) and 40.3% (29 of 72), respectively. For elderly patients with primary glomerular diseases (n = 44), membranous nephropathy was the most frequent pathological type (24 of 44; 54.5%). For elderly patients with secondary glomerular diseases (n = 25), anti-neutrophil cytoplasmic antibody-associated vasculitis was the most frequent aetiology (nine of 25; 36.0%). Requirement for renal replacement therapy (RRT) was an independent risk factor for poor prognosis.

Conclusions

Kidney diseases in the elderly have distinctive characteristics. Requirement for RRT was associated with poor prognosis in the elderly with biopsy-proven kidney diseases.

Decreased glomerular filtration rate estimated by 2009 CKD-EPI equation predicts mortality in older hip fracture population

OBJECTIVE

We examined estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology equation (eGFRCDK-EPI), removal of urinary catheter during hospitalization and polypharmacy as predictors of mortality in older hip fracture patients.

METHODS

Population-based prospective data were collected on 1425 consecutive hip fracture patients aged ≥65 years. Outcome was mortality at one year. Independent variables were age, sex, body mass index, fracture type, American Society of Anesthesiology score, delay to surgery, urinary catheter removal during acute hospitalization, eGFRCDK-EPI, number of daily medications, diagnosis of memory disorder, prefracture mobility and living arrangements.

RESULTS

Of the 1425 patients, 567 (40%) had renal dysfunction on admission, 526 (37%) had their urinary catheters removed during hospitalization and 1177 (83%) were taking ≥4 medications regularly before the fracture. In the multivariate analyses with the Cox proportional hazards model adjusted simultaneously for all the independent variables, eGFRCDK-EPI 30-44ml/min/1.73m(2) (HR 1.91, 95% CI 1.44-2.52) and <30ml/min/1.73m(2) (HR 1.95, 95% CI 1.36-2.78), non-removal of the urinary catheter (HR 1.45, 95% CI 1.12-1.88) and large number of daily medications (4-10 HR 1.81, 95% CI 1.78-2.79, >10 HR 2.21, 95% CI 1.38-3.54) were associated with mortality.

CONCLUSIONS

In older hip fracture patients, moderate to severe level renal dysfunction measured by eGFRCDK-EPI, non-removal of urinary catheter before discharge and polypharmacy increase mortality after hip fracture. Careful assessment of renal function and medications and following the care protocols on urinary catheter removal are essential in the care of geriatric hip fracture patients.

Frailty as a Predictor of Acute Kidney Injury in Hospitalized Elderly Patients: A Single Center, Retrospective Cohort Study

BACKGROUND

Elderly patients have an increased risk for acute kidney injury (AKI). However, few studies have reported on predictors for AKI in geriatric patients. Therefore, we aimed at determining the effect of frailty as a predictor of AKI.

METHODS

We retrospectively enrolled 533 hospitalized elderly patients (aged ≥ 65 years) who had their creatinine levels measured (≥ 1 measurement) during admission for a period of 1 year (2013) and conducted a comprehensive geriatric assessment (CGA) within 1 year before the index hospitalization. We examined five variables (activity of daily living [ADL] and instrumental ADL dependence, dementia, nutrition, and polypharmacy) from CGA. We categorized the patients into 3 groups according to the tertile of aggregate frailty scores: Group 1, score 1-2; Group 2, score 3-4; Group 3, score 5-8).

RESULTS

Fifty-four patients (10.1%) developed AKI (median duration, 4 days). The frailest group (Group 3) showed an increased risk of AKI as compared to Group 1, (hazard ratio [HR] = 3.536, P = 0.002). We found that discriminatory accuracy for AKI improved with the addition of the tertile of aggregate frailty score to covariates (area under the receiver operator characteristics curves [AUROC] 0.641, AUROC 0.739, P = 0.004). Forty-six patients (8.6%) were transferred to nursing facilities and 477 patients (89.5%) were discharged home. The overall 90-day and 1-year mortality for elderly inpatients were 7.9% and 26.3%. The frailest group also demonstrated an increased risk of discharge to nursing facilities, and 90-day and 1-year mortality as compared to Group 1, independent of AKI severity (nursing facilities: odd ratio = 4.843, P = 0.002; 90-day mortality: HR = 6.555, P = 0.002; 1-year mortality: HR = 3.249, P = 0.001).

CONCLUSIONS

We found that frailty may independently predict the development of AKI and adverse outcomes in geriatric inpatients.

Bridging translation for acute kidney injury with better preclinical modeling of human disease

The current lack of effective therapeutics for patients with acute kidney injury (AKI) represents an important and unmet medical need. Given the importance of the clinical problem, it is time for us to take a few steps back and reexamine current practices. The focus of this review is to explore the extent to which failure of therapeutic translation from animal studies to human studies stems from deficiencies in the preclinical models of AKI. We will evaluate whether the preclinical models of AKI that are commonly used recapitulate the known pathophysiologies of AKI that are being modeled in humans, focusing on four common scenarios that are studied in clinical therapeutic intervention trials: cardiac surgery-induced AKI; contrast-induced AKI; cisplatin-induced AKI; and sepsis associated AKI. Based on our observations, we have identified a number of common limitations in current preclinical modeling of AKI that could be addressed. In the long term, we suggest that progress in developing better preclinical models of AKI will depend on developing a better understanding of human AKI. To this this end, we suggest that there is a need to develop greater in-depth molecular analyses of kidney biopsy tissues coupled with improved clinical and molecular classification of patients with AKI.

Renoprotective approaches and strategies in acute kidney injury

Acute kidney injury (AKI) is a major renal disease associated with high mortality rate and increasing prevalence. Decades of research have suggested numerous chemical and biological agents with beneficial effects in AKI. In addition, cell therapy and molecular targeting have been explored for reducing kidney tissue damage and promoting kidney repair or recovery from AKI. Mechanistically, these approaches may mitigate oxidative stress, inflammation, cell death, and mitochondrial and other organellar damage, or activate cytoprotective mechanisms such as autophagy and pro-survival factors. However, none of these findings has been successfully translated into clinical treatment of AKI. In this review, we analyze these findings and propose experimental strategies for the identification of renoprotective agents or methods with clinical potential. Moreover, we propose the consideration of combination therapy by targeting multiple targets in AKI.

The perfect storm: older adults and acute kidney injury

Older adults have a high risk for acute kidney injury (AKI), often necessitating critical care admission. The majority of older adults live with 1 or more chronic conditions requiring multiple medications, and when faced with acute illness increased vulnerability can lead to poor health outcomes. When combined with circumstances that exacerbate chronic conditions, clinicians may witness the perfect storm. Some factors that contribute to AKI risk include the aging kidney, sepsis, polypharmacy, and nephrotoxic medications and contrast media. This paper discusses specific risks and approaches to care for older adults with AKI who are in critical care.

Atherosclerosis burden of the aortic valve and aorta and risk of acute kidney injury after transcatheter aortic valve implantation

BACKGROUND

Atheroembolic renal disease, due to dislodgement of cholesterol crystals during maneuvering of a large catheter across the aorta and deployment of the transcatheter prosthesis within a calcified aortic valve, may be one of the pathophysiological mechanisms of acute kidney injury (AKI) complicating transcatheter aortic valve implantation (TAVI).

OBJECTIVE

To investigate the association between the atherosclerotic burden and plaque characteristics of the aortic valve and thoracic aorta, evaluated with multidetector CT (MDCT), and the occurrence of AKI after TAVI.

METHODS

Aortic valve calcification, atherosclerosis burden, and plaque characteristics of the thoracic aorta (including aortic root, ascending aorta, aortic arch, and descending aorta) were analyzed in preprocedural MDCT data of 210 TAVI patients (age, 81 ± 7.1 years; 51.4% men). The thoracic aorta was divided into ascending aorta, aortic arch, and descending thoracic aorta which was further divided into 5 to 8 segments according to the posterior intercostal arteries. Each segment where the maximum wall thickness exceeded ≥ 2 mm was defined as diseased segment with atherosclerotic plaque. Aortic atherosclerosis burden was defined as the proportion of thoracic aortic segments with atherosclerosis. AKI was defined by a creatinine level ≥ 1.5 × baseline or ≥ 26.4 μmol/L above baseline. MDCT data were correlated with the occurrence of postprocedural AKI in a multivariate logistic regression model.

RESULTS

Postprocedural AKI occurred in 51 patients (24.3%). In patients with AKI, the burden of overall (87.5% [75%-90%] vs 71.4% [50%-87.5%]; P < .001) and noncalcified atherosclerosis (42.9% [22.2%-62.5%] vs 12.5% [0%-28.6%]; P < .001) and the maximum plaque thickness (5.7 ± 1.8 mm vs 4.5 ± 1.4 mm; P < .001) were larger compared with patients without AKI. The burden of noncalcified atherosclerosis remained independently associated with AKI (odds ratio, 1.03 [per each 1% of increase in aortic segments with noncalcified atherosclerosis]; 95% confidence interval 1.01-1.05; P = .006) after adjusting for baseline renal function, logistic EuroSCORE, and procedural access. In contrast, aortic valve calcification was not independently associated with AKI.

CONCLUSION

In patients undergoing TAVI, occurrence of postprocedural AKI was associated with the extent of noncalcified atherosclerotic plaque burden of the thoracic aorta.

Determining the incidence of drug-associated acute kidney injury in nursing home residents

OBJECTIVE

Although acute kidney injury (AKI) is well studied in the acute care setting, investigation of AKI in the nursing home (NH) setting is virtually nonexistent. The goal of this study was to determine the incidence of drug-associated AKI using the RIFLE (Risk, Injury, Failure, Loss of kidney function, or End-Stage kidney disease) criteria in NH residents.

DESIGN/SETTING/PARTICIPANTS/MEASUREMENTS

We conducted a retrospective study between February 9, 2012, and February 8, 2013, for all residents at 4 UPMC NHs located in southwest Pennsylvania. The TheraDoc™ Clinical Surveillance Software System, which monitors laboratory and medication data and fires alerts when patients have a sufficient increase in serum creatinine, was used for automated case detection. An increase in serum creatinine in the presence of an active medication order identified to potentially cause AKI triggered an alert, and drug-associated AKI was staged according to the RIFLE criteria. Data were analyzed by frequency and distribution of alert type by risk, injury, and failure.

RESULTS

Of the 249 residents who had a drug-associated AKI alert fire, 170 (68.3%) were women, and the mean age was 74.2 years. Using the total number of alerts (n = 668), the rate of drug-associated AKI was 0.41 events per 100 resident-days. Based on the RIFLE criteria, there were 191, 70, and 44 residents who were classified as AKI risk, injury, and failure, respectively. The most common medication classes included in the AKI alerts were diuretics, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEIs/ARBs), and antibiotics.

CONCLUSION

Drug-associated AKI was a common cause of potential adverse drug events. The vast majority of cases were related to the use of diuretics, ACEIs/ARBs, and antibiotics. Future studies are needed to better understand patient, provider, and facility risk factors, as well as strategies to enhance the detection and management of drug-associated AKI in the NH.

The aging kidney: increased susceptibility to nephrotoxicity

Three decades have passed since a series of studies indicated that the aging kidney was characterized by increased susceptibility to nephrotoxic injury. Data from these experimental models is strengthened by clinical data demonstrating that the aging population has an increased incidence and severity of acute kidney injury (AKI). Since then a number of studies have focused on age-dependent alterations in pathways that predispose the kidney to acute insult. This review will focus on the mechanisms that are altered by aging in the kidney that may increase susceptibility to injury, including hemodynamics, oxidative stress, apoptosis, autophagy, inflammation and decreased repair.

Acute kidney injury in the elderly hospitalized patients

OBJECTIVE

We aimed to evaluate acute kidney injury (AKI), occurrence of recovery and risk factors associated with permanent kidney injury and mortality in the elderly individuals.

DESIGN

Evidence for this study was obtained from retrospective cohort study from our center.

PATIENTS

A total of 193 patients (>65 years, mean age: 79.99 ± 6.93) with acute kidney injury were enrolled in this study between 2011 and 2012. PATIENTS with kidney failure or renal replacement therapy (RRT) history at admission were excluded.

INTERVENTION

Main outcome measurements: serum creatinine (SCr), estimated GFR (with CKD-Epi) and complete blood counts were evaluated at baseline and daily basis thereafter. The AKI was defined based on Kidney Disease Improving Global Outcomes (KDIGO) classification.

RESULTS

Among 193 patients, 43 (22%) patients required RRT. Mortality rate was 18% (n = 36) SCr levels were restored within 9.9 ± 6.7days on average (8-39 days). Sixteen patients (12.7%) required RRT after discharge. The mean hospital stay was 10.1 ± 8.6 days (7-41 days). Mortality rate of patients who have no renal recovery was higher (44.8% vs. 4.8%) than renal recovery group (p < 0.01).

CONCLUSION

The AKI represents a frequent complication in the elderly patients with longer hospital stay and increased mortality and morbidity. Our results show that dialytic support requirement is an independent predictor of permeant kidney injury in the elderly AKI patients. Older age, low diastolic blood pressure, high CRP and low hemoglobin levels were independent risk factors for mortality.