Acute kidney injury is more common in men than women after accounting for socioeconomic status, ethnicity, alcohol intake and smoking history

Urban-Rural Differences in Acute Kidney Injury Mortality in the United States

INTRODUCTION

Acute kidney injury (AKI) is associated with increased mortality. AKI-related mortality trends by U.S. urban and rural counties were assessed.

METHODS

In the cross-sectional study, based on the Centers for Disease Control and Prevention WONDER (Wide-ranging ONline Data for Epidemiologic Research) Multiple Cause of Death data, age-standardized mortality with AKI as the multiple cause was obtained among adults aged ≥25 years from 2001-2020, by age, sex, race and ethnicity, stratified by urban-rural counties. Joinpoint regressions were used to assess trends from 2001-2019 in AKI-related mortality rate. Pairwise comparison was used to compare mean differences in mortality between urban and rural counties from 2001-2019.

RESULTS

From 2001-2020, age-standardized AKI-related mortality was consistently higher in rural than urban counties. AKI-related mortality (per 100,000 population) increased from 18.95 in 2001 to 29.46 in 2020 in urban counties and from 20.10 in 2001 to 38.24 in 2020 in rural counties. In urban counties, AKI-related mortality increased annually by 4.6% during 2001-2009 and decreased annually by 1.8% until 2019 (p<0.001). In rural counties, AKI-related mortality increased annually by 5.0% during 2001-2011 and decreased by 1.2% until 2019 (p<0.01). The overall urban-rural difference in AKI-related mortality was greater after 2009-2011. AKI-related mortality was significantly higher among older adults, men, and non-Hispanic Black adults than their counterparts in both urban and rural counties. Higher mortality was concentrated in rural counties in the Southern United States.

CONCLUSIONS

Multidisciplinary efforts are needed to increase AKI awareness and implement strategies to reduce AKI-related mortality in rural and high-risk populations.

Decadal Analysis of Age-Adjusted Mortality Rates for Acute and Chronic Kidney Disease in Brazil, 2000-2021

Introduction Renal failure, comprising acute kidney injury (AKI) and chronic kidney disease (CKD), involves a decline or loss of kidney function. AKI is sudden and reversible, with a rapid decline in function over hours to days, while CKD involves persistent abnormalities lasting at least three months. Developing countries are seeing a rise in AKI cases, especially in critically ill patients. Globally, there's a growing occurrence and mortality rate linked to CKD. Methods The study used a retrospective cross-sectional design to analyze AKI and CKD mortality rates in Brazil from 2019 to 2022. Data on population and demographics, including sex and age, were obtained from the Brazilian Institute of Geography and Statistics. Mortality data for kidney diseases were sourced from the Brazilian Hospital Information System. The analysis utilized the Joinpoint Regression Program to calculate average annual percentage changes (AAPCs) and their respective 95% confidence intervals. Weighted Bayesian information criterion was used to determine the significance levels and identify the best-fitting combination of line segments and joinpoints. Results The study findings revealed a significant rise in AKI mortality rates for both males and females, from 2008 to 2021 (APC = 3.16; CI: 2.29 to 5.93), with higher mortality rates recorded among males compared to women over the entire study period. Analyses according to age groups showed that males between the ages 40 to 49 experienced the most rapid increase in mortality during the 2019 - 2021 period (APC = 35.41; CI: 16.72 to 46.57); meanwhile, the most rapid increase in mortality for females was observed from 2019 to 2021, and this was among those aged 30 to 39 (APC = 40.33; CI = 6.48 to 59.78). Furthermore, there was an observable upward trend in mortality related to CKD (APC = 0.70; CI: 0.41 to 1.01), with males consistently having higher mortality rates throughout the entire study period. The elderly population, both males and females, experienced the most rapid increase in CKD-related mortality, with AAPC values of 2.32 (CI: 1.82 to 2.89) for males and 1.62 (CI: 1.08 to 2.10) for females. Conclusion We observed a consistent increase in mortality rates from acute kidney diseases for both males and females since 2008, with males experiencing higher mortality rates overall. The study highlighted the need for further research to understand the underlying factors contributing to these trends. Additionally, interventions targeting modifiable risk factors and improving access to healthcare could help reduce mortality related to renal failure.

Performances of acute kidney injury biomarkers vary according to sex

Background

Before implementing individualized strategies to treat acute kidney injury (AKI), identifying clusters of patients with divergent pathophysiological mechanisms, diagnosis criteria or outcomes is of the utmost importance. Here we studied sex-related molecular mechanisms in cardiac bypass (CBP) surgery patients developing AKI.

Methods

We compared the characteristics of 1170 patients referred for CBP surgery using multivariate logistic regression and propensity score-based analysis. Performances of the candidate urinary biomarkers at <4 h post-surgery, urinary neutrophil gelatinase-associated lipocalin (uNGAL), [IGFBP7]·[TIMP-2] product (NephroCheck) and a recently developed AKI signature of 204 urinary peptides (AKI204) to predict AKI were compared in both sexes.

Results

Incidence (∼25%) and severity of AKI were similar in men and women, even after adjustment for the usual risk factors of AKI, including baseline estimated glomerular filtration rate, age, diabetes mellitus, length of CBP and red blood cell transfusion. However, at the molecular level, performances of uNGAL, NephroCheck and AKI204 to predict AKI strongly diverged between men and women. In the full cohort, as well as in subgroups of men and women, the multimarker AKI204 signature outperformed uNGAL and NephroCheck and predicted the development of AKI significantly better in women than in men. Analysis of AKI204 at the single-peptide level suggested divergences of AKI mechanisms between sexes due to increased kidney inflammation in women (increased abundance of urinary fragments of osteopontin and uromodulin).

Conclusions

In patients referred for CBP surgery, significant clinical and biological differences between men and women as well as sexual dimorphism of AKI biomarker performances were identified. The urinary peptide signature points to sex-related molecular mechanisms underlying AKI.

Development and validation of a medication-based risk prediction model for acute kidney injury in older outpatients

BACKGROUND

Older adults are at an increased risk of acute kidney injury (AKI), particularly in community settings, often due to medications. Effective prevention hinges on identifying high-risk patients, yet existing models for predicting AKI risk in older outpatients are scarce, particularly those incorporating medication variables. We aimed to develop an AKI risk prediction model that included medication-related variables for older outpatients.

METHODS

We constructed a cohort of 2,272,257 outpatients aged ≥65 years using a national claims database. This cohort was split into a development (70%) and validation (30%) groups. Our primary goal was to identify newly diagnosed AKI within one month of cohort entry in an outpatient context. We screened 170 variables and developed a risk prediction model using logistic regression.

RESULTS

The final model integrated 12 variables: 2 demographic, 4 comorbid, and 6 medication-related. It showed good performance with acceptable calibration. In the validation cohort, the area under the receiver operating characteristic curve value was 0.720 (95% confidence interval, 0.692-0.748). Sensitivity and specificity were 69.9% and 61.9%, respectively. Notably, the model identified high-risk patients as having a 27-fold increased AKI risk compared with low-risk individuals.

CONCLUSION

We have developed a new AKI risk prediction model for older outpatients, incorporating critical medication-related variables with good discrimination. This tool may be useful in identifying and targeting patients who may require interventions to prevent AKI in an outpatient setting.

Parental recovered acute kidney injury causes prenatal renal dysfunction and fetal growth restriction with sexually dimorphic implications for adult offspring

Introduction: Acute kidney injury (AKI) is rapidly increasing in global incidence and a healthcare burden. Prior maternal AKI diagnosis correlates with later pregnancy complications. As pregnancy influences developmental programming, we hypothesized that recovered parental AKI results in poor pregnancy outcomes, impaired fetal growth, and adult offspring disease. Methods: Using a well-characterized model of rhabdomyolysis-induced acute kidney injury (RIAKI), a form of AKI commonly observed in young people, we confirmed functional renal recovery by assessing glomerular filtration rate (GFR) 2 weeks following RIAKI. We bred sham and recovered RIAKI sires and dams in timed, matched matings for gestational day (GD) 16.5 and offspring (birth-12 weeks, 6 months) study. Results: Despite a normal GFR pre-pregnancy, recovered RIAKI dams at GD16.5 had impaired renal function, resulting in reduced fetoplacental ratios and offspring survival. Pregnant RIAKI dams also had albuminuria and less renal megalin in the proximal tubule brush border than shams, with renal subcapsular fibrosis and higher diastolic blood pressure. Growth-restricted offspring had a reduced GFR as older adults, with evidence of metabolic inefficiency in male offspring; this correlated with reduced renal AngII levels in female offspring from recovered RIAKI pairings. However, the blood pressures of 6-month-old offspring were unaffected by parental RIAKI. Conclusions: Our mouse model demonstrated a causal relationship among RIAKI, gestational risk, and developmental programming of the adult-onset offspring GFR and metabolic dysregulation despite parental recovery.

Incidence and predictors of acute kidney injury after elective surgery for lumbar degenerative disease: A 13-year analysis of the US Nationwide Inpatient Sample

BACKGROUND

Acute kidney injury (AKI) is a severe postoperative complication associated with poor clinical outcomes, including the development of chronic kidney disease (CKD) and death. This study aimed to investigate the incidence and determinants of AKI following elective surgeries for degenerative lumbar spine disease.

METHODS

All patient data were extracted from the US Nationwide Inpatient Sample database. After surgery, AKI's incidence and risk factors were identified for lumbar degenerative disease. ICD-9 and ICD-10 codes defined lumbar spine degenerative disease, fusion, decompression, and AKI. The study cohort was categorized by type of surgery, that is, decompression alone or spinal fusion. Regression analysis was used to identify associations between AKI and risk factors organized by surgery type.

RESULTS

The incidence of AKI after decompression or fusion was 1.1% and 1.8%, respectively. However, the incidence of AKI in the United States is rising. The strongest predictor of AKI was underlying CKD, which was associated with an 9.0- to 12.9-fold more significant risk of AKI than in subjects without comorbid CKD. In this setting, older age, congestive heart failure, anemia, obesity, coagulopathy and hospital-acquired infections were also strong predictors of AKI. In contrast, long-term aspirin/anticoagulant usage was associated with lowered AKI risk.

CONCLUSION

Findings of this study inform risk stratification for AKI and may help to optimize treatment decisions and care planning after elective surgery for lumbar degenerative disease.

Evaluation of risk stratification for acute kidney injury: a comparative analysis of EKFC, 2009 and 2021 CKD-EPI glomerular filtration estimating equations

BACKGROUND

The adoption of the 2021 CKD-EPIcr equation for glomerular filtration rate (GFR) estimation provided a race-free eGFR calculation. However, the discriminative performance for AKI risk has been rarely validated. We aimed to evaluate the differences in acute kidney injury (AKI) prediction or reclassification power according to the three eGFR equations.

METHODS

We performed a retrospective observational study within a tertiary hospital from 2011 to 2021. Acute kidney injury was defined according to KDIGO serum creatinine criteria. Glomerular filtration rate estimates were calculated by three GFR estimating equations: 2009 and 2021 CKD-EPIcr, and EKFC. In three equations, AKI prediction performance was evaluated with area under receiver operator curves (AUROC) and reclassification power was evaluated with net reclassification improvement analysis.

RESULTS

A total of 187,139 individuals, including 27,447 (14.7%) AKI and 159,692 (85.3%) controls, were enrolled. In the multivariable regression prediction model, the 2009 CKD-EPIcr model (continuous eGFR model 2, 0.7583 [0.755-0.7617]) showed superior performance in AKI prediction to the 2021 CKD-EPIcr (0.7564 [0.7531-0.7597], < 0.001) or EKFC model in AUROC (0.7577 [0.7543-0.761], < 0.001). Moreover, in reclassification of AKI, the 2021 CKD-EPIcr and EKFC models showed a worse classification performance than the 2009 CKD-EPIcr model. (- 7.24 [- 8.21-- 6.21], - 2.38 [- 2.72-- 1.97]).

CONCLUSION

Regarding AKI risk stratification, the 2009 CKD-EPIcr equation showed better discriminative performance compared to the 2021 CKD-EPIcr equation in the study population.

Sexually dimorphic renal expression of Klotho is directed by a kidney-specific distal enhancer responsive to HNF1b

Transcription enhancers are genomic sequences regulating common and tissue-specific genes and their disruption can contribute to human disease development and progression. Klotho, a sexually dimorphic gene specifically expressed in kidney, is well-linked to kidney dysfunction and its deletion from the mouse genome leads to premature aging and death. However, the sexually dimorphic regulation of Klotho is not understood. Here, we characterize two candidate Klotho enhancers using H3K27ac epigenetic marks and transcription factor binding and investigate their functions, individually and combined, through CRISPR-Cas9 genome engineering. We discovered that only the distal (E1), but not the proximal (E2) candidate region constitutes a functional enhancer, with the double deletion not causing Klotho expression to further decrease. E1 activity is dependent on HNF1b transcription factor binding site within the enhancer. Further, E1 controls the sexual dimorphism of Klotho as evidenced by qPCR and RNA-seq. Despite the sharp reduction of Klotho mRNA, unlike germline Klotho knockouts, mutant mice presented normal phenotype, including weight, lifespan, and serum biochemistry. Lastly, only males lacking E1 display more prominent acute, but not chronic kidney injury responses, indicating a remarkable range of potential adaptation to isolated Klotho loss, especially in female E1 knockouts, retaining renoprotection despite over 80% Klotho reduction.

Association between albumin-corrected anion gap level and the risk of acute kidney injury in intensive care unit

PURPOSE

This study was to investigate the association between albumin-corrected anion gap (AG) (ACAG) levels and the risk of acute kidney injury (AKI) in intensive care unit (ICU) patients.

METHODS

The ICU patients of this retrospective cohort study were collected from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database between 2008 and 2019. ACAG = AG + {4.4 - [albumin (g/dl)]} × 2.5. The incidence of AKI was determined using the Kidney Disease: Improving Global Outcomes (KDIGO) definition. The logistic regression model was used to evaluate the association between ACAG levels and the risk of AKI. Subgroup analyses were applied based on age, gender, mechanical ventilation, vasopressors, the Charlson comorbidity index (CCI), and the Simplified Acute Physiology Score II (SAPS II).

RESULTS

Totally, 5586 patients were enrolled, of which 1929 patients (34.53%) occurred AKI. The higher levels of ACAG were associated with the risk of AKI in ICU patients, with the odds ratio (OR) value being 1.23 [95% confidence interval (CI): 1.22-1.24, P = 0.005] in ACAG level between 16.5 and 19.5, and OR value being 1.20 (95% CI 1.16-1.24, P = 0.016) in ACAG level > 19.5. A higher ACAG level was associated with a higher risk of AKI in ICU patients aged < 65 years, in ICU patients of female gender, in ICU patients who used mechanical ventilation, in ICU patients who did not use vasopressors, in patients without cardiogenic shock, and in ICU patients with CCI ≥ 2, and SAPS II > 31 (all P < 0.05).

CONCLUSION

There is an association between ACAG level and the risk of AKI in ICU patients. A higher ACAG value in ICU patients should therefore receive more attention.

Predictors of oliguria in post-traumatic acute kidney injury

BACKGROUND

Acute kidney injury is classified by urine output into non-oliguric and oliguric variants. Non-oliguric acute kidney injury has lower morbidity and mortality and accounts for up to 64% of acute kidney injury in hospitalized patients. However, the incidence of non-oliguric acute kidney injury in the trauma population and whether the 2 variants of acute kidney injury share the same risk factors is unknown. We hypothesized that oliguria would be present in the majority of acute kidney injury in severely injured trauma patients and that unique risk factors would predispose patients to the development of oliguria.

METHODS

Patients admitted to the trauma intensive care unit and diagnosed with an acute kidney injury between 2016 to 2021 were identified. Cases were categorized based on urine output into oliguric (<400 mL per day) and non-oliguric (>400 mL per day) disease. Risk factors, management, and outcomes were compared. Logistic regression was used to identify risk factors associated with oliguria.

RESULTS

A total of 227 patients met inclusion criteria. Non-oliguric acute kidney injury accounted for 74% of all cases and was associated with greater survival (78% vs 35.6%, P < .001). Using logistic regression, female sex, vasopressor use, and a greater net fluid balance at 48 hours were all predictive of oliguria (while controlling for age, race, shock index, massive transfusion, operative intervention, cardiac arrest, and nephrotoxic medication exposure).

CONCLUSION

Non-oliguria accounts for the majority of post-traumatic acute kidney injury and is associated with improved survival. Specific risk factors for the development of oliguric acute kidney injury include female sex, vasopressor use, and a higher net fluid balance at 48 hours.

Prevalence of acute kidney injury among dengue cases: a systematic review and meta-analysis

Numerous studies have shown a correlation between dengue virus (DENV) infection and kidney disease. However, there is no existing meta-analysis on the prevalence of kidney diseases in the dengue population. A thorough systematic review and meta-analysis were undertaken to determine the prevalence of renal problems in people with DENV infection in order to fill this knowledge gap. A rigorous electronic literature search was carried out up to 25 January 2023 in a number of databases, including ProQuest, EBSCOhost, Scopus, PubMed and Web of Science. The search aimed to find articles that reported on the prevalence of kidney diseases in patients with DENV infection. Using the modified Newcastle-Ottawa Scale, the quality of the included studies was assessed. The meta-analysis included a total of 37 studies with 21 764 participants reporting on the prevalence of acute kidney injury (AKI) in individuals with DENV infection. The pooled prevalence of AKI in dengue patients was found to be 8% (95% confidence interval 6 to 11), with high heterogeneity across studies. The studies included are of moderate quality. The study revealed a high AKI prevalence in dengue patients, underlining the need for regular renal examination to detect AKI early and reduce hospitalization risk. Further research is needed to understand the dengue-kidney relationship and develop effective management strategies.

Improving acute kidney injury alerts in tertiary care by linking primary care data: An observational cohort using routine care data

Objective

Acute kidney injury (AKI) is easily missed and underdiagnosed in routine clinical care. Timely AKI management is important to decrease morbidity and mortality risks. We recently implemented an AKI e-alert at the University Medical Center Utrecht, comparing plasma creatinine concentrations with historical creatinine baselines, thereby identifying patients with AKI. This alert is limited to data from tertiary care, and primary care data can increase diagnostic accuracy for AKI. We assessed the added value of linking primary care data to tertiary care data, in terms of timely diagnosis or excluding AKI.

Methods

With plasma creatinine tests for 84,984 emergency department (ED) visits, we applied the Kidney Disease Improving Global Outcome guidelines in both tertiary care-only data and linked data and compared AKI cases.

Results

Using linked data, the presence of AKI could be evaluated in an additional 7886 ED visits. Sex- and age-stratified analyses identified the largest added value for women (an increase of 4095 possible diagnoses) and patients ≥60 years (an increase of 5190 possible diagnoses). We observed 398 additional visits where AKI was diagnosed, as well as 185 cases where AKI could be excluded. We observed no overall decrease in time between baseline and AKI diagnosis (28.4 days vs. 28.0 days). For cases where AKI was diagnosed in both data sets, we observed a decrease of 2.8 days after linkage, indicating a timelier diagnosis of AKI.

Conclusions

Combining primary and tertiary care data improves AKI diagnostic accuracy in routine clinical care and enables timelier AKI diagnosis.

Differences in the epidemiology, management and outcomes of kidney disease in men and women

Improved understanding of differences in kidney disease epidemiology, management and outcomes in men and women could help nephrologists to better meet the needs of their patients from a sex- and gender-specific perspective. Evidence of sex differences in the risk and outcomes of acute kidney injury is mixed and dependent on aetiology. Women have a higher prevalence of chronic kidney disease (CKD) stages 3-5 than men, whereas men have a higher prevalence of albuminuria and hence CKD stages 1-2. Men show a faster decline in kidney function, progress more frequently to kidney failure and have higher mortality and risk of cardiovascular disease than women. However, the protective effect of female sex is reduced with CKD progression. Women are less likely than men to be aware of, screened for and diagnosed with CKD, started on antiproteinuric medication and referred to nephrologist care. They also consistently report a poorer health-related quality of life and a higher symptom burden than men. Women experience greater barriers than men to access the waiting list for kidney transplantation, particularly with respect to older age and obesity. However, women also have longer survival than men after transplantation, which may partly explain the comparable prevalence of transplantation between the sexes.

Gender differences and risk factors for acute kidney injury following cardiac surgery: A single center retrospective cohort study

Background

We studied AKI incidence and prognosis in cardiac surgery patients under and over 60 years old.

Methods

We studied AKI in patients who underwent cardiac surgery at the First Affiliated Hospital of Wenzhou Medical University between Jan 2020 and Dec 2021, using improved global prognostic criteria for diagnosis.

Results

After analyzing 781 patients (402 males, 379 females), AKI incidence after surgery was 30.22 %. Adjusting for propensity scores revealed no significant difference in AKI incidence between young males (24.1 %) and females (19.3 %). However, young females had higher AKI stages. Among older patients, AKI incidence was comparable between males (43.4 %) and females (42.2 %), but females had longer intubation times. Independent risk factors for AKI included age, male gender, and BMI, while intraoperative hemoglobin level was protective.

Conclusions

No gender gap in AKI frequency for <60 years old and ≥60 years old post-cardiac surgery, yet women display increased AKI severity and extended intubation duration.

ICU Admission Risk Factors for Latinx COVID-19 Patients at a U.S.-Mexico Border Hospital

OBJECTIVE

Few studies have examined the impact of coronavirus disease 2019 (COVID-19) on the primarily Latinx community along the U.S.-Mexico border. This study explores the socioeconomic impacts which contribute to strong predictors of severe COVID-19 complications such as intensive care unit (ICU) hospitalization in a primarily Latinx/Hispanic U.S.-Mexico border hospital.

METHODS

A retrospective, observational study of 156 patients (≥ 18 years) Latinx/Hispanic patients who were admitted for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at a U.S.-Mexico border hospital from April 10, 2020, to May 30, 2020. Descriptive statistics of sex, age, body mass index (BMI), and comorbidities (coronary artery disease, hypertension, diabetes, cancer/lymphoma, current use of immunosuppressive drug therapy, chronic kidney disease/dialysis, or chronic respiratory disease). Multivariate regression models were produced from the most significant variables and factors for ICU admission.

RESULTS

Of the 156 hospitalized Latinx patients, 63.5% were male, 84.6% had respiratory failure, and 45% were admitted to the ICU. The average age was 67.2 (± 12.2). Those with body mass index (BMI) ≥ 25 had a higher frequency of ICU admission. Males had a 4.4 (95% CI 1.58, 12.308) odds of ICU admission (p = 0.0047). Those who developed acute kidney injury (AKI) and BMI 25-29.9 were strong predictors of ICU admission (p < 0.001 and p = 0.0020, respectively). Those with at least one reported comorbidity had 1.98 increased odds (95% CI 1.313, 2.99) of an ICU admission.

CONCLUSION

Findings show that age, AKI, and male sex were the strongest predictors of COVID-19 ICU admissions in the primarily Latinx population at the U.S.-Mexico border. These predictors are also likely driven by socioeconomic inequalities which are most apparent in border hospitals.

Hepatocyte nuclear factor 4α mediated quinolinate phosphoribosylltransferase (QPRT) expression in the kidney facilitates resilience against acute kidney injury

Nicotinamide adenine dinucleotide (NAD+) levels decline in experimental models of acute kidney injury (AKI). Attenuated enzymatic conversion of tryptophan to NAD+ in tubular epithelium may contribute to adverse cellular and physiological outcomes. Mechanisms underlying defense of tryptophan-dependent NAD+ production are incompletely understood. Here we show that regulation of a bottleneck enzyme in this pathway, quinolinate phosphoribosyltransferase (QPRT) may contribute to kidney resilience. Expression of QPRT declined in two unrelated models of AKI. Haploinsufficient mice developed worse outcomes compared to littermate controls whereas novel, conditional gain-of-function mice were protected from injury. Applying these findings, we then identified hepatocyte nuclear factor 4 alpha (HNF4α) as a candidate transcription factor regulating QPRT expression downstream of the mitochondrial biogenesis regulator and NAD+ biosynthesis inducer PPARgamma coactivator-1-alpha (PGC1α). This was verified by chromatin immunoprecipitation. A PGC1α - HNF4α -QPRT axis controlled NAD+ levels across cellular compartments and modulated cellular ATP. These results propose that tryptophan-dependent NAD+ biosynthesis via QPRT and induced by HNF4α may be a critical determinant of kidney resilience to noxious stressors.

Predictors and outcomes of acute kidney injury after bariatric surgery: analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry

BACKGROUND

Acute kidney injury (AKI) after surgery increases long-term risk of kidney dysfunction. The major risk factor for AKI after bariatric surgery is having preoperative renal insufficiency. Little is known about the outcomes and risk factors for developing AKI in patients undergoing bariatric surgery with normal renal function.

OBJECTIVE

We aimed to describe factors that may increase risk of AKI after primary bariatric surgery in patients without history of kidney disease.

SETTING

Academic hospital, United States.

METHODS

We performed a retrospective analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry for patients aged ≥18 years undergoing laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass (LRYGB) from 2015 to 2019. Patients with diagnosis of chronic kidney disease were excluded. The primary outcome was incidence of AKI. Secondary outcomes included 30-day complications, readmissions, reoperations, and mortality. Univariate and multivariate analyses were performed to identify differences between patients with and without AKI.

RESULTS

A total of 747,926 patients were included in our analysis (laparoscopic sleeve gastrectomy = 73.1%, LRYGB = 26.8%). Mean age was 44.40 ± 11.94 years, with female predominance (79.7%). AKI occurred in 446 patients (.05%). Patients with postoperative AKI had higher rates of complications, readmissions, reoperations, and mortality. Significant predictors of AKI were male sex, history of venous thromboembolism, hypertension, limitation for ambulation, and LRYGB. High albumin levels and White race were protective factors.

CONCLUSIONS

New-onset AKI was associated with adverse 30-day outcomes in patients undergoing bariatric surgery. Male sex, venous thromboembolism, hypertension, limited ambulation, and LRYGB were independent predictors of AKI. Prospective studies are needed to better describe these results.

Association of the perfusion index with postoperative acute kidney injury: a retrospective study

BACKGROUND

Many studies have examined the risk factors for postoperative acute kidney injury (AKI), but few have focused on intraoperative peripheral perfusion index (PPI) that has recently been shown to be associated with postoperative morbidity and mortality. Therefore, this study aimed to evaluate the relationship between intraoperative PPI and postoperative AKI under the hypothesis that lower intraoperative PPI is associated with AKI occurrence.

METHODS

We retrospectively searched electronic medical records to identify patients who underwent surgery at the general surgery department from May 2021 to November 2021. Patient baseline characteristics, pre- and post-operative laboratory test results, comorbidities, intraoperative vital signs, and discharge profiles were obtained from the Institutional Clinical Data Warehouse and VitalDB. Intraoperative PPI was the primary exposure variable, and the primary outcome was postoperative AKI.

RESULTS

Overall, 2,554 patients were identified and 1,586 patients were included in our analysis. According to Kidney Disease Improving Global Outcomes (KDIGO) criteria, postoperative AKI occurred in 123 (7.8%) patients. We found that risks of postoperative AKI increased (odds ratio: 2.00, 95% CI [1.16, 3.44], P = 0.012) when PPI was less than 0.5 for more than 10% of surgery time. Other risk factors for AKI occurrence were male sex, older age, higher American Society of Anesthesiologists physical status, obesity, underlying renal disease, prolonged operation time, transfusion, and emergent operation.

CONCLUSIONS

Low intraoperative PPI was independently associated with postoperative AKI.

Longitudinal tracking of acute kidney injury reveals injury propagation along the nephron

Acute kidney injury (AKI) is an important risk factor for chronic kidney disease (CKD), but the underlying mechanisms of failed tubule repair and AKI-CKD transition are incompletely understood. In this study, we aimed for dynamic tracking of tubule injury and remodeling to understand if focal injury upon AKI may spread over time. Here, we present a model of AKI, in which we rendered only half of the kidney ischemic. Using serial intravital 2-photon microscopy and genetic identification of cycling cells, we tracked dynamic tissue remodeling in post- and non-ischemic kidney regions simultaneously and over 3 weeks. Spatial and temporal analysis of cycling cells relative to initial necrotic cell death demonstrated pronounced injury propagation and expansion into non-necrotic tissue regions, which predicted tubule atrophy with epithelial VCAM1 expression. In summary, our longitudinal analyses of tubule injury, remodeling, and fate provide important insights into AKI pathology.

Risk factors associated with contrast-associated acute kidney injury in ST-segment elevation myocardial infarction patients: a systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the risk factors for contrast-associated acute kidney injury (CA-AKI) in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched the databases of PubMed, Embase and Ovid, up to February 2022, for observational studies that investigated the association between risk factors and CA-AKI.

RESULTS

A total of 21 studies were included in the meta-analysis. Of the total 22 015 participants, 2728 developed CA-AKI. Pooled incidence was 11.91% (95% CI 9.69%, 14.14%). Patients with CA-AKI were more likely to be older, female, also had comorbidities (hypertension, diabetes, previous heart failure). Smoking (OR: 0.60; 95% CI 0.52, 0.69) and family history of CAD (coronary artery disease) (OR: 0.76; 95% CI 0.60, 0.95) were associated with lower risk of CA-AKI. Left anterior descending (LAD) artery occlusion (OR: 1.39; 95% CI 1.21, 1.59), left main disease (OR: 4.62; 95% CI 2.24, 9.53) and multivessel coronary disease (OR: 1.33; 95% CI 1.11, 1.60) were risk factors for CA-AKI. Contrast volume (weighted mean difference: 20.40; 95% CI 11.02, 29.79) was associated with increased risk in patients receiving iso-osmolar or low-osmolar non-ionic contrast.

CONCLUSIONS

In addition to the known risk factors, LAD artery infarction, left main disease and multivessel disease are risk factors for CA-AKI. The unexpected favourable association between smoking, as well as family history of CAD, and CA-AKI requires further investigation.

PROSPERO REGISTRATION NUMBER

CRD42021289868.

Kidney disease in patients with chronic liver disease: Does sex matter?

Kidney disease in patients with liver disease is serious and increases mortality. Up to 50% of patients hospitalized experience an episode of acute kidney injury. In general, men with liver disease are thought to be at increased risk of kidney disease. However, this association should be considered with caution because most studies use creatinine-based inclusion criteria, which is negatively biased against women. In this review, we synthesize data on sex differences in kidney disease in patients with chronic liver disease in the clinical setting and discuss potential physiologic underpinnings.

Post-injury Inhibition of Endothelin-1 Dependent Renal Vasoregulation Mitigates Rhabdomyolysis-Induced Acute Kidney Injury

In patients with rhabdomyolysis, the overwhelming release of myoglobin into the circulation is the primary cause of kidney injury. Myoglobin causes direct kidney injury as well as severe renal vasoconstriction. An increase in renal vascular resistance (RVR) results in renal blood flow (RBF) and glomerular filtration rate (GFR) reduction, tubular injury, and acute kidney injury (AKI). The mechanisms that underlie rhabdomyolysis-induced AKI are not fully understood but may involve the local production of vasoactive mediators in the kidney. Studies have shown that myoglobin stimulates endothelin-1 (ET-1) production in glomerular mesangial cells. Circulating ET-1 is also increased in rats subjected to glycerol-induced rhabdomyolysis. However, the upstream mechanisms of ET-1 production and downstream effectors of ET-1 actions in rhabdomyolysis-induced AKI remain unclear. Vasoactive ET-1 is generated by ET converting enzyme 1 (ECE-1)-induced proteolytic processing of inactive big ET to biologically active peptides. The downstream ion channel effectors of ET-1-induced vasoregulation include the transient receptor potential cation channel, subfamily C member 3 (TRPC3). This study demonstrates that glycerol-induced rhabdomyolysis in Wistar rats promotes ECE-1-dependent ET-1 production, RVR increase, GFR decrease, and AKI. Rhabdomyolysis-induced increases in RVR and AKI in the rats were attenuated by post-injury pharmacological inhibition of ECE-1, ET receptors, and TRPC3 channels. CRISPR/Cas9-mediated knockout of TRPC3 channels attenuated ET-1-induced renal vascular reactivity and rhabdomyolysis-induced AKI. These findings suggest that ECE-1-driven ET-1 production and downstream activation of TRPC3-dependent renal vasoconstriction contribute to rhabdomyolysis-induced AKI. Hence, post-injury inhibition of ET-1-mediated renal vasoregulation may provide therapeutic targets for rhabdomyolysis-induced AKI.

Factors Predictive of Development of Acute Kidney Injury in Patients With COVID-19 in Brunei Darussalam

INTRODUCTION

Acute kidney injury (AKI) in coronavirus disease 2019 (COVID-19) patients affects their health outcomes. Incidence and outcomes varied in the literature, particularly with different population and epidemiological demographics. Data remain scarce in the Southeast Asia region. We report the incidence, outcomes, pattern, types of AKI, and factors that influence AKI patient outcomes in Brunei Darussalam.

METHODS

All patients (N = 930) with COVID-19 who were admitted to the National Isolation Center (between 7th August 2021 and 30thSeptember 2021) were included in the study. The confirmation of AKI was based on the KDIGO (Kidney Disease Improving Global Outcomes) criteria.

RESULTS

The mean age of the patients was 41.9 ± 14.4 years with diabetes mellitus (DM), hypertension (HT), and chronic kidney disease (CKD) accounting for 11.7%, 29.1%, and 4.8% of comorbidities, respectively. Overall, 109 (11.7%) had AKI (KDIGO Stage 1 [67.9%], 2 [13.8%], and 3 [18.3%]), while 75.2% of the cases occurred pre-admission and 26.6% were cases of acute exacerbation of CKD. Univariate analysis identified age (odd ratio [OR] 1.06), male gender (OR 1.63), local nationality (OR 8.03), DM (OR 4.44), HT (OR 5.29), vascular disease (OR 6.08), presence of gastrointestinal symptoms (OR 2.08), antibiotic (OR 3.70) and nephrotoxins exposures (OR 8.57) as significant variables. Multivariate analysis showed age (adjusted OR [AOR] 1.04), male gender (AOR 1.67), gastrointestinal symptoms (AOR 1.61), antibiotic (AOR 2.34), and nephrotoxins exposure (AOR 4.73) as significant.

CONCLUSIONS

Our study showed that one in nine patients with COVID-19 developed AKI with almost a third having stages 2 and 3 AKI. Older age, male gender, presence of GI symptoms, and antibiotic and nephrotoxin exposures were significant predictors of AKI. Patients with these factors should be prioritized for admission and treatment. Even though manifestations are generally now less severe, findings from this study can guide the management of COVID-19 as the disease enters the endemic stage. Furthermore, lessons learned from the COVID-19 pandemic will provide useful information and knowledge for future viral outbreaks or pandemics.

Increase in Registered Acute Kidney Injuries in German Hospitals

BACKGROUND

Currently, the development of the incidence of acute kidney injury (AKI) and the influence of age and gender on the condition in Germany is unclear.

MATERIALS AND METHODS

Data were extracted from the national database of Federal Health Reporting. It was then normalized for demographic changes. Poisson regression was performed on 933,684 cases to quantify the correlation between age, years, and AKI incidence. Analysis of variance was performed on the same collection to evaluate gender disparities in different age groups.

RESULTS

In absolute numbers, registered AKI increased almost sevenfold from 11,964 to 77,719 between 2000 and 2019. After adjusting for demographic changes, the most AKI - 6300.5 per million person-years - occur in the elderly (>79 years old). Males have a higher risk for the development of an AKI. The male and female AKI incidence ratio varies significantly between different age groups, and it is the lowest in people <20 and >79 years old.

CONCLUSIONS

The registered incidence of AKI has risen substantially in the first 20 years of the millennium. The increase can partly be attributed to an increased diagnostic sensitivity provided by changes in the classification of AKI. It could also be shown that men suffer from AKI more often than women, particularly in the younger age groups.

FGFR regulator Memo1 is dispensable for FGF23 expression by osteoblasts during folic acid-driven kidney injury

Loss of the mediator Of cell motility 1 (Memo1) in mice caused kidney disease and a bone disease with diminished osteoblast and osteoclast biomarkers in serum, resembling alterations occurring in adynamic bone disease in humans with chronic kidney disease or in Klotho-deficient mice. Here, we investigated whether Memo1 expression in osteoblasts is required for normal bone structure and FGF23 expression. We deleted Memo1 in the osteoblast-osteocyte lineage in Memo fl/fl mice using a Cre under Col1a1 promotor to obtain osteoblast-specific knockout (obKO) mice. We studied organs by micro-computed tomography, qPCR, and western blot. We challenged mice with folic acid for acute kidney injury (AKI) and analyzed organs. Memo obKO were viable without changes in gross anatomy, serum electrolytes, or circulating FGF23 concentrations compared to controls. Memo1 expression was blunted in bones of Memo obKO, whereas it remained unchanged in other organs. Micro-CT revealed no differences between genotypes in bone structure of vertebrae, femur, and tibia. During AKI, Fgf23 expression in calvaria, and renal transcriptional changes were comparable between genotypes. However, renal injury marker expression, circulating FGF23, and parathyroid hormone revealed a sex difference with more severely affected females than males of either genotype. The present data imply that Memo1 in osteoblasts is dispensable for bone structure and expression of Fgf23. Moreover, we found evidence of potential sex differences in murine folic acid nephropathy similar to other experimental models of renal injury that are important to consider when using this experimental model of renal injury.

Acute Kidney Injury Among Patients with Multi-Drug Resistant Infection: A Study from Jordan

Background

Acute kidney injury (AKI) is a well-known complication for hospitalized patients. Sepsis and various infections play a significant role in increasing the incidence of AKI. The present study evaluated the risk for Multidrug-resistant (MDR) infections and its effect on the incidence of AKI, hospitalization, need for dialysis, and mortality.

Methods

In a retrospective study design, data were collected from all adult patients with a positive multi-drug resistant culture who were admitted to King Abdullah University Hospital (KAUH). Records of 436 patients were reviewed between January 2017 - December 2018 with at least one year of follow-up.

Results

The mean age was 57.3 years (SD± 23.1), and 58.5% were males. The most common source of positive cultures was sputum, with 50% positive cultures. The incidence of AKI was 59.2%. The most isolated microorganism was Acinetobacter baumannii (76.8%), followed by Pseudomonas aeruginosa (14.9%).On multivariate analysis, age (OR 1.1, 95% CI 1.1-1.2, P=0.001), HTN (OR 1.8, 95% CI 1.0-3.3, P=0.02), DM (OR 1.1, 95% CI 0.6-1.9, P=0.69) and the use of Foley catheter on chronic bases (OR 4.3, 95% CI 2.6-6.8, P<0.0001) were strong predictors of AKI. Among patients with AKI, 74.4% died compared to 44.4% among non-AKI patients (p<0.001).

Conclusion

In patients with MDR, AKI incidence, hospitalization, and mortality were high. Early detection and addressing the problem may decrease bad outcomes, and health education for reducing antibiotic abuse is needed to lower MDR.

Relation of Gender to the Occurrence of AKI in STEMI Patients

Patients undergoing percutaneous coronary interventions (PCIs) are prone to a wide range of complications; one complication that is constantly correlated with a worse prognosis is acute kidney injury (AKI). Gender as an independent risk factor for said complications has raised some interest; however, studies have shown conflicting results so far. We aimed to investigate the possible relation of gender to the occurrence of AKI in STEMI patients undergoing PCI. This retrospective observational study cohort included 2967 consecutive patients admitted with STEMI between the years 2008 and 2019. Their renal outcomes were assessed according to KDIGO criteria (AKI serum creatinine ≥ 0.3 mg/dL from baseline within 48 h from admission), and in-hospital complications and mortality were reviewed. Our main results show that female patients were older (69 vs. 60, p < 0.001) and had higher rates of diabetes (29.2% vs. 23%, p < 0.001), hypertension (62.9% vs. 41.3%, p < 0.001), and chronic kidney disease (26.7% vs. 19.3%, p < 0.001). Females also had a higher rate of AKI (12.7% vs. 7.8%, p < 0.001), and among patients with AKI, severe AKI was also more prevalent in females (26.1% vs. 14.5%, p = 0.03). However, in multivariate analyses, after adjusting for the baseline characteristics above, the female gender was a non-significant predictor for AKI (adjusted OR 1.01, 95% CI 0.73−1.4, p = 0.94) or severe AKI (adjusted OR 1.65, 95% CI 0.80−1.65, p = 0.18). In conclusion, while females had higher rates of AKI and severe AKI, gender was not independently associated with AKI after adjusting for other confounding variables. Other comorbidities that are more prevalent in females can account for the difference in AKI between genders.

Comparison of Adverse Kidney Outcomes With Empagliflozin and Linagliptin Use in Patients With Type 2 Diabetic Patients in a Real-World Setting

Background: To compare the effects of empagliflozin and linagliptin use on kidney outcomes of type 2 diabetes mellitus (T2DM) patients in a real-world setting. Methods: The study involved a propensity score-matched cohort comprising new users of empagliflozin or linagliptin with T2DM between January 1, 2013 and December 31, 2018 from a large healthcare delivery system in Taiwan. Clinical outcomes assessed: acute kidney injury (AKI), post-AKI dialysis, and mortality. Cox proportional hazard model was used to estimate the relative risk of empagliflozin or linagliptin use; a linear mixed model was used to compare the average change in estimated glomerular filtration rate (eGFR) over time. Results: Of the 7,042 individuals, 67 of 3,521 (1.9%) in the empagliflozin group and 144 of 3,521 (4.1%) in the linagliptin group developed AKI during the 2 years follow-up. Patients in the empagliflozin group were at a 40% lower risk of developing AKI compared to those in the linagliptin group (adjusted hazard ratio [aHR], 0.60; 95% confidence interval [CI], 0.45-0.82, p = 0.001). Stratified analysis showed that empagliflozin users ≥65 years of age (aHR, 0.70; 95% CI, 0.43-1.13, p = 0.148), or with a baseline eGFR <60 ml/min/1.73 m² (aHR, 0.97; 95% CI, 0.57-1.65, p = 0.899), or with a baseline glycohemoglobin ≦7% (aHR, 1.01; 95% CI, 0.51-2.00, p =0.973) experienced attenuated benefits with respect to AKI risk. A smaller decline in eGFR was observed in empagliflozin users compared to linagliptin users regardless of AKI occurrence (adjusted β = 1.51; 95% CI, 0.30-2.72 ml/min/1.73 m², p = 0.014). Conclusion: Empagliflozin users were at a lower risk of developing AKI and exhibited a smaller eGFR decline than linagliptin users. Thus, empagliflozin may be a safer alternative to linagliptin for T2DM patients.