Reduced Mortality Associated with Acute Kidney Injury Requiring Dialysis in the United States

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 US 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.

Acute Kidney Injury Receiving Dialysis and Dialysis Care after Hospital Discharge

The number of patients with AKI receiving outpatient hemodialysis (AKI-D) is increasing. At present, on the basis of limited data, approximately one third of patients with AKI-D who receive outpatient dialysis after hospital discharge survive and regain sufficient kidney function to discontinue dialysis. Data to inform dialysis management strategies that promote kidney function recovery and processes of care among patients with AKI-D receiving outpatient dialysis are lacking. In this article, we detail current trends in the incidence, risk factors, clinical outcomes, proposed management, and health policy landscape for patients with AKI-D receiving outpatient dialysis and identify areas for further research.

Characteristics of and Outcomes After Dialysis-Treated Acute Kidney Injury, 2009-2018: A Taiwanese Multicenter Study

RATIONALE & OBJECTIVE

Dialysis-treated acute kidney injury (AKI) is increasingly common in intensive care units (ICUs) and is associated with poor outcomes. Few studies have explored the temporal trends in severity of acute illness at dialysis initiation, indications for dialysis, and their association with patient outcomes.

STUDY DESIGN

Multicenter retrospective cohort study.

SETTING & PARTICIPANTS

9,535 adult patients admitted to the ICU who received their first dialysis treatment from Chang Gung Memorial Hospital system in Taiwan from 2009 through 2018.

EXPOSURE

Calendar year.

OUTCOMES

ICU mortality and dialysis treatment at discharge among hospital survivors.

ANALYTICAL APPROACH

The temporal trends during the study period were investigated using test statistics suited for continuous or categorical data. The association between the study year and the risk of mortality was analyzed using multivariable Cox regression with adjustment for relevant clinical variables, including the severity of acute illness, defined by Sequential Organ Failure Assessment (SOFA) score.

RESULTS

The mean SOFA score at dialysis initiation decreased slightly from 14.0 in 2009 to 13.6 in 2018. There was no significant trend in the number of indications for dialysis initiation that were fulfilled over time. Observed ICU mortality decreased over time, and the curve appeared to be reverse J-shaped, with a substantial decrease from 56.1% in 2009 to 46.3% in 2015 and a slight increase afterward. The risk of mortality was significantly reduced from 2013 to 2018 compared with 2009 in adjusted models. The decreasing trend in ICU mortality over time remained significant. There was an increase in dialysis treatment at discharge among survivors, mainly in patients with estimated glomerular filtration rate<60mL/min/1.73m², from 36.8% in 2009 to 43.9% in 2018.

LIMITATIONS

Residual confounding from unmeasured factors over time such as severity of comorbidities, detailed medication interventions, and delivered dialysis dose.

CONCLUSIONS

We observed reductions in mortality among ICU patients with dialysis-treated acute kidney injury between 2009 and 2018, even after adjusting for dialysis indication and severity of illness at dialysis initiation. However, dialysis treatment at discharge among survivors has increased over time, mainly in patients with preexisting kidney disease.

Modelling kidney outcomes based on MELD eras - impact of MELD score in renal endpoints after liver transplantation

Background

Acute kidney injury is a common complication in solid organ transplants, notably liver transplantation. The MELD is a score validated to predict mortality of cirrhotic patients, which is also used for organ allocation, however the influence of this allocation criteria on AKI incidence and mortality after liver transplantation is still uncertain.

Methods

This is a retrospective single center study of a cohort of patients submitted to liver transplant in a tertiary Brazilian hospital: Jan/2002 to Dec/2013, divided in two groups, before and after MELD implementation (pre-MELD and post MELD). We evaluate the differences in AKI based on KDIGO stages and mortality rates between the two groups.

Results

Eight hundred seventy-four patients were included, 408 in pre-MELD and 466 in the post MELD era. The proportion of patients that developed AKI was lower in the post MELD era (p 0.04), although renal replacement therapy requirement was more frequent in this group (p < 0.01). Overall mortality rate at 28, 90 and 365 days was respectively 7%, 11% and 15%. The 1-year mortality rate was lower in the post MELD era (20% vs. 11%, p < 0.01). AKI incidence was 50% lower in the post MELD era even when adjusted for clinically relevant covariates (p < 0.01).

Conclusion

Liver transplants performed in the post MELD era had a lower incidence of AKI, although there were more cases requiring dialysis. 1-year mortality was lower in the post MELD era, suggesting that patient care was improved during this period.

In-Hospital and 1-Year Mortality Trends in a National Cohort of US Veterans with Acute Kidney Injury

BACKGROUND AND OBJECTIVES

AKI, a frequent complication among hospitalized patients, confers excess short- and long-term mortality. We sought to determine trends in in-hospital and 1-year mortality associated with AKI as defined by Kidney Disease Improving Global Outcomes consensus criteria.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study used data from the national Veterans Health Administration on all patients hospitalized from October 1, 2008 to September 31, 2017. AKI was defined by Kidney Disease Improving Global Outcomes serum creatinine criteria. In-hospital and 1-year mortality trends were analyzed in patients with and without AKI using Cox regression with year as a continuous variable.

RESULTS

We identified 1,688,457 patients and 2,689,093 hospitalizations across the study period. Among patients with AKI, 6% died in hospital, and 28% died within 1 year. In contrast, in-hospital and 1-year mortality rates were 0.8% and 14%, respectively, among non-AKI hospitalizations. During the study period, there was a slight decline in crude in-hospital AKI-associated mortality (hazard ratio, 0.98 per year; 95% confidence interval, 0.98 to 0.99) that was attenuated after accounting for patient demographics, comorbid conditions, and acute hospitalization characteristics (adjusted hazard ratio, 0.99 per year; 95% confidence interval, 0.99 to 1.00). This stable temporal trend in mortality persisted at 1 year (adjusted hazard ratio, 1.00 per year; 95% confidence interval, 0.99 to 1.00).

CONCLUSIONS

AKI associated mortality remains high, as greater than one in four patients with AKI died within 1 year of hospitalization. Over the past decade, there seems to have been no significant progress toward improving in-hospital or long-term AKI survivorship.

The landscape of renal replacement therapy in Veterans Affairs Medical Center intensive care units

Background

Outpatient dialysis is standardized with several evidence-based measures of adequacy and quality that providers aim to meet while providing treatment. By contrast, in the intensive care unit (ICU) there are different types of prolonged and continuous renal replacement therapies (PIRRT and CRRT, respectively) with varied strategies for addressing patient care and a dearth of nationally accepted quality parameters. To eventually describe appropriate quality measures for ICU-related renal replacement therapy (RRT), we first aimed to capture the variety and prevalence of basic strategies and equipment utilized in the ICUs of Veteran Affairs (VA) medical facilities with inpatient hemodialysis capabilities.

Methods

Via email to the dialysis directors of all VA facilities that provided inpatient hemodialysis during 2018, we requested survey participation regarding aspects of RRT in VA ICUs. Questions centered around the mode of therapy, equipment, solutions, prescription authority, nursing, anticoagulation, antimicrobial dosing, and access.

Results

Seventy-six centers completed the questionnaire, achieving a response rate of 87.4%. Fifty-five centers reported using PIRRT or CRRT in addition to intermittent hemodialysis. Of these centers, 42 reported being specifically CRRT-capable. Over half of respondents had the capabilities to perform PIRRT. Twelve centers (21.8%) were equipped to use slow low efficient dialysis (SLED) alone. Therapy was largely prescribed by nephrologists (94.4% of centers).

Conclusions

Within the VA system, ICU-related RRT practice is quite varied. Variation in processes of care, prescription authority, nursing care coordination, medication management, and safety practices present opportunities for developing cross-cutting measures of quality of intensive care RRT that are agnostic of modality choice.

The Emergency Surgery Score accurately predicts the need for postdischarge respiratory and renal support after emergent laparotomies: A prospective EAST multicenter study

BACKGROUND

The Emergency Surgery Score (ESS) was recently validated as an accurate mortality risk calculator for emergency general surgery. We sought to prospectively evaluate whether ESS can predict the need for respiratory and/or renal support (RRS) at discharge after emergent laparotomies (EL).

METHODS

This is a post hoc analysis of a 19-center prospective observational study. Between April 2018 and June 2019, all adult patients undergoing EL were enrolled. Preoperative, intraoperative, and postoperative variables were systematically collected. In this analysis, patients were excluded if they died during the index hospitalization, were discharged to hospice, or transferred to other hospitals. A composite variable, the need for RRS, was defined as the need for one or more of the following at hospital discharge: tracheostomy, ventilator dependence, or dialysis. Emergency Surgery Score was calculated for all patients, and the correlation between ESS and RRS was examined using the c-statistics method.

RESULTS

From a total of 1,649 patients, 1,347 were included. Median age was 60 years, 49.4% were men, and 70.9% were White. The most common diagnoses were hollow viscus organ perforation (28.1%) and small bowel obstruction (24.5%); 87 patients (6.5%) had a need for RRS (4.7% tracheostomy, 2.7% dialysis, and 1.3% ventilator dependence). Emergency Surgery Score predicted the need for RRS in a stepwise fashion; for example, 0.7%, 26.2%, and 85.7% of patients required RRS at an ESS of 2, 12, and 16, respectively. The c-statistics for the need for RRS, the need for tracheostomy, ventilator dependence, or dialysis at discharge were 0.84, 0.82, 0.79, and 0.88, respectively.

CONCLUSION

Emergency Surgery Score accurately predicts the need for RRS at discharge in EL patients and could be used for preoperative patient counseling and for quality of care benchmarking.

LEVEL OF EVIDENCE

Prognostic and epidemiological, level III.

Recovery of kidney function after dialysis initiation in children and adults in the US: A retrospective study of United States Renal Data System data

BACKGROUND

Little is known about factors associated with recovery of kidney function-and return to dialysis independence-or temporal trends in recovery after starting outpatient dialysis in the United States. Understanding the characteristics of individuals who may have the potential to recover kidney function may promote better recognition of such events. The goal of this study was to determine factors associated with recovery of kidney function in children compared with adults starting dialysis in the US.

METHODS AND FINDINGS

We determined factors associated with recovery of kidney function-defined as survival and discontinuation of dialysis for ≥90-day period-in children versus adults who started maintenance dialysis between 1996 and 2015 according to the United States Renal Data System (USRDS) followed through 2016 in a retrospective cohort study. We also examined temporal trends in recovery rates over the last 2 decades in this cohort. Among 1,968,253 individuals included for study, the mean age was 62.6 ± 15.8 years, and 44% were female. Overall, 4% of adults (83,302/1,953,881) and 4% of children (547/14,372) starting dialysis in the outpatient setting recovered kidney function within 1 year. Among those who recovered, the median time to recovery was 73 days (interquartile range [IQR] 43-131) in adults and 100 days (IQR 56-189) in children. Accounting for the competing risk of death, children were less likely to recover kidney function compared with adults (sub-hazard ratio [sub-HR] 0.81; 95% CI 0.74-0.89, p-value <0.001; point estimates <1 indicating increased risk for a negative outcome). Non-Hispanic black (NHB) adults were less likely to recover compared with non-Hispanic white (NHW) adults, but these racial differences were not observed in children. Of note, a steady increase in the incidence of recovery of kidney function was noted initially in adults and children between 1996 and 2010, but this trend declined thereafter. The diagnoses associated with the highest recovery rates of recovery were acute tubular necrosis (ATN) and acute interstitial nephritis (AIN) in both adults and children, where 25%-40% of patients recovered kidney function depending on the calendar year of dialysis initiation. Limitations to our study include the potential for residual confounding to be present given the observational nature of our data.

CONCLUSIONS

In this study, we observed that discontinuation of outpatient dialysis due to recovery occurred in 4% of patients with end-stage kidney disease (ESKD) and was more common among those with ATN or AIN as the cause of their kidney disease. While recovery rates rose initially, they declined starting in 2010. Additional studies are needed to understand how to best recognize and promote recovery in patients whose potential to discontinue dialysis is high in the outpatient setting.

Changing epidemiology and outcomes of acute kidney injury in hospitalized patients with cirrhosis - a US population-based study

BACKGROUND & AIMS

Acute kidney injury (AKI) is a significant clinical event in cirrhosis yet contemporary population-based studies on the impact of AKI on hospitalized cirrhotics are lacking. We aimed to characterize longitudinal trends in incidence, healthcare burden and outcomes of hospitalized cirrhotics with and without AKI using a nationally representative dataset.

METHODS

Using the 2004-2016 National Inpatient Sample (NIS), admissions for cirrhosis with and without AKI were identified using ICD-9 and ICD-10 codes. Regression analysis was used to analyze the trends in hospitalizations, costs, length of stay and inpatient mortality. Descriptive statistics, simple and multivariable logistic regression were used to assess associations between individual characteristics, comorbidities, and cirrhosis complications with AKI and death.

RESULTS

In over 3.6 million admissions for cirrhosis, 22% had AKI. AKI admissions were more costly (median $13,127 [IQR $7,367-$24,891] vs. $8,079 [IQR $4,956-$13,693]) and longer (median 6 [IQR 3-11] days vs. 4 [IQR 2-7] days). Over time, AKI prevalence doubled from 15% in 2004 to 30% in 2016. CKD was independently and strongly associated with AKI (adjusted odds ratio 3.75; 95% CI 3.72-3.77). Importantly, AKI admissions were 3.75 times more likely to result in death (adjusted odds ratio 3.75; 95% CI 3.71-3.79) and presence of AKI increased risk of mortality in key subgroups of cirrhosis, such as those with infections and portal hypertension-related complications.

CONCLUSIONS

The prevalence of AKI is significantly increased among hospitalized cirrhotics. AKI substantially increases the healthcare burden associated with cirrhosis. Despite advances in cirrhosis care, a significant gap remains in outcomes between cirrhotics with and without AKI, suggesting that AKI continues to represent a major clinical challenge.

LAY SUMMARY

Sudden damage to the kidneys is becoming more common in people who are hospitalized and have cirrhosis. Despite advances in cirrhosis care, those with damage to the kidneys remain at higher risk of dying.

Survival and renal recovery after acute kidney injury requiring dialysis outside of intensive care units

BACKGROUND

The incidence of acute kidney injury requiring dialysis (AKI-D) is increasing globally and it is usually associated to chronic kidney disease (CKD) and high mortality. Literature is lacking in short- and intermediate-term data on recovery of renal function after acute kidney injury (AKI).

OBJECTIVES

The objective was to evaluate the overall survival and renal recovery after an episode of AKI requiring dialysis out of intensive care units (ICUs).

MATERIALS AND METHODS

Retrospective study including patients admitted in two nephrology units along a period of 2 years. Patients admitted to ICUs and renal transplant patients were excluded. Baseline renal function, mortality and glomerular filtration rate (GFR) improvement were evaluated.

RESULTS

151 consecutive adult patients with AKI requiring renal replacement therapy (RRT) were included. Mean age was 70.5 ± 15.2 years, 60.3% were males. Median baseline creatinine (bCr) and baseline GFR (bGFR) were 1.4 mg/dL and 46 mL/min/1.73 m², respectively. After 1 year of follow-up, we completed the monitoring of 94 patients: 64.9% had died, 10.6% were alive on dialysis and 24.5% were alive without need for RRT. Patients with bGFR > 60 mL/min/1.73 m² prior to AKI episode had a slower but sustained GFR improvement through the follow-up in comparison with patients with bGFR < 60 mL/min/1.73 m² whose recovery was incomplete.

CONCLUSIONS

Patients with AKI requiring RRT have high short- and intermediate-term mortality and some require maintenance dialysis. Patients with GFR > 60 mL/min/1.73 m² prior to AKI had a renal recovery closer to the basal renal function than in patients with a previously diminished GFR.

US Trends in Hospitalizations for Dialysis-Requiring Acute Kidney Injury in People With Versus Without Diabetes

RATIONALE & OBJECTIVE

Dialysis-requiring acute kidney injury (AKI-D) has increased substantially in the United States. We examined trends in and comorbid conditions associated with hospitalizations and in-hospital mortality in the setting of AKI-D among people with versus without diabetes.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

Nationally representative data from the National Inpatient Sample and National Health Interview Survey were used to generate 16 cross-sectional samples of US adults (aged ≥18 years) between 2000 and 2015.

EXPOSURE

Diabetes, defined using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes.

OUTCOME

AKI-D, defined using ICD-9-CM diagnosis and procedure codes.

ANALYTICAL APPROACH

Annual age-standardized rates of AKI-D and AKI-D mortality were calculated for adults with and without diabetes, by age and sex. Data were weighted to be representative of the US noninstitutionalized population. Trends were assessed using join point regression with annual percent change (Δ/y) reported.

RESULTS

In adults with diabetes, AKI-D increased between 2000 and 2015 (from 26.4 to 41.1 per 100,000 persons; Δ/y, 3.3%; P < 0.001), with relative increases greater in younger versus older adults. In adults without diabetes, AKI-D increased between 2000 and 2009 (from 4.8 to 8.7; Δ/y, 6.5%; P < 0.001) and then plateaued. AKI-D mortality significantly declined in people with and without diabetes. In adults with and without diabetes, the proportion of AKI-D hospitalizations with liver, rheumatic, and kidney disease comorbid conditions increased between 2000 and 2015, while the proportion of most cardiovascular comorbid conditions decreased.

LIMITATIONS

Lack of laboratory data to corroborate AKI diagnosis; National Inpatient Sample data are hospital-level rather than person-level data; no data for type of diabetes; residual unmeasured confounding.

CONCLUSIONS

Hospitalization rates for AKI-D have increased considerably while mortality has decreased in adults with and without diabetes. Hospitalization rates for AKI-D remain substantially higher in adults with diabetes. Greater AKI risk-factor mitigation is needed, especially in young adults with diabetes.

Acute Renal Failure of Nosocomial Origin

BACKGROUND

10-20% of hospitalized patients develop acute kidney injury (AKI)/acute renal failure during their hospital stay. The mortality of nosocomial AKI is approximately 30%.

METHODS

This review is based on relevant publications retrieved by a search in multiple databases (PubMed and Uptodate), archives, and pertinent medical journals.

RESULTS

The most common causes of nosocomial AKI are volume depletion, sepsis, heart diseases, polytrauma, liver diseases, and drug toxicity. AKI can also be of postrenal (obstructive) origin, or a result of renal diseases including glomeruloneph- ritis, vasculitis, tubulointerstitial nephritis, and cholesterol embolism. In about 13% of cases, nosocomial AKI develops on the basis of pre-existing chronic renal disease. Patients with AKI are at elevated risk of developing chronic renal disease and must be followed up appropriately after they are discharged from the hospital. Indispens- able elements of the evaluation of nosocomial AKI include renal ultrasonography, the exclusion of postrenal obstruction, urine chemistry, and microbiological urinaly- sis. Potentially nephrotoxic drugs and those that impair renal hemodynamics must be avoided to the greatest possible extent in patients with acute renal damage. Hypotension must be avoided as well.

CONCLUSION

Early, specific nephrological diagnosis and treatment are important components of the management of nosocomial AKI, particularly because causally directed treatment is available for some of the conditions that underlie it.

Incident infection following acute kidney injury with recovery to baseline creatinine: A propensity score matched analysis

Background

Severe acute kidney injury (AKI) is associated with subsequent infection. Whether AKI followed by a return to baseline creatinine is associated with incident infection is unknown.

Objective

We hypothesized that risk of both short and long term infection would be higher among patients with AKI and return to baseline creatinine than in propensity score matched peers without AKI in the year following a non-infectious hospital admission.

Design

Retrospective, propensity score matched cohort study.

Participants

We identified 494 patients who were hospitalized between January 1, 1999 and December 31, 2009 and had AKI followed by return to baseline creatinine. These were propensity score matched to controls without AKI.

Main Measures

The predictor variable was AKI defined by International Classification of Diseases, Ninth Revision (ICD-9) codes and by the Kidney Disease Improving Global Outcomes definition, with return to baseline creatinine defined as a decrease in serum creatinine level to within 10% of the baseline value within 7 days of hospital discharge. The outcome variable was incident infection defined by ICD-9 code within 1 year of hospital discharge.

Results

AKI followed by return to baseline creatinine was associated with a 4.5-fold increased odds ratio for infection (odds ratio 4.53 [95% CI, 2.43–8.45]; p<0.0001) within 30 days following discharge. The association between AKI and subsequent infection remained significant at 31–60 days and 91 to 365 days but not during 61–90 days following discharge.

Conclusion

Among patients from an integrated health care delivery system, non-infectious AKI followed by return to baseline creatinine was associated with an increased odds ratio for infection in the year following discharge.

Outpatient Dialysis for Acute Kidney Injury: Progress and Pitfalls

Dialysis-requiring acute kidney injury (AKI) has increased markedly in the United States. At the same time, mortality rates have recently improved. As such, increasing numbers of patients with AKI are surviving to hospital discharge, including up to 30% who will continue to require outpatient dialysis. In recent years, policy changes have significantly affected the care of this high-risk population. Beginning in 2017, new legislation reversed a previous Centers for Medicare & Medicaid Services policy that prohibited dialysis for AKI at end-stage renal disease (ESRD) facilities. This has improved dialysis options for patients, but the impact on patient outcomes remains uncertain. Unfortunately, there is currently a lack of evidence basis to guide management of this vulnerable patient population. Moving forward, additional data reporting and analyses will be required, analogous to how the US Renal Data System has helped inform ESRD care. As the dialysis setting for patients with AKI shifts to the ESRD setting, it is incumbent on the nephrology community to identify best practices to promote kidney recovery, recognizing that these practices will differ from standard ESRD protocols.

Increased incidence of acute kidney injury requiring dialysis in metropolitan France

Background

Acute kidney injury requiring dialysis (AKI-D) is associated with high mortality. Information about its epidemiology is nonetheless sparse in some countries. The objective of this study was to assess its epidemiology and prognosis in metropolitan France.

Methods

Using the French hospital discharge database, the study focused on adults hospitalized in metropolitan France between 2009 and 2014 and diagnosed with AKI-D according to the codes of the French common classification of medical procedures. Crude and standardized incidence rates (SIR) by gender and age were calculated. We explored the changes in patients’ characteristics, modalities of renal replacement therapy (RRT), in-hospital care, and mortality, along with their determinants. Trends over time in the SIR for AKI-D, its principal diagnoses, and comorbidities were analyzed with joinpoint models.

Results

Between 2009 and 2014, the AKI-D SIR increased from 475 (95% CI, 468 to 482) to 512 per million population (95% CI, 505 to 519). AKI-D was twice as high in men as women. Median age was 68 years. Over the study period, the AKI-D SIR steadily increased in all age groups, particularly in the elderly. The most common comorbidities were cardio-cerebrovascular diseases (64.8%), pulmonary disease (42.2%), CKD (33.8%), and diabetes (26.0%); all of these except CKD increased significantly over time. In 2009, heart failure (17.2%), sepsis (17.0%), AKI (13.0%), digestive diseases (10.7%), and shock (6.6%) were the most frequent principal diagnoses, with a significant increase in heart failure and digestive diseases. The proportion of patients with at least one ICU stay and continuous RRT increased from 80.3% to 83.9% and from 56.9% to 61.8% (p<0.001), respectively. In-hospital mortality was high but stable (47%) and higher in patients with an ICU stay.

Conclusions

This is the first exhaustive study in metropolitan France of the SIR for AKI-D. It shows this SIR has increased significantly over 6 years, together with ICU care and continuous RRT. In-hospital mortality is high but stable.

Epidemiology of acute kidney injury and chronic kidney disease in the intensive care unit

OBJECTIVE

To describe the epidemiology of acute kidney injury, its relationship to chronic kidney disease, and the factors associated with its incidence.

METHODS

A cohort study and follow-up were conducted in an intensive care unit in Montevideo, Uruguay. We included patients admitted between November 2014 and October 2015 who were older than 15 years of age and who had at least two measurements of serum creatinine. We excluded patients who were hospitalized for less than 48 hours, patients who died at the time of hospitalization, and patients with chronic renal disease who were on hemodialysis or peritoneal dialysis. There were no interventions. Acute kidney injury was defined according to the criteria set forth in Acute Kidney Injury Disease: Improving Global Outcomes, and chronic kidney disease was defined according to the Chronic Kidney Disease Work Group.

RESULTS

We included 401 patients, 56.6% male, median age of 68 years (interquartile range (IQR) 51-79 years). The diagnosis at admission was severe sepsis 36.3%, neurocritical 16.3%, polytrauma 15.2%, and other 32.2%. The incidence of acute kidney injury was 50.1%, and 14.1% of the patients suffered from chronic kidney disease. The incidence of acute septic kidney injury was 75.3%. Mortality in patients with or without acute kidney injury was 41.8% and 14%, respectively (p < 0.001). In the multivariate analysis, the most significant variables for acute kidney injury were chronic kidney disease (odds ratio (OR) 5.39, 95%CI 2.04 - 14.29, p = 0.001), shock (OR 3.94, 95%CI 1.72 - 9.07, p = 0.001), and severe sepsis (OR 7.79, 95%CI 2.02 - 29.97, p = 0.003).

CONCLUSION

The incidence of acute kidney injury is high mainly in septic patients. Chronic kidney disease was independently associated with the development of acute kidney injury.

Does NGAL reduce costs? A cost analysis of urine NGAL (uNGAL) & serum creatinine (sCr) for acute kidney injury (AKI) diagnosis

Introduction

Urine neutrophil gelatinase-associated lipocalin (uNGAL) is a sensitive and specific diagnostic test for acute kidney injury (AKI) in the Emergency Department (ED), but its economic impact has not been investigated. We hypothesized that uNGAL used in combination with serum creatinine (sCr) would reduce costs in the management of AKI in patients presenting to the ED in comparison to using sCr alone.

Materials and methods

A cost simulation model was developed for clinical algorithms to diagnose AKI based on sCr alone vs. uNGAL plus sCr (uNGAL+sCr). A cost minimization analysis was performed to determine total expected costs for patients with AKI. uNGAL test characteristics were validated with eight-hundred forty-nine patients with sCr ≥1.5 from a completed study of 1635 patients recruited from EDs at two U.S. hospitals from 2007–8. Biomarker test, AKI work-up, and diagnostic imaging costs were incorporated.

Results

For a hypothetical cohort of 10,000 patients, the model predicted that the expected costs were $900 per patient (pp) in the sCr arm and $950 in the uNGAL+sCr arm. uNGAL+sCr resulted in 1,578 fewer patients with delayed diagnosis and treatment than sCr alone (2,013 vs. 436 pts) at center 1 and 1,973 fewer patients with delayed diagnosis and treatment than sCr alone at center 2 (2,227 vs. 254 patients). Although initial evaluation costs at each center were $50 pp higher in with uNGAL+sCr, total costs declined by $408 pp at Center 1 and by $522 pp at Center 2 due to expected reduced delays in diagnosis and treatment. Sensitivity analyses confirmed savings with uNGAL + sCr for a range of cost inputs.

Discussion

Using uNGAL with sCr as a clinical diagnostic test for AKI may improve patient management and reduce expected costs. Any cost savings would likely result from avoiding delays in diagnosis and treatment and from avoidance of unnecessary testing in patients given a false positive AKI diagnosis by use of sCr alone.

Renal Replacement Therapy in Acute Kidney Injury: Controversies and Consensus

Acute kidney injury (AKI) is a common complication among critically ill patents, and 5% of intensive care unit (ICU) patients require initiation of renal replacement therapy (RRT). In recent years, clinical trials have provided evidence-based guidance for some important aspects of RRT management in patients with AKI, such as dialysis dosing and approaches to anticoagulation in patients undergoing continuous RRT. However, there remain many areas of uncertainty, and delivery of RRT in the ICU requires clinical judgment, flexibility, and an understanding of dialysis principles. This article reviews the components of RRT prescription and provides an update on best practices.