Secular Trends in Incidence, Modality and Mortality with Dialysis Receiving AKI in Children in Ontario: A Population-Based Cohort Study

An update on the role of fluid overload in the prediction of outcome in acute kidney injury

Over the past two decades, our understanding of the impact of acute kidney injury, disorders of fluid balance, and their interplay have increased significantly. In recent years, the epidemiology and impact of fluid balance, including the pathologic state of fluid overload on outcomes has been studied extensively across multiple pediatric and neonatal populations. A detailed understating of fluid balance has become increasingly important as it is recognized as a target for intervention to continue to work to improve outcomes in these populations. In this review, we provide an update on the epidemiology and outcomes associated with fluid balance disorders and the development of fluid overload in children with acute kidney injury (AKI). This will include a detailed review of consensus definitions of fluid balance, fluid overload, and the methodologies to define them, impact of fluid balance on the diagnosis of AKI and the concept of fluid corrected serum creatinine. This review will also provide detailed descriptions of future directions and the changing paradigms around fluid balance and AKI in critical care nephrology, including the incorporation of the sequential utilization of risk stratification, novel biomarkers, and functional kidney tests (furosemide stress test) into research and ultimately clinical care. Finally, the review will conclude with novel methods currently under study to assess fluid balance and distribution (point of care ultrasound and bioimpedance).

Programs and processes for advancing pediatric acute kidney support therapy in hospitalized and critically ill children: a report from the 26th Acute Disease Quality Initiative (ADQI) consensus conference

Pediatric acute kidney support therapy (paKST) programs aim to reliably provide safe, effective, and timely extracorporeal supportive care for acutely and critically ill pediatric patients with acute kidney injury (AKI), fluid and electrolyte derangements, and/or toxin accumulation with a goal of improving both hospital-based and lifelong outcomes. Little is known about optimal ways to configure paKST teams and programs, pediatric-specific aspects of delivering high-quality paKST, strategies for transitioning from acute continuous modes of paKST to facilitate rehabilitation, or providing effective short- and long-term follow-up. As part of the 26th Acute Disease Quality Initiative Conference, the first to focus on a pediatric population, we summarize here the current state of knowledge in paKST programs and technology, identify key knowledge gaps in the field, and propose a framework for current best practices and future research in paKST.

Acute kidney injury: exploring endoplasmic reticulum stress-mediated cell death

Acute kidney injury (AKI) is a global health problem, given its substantial morbidity and mortality rates. A better understanding of the mechanisms and factors contributing to AKI has the potential to guide interventions aimed at mitigating the risk of AKI and its subsequent unfavorable outcomes. Endoplasmic reticulum stress (ERS) is an intrinsic protective mechanism against external stressors. ERS occurs when the endoplasmic reticulum (ER) cannot deal with accumulated misfolded proteins completely. Excess ERS can eventually cause pathological reactions, triggering various programmed cell death (autophagy, ferroptosis, apoptosis, pyroptosis). This article provides an overview of the latest research progress in deciphering the interaction between ERS and different programmed cell death. Additionally, the report consolidates insights into the roles of ERS in AKI and highlights the potential avenues for targeting ERS as a treatment direction toward for AKI.

Prevalence and Mortality Rates of Acute Kidney Injury among Critically Ill Patients: A Retrospective Study

Acute kidney injury (AKI) poses a significant challenge in critically ill patients. To determine the prevalence, risk factors, and mortality rate of AKI among nonsurgical critically ill patients in Jordan University Hospital, we conducted a retrospective study using a consecutive sampling method, including 457 nonsurgical critically ill patients admitted to the medical intensive care unit (MICU) from January to June 2021. The mean age was 63.8 ± 18 years, with 196 (42.8%) developing AKI during their stay in the MICU. Among AKI nonsurgical patients, pulmonary diseases (n = 52; 34.5%) emerged as the primary cause for admission, exhibiting the highest prevalence, followed by sepsis (n = 40; 20.4%). Furthermore, we found that older age (adjusted OR (AOR): 1.04; 95% confidence interval (CI): 1.04-1.06; p = 0.003), preadmission use of diuretics (AOR: 2.12; 95% CI: 1.06-4.25; p = 0.03), use of ventilators (2.19; 95% CI: 1.12-2.29; p = 0.02), and vasopressor use during MICU stay (AOR: 4.25; 95% CI: 2.1308.47; p = 0.001) were observed to have higher mortality rates. Prior utilization of statins before admission exhibited a significant association with reduced mortality rate (AOR: 0.42; 95% CI: 0.2-0.85; p = 0.02). Finally, AKI was associated with a higher mortality rate during MICU stay (AOR: 2.44; 95% CI: 1.07-5.56; p = 0.03). The prevalence of AKI among nonsurgical patients during MICU stay is higher than what has been reported previously in the literature, which highlights the nuanced importance of identifying more factors contributing to AKI in developing countries, and hence providing preventive measures and adhering to global strategies are recommended.

A simplified protocol of regional citrate anticoagulation with phosphate-containing solutions in infants and children treated with continuous kidney replacement therapy

BACKGROUND

Regional citrate anticoagulation (RCA) is the preferred modality of anticoagulation used in continuous kidney replacement therapy (CKRT) in adults and less extensively in children. Potential metabolic complications limit widespread use in infants, neonates, and in children with liver failure.

METHODS

We report our experience with a simplified protocol in 50 critically ill children, infants, and neonates, some of them with liver failure, with commercially available solutions containing phosphorous and higher concentration of potassium and magnesium.

RESULTS

RCA allowed attainment of a mean filter lifetime of 54.5 ± 18.2 h, 42.5% of circuits lasted more than 70 h, and scheduled change was the most frequent cause of CKRT interruption. Patient Ca++ and circuit Ca++ were maintained in the target range with mean values of 1.15 ± 0.13 mmol/l and 0.38 ± 0.07 mmol/l, respectively. No session had to be stopped because of metabolic complications. The most frequent complications were hyponatremia, hypomagnesemia, and metabolic acidosis mostly related to primary disease and critical illness. No session had to be stopped because of citrate accumulation (CA). Transitory CA occurred in 6 patients and was managed without requiring RCA interruption. No patients with liver failure presented CA episodes.

CONCLUSIONS

In our experience, RCA with commercially available solutions was easily applied and managed in critically ill children, even in patients with low weight or with liver failure. Solutions containing phosphate and higher concentrations of magnesium and potassium allowed reduction of metabolic derangement during CKRT. Prolonged filter life was ensured with no detrimental effects on patients and reduced staff workload. A higher resolution version of the Graphical abstract is available as Supplementary information.

Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK)

Introduction

Continuous renal replacement therapy (CRRT) is used for the symptomatic management of acute kidney injury (AKI) and fluid overload (FO). Contemporary reports on pediatric CRRT are small and single center in design. Large international studies evaluating CRRT practice and outcomes are lacking. Herein, we describe the design of a multinational collaborative.

Methods

The Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK) is an international collaborative of pediatric specialists whose mission is to improve short- and long-term outcomes of children treated with CRRT. The aims of this multicenter retrospective study are to describe the epidemiology, liberation patterns, association of fluid balance and timing of CRRT initiation, and CRRT prescription with outcomes.

Results

We included children (n = 996, 0-25 years) admitted to an intensive care unit (ICU) and treated with CRRT for AKI or FO at 32 centers (in 7 countries) from 2018 to 2021. Demographics and clinical characteristics before CRRT initiation, during the first 7 days of both CRRT, and liberation were collected. Outcomes include the following: (i) major adverse kidney events at 90 days (mortality, dialysis dependence, and persistent kidney dysfunction), and (ii) functional outcomes (functional stats scale).

Conclusion

The retrospective WE-ROCK study represents the largest international registry of children receiving CRRT for AKI or FO. It will serve as a broad and invaluable resource for the field of pediatric critical care nephrology that will improve our understanding of practice heterogeneity and the association of CRRT with clinical and patient-centered outcomes. This will generate preliminary data for future interventional trials in this area.

Long-term Health Care Utilization and Associated Costs After Dialysis-Treated Acute Kidney Injury in Children

RATIONALE & OBJECTIVE

Acute kidney injury (AKI) is common among hospitalized children and is associated with increased hospital length of stay and costs. However, there are limited data on postdischarge health care utilization after AKI hospitalization. Our objectives were to evaluate health care utilization and physician follow-up patterns after dialysis-treated AKI in a pediatric population.

STUDY DESIGN

Retrospective cohort study, using provincial health administrative databases.

SETTING & PARTICIPANTS

All children (0-18 years) hospitalized between 1996 and 2017 in Ontario, Canada. Excluded individuals comprised non-Ontario residents; those with metabolic disorders or poisoning; and those who received dialysis or kidney transplant before admission, a kidney transplant by 104 days after discharge, or were receiving dialysis 76-104 days from dialysis start date.

EXPOSURE

Episodes of dialysis-treated AKI, identified using validated health administrative codes. AKI survivors were matched to 4 hospitalized controls without dialysis-treated AKI by age, sex, and admission year.

OUTCOME

Our primary outcome was postdischarge hospitalizations, emergency department visits, and outpatient physician visits. Secondary outcomes included outpatient visits by physician type and composite health care costs.

ANALYTICAL APPROACH

Proportions with≥1 event and rates (per 1,000 person-years). Total and median composite health care costs. Adjusted rate ratios using negative binomial regression models.

RESULTS

We included 1,688 pediatric dialysis-treated AKI survivors and 6,752 matched controls. Dialysis-treated AKI survivors had higher rehospitalization and emergency department visit rates during the analyzed follow-up periods (0-1, 0-5, and 0-10 years postdischarge, and throughout follow-up), and higher outpatient visit rates in the 0-1-year follow-up period. The overall adjusted rate ratio for rehospitalization was 1.46 (95% CI, 1.25-1.69; P<0.0001) and for outpatient visits was 1.16 (95% CI, 1.09-1.23; P=0.01). Dialysis-treated AKI survivors also had higher health care costs. Nephrologist follow-up was infrequent among dialysis-treated AKI survivors (18.6% by 1 year postdischarge).

LIMITATIONS

Potential miscoding of study exposures or outcomes. Residual uncontrolled confounding. Data for health care costs and emergency department visits was unavailable before 2006 and 2001, respectively.

CONCLUSIONS

Dialysis-treated AKI survivors had greater postdischarge health care utilization and costs versus hospitalized controls. Strategies are needed to improve follow-up care for children after dialysis-treated AKI to prevent long-term complications.

Delivering optimal renal replacement therapy to critically ill patients with acute kidney injury

Critical illness is often complicated by acute kidney injury (AKI). In patients with severe AKI, renal replacement therapy (RRT) is deployed to address metabolic dysfunction and volume excess until kidney function recovers. This review is intended to provide a comprehensive update on key aspects of RRT prescription and delivery to critically ill patients. Recently completed trials have enhanced the evidence base regarding several RRT practices, most notably the timing of RRT initiation and anticoagulation for continuous therapies. Better evidence is still needed to clarify several aspects of care including optimal targets for ultrafiltration and effective strategies for RRT weaning and discontinuation.

Health care utilization and costs following Kawasaki disease

Objectives

Kawasaki disease (KD) is a common childhood vasculitis with increasing incidence in Canada. Acute KD hospitalizations are associated with high health care costs. However, there is minimal health care utilization data following initial hospitalization. Our objective was to determine rates of health care utilization and costs following KD diagnosis.

Methods

We used population-based health administrative databases to identify all children (0 to 18 years) hospitalized for KD in Ontario between 1995 and 2018. Each case was matched to 100 nonexposed comparators by age, sex, and index year. Follow-up continued until death or March 2019. Our primary outcomes were rates of hospitalization, emergency department (ED), and outpatient physician visits. Our secondary outcomes were sector-specific and total health care costs.

Results

We compared 4,597 KD cases to 459,700 matched comparators. KD cases had higher rates of hospitalization (adjusted rate ratio 2.07, 95%CI 2.00 to 2.15), outpatient visits (1.30, 95%CI 1.28 to 1.33), and ED visits (1.22, 95%CI 1.18 to 1.26) throughout follow-up. Within 1 year post-discharge, 717 (15.6%) KD cases were re-hospitalized, 4,587 (99.8%) had ≥1 outpatient physician visit and 1,695 (45.5%) had ≥1 ED visit. KD cases had higher composite health care costs post-discharge (e.g., median cost within 1 year: $2466 CAD [KD cases] versus $234 [comparators]). Total health care costs for KD cases, respectively, were $13.9 million within 1 year post-discharge and $54.8 million throughout follow-up (versus $2.2 million and $23.9 million for an equivalent number of comparators).

Conclusions

Following diagnosis, KD cases had higher rates of health care utilization and costs versus nonexposed children. The rising incidence and costs associated with KD could place a significant burden on health care systems.

Acute pediatric kidney replacement therapies in Europe: demographic results from the EurAKId Registry

BACKGROUND

Acute kidney injury (AKI), particularly that requiring dialysis, is a severe complication in hospitalized children associated with high morbidity and mortality. A prospective European AKI registry (EurAKId registry, NCT02960867) was created to describe the epidemiology and outcomes of pediatric patients treated with acute dialysis.

METHODS

Children were recruited who were between 0 and 18 years of age and were treated both in and outside the Pediatric Intensive Care Unit (PICU) with peritoneal dialysis (PD), hemodialysis (HD) or continuous kidney replacement therapy (CKRT) for AKI or metabolic derangement, fluid overload (FO), sepsis, or respiratory distress. Five age groups and 12 categories of primary diseases were defined.

RESULTS

Data on 340 patients were analyzed, of whom 86% received dialysis for AKI and 14% for reasons other than AKI. Boys accounted for 60% of the patients. Illness severity was greater in children with cardiac and hematologic diseases than those with kidney diseases. Most patients received dialysis in the PICU (84%). The most frequently used dialysis modality was CKRT (64%), followed by PD (14%) and HD (14%). The overall survival rate was 65%. Survival was significantly lower in children with three comorbidities than in children with no comorbidities (41% and 83%, p < 0.001).

CONCLUSIONS

The EurAKId registry is the first prospective registry considering pediatric acute kidney replacement therapies (KRT) in both critical and non-critical care settings, focusing on the three dialysis modalities in Europe. The clinical indications for KRT have expanded; our population was characterized by critically ill patients, primarily boys, who frequently received dialysis in the PICU with CKRT.

Incidence of Chronic Immune-Mediated Inflammatory Diseases After Diagnosis with Kawasaki Disease: A Population-Based Cohort Study

OBJECTIVES

Kawasaki disease (kDa) is an immune-mediated vasculitis of childhood with multi-organ inflammation. We determined the risk of subsequent immune-mediated inflammatory disease (IMID), including arthritis, type 1 diabetes, inflammatory bowel disease (IBD), autoimmune liver disease (ALD), primary sclerosing cholangitis (PSC) and multiple sclerosis (MS).

METHODS

We conducted a matched population-based cohort study using health administrative data from Ontario, Canada. Children aged <18 years born between 1991-2016 diagnosed with kDa (n = 3,753) were matched to 5 non-kDa controls from the general population (n = 18 749). We determined the incidence of IMIDs after resolution of kDa. Three- and 12-month washout periods were used to exclude kDa-related symptoms.

RESULTS

There was an elevated risk of arthritis in kDa patients compared with non-kDa controls starting three months after index date (103.0 vs 12.7 per 100 000 person-years (PYs); incidence rate ratio (IRR) 8.07 (95% CI 4.95-13.2); hazard ratio (HR) 8.08 (95% CI 4.95-13.2), resulting in the overall incidence of IMIDs being elevated in kDa patients (175.1 vs 68.0 per 100 000 PYs; IRR 2.58 (95% CI 1.93-3.43); HR 2.58, 95% CI 1.94-3.43). However, there was no increased risk for diabetes, IBD, ALD, PSC or MS in kDa patients. Similar results were observed using a 12-month washout period.

CONCLUSIONS

Children diagnosed with kDa were at increased risk of arthritis following the acute kDa event, but not other IMIDs. Health care providers should monitor for arthritis in children following a diagnosis of kDa.

Late Kidney Effects of Childhood Cancer and Cancer Therapies

Childhood cancer therapy carries a high risk of treatment-related toxicities and complications that can impact kidney function. Although many of these adverse effects in the acute setting are well described, less is known about the latent effects of childhood cancer treatments on long-term kidney health. With decades of advancements in treatment protocols for many pediatric malignancies, more children than ever before are surviving into adulthood after being cured of their disease and with lower long-term morbidity. Although there is decreased prevalence of many chronic health conditions in cancer survivors, including gastrointestinal, endocrine, and musculoskeletal disorders, the long-term risk of kidney dysfunction has increased. In this review, we summarize the epidemiology of kidney disease in survivors of childhood cancer and describe the treatment-related risk factors associated with long-term impairment of kidney health. We organize this review by specific kidney disease-related outcomes of interest (chronic electrolyte abnormalities, CKD, proteinuria, and hypertension) to highlight what specific aspects of cancer treatment have been associated with these outcomes. Finally, we conclude by comparing different clinical practice guidelines that exist for long-term kidney function monitoring and include recommendations for when a childhood cancer survivor would benefit from long-term nephrology care.

Incidence and short-term outcomes of Kawasaki disease

OBJECTIVE

Kawasaki disease (KD) is a childhood vasculitis with conflicting reported North American trends in incidence and patient characteristics.

OBJECTIVES

(1) determine KD incidence between 1995 and 2017; (2) compare patient characteristics by era and age group; (3) determine complication and cardiovascular follow-up rates.

METHODS

We used population-based health administrative data to identify children (0-18 yr) hospitalized with KD in Ontario, Canada between 1995 and 2017. We excluded children with prior KD diagnosis or incomplete records. We determined the annualized incidence and follow-up trends.

RESULTS

KD was diagnosed in 4,346 children between 1995 and 2017. Annual KD incidence was 22.0 (<5 yr), 6.1 (5-9 yr), and 0.6 (10-18 yr) per 100,000 children. KD incidence increased significantly for all age groups, including from 18.4 to 25.0 cases per 100,000 children <5 yr. Ninety-day mortality occurred in ≤5 children (≤0.1%). Coronary artery aneurysm (CAA) occurred in 106 children (2.4%, 95% confidence interval 2.0-2.9) during admission and 151 (3.5%, 95% confidence interval 3.0-4.1) during 11-year median follow-up. Children 10-18 yr had longer hospitalizations (4.3 vs. 3.5 days, p = 0.003) and more CAA (7.4% vs. 3.4%, p = 0.007). By 1-year post-diagnosis, 3970 (91.3%) and 2576 (59.3%) children had echocardiography and cardiology follow-up, respectively.

CONCLUSIONS

KD incidence is increasing in Ontario, with greater healthcare utilization from hospitalizations and subsequent follow-up.

IMPACT

4346 children were hospitalized for Kawasaki disease over 22 years in Ontario, and Kawasaki disease incidence increased significantly for all age groups, males and females. Older children (10-18 years) had longer hospital length of stay, more PICU admissions and more frequent coronary artery aneurysms. Nearly all children with Kawasaki disease had follow-up echocardiography within 1 year.

Long-Term Kidney Outcomes Following Dialysis-Treated Childhood Acute Kidney Injury: A Population-Based Cohort Study

BACKGROUND

AKI is common during pediatric hospitalizations and associated with adverse short-term outcomes. However, long-term outcomes among survivors of pediatric AKI who received dialysis remain uncertain.

METHODS

To determine the long-term risk of kidney failure (defined as receipt of chronic dialysis or kidney transplant) or death over a 22-year period for pediatric survivors of dialysis-treated AKI, we used province-wide health administrative databases to perform a retrospective cohort study of all neonates and children (aged 0-18 years) hospitalized in Ontario, Canada, from April 1, 1996, to March 31, 2017, who survived a dialysis-treated AKI episode. Each AKI survivor was matched to four hospitalized pediatric comparators without dialysis-treated AKI, on the basis of age, sex, and admission year. We reported the incidence of each outcome and performed Cox proportional hazards regression analyses, adjusting for relevant covariates.

RESULTS

We identified 1688 pediatric dialysis-treated AKI survivors (median age 5 years) and 6752 matched comparators. Among AKI survivors, 53.7% underwent mechanical ventilation and 33.6% had cardiac surgery. During a median 9.6-year follow-up, AKI survivors were at significantly increased risk of a composite outcome of kidney failure or death versus comparators. Death occurred in 113 (6.7%) AKI survivors, 44 (2.6%) developed kidney failure, 174 (12.1%) developed hypertension, 213 (13.1%) developed CKD, and 237 (14.0%) had subsequent AKI. AKI survivors had significantly higher risks of developing CKD and hypertension versus comparators. Risks were greatest in the first year after discharge and gradually decreased over time.

CONCLUSIONS

Survivors of pediatric dialysis-treated AKI are at higher long-term risks of kidney failure, death, CKD, and hypertension, compared with a matched hospitalized cohort.

Changing trends in dialysis modalities utilization and mortality in children, adolescents and young adults with acute kidney injury, 2010-2017

The aim of the study was to assess trends in the relative use of dialysis modalities in the hospital-based pediatric cohort and to determine risk factors associated with in-hospital morality among pediatric patients receiving dialysis for acute kidney injury (AKI). Patients aged < 20 years who received dialysis between 2010 and 2017 were identified from electronic health records databases of a Taiwan's healthcare delivery system. The annual uses of intermittent hemodialysis (HD), continuous and automated peritoneal dialysis (PD) and continuous kidney replacement therapy (CKRT) were assessed using Cochran-Armitage Tests for trend. Among patients who received their first dialysis as inpatients for AKI, a multivariate logistic regression model was employed to assess mortality risks associated with dialysis modalities, patient demographics, complexity of baseline chronic disease, and healthcare service use during their hospital stays. Kidney dialysis was performed 37.9 per patient per year over the study period. Intermittent hemodialysis (HD) (73.3%) was the most frequently used dialysis modality. In the inpatient setting, the relative annual use of CKRT increased over the study period, while HD use concomitantly declined (P < 0.0001). The overall in-hospital mortality rate after dialysis for AKI was 33.6%, which remained steady over time (P = 0.2411). Patients aged < 2 years [adjusted odds ratio: (aOR) 3.36; 95% confidence interval (CI) 1.34-8.93] and greater vasoactive regimen use (aOR: 17.1; 95% CI: 5.3-55.21) were significantly associated with dialysis-related mortality. Overall treatment modality used for dialysis in pediatric patients increased slowly in the study period, and HD and CRKT modality uses largely evolved in the inpatient setting. Younger ages and use of more vasoactive medication regimens were independently associated with increased early mortality in patients on AKI-dialysis.

Evolution and change in paradigm of hemodialysis in children: a systematic review

BACKGROUND

There are similarities in hemodialysis (HD) between adults and children and also unique pediatric aspects. In this systematic review, we evaluated the existing HD literature, including vascular access, indications, parameters, and outcomes as a reflection on real-life HD practices.

METHODS

Medline, Embase, CINAHL, Web of Science, and Cochrane Library were systematically searched for literature on HD in children (1-20 years). Two reviewers independently assessed the literature and data on indications; vascular access, outcomes, and specific parameters for HD were extracted.

RESULTS

Fifty-four studies (8751 patients) were included in this review. Studies were stratified into age groups 1-5, 6-12, and 13-20 years based on median/mean age reported in the study, as well as era of publication (1990-2000, 2001-2010, and 2011-2019). Across all age groups, both arteriovenous fistulas and central venous catheters were utilized for vascular access. Congenital abnormalities and glomerulopathy were the most common HD indications. HD parameters including HD session duration, dialysate and blood flow rates, urea reduction ratio, and ultrafiltration were characterized for each age group, as well as common complications including catheter dysfunction and intradialytic hypotension. Median mortality rates were 23.3% (3.3), 7.6% (14.5), and 2.0% (3.0) in ages 1-5, 6-12, and 13-20 years, respectively. Median transplantation rates were 41.6% (38.3), 52.0% (32.0), and 21% (25.6) in ages 1-5, 6-12, and 13-20, respectively.

CONCLUSION

This comprehensive systematic review summarizes available literature on HD in children and young adults, including best vascular access, indications, technical aspects, and outcomes, and reflects on HD practices over the last three decades.

The need for hemodialysis is associated with increased mortality in mechanically ventilated children: a propensity score-matched outcome study

BACKGROUND

Kidney replacement therapy (KRT) is frequently used in critically ill children. The objective of this study is to investigate if the requirement for hemodialysis (HD) is an independent risk factor for mortality in mechanically ventilated children METHODS: In this retrospective cohort study, we analyzed the 2012 and 2016 Kids Inpatient Database and used a weighted sample to obtain a national outcome estimate. For our analysis, we included children aged one month to 17 years who were mechanically ventilated; we then compared the demographics, comorbidities, and mortality rates of those patients who had undergone HD with those who did not. Statistical analysis was performed using the chi-squared test and regression models. The patients were matched 1:2 with a correlative propensity score using age, weekend admission, elective admission, gender, hospital region, income quartiles, race, presence of kidney failure, bone marrow transplantation (BMT), cardiac surgery, trauma, and All Patients Refined Diagnosis Related Groups (APR-DRG) severity score. The mortality rate was compared between the matched groups.

RESULTS

Out of 100,289 mechanically ventilated children, 1393 (1.4%) underwent HD. The mortality rate was 32.5% in the HD group, compared with 8.8% in the control group (p < 0.05). Factors that were associated with higher mortality in HD patients included severe sepsis, BMT, cardiopulmonary resuscitation (CPR), and extracorporeal membrane oxygenation therapy (ECMO). After propensity score-matched analysis, HD was still significantly associated with a higher risk of mortality (31.9% vs. 22.0%, p < 0.05) CONCLUSIONS: The requirement for HD in mechanically ventilated children is associated with higher mortality.

A Review on the Application and Limitations of Administrative Health Care Data for the Study of Acute Kidney Injury Epidemiology and Outcomes in Children

Administrative health care databases contain valuable patient information generated by health care encounters. These "big data" repositories have been increasingly used in epidemiological health research internationally in recent years as they are easily accessible and cost-efficient and cover large populations for long periods. Despite these beneficial characteristics, it is also important to consider the limitations that administrative health research presents, such as issues related to data incompleteness and the limited sensitivity of the variables. These barriers potentially lead to unwanted biases and pose threats to the validity of the research being conducted. In this review, we discuss the effectiveness of health administrative data in understanding the epidemiology of and outcomes after acute kidney injury (AKI) among adults and children. In addition, we describe various validation studies of AKI diagnostic or procedural codes among adults and children. These studies reveal challenges of AKI research using administrative data and the lack of this type of research in children and other subpopulations. Additional pediatric-specific validation studies of administrative health data are needed to promote higher volume and increased validity of this type of research in pediatric AKI, to elucidate the large-scale epidemiology and patient and health systems impacts of AKI in children, and to devise and monitor programs to improve clinical outcomes and process of care.