Five-year risk of end-stage renal disease among intensive care patients surviving dialysis-requiring acute kidney injury: a nationwide cohort study

Long-Term Mortality and Health-Related Quality of Life After Continuous Versus Intermittent Renal Replacement Therapy in ICU Survivors: A Secondary Analysis of the Quality of Life After ICU Study

Purpose: We assessed long-term outcomes in intensive care unit (ICU) survivors with acute kidney injury (AKI) submitted to intermittent or continuous renal replacement therapy (RRT) for comparisons between groups. Methods: The multicenter prospective cohort study included 195 adult ICU survivors with an ICU stay >72 h in 10 ICUs that had at least one episode of AKI treated with intermittent RRT (IRRT) or continuous RRT (CRRT) during ICU stay. The main outcomes were mortality and health-related quality of life (HRQoL). Hospital readmissions and physical dependence were also assessed. Results: Regarding RRT, 83 (42.6%) patients received IRRT and 112 (57.4%) received CRRT. Despite the similarity regarding sociodemographic characteristics, pre-ICU state of health and type of admission between groups, the risk of death (23.5% vs 42.7%; P < .001), the prevalence of sepsis (60.7%) and acute respiratory distress syndrome (17%) were higher at ICU admission among CRRT patients. The severity of critical illness was higher among CRRT patients, regarding the need for mechanical ventilation (75.0% vs 50.6%, P = .002) and vasopressors (91.1% vs 63.9%, P < .001). One year after ICU discharge, 67 of 195 ICU survivors died (34.4%) and, after adjustment for confounders, there were no significant differences in mortality when comparing IRRT and CRTT patients (34.9% vs 33.9%; P = .590), on HRQoL in both physical (41.9% vs 42.2%; P = .926) and mental dimensions (57.6% vs 56.6%; P = .340), and on the number of hospital readmissions and physical dependence. Conclusions: Our study suggests that among ICU survivors RRT modality (IRRT vs CRRT) in the ICU does not impact long-term outcomes after ICU discharge.

Ensemble Machine Learning for Predicting 90-Day Outcomes and Analyzing Risk Factors in Acute Kidney Injury Requiring Dialysis

Purpose

Our objectives were to (1) employ ensemble machine learning algorithms utilizing real-world clinical data to predict 90-day prognosis, including dialysis dependence and mortality, following the first hospitalized dialysis and (2) identify the significant factors associated with overall outcomes.

Patients and Methods

We identified hospitalized patients with Acute kidney injury requiring dialysis (AKI-D) from a dataset of the Taipei Medical University Clinical Research Database (TMUCRD) from January 2008 to December 2020. The extracted data comprise demographics, comorbidities, medications, and laboratory parameters. Ensemble machine learning models were developed utilizing real-world clinical data through the Google Cloud Platform.

Results

The Study Analyzed 1080 Patients in the Dialysis-Dependent Module, Out of Which 616 Received Regular Dialysis After 90 Days. Our Ensemble Model, Consisting of 25 Feedforward Neural Network Models, Demonstrated the Best Performance with an Auroc of 0.846. We Identified the Baseline Creatinine Value, Assessed at Least 90 Days Before the Initial Dialysis, as the Most Crucial Factor. We selected 2358 patients, 984 of whom were deceased after 90 days, for the survival module. The ensemble model, comprising 15 feedforward neural network models and 10 gradient-boosted decision tree models, achieved superior performance with an AUROC of 0.865. The pre-dialysis creatinine value, tested within 90 days prior to the initial dialysis, was identified as the most significant factor.

Conclusion

Ensemble machine learning models outperform logistic regression models in predicting outcomes of AKI-D, compared to existing literature. Our study, which includes a large sample size from three different hospitals, supports the significance of the creatinine value tested before the first hospitalized dialysis in determining overall prognosis. Healthcare providers could benefit from utilizing our validated prediction model to improve clinical decision-making and enhance patient care for the high-risk population.

CHOP-mediated Gasdermin E expression promotes pyroptosis, inflammation, and mitochondrial damage in renal ischemia-reperfusion injury

In clinical practice, renal ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), often leading to acute renal failure or end-stage renal disease (ESRD). The current understanding of renal IRI mechanisms remains unclear, and effective therapeutic strategies and clear targets are lacking. Therefore, the need to find explicit and effective ways to reduce renal IRI remains a scientific challenge. The current study explored pyroptosis, a type of inflammation-regulated programmed cell death, and the role of Gasdermins E (GSDME)-mediated pyroptosis, mitochondrial damage, and inflammation in renal IRI. The analysis of human samples showed that the expression levels of GSDME in normal human renal tissues were higher than those of GSDMD. Moreover, our study demonstrated that GSDME played an important role in mediating pyroptosis, inflammation, and mitochondrial damage in renal IRI. Subsequently, GSDME-N accumulated in the mitochondrial membrane, leading to mitochondrial damage and activation of caspase3, which generated a feed-forward loop of self-amplification injury. However, GSDME knockout resulted in the amelioration of renal IRI. Moreover, the current study found that the transcription factor CHOP was activated much earlier in renal IRI. Inhibition of BCL-2 by CHOP leaded to casapse3 activation, resulting in mitochondrial damage and apoptosis; not only that, but CHOP positively regulated GSDME thereby causing pyroptosis. Therefore, this study explored the transcriptional mechanisms of GSDME during IRI development and the important role of CHOP/Caspase3/GSDME mechanistic axis in regulating pyroptosis in renal IRI. This axis might serve as a potential therapeutic target.

Central venous pressure combined with renal venous impedance index in predicting the acute kidney injury after thoracic and abdominal (non-cardiac) surgery

BACKGROUND

In the 21st century, 13% of patients undergoing open abdominal surgery, 25% of patients undergoing heart surgery, and 57% of patients admitted to the intensive care unit (ICU) are affected by acute kidney injury (AKI).

METHODS

This prospective observational study included patients admitted directly to the ICU between June 2021 and December 2021.

RESULTS

A total of 81 patients were enrolled after thoracic and abdominal (non-cardiac) surgery; 36 patients (44.4%) were diagnosed with AKI occurred within 7 days after surgery. Six-hour postoperative central venous pressure(CVP) was a risk factor for AKI in thoracic and abdominal (non-cardiac) postoperative patients (odds ratio [OR], 1.418; 95% confidence intervals [CI], 1.106-1.819; P = 0.006). Six-hour postoperative vein impedance index(VII) and CVP were significantly positively correlated (P = 0.031). The combination of 6-h postoperative VII with CVP (VII ≥0.34, CVP ≥7.5 mmHg) showed an area under the curve (AUC) of 0.787, In the subgroup analysis of patients with 6-h postoperative CVP <7.5 mmHg, there was a significant statistical difference in 6-h postoperative VII between the groups and those without AKI (P = 0.048). At 6-h postoperative CVP <7.5 mmHg, VII of ≥0.44 had a predictive value for AKI after thoracic and abdominal (non-cardiac) surgery, with an AUC of 0.669, a sensitivity of 41.2%, and a specificity of 94.4%.

CONCLUSION

Six-hour postoperative CVP combined with VII can better predict the occurrence of AKI occurred within 7 days after thoracic and abdominal (non-cardiac) surgery but cannot predict the severity of AKI.

Clinical trajectories and impact of acute kidney disease after acute kidney injury in the intensive care unit: a 5-year single-centre cohort study

BACKGROUND

Patients suffering from acute kidney injury(AKI) in the intensive care unit (ICU) can have various renal trajectories and outcomes. Aims were to assess the various clinical trajectories after AKI in the ICU and to determine risk factors for developing chronic kidney disease (CKD).

METHODS

We conducted a prospective 5-year follow-up study in a medical ICU at Bordeaux University Hospital (France). The patients who received invasive mechanical ventilation, catecholamine infusion or both and developed an AKI from September 2013 to May 2015 were included. In the Cox analysis, the violation of the proportional hazard assumption for AKD was handled using appropriate interaction terms with time, resulting in a time-dependent hazard ratio (HR).

RESULTS

A total of 232 patients were enrolled, with an age of 62 ± 16 years and a median follow-up of 52 days (interquartile range 6-1553). On day 7, 109/232 (47%) patients progressed to acute kidney disease (AKD) and 66/232 (28%) recovered. A linear trajectory (AKI, AKD to CKD) was followed by 44/63 (70%) of the CKD patients. The cumulative incidence of CKD was 30% [95% confidence interval (CI) 24-36] at the 5-year follow-up. In a multivariable Cox model, in the 6 months following AKI, the HR for CKD was higher in AKD patients [HR 29.2 (95% CI 8.5-100.7); P < 0.0001). After 6 months, the HR for CKD was 2.2 (95% CI 0.6-7.9; P = 0.21; n = 172 patients).

CONCLUSION

There were several clinical trajectories of kidney disease after ICU-acquired AKI. CKD risk was higher in AKD patients only in the first 6 months. Lack of renal recovery rather than AKD per se was associated with the risk of CKD.

Predictive factors for severe long-term chronic kidney disease after acute kidney injury requiring renal replacement therapy in critically ill patients: an ancillary study of the ELVIS randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is a serious complication in the ICU that results in increased mortality and risk of chronic kidney disease (CKD). Some studies suggest RRT modality may have an impact on long-term renal recovery after AKI. However, other predictive factors of severe long-term CKD in ICU patients with AKI requiring RRT are unknown.

METHODS

We performed an ancillary study of the multicenter ELVIS trial in the population with AKI requiring RRT. Patients alive 3 months after RRT initiation were eligible. Serum creatinine levels available at 3, 6 and 12 months and 3 and 5 years were recorded. CKD stage was determined according to the glomerular filtration rate as estimated by the CKD-EPI formula. At each timepoint, two groups of patients were compared, a no/mild CKD group with normal or mildly to moderately decreased renal function (stages 1, 2 and 3 of the international classification) and a severe CKD group (stages 4 and 5). Our objective was to identify predictive factors of severe long-term CKD.

RESULTS

Of the 287 eligible patients, 183 had follow-up at 3 months, 136 (74.3%) from the no/mild CKD group and 47 (25.7%) from the severe CKD group, and 122 patients at 5 years comprising 96 (78.7%) from the no/mild CKD group and 26 (21.3%) from the severe CKD group. Multivariate analysis showed that a long RRT period was associated with severe CKD up to 12 months (OR_M12 = 1.03 95% CI [1.02-1.05] per day) and that a high SOFA score at the initiation of RRT was not associated with severe CKD up to 5 years (OR_M60 = 0.85 95% CI [0.77-0.93] per point).

CONCLUSION

Severe long-term CKD was found in 21% of ICU survivors who underwent RRT for AKI. The duration of the RRT in AKI patients was identified as a new predictive factor for severe long-term CKD. This finding should be taken into consideration in future studies on the prognosis of ICU patients with AKI requiring RRT. Trial registration ELVIS trial was registered with ClinicalTrials.gov, number: NCT00875069 (June 16, 2014), and this ancillary study was registered with ClinicalTrials.gov, number: NCT03302624 (October 6, 2017).

Early Comprehensive Kidney Care in Dialysis-Requiring Acute Kidney Injury Survivors: A Populational Study

Background

For patients with Acute Kidney Injury (AKI), a strong and graded relationship exists between AKI severity and mortality. One of the most severe entities of AKI is Dialysis-Requiring Acute Kidney Injury (D-AKI), which is associated with high rates of mortality and end-stage renal disease (ESRD). For this high-risk population group, there is a lack of evidence regarding optimal post-AKI care. We propose that post-AKI care through the combined efforts of the nephrologist and the multidisciplinary care team may improve outcomes. Our aim here is to study for survivors of dialysis-requiring acute kidney injury, the effects of implementing early comprehensive kidney care.

Methods

This is a retrospective longitudinal cohort study of Taiwanese through analyzing the National Health Insurance Research Database (NHIRD). We included patients with acute dialysis during hospitalization from January 1, 2015 to December 31, 2018. Propensity match was done at 1:1, including estimated glomerular filtration rate (eGFR) based on CKD-EPI which was performed due to large initial disparities between these two cohorts.

Results

After the propensity match, each cohort had 4,988 patients. The mean eGFR based on CKD-EPI was 27.5 ml/min/1.73 m2, and the mean follow-up period was 1.4 years.

The hazard ratio for chronic dialysis or ESRD was 0.55 (95% CI, 0.49–0.62; p &lt; 0.001). The hazard ratio for all-cause mortality was 0.79 (95% CI, 0.57–0.88; p &lt; 0.001). Both outcomes favored early comprehensive kidney care.

Conclusions

For survivors of dialysis-requiring acute kidney injury, early comprehensive kidney care significantly lowered risks of chronic dialysis and all-cause mortality.

[Acute kidney injury in intensive care unit: A review]

Acute kidney injury is a common complication in intensive care unit. Its incidence is variable according to the studies. It is considered to occur in more than 50 % of patients. Acute kidney injury is responsible for an increase in morbidity (length of hospitalization, renal replacement therapy) but also for excess mortality. The commonly accepted definition of acute kidney injury comes from the collaborative workgroup named Kidney Disease: Improving Global Outcomes (KDIGO). It made it possible to standardize practices and raise awareness among practitioners about monitoring plasma creatinine and also diuresis. Acute kidney injury in intensive care unit is a systemic disease including circulatory, endothelial, epithelial and cellular function involvement and an acute kidney injury is not accompanied by ad integrum repair. After prolonged injury, inadequate repair begins with a fibrotic process. Several mechanisms are involved (cell cycle arrest, epithelial-mesenchymal transition, mitochondrial dysfunction) and result in improper repair. A continuum exists between acute kidney disease and chronic kidney disease, characterized by different renal recovery phenotypes. Thus, preventive measures to prevent the occurrence of kidney damage play a major role in management. The nephrologist must be involved at every stage, from the prevention of the first acute kidney injury (upon arrival in intensive care unit) to long-term follow-up and the care of a chronic kidney disease.

Does Artificial Intelligence Make Clinical Decision Better? A Review of Artificial Intelligence and Machine Learning in Acute Kidney Injury Prediction

Acute kidney injury (AKI) is a common complication of hospitalization that greatly and negatively affects the short-term and long-term outcomes of patients. Current guidelines use serum creatinine level and urine output rate for defining AKI and as the staging criteria of AKI. However, because they are not sensitive or specific markers of AKI, clinicians find it difficult to predict the occurrence of AKI and prescribe timely treatment. Advances in computing technology have led to the recent use of machine learning and artificial intelligence in AKI prediction, recent research reported that by using electronic health records (EHR) the AKI prediction via machine-learning models can reach AUROC over 0.80, in some studies even reach 0.93. Our review begins with the background and history of the definition of AKI, and the evolution of AKI risk factors and prediction models is also appraised. Then, we summarize the current evidence regarding the application of e-alert systems and machine-learning models in AKI prediction.

Recovery after Critical Illness and Acute Kidney Injury

AKI is a common complication in hospitalized and critically ill patients. Its incidence has steadily increased over the past decade. Whether transient or prolonged, AKI is an independent risk factor associated with poor short- and long-term outcomes, even if patients do not require KRT. Most patients with early AKI improve with conservative management; however, some will require dialysis for a few days, a few weeks, or even months. Approximately 10%-30% of AKI survivors may still need dialysis after hospital discharge. These patients have a higher associated risk of death, rehospitalization, recurrent AKI, and CKD, and a lower quality of life. Survivors of critical illness may also suffer from cognitive dysfunction, muscle weakness, prolonged ventilator dependence, malnutrition, infections, chronic pain, and poor wound healing. Collaboration and communication among nephrologists, primary care physicians, rehabilitation providers, physical therapists, nutritionists, nurses, pharmacists, and other members of the health care team are essential to create a holistic and patient-centric care plan for overall recovery. Integration of the patient and family members in health care decisions, and ongoing education throughout the process, are vital to improve patient well-being. From the nephrologist standpoint, assessing and promoting recovery of kidney function, and providing appropriate short- and long-term follow-up, are crucial to prevent rehospitalizations and to reduce complications. Return to baseline functional status is the ultimate goal for most patients, and dialysis independence is an important part of that goal. In this review, we seek to highlight the varying aspects and stages of recovery from AKI complicating critical illness, and propose viable strategies to promote recovery of kidney function and dialysis independence. We also emphasize the need for ongoing research and multidisciplinary collaboration to improve outcomes in this vulnerable population.

Epidemiology of Sepsis-Associated Acute Kidney Injury in Beijing, China: A Descriptive Analysis

Background

Sepsis is the most common contributing factor towards development of acute kidney injury (AKI), which is strongly associated to poor prognostic outcomes. There are numerous epidemiological studies about sepsis-associated acute kidney injury (S-AKI), however current literature is limited with the majority of studies being conducted only in the intensive care unit (ICU) setting. The aim of this study was to assess the epidemiology of S-AKI in all hospitalized in-patients.

Methods

This was a retrospective population-based study using a large regional population database in Beijing city from January, 2005 to December, 2017. It included patients with S-AKI. Patients with pre-existing end-stage kidney disease (ESKD), previous history of kidney transplantation, or being pregnant were excluded. Patients’ demographic characteristics, incidence, risk factors and outcomes of S-AKI were analyzed. The contrast between different time periods, different levels of hospitals, and types of the hospitals (traditional Chinese medicine hospitals (TCMHs) and western medicine hospitals (WMHs)) was also compared using Mann–Whitney U-test.

Results

A total of 19,579 patients were included. The overall incidence of S-AKI in all in-patients was 48.1%. The significant risk factors by multivariate analysis for AKI included: age, male, being treated in a level-II hospital, pre-existing hypertension, chronic kidney disease (CKD), cirrhosis, atrial fibrillation (AF), ischemic heart disease (IHD), being admitted from emergency room, ICU admission, shock, pneumonia, intra-abdominal infection, bloodstream infection, respiratory insufficiency, acute liver injury, disseminated intravascular coagulation (DIC) and metabolic encephalopathy. The overall mortality rate in this cohort was 55%. The multivariate analysis showed that the significant risk factors for mortality included: age, being treated in a level-II hospital and TCMHs, being admitted from emergency room, pre-existing comorbidities (CKD, malignancy, cirrhosis and AF), shock, pneumonia, intra-abdominal infection, bloodstream infection, central nervous system (CNS) infection and respiratory insufficiency.

Conclusion

AKI is a common complication in patients with sepsis, and its incidence increases over time, especially when ICU admission is required. Exploring interventional strategies to address modifiable risk factors will be important to reduce incidence and mortality of S-AKI.

Rationale and Design of Assessing the Effectiveness of Short-Term Low-Dose Lithium Therapy in Averting Cardiac Surgery-Associated Acute Kidney Injury: A Randomized, Double Blinded, Placebo Controlled Pilot Trial

Background: Burgeoning pre-clinical evidence suggests that therapeutic targeting of glycogen synthase kinase 3β (GSK3β), a convergence point of multiple cellular protective signaling pathways, confers a beneficial effect on acute kidney injury (AKI) in experimental models. However, it remains unknown if GSK3β inhibition likewise mitigates AKI in humans. Cardiac surgery associated acute kidney injury (CSA-AKI) poses a significant challenge for clinicians and currently the only treatment available is general supportive measures. Lithium, an FDA approved mood stabilizer, is the best-known GSK3β inhibitor and has been safely used for over half a century as the first line regimen to treat bipolar affective disorders. This study attempts to examine the effectiveness of short term low dose lithium on CSA-AKI in human patients.

Methods/Design: This is a single center, prospective, randomized, double blinded, placebo controlled pilot study on patients undergoing cardiac surgery with cardiopulmonary bypass. Patients will be randomized to receive a small dose of lithium or placebo treatment for three consecutive days. Renal function will be measured via creatinine as well as novel AKI biomarkers. The primary outcome is incidence of AKI according to Acute Kidney Injury Network (AKIN) criteria, and secondary outcomes include receipt of new dialysis, days on dialysis, days on mechanical ventilation, infections within 1 month of surgery, and death within 90 days of surgery.

Discussion: As a standard selective inhibitor of GSK3β, lithium has been shown to exert a beneficial effect on tissue repair and regeneration upon acute injury in multiple organ systems, including the central nervous system and hematopoietic system. In experimental AKI, lithium at small doses is able to ameliorate AKI and promote kidney repair. Successful completion of this study will help to assess the effectiveness of lithium in CSA-AKI and could potentially pave the way for large-scale randomized trials to thoroughly evaluate the efficacy of this novel regimen for preventing AKI after cardiac surgery.

Trial Registration: This study was registered prospectively on the 17th February 2017 at ClinicalTrials.gov (NCT03056248, https://clinicaltrials.gov/ct2/show/NCT03056248?term=NCT03056248&draw=2&rank=1).

Outcome of Organ Dysfunction in the Perioperative Period

While intraoperative mortality has diminished greatly over the last several decades, the risk of death within 30 days of surgery remains stubbornly high and is ultimately related to perioperative organ failure. Perioperative strokes, while rare (<2% in noncardiac surgery), are associated with a more than 10-fold increase in mortality. Rapid identification and treatment are key to maximizing long-term outcomes. Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are separate but related perioperative neurological disorders, both of which are associated with poor long-term outcomes. To date, there are few known interventions that can ameliorate the risk of perioperative central nervous system dysfunction. Major adverse cardiac events (MACE) are a major contributor to adverse clinical outcomes following surgical procedures. Recently, advances in diagnostic strategies (eg, high-sensitivity cardiac troponin [hs-cTn] assays) have improved our understanding of MACE. Recently, the dabigatran in patients with myocardial injury after noncardiac surgery (MINS; Management of myocardial injury After NoncArdiac surGEry) trial demonstrated that a direct thrombin inhibitor could improve outcomes following MINS. While the risk of acute respiratory distress syndrome (ARDS) after surgery is approximately 0.2%, other less severe complications (eg, pneumonia, reintubation) are closer to 2%. While intensive care unit (ICU) concepts related to ARDS have migrated into the operating room, whether or not adverse pulmonary outcomes impact long-term outcomes in surgical patients remains a matter of debate. The standardization of acute kidney injury (AKI) definition has improved the ability of clinicians to measure and study the incidence of this important source of perioperative morbidity. AKI is associated with increased mortality as well as nonrenal morbidity (eg, myocardial infarction) after major surgery. Gastrointestinal complications after surgery range from ileus (common in abdominal procedures and associated with an increased length of stay) to less common complications such as mesenteric ischemia and gastrointestinal bleeding, both of which are associated with very high mortality. Outside of cardiothoracic surgery, the incidence of perioperative hepatic injury is not well described but, in this population, is associated with worsened long-term outcomes. Hyperglycemia is a common perioperative complication and occurs in patients undergoing both cardiac and noncardiac surgery. Both hyper- and hypoglycemia are associated with worsened long-term outcomes in cardiac and noncardiac surgery. Better diagnosis and increased understanding of perioperative organ injury has led to an increased appreciation for the specific role that particular organ systems play in poor long-term outcomes and has set the stage for targeted therapeutic interventions.

Acute Kidney Injury Requiring Dialysis and Incident Dialysis Patient Outcomes in US Outpatient Dialysis Facilities

BACKGROUND AND OBJECTIVES

About 30% of patients with AKI may require ongoing dialysis in the outpatient setting after hospital discharge. A 2017 Centers for Medicare & Medicaid Services policy change allows Medicare beneficiaries with AKI requiring dialysis to receive outpatient treatment in dialysis facilities. Outcomes for these patients have not been reported. We compare patient characteristics and mortality among patients with AKI requiring dialysis and patients without AKI requiring incident dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a retrospective cohort design with 2017 Medicare claims to follow outpatients with AKI requiring dialysis and patients without AKI requiring incident dialysis up to 365 days. Outcomes are unadjusted and adjusted mortality using Kaplan-Meier estimation for unadjusted survival probability, Poisson regression for monthly mortality, and Cox proportional hazards modeling for adjusted mortality.

RESULTS

In total, 10,821 of 401,973 (3%) Medicare patients requiring dialysis had at least one AKI claim, and 52,626 patients were Medicare patients without AKI requiring incident dialysis. Patients with AKI requiring dialysis were more likely to be White (76% versus 70%), non-Hispanic (92% versus 87%), and age 60 or older (82% versus 72%) compared with patients without AKI requiring incident dialysis. Unadjusted mortality was markedly higher for patients with AKI requiring dialysis compared with patients without AKI requiring incident dialysis. Adjusted mortality differences between both cohorts persisted through month 4 of the follow-up period (all P=0.01), then, they declined and were no longer statistically significant. Adjusted monthly mortality stratified by Black and other race between patients with AKI requiring dialysis and patients without AKI requiring incident dialysis was lower throughout month 4 (1.5 versus 0.60, 1.20 versus 0.84, 1.00 versus 0.80, and 0.95 versus 0.74; all P<0.001), which persisted through month 7. Overall adjusted mortality risk was 22% higher for patients with AKI requiring dialysis (1.22; 95% confidence interval, 1.17 to 1.27).

CONCLUSIONS

In fully adjusted analyses, patients with AKI requiring dialysis had higher early mortality compared with patients without AKI requiring incident dialysis, but these differences declined after several months. Differences were also observed by age, race, and ethnicity within both patient cohorts.

Evaluation of peptidylarginine deiminase 4 and PADI4 polymorphisms in sepsis-induced acute kidney injury

BACKGROUND

The aim of this study is to evaluate the peptidylarginine deiminase 4 (PAD 4) concentration and PADI4 polymorphisms as predictors of acute kidney injury (AKI) development, the need for renal replacement therapy (RRT), and mortality in patients with septic shock.

METHODS

We included all individuals aged ≥ 18 years, with a diagnosis of septic shock at ICU admission. Blood samples were taken within the first 24 hours of the patient's admission to determine serum PAD4 concentration and its PADI4 polymorphism (rs11203367) and (rs874881). Patients were monitored during their ICU stay and the development of SAKI was evaluated. Among the patients in whom SAKI developed, mortality and the need for RRT were also evaluated.

RESULTS

There were 99 patients, 51.5% of whom developed SAKI and of these, 21.5% needed RRT and 80% died in the ICU. There was no difference between PAD4 concentration (p = 0.116) and its polymorphisms rs11203367 (p = 0.910) and rs874881 (p = 0.769) in patients in whom SAKI did or did not develop. However, PAD4 had a positive correlation with plasma urea concentration (r = 0.269 and p = 0.007) and creatinine (r = 0.284 and p = 0.004). The PAD4 concentration and PADI4 polymorphisms were also not associated with RRT and with mortality in patients with SAKI.

CONCLUSION

PAD4 concentration and its polymorphisms were not associated with SAKI development, the need for RRT, or mortality in patients with septic shock. However, PAD4 concentrations were associated with creatinine and urea levels in these patients.

Mild Stage 1 post-operative acute kidney injury: association with chronic kidney disease and long-term survival

Background

Mild cases of acute kidney injury (AKI) are identified by a small rise in serum creatinine (SCr) according to the KDIGO AKI definition. The aim of this study was to examine the long-term outcomes of individuals with mild AKI.

Methods. This was a retrospective cohort study of all adult patients who underwent abdominal, cardiothoracic, vascular or orthopaedic surgery at Landspitali–The National University Hospital of Iceland in 1998–2015. Incident chronic kidney disease (CKD), progression of pre-existing CKD and long-term survival were compared between patients with mild Stage 1 AKI (defined as a rise in SCr of ≥26.5 μmol/L within 48 h post-operatively without reaching 1.5× baseline SCr within 7 days), and a propensity score-matched control group without AKI stratified by the presence of CKD.

Results

Pre- and post-operative SCr values were available for 47 333 (42%) surgeries. Of those, 1161 (2.4%) had mild Stage 1 AKI and 2355 (5%) more severe forms of AKI. Mild Stage 1 AKI was associated with both incident CKD and progression of pre-existing CKD (P < 0.001). After exclusion of post-operative deaths within 30 days, mild Stage 1 AKI was not associated with worse 1-year survival in patients with preserved kidney function (94% versus 94%, P = 0.660), and same was true for patients with pre-operative CKD (83% versus 82%, P = 0.870) compared with their matched individuals.

Conclusions. Mild Stage 1 AKI is associated with development and progression of CKD, but not with inferior 1-year survival. These findings support the inclusion of a small absolute increase in SCr in the definition of AKI.

The Incidence of Chronic Kidney Disease Three Years after Non-Severe Acute Kidney Injury in Critically Ill Patients: A Single-Center Cohort Study

The risk of chronic kidney disease (CKD) following severe acute kidney injury (AKI) in critically ill patients is well documented, but not after less severe AKI. The main objective of this study was to evaluate the long-term incidence of CKD after non-severe AKI in critically ill patients. This prospective single-center observational three-years follow-up study was conducted in the medical intensive care unit in Bordeaux's hospital (France). From 2013 to 2015, all patients with severe (kidney disease improving global outcomes (KDIGO) stage 3) and non-severe AKI (KDIGO stages 1, 2) were enrolled. Patients with prior eGFR < 90 mL/min/1.73 m² were excluded. Primary outcome was the three-year incidence of CKD stages 3 to 5 in the non-severe AKI group. We enrolled 232 patients. Non-severe AKI was observed in 112 and severe AKI in 120. In the non-severe AKI group, 71 (63%) were male, age was 62 ± 16 years. The reason for admission was sepsis for 56/112 (50%). Sixty-two (55%) patients died and nine (8%) were lost to follow-up. At the end of the follow-up the incidence of CKD was 22% (9/41); Confidence Interval (CI) _95% (9.3-33.60)% in the non-severe AKI group, tending to be significantly lower than in the severe AKI group (44% (14/30); CI _95% (28.8-64.5)%; p = 0.052). The development of CKD three years after non-severe AKI, despite it being lower than after severe AKI, appears to be a frequent event highlighting the need for prolonged follow-up.

Risk factors and outcomes of acute kidney injury in South African critically ill adults: a prospective cohort study

Background

There is a marked paucity of data concerning AKI in Sub-Saharan Africa, where there is a substantial burden of trauma and HIV.

Methods

Prospective data was collected on all patients admitted to a multi-disciplinary ICU in South Africa during 2017. Development of AKI (before or during ICU admission) was recorded and renal recovery 90 days after ICU discharge was determined.

Results

Of 849 admissions, the mean age was 42.5 years and mean SAPS 3 score was 48.1. Comorbidities included hypertension (30.5%), HIV (32.6%), diabetes (13.3%), CKD (7.8%) and active tuberculosis (6.2%). The most common reason for admission was trauma (26%). AKI developed in 497 (58.5%). Male gender, illness severity, length of stay, vasopressor drugs and sepsis were independently associated with AKI. AKI was associated with a higher in-hospital mortality rate of 31.8% vs 7.23% in those without AKI. Age, active tuberculosis, higher SAPS 3 score, mechanical ventilation, vasopressor support and sepsis were associated with an increased adjusted odds ratio for death. HIV was not independently associated with AKI or hospital mortality. CKD developed in 14 of 110 (12.7%) patients with stage 3 AKI; none were dialysis-dependent.

Conclusions

In this large prospective multidisciplinary ICU cohort of younger patients, AKI was common, often associated with trauma in addition to traditional risk factors and was associated with good functional renal recovery at 90 days in most survivors. Although the HIV prevalence was high and associated with higher mortality, this was related to the severity of illness and not to HIV status per se.

Acute Kidney Injury in the Outpatient Setting Associates with Risk of End-Stage Renal Disease and Death in Patients with CKD

Current acute kidney injury (AKI) diagnostic criteria are restricted to the inpatient setting. We proposed a new AKI diagnostic algorithm for the outpatient setting and evaluate whether outpatient AKI (AKI_OPT) modifies the disease course among patients with chronic kidney disease (CKD) enrolled in the national predialysis registry. AKI_OPT was detected when a 50% increase in serum creatinine level or 35% decline in eGFR was observed in the 180-day period prior to enrollment in the predialysis care program. Outcomes were progression to end-stage renal disease (ESRD) and all-cause mortality. Association analyses were performed using multiple Cox regression and coarsened exact matching (CEM) analysis. Among 6,046 patients, 31.5% (1,905 patients) had developed AKI_OPT within the 180-day period before enrollment. The adjusted hazard ratios of the 1-year and overall risk of ESRD among patients with preceding AKI_OPT compared with those without AKI_OPT were 2.61 (95% CI: 2.15-3.18) and 1.97 (1.72-2.26), respectively. For 1-year and overall risk of all-cause mortality, patients with AKI_OPT had respectively a 141% (95% CI: 89-209%) and 84% (56-117%) higher risk than those without AKI_OPT. This statistical inference remained robust in CEM analysis. We also discovered a complete reversal in the eGFR slope before and after the AKI_OPT from -10.61 ± 0.32 to 0.25 ± 0.30 mL/min/1.73 m² per year; however, the loss of kidney function is not recovered. The new AKI_OPT diagnostic algorithm provides prognostic insight in patients with CKD.

Associated factors of dialysis-dependence among acute kidney injury patients in intensive care unit

Acute kidney injury (AKI) is a common problem in hospitals and many end up requiring dialysis. The aim was to identify the associated factors of dialysis-dependent of AKI patients admitted to the intensive care units (ICUs). A retrospective cohort study was conducted where a list of 121 AKI patients admitted to ICU in Hospital Universiti Sains Malaysia was retrospectively reviewed. AKI patients aged below 18 years old, had kidney transplantation or chronic dialysis before ICU admission and had incomplete medical record were excluded from the study. Simple and multiple logistic regression analysis were used. The mean [standard deviation (SD)] age of patients was 56 (17.15) years. Majority of patients were males (63.2%) and Malay ethnic (54.1%). 49.3% of patients were in stage I, 48.3% in stage II and 76.2% in stage III. The mean (SD) duration of patients stayed in ICU was 7 days (6.92) for non-dialysis dependent and 12 days (8.37) for dialysis-dependent. The associated factors were male gender [adjusted odds ratio (OR): 3.68; 95% confidence interval [CI]: 1.53, 8.86; P = 0.004], AKI Stage III (adjusted OR: 4.51; 95% CI: 1.28, 15.91; P = 0.019), admitted in ICU (adjusted OR: 3.05; 95% CI: 1.28, 7.29; P = 0.012), and longer length of stay (adjusted OR: 1.10; 95% CI: 1.03, 1.18; P = 0.003). The factors influence of dialysis-requiring AKI were observed to be dependent on the male male gender, suffer from the advanced stage (Stage III), admitted to the ICU and had a longer length of stay in ICU. Therefore, it is important for physicians to identify patients who are at high risk of developing AKI and implement preventive strategies.

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.

Postdischarge Major Adverse Cardiovascular Events of ICU Survivors Who Received Acute Renal Replacement Therapy

OBJECTIVES

Long-term risk of a major adverse cardiovascular events in ICU survivors who underwent acute renal replacement therapy requires further investigation.

DESIGN

Nationwide population-based study using the claims database of Korea.

SETTING

Index admission cases of ICU survivors in government-designated tertiary hospitals PATIENTS:: The study group consisted of ICU survivors who underwent acute renal replacement therapy, and the control group consisted of those without acute renal replacement therapy. Patients were excluded if they 1) were under age 20, 2) expired within 30 days after discharge, 3) received ICU care for less than 24 hours, 4) had a previous ICU admission, 5) had a history of major adverse cardiovascular event, or 6) had a major adverse cardiovascular event-related cardio/cerebrovascular diseases. The outcomes of the patients who received continuous renal replacement therapy were compared with those of patients who received only intermittent renal replacement therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Information regarding patient characteristics and treatment modalities was collected and adjusted. The main outcome was major adverse cardiovascular event, including acute myocardial infarction, revascularization, and acute ischemic stroke. Patient mortality and progression to end-stage renal disease were also evaluated. We included 12,380 acute renal replacement therapy patients and 382,018 patients in the control group. Among the study group, 6,891 patients were included in the continuous renal replacement therapy group, and 5,034 in the intermittent renal replacement therapy group. The risks of major adverse cardiovascular event (adjusted hazard ratio, 1.463 [1.323-1.619]; p < 0.001), all-cause mortality (adjusted hazard ratio, 1.323 [1.256-1.393]; p < 0.001), and end-stage renal disease (adjusted hazard ratio, 18.110 [15.779-20.786]; p < 0.001) were higher in the acute renal replacement therapy patients than the control group. When we compared the continuous renal replacement therapy patients with the intermittent renal replacement therapy patients, the risk of major adverse cardiovascular event was comparable (adjusted hazard ratio, 1.049 [0.888-1.239]; p = 0.575).

CONCLUSIONS

Clinicians should note the increased risk of a long-term major adverse cardiovascular event in acute renal replacement therapy patients and consider appropriate risk factor management. Significant difference in the risk of postdischarge major adverse cardiovascular event was not identified between continuous renal replacement therapy and intermittent renal replacement therapy.

The acute kidney injury to chronic kidney disease transition in a mouse model of acute cardiorenal syndrome emphasizes the role of inflammation

Acute cardiorenal syndrome is a common complication of acute cardiovascular disease. Studies of acute kidney injury (AKI) to chronic kidney disease (CKD) transition, including patients suffering acute cardiovascular disease, report high rates of CKD development. Therefore, acute cardiorenal syndrome associates with CKD, but no study has established causation. To define this we used a murine cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) model or sham procedure on male mice. CA was induced with potassium chloride while CPR consisted of chest compressions and epinephrine eight minutes later. Two weeks after AKI was induced by CA/CPR, the measured glomerular filtration rate (GFR) was not different from sham. However, after seven weeks the mice developed CKD, recapitulating clinical observations. One day, and one, two, and seven weeks after CA/CPR, the GFR was measured, and renal tissue sections were evaluated for various indices of injury and inflammation. One day after CA/CPR, acute cardiorenal syndrome was indicated by a significant reduction of the mean GFR (649 in sham, vs. 25 μL/min/100g in CA/CPR animals), KIM-1 positive tubules, and acute tubular necrosis. Renal inflammation developed, with F4/80 positive and CD3-positive cells infiltrating the kidney one day and one week after CA/CPR, respectively. Although there was functional recovery with normalization of GFR two weeks after CA/CPR, deposition of tubulointerstitial matrix proteins α-smooth muscle actin and fibrillin-1 progressed, along with a significantly reduced mean GFR (623 in sham vs. 409 μL/min/100g in CA/CPR animals), proteinuria, increased tissue transforming growth factor-β, and fibrosis establishing the development of CKD seven weeks after CA/CPR. Thus, murine CA/CPR, a model of acute cardiorenal syndrome, causes an AKI-CKD transition likely due to prolonged renal inflammation.

Long term renal recovery in survivors after OHCA

BACKGROUNDS

In survivors of out-of-hospital cardiac arrest (OHCA), acute kidney injury (AKI) is frequent and is associated with numerous factors of definitive renal injury. We made the hypothesis that AKI after OHCA was a strong risk factor of long-term chronic kidney disease (CKD). We aimed to evaluate long-term renal outcome of OHCA survivors according the occurrence of AKI in ICU.

METHODS

We used prospectively collected data from consecutive OHCA patients admitted between 2007 and 2012 in a tertiary medical ICU. AKI was defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Long-term creatinine level was the last blood creatinine assessment we were able to retrieve. The main outcome was the occurrence of CKD, defined by an estimated glomerular filtration rate (eGFR) lower than 60 mL/min/1.73m² according to the MDRD equation. Long-term mortality was evaluated as well. Factors associated with CKD occurrence were evaluated by competing risk survival analysis (Fine Gray and Cox cause specific models).

RESULTS

Among the 246 OHCA patients who were discharged alive, outcome of 133 patients was available (median age 55 [iqr 46, 68], 75.2% of male). During a median follow-up time of 1.8 [0.8-2.5] years, CKD occurred in 17 (12.7%) patients and 24 (18%) patients died. A previous history of arterial hypertension (sHR = 3.28[1.15;9.39], p = 0.027; CSH = 4.83 [1.57;14.9], p = 0.006), AKI during ICU stay (sHR = 3.72[1.40;9.84], p = 0.008; CSH = 5.41[1.79;16.3], p = 0.003) and an age higher than 55 (sHR = 6.13[1.55;24.3], p = 0.009; CSH = 2.16[1.72;43.8], p = 0.006) were independently associated with CKD occurrence. AKI was not associated with long-term mortality (sHR = 0.73 [0.27;1.99], p = 0.55; CSH = 0.75 [0.28;2.01], p = 0.57).

CONCLUSION

In OHCA survivors, CKD was a frequent long-term complication. AKI during ICU stay was a strong determinant of long-term CKD occurrence.

Lower short-term mortality in ICU patients on chronic dialysis than in those requiring acute dialysis

BACKGROUND

In ICU patients, we aimed to describe the outcomes of those with end-stage renal disease (ESRD) as compared to those requiring acute renal replacement therapy (RRT).

METHODS

Retrospective analysis of all adult patients admitted to a general, university hospital ICU from 2005 to 2012. ESRD was defined as use of chronic RRT >90 days prior to admission.

RESULTS

We included 5927 patients of whom 1004 (17%) received acute RRT and 161 (3%) had pre-existing ESRD requiring RRT. Thirty-day mortality was 42% vs 28% for acute RRT vs ESRD patients (adjusted hazard ratio (aHR) 0.90 (0.61-1.34)), and 16% for those not requiring RRT (aHR 0.91 (0.60-1.38) compared to ESRD patients). Ninety-day mortality was 55% vs 45% for acute RRT vs ESRD patients (aHR 0.96 (0.70-1.31)), and 22% for those not requiring RRT (aHR 1.19 (0.84-1.67) compared to ESRD patients). Ninety-day ESRD survivors were younger, less severely ill and needed less vasopressor treatment than 90-day ESRD non-survivors. Five-year mortality was 68% vs 69% for acute RRT vs ESRD patients (aHR 1.06 (0.81-1.39)), and 38% for those not requiring RRT (aHR 1.31 (0.99-1.74) compared to ESRD patients).

CONCLUSIONS

The crude mortality for patients with pre-existing ESRD was high. Short-term mortality was within range of those not receiving RRT when adjusted for confounders. The severity of acute illness and the burden of comorbidities may be more important than the lack of kidney function per se for the short-term prognosis of RRT patients in the ICU.

Determining the Incidence of Acute Kidney Injury Using the RIFLE Criteria in the Medical Intensive Care Unit in a Tertiary Care Hospital Setting in Pakistan

Background

Acute kidney injury (AKI) is a frequently encountered clinical condition in hospitalized patients, particularly those admitted to intensive care units (ICU). AKI has its systemic sequelae and contributes to the morbidity of underlying diseases.

Methods

This descriptive case series aimed to determine the frequency of acute kidney injury in critically ill patients admitted to the ICU at Shifa International Hospital, Islamabad, according to the RIFLE (risk, injury, failure, loss, and end-stage) criteria. A total of 124 patients were enrolled in this study. RIFLE criteria were applied to determine the frequency of AKI in critically ill patients.

Results

The frequency of AKI was 68.55% and mortality was 18.55%. The severity of AKI was found to be significantly associated with mortality (p < 0.001).

Conclusion

AKI is very common in critically ill patients and contributes to the mortality and morbidity of the patients. Early identification of AKI can reduce mortality in critically ill patients.

Long-term risk of adverse outcomes after acute kidney injury: a systematic review and meta-analysis of cohort studies using consensus definitions of exposure

Reliable estimates of the long-term outcomes of acute kidney injury (AKI) are needed to inform clinical practice and guide allocation of health care resources. This systematic review and meta-analysis aimed to quantify the association between AKI and chronic kidney disease (CKD), end-stage kidney disease (ESKD), and death. Systematic searches were performed through EMBASE, MEDLINE, and grey literature sources to identify cohort studies in hospitalized adults that used standardized definitions for AKI, included a non-exposed comparator, and followed patients for at least 1 year. Risk of bias was assessed by the Newcastle-Ottawa Scale. Random effects meta-analyses were performed to pool risk estimates; subgroup, sensitivity, and meta-regression analyses were used to investigate heterogeneity. Of 4973 citations, 82 studies (comprising 2,017,437 participants) were eligible for inclusion. Common sources of bias included incomplete reporting of outcome data, missing biochemical values, and inadequate adjustment for confounders. Individuals with AKI were at increased risk of new or progressive CKD (HR 2.67, 95% CI 1.99-3.58; 17.76 versus 7.59 cases per 100 person-years), ESKD (HR 4.81, 95% CI 3.04-7.62; 0.47 versus 0.08 cases per 100 person-years), and death (HR 1.80, 95% CI 1.61-2.02; 13.19 versus 7.26 deaths per 100 person-years). A gradient of risk across increasing AKI stages was demonstrated for all outcomes. For mortality, the magnitude of risk was also modified by clinical setting, baseline kidney function, diabetes, and coronary heart disease. These findings establish the poor long-term outcomes of AKI while highlighting the importance of injury severity and clinical setting in the estimation of risk.

Derivation and validation of plasma endostatin for predicting renal recovery from acute kidney injury: a prospective validation study

BACKGROUND

Acute kidney injury (AKI) is associated with high morbidity and mortality in surgical patients. Nonrecovery from AKI may increase mortality and early risk stratification seems key to improving clinical outcomes. The aim of the current study was to explore and validate the value of endostatin for predicting failure to recover from AKI.

METHODS

We conducted a prospective cohort study of 198 patients without known chronic kidney disease who underwent noncardiac major surgery and developed new-onset AKI in the first 48 h after admission to the ICU. The biomarkers of plasma endostatin, neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were detected immediately after AKI diagnosis. The primary endpoint was nonrecovery from AKI (within 7 days). Cutoff values of the biomarkers for predicting nonrecovery were determined in a derivation cohort (105 AKI patients). Predictive accuracy was then analyzed in a validation cohort (93 AKI patients).

RESULTS

Seventy-six of 198 (38.4%) patients failed to recover from AKI onset, with 41 in the derivation cohort and 35 in the validation cohort. Compared with NGAL and cystatin C, endostatin showed a better prediction for nonrecovery, with an area under the receiver operating characteristic curve (AUC) of 0.776 (95% confidence interval (CI) 0.654-0.892, p < 0.001) and an optimal cutoff value of 63.7 ng/ml. The predictive ability for nonrecovery was greatly improved by the prediction model combining endostatin with clinical risk factors of Sequential Organ Failure Assessment (SOFA) score and AKI classification, with an AUC of 0.887 (95% CI 0.766-0.958, p < 0.001). The value of the endostatin-clinical risk prediction model was superior to the NGAL-clinical risk and cystatin C-clinical risk prediction models in predicting failure to recover from AKI, which was supported by net reclassification improvement and integrated discrimination improvement. Further, the endostatin-clinical risk prediction model achieved sensitivity and specificity of 94.6% (76.8-99.1) and 72.7% (57.2-85.0), respectively, when validated in the validation cohort.

CONCLUSION

Plasma endostatin shows a useful value for predicting failure to recover from AKI. The predictive ability can be greatly improved when endostatin is combined with the SOFA score and AKI classification.

Female sex reduces the risk of hospital-associated acute kidney injury: a meta-analysis

Background

Female sex has been included as a risk factor in models developed to predict the development of AKI. In addition, the commentary to the Kidney Disease Improving Global Outcomes Clinical Practice Guideline for AKI concludes that female sex is a risk factor for hospital-acquired AKI. In contrast, a protective effect of female sex has been demonstrated in animal models of ischemic AKI.

Methods

To further explore this issue, we performed a meta-analysis of AKI studies published between January, 1978 and April, 2018 and identified 83 studies reporting sex-stratified data on the incidence of hospital-associated AKI among nearly 240,000,000 patients.

Results

Twenty-eight studies (6,758,124 patients) utilized multivariate analysis to assess risk factors for hospital-associated AKI and provided sex-stratified ORs. Meta-analysis of this cohort showed that the risk of developing hospital-associated AKI was significantly greater in men than in women (OR 1.23 (1.11,1.36). Since AKI is not a single disease but instead represents a heterogeneous group of disorders characterized by an acute reduction in renal function, we performed subgroup meta-analyses. The association of male sex with AKI was strongest among studies of patients who underwent non-cardiac surgery. Male sex was also associated with AKI in studies which included unselected hospitalized patients and in studies of critically ill patients who received care in an intensive care unit. In contrast, cardiac surgery-associated AKI and radiocontrast-induced AKI showed no sexual dimorphism.

Conclusions

Our meta-analysis contradicts the established belief that female sex confers a greater risk of AKI and instead suggests a protective role.

One- and three-year outcomes in patients treated with intermittent hemodialysis for acute kidney injury: prospective observational multicenter post-hoc FINNAKI study

BACKGROUND

Studies reporting renal and overall survival after acute kidney injury (AKI) treated exclusively with intermittent modalities of renal replacement therapy (IRRT) are rare. This study focused on outcomes of AKI patients treated with IRRT both in intensive care units (ICUs) and non-ICU dialysis units.

METHODS

This prospective observational study was carried on during a 5-month period in 17 ICUs and 17 non-ICUs. ICU and non-ICU patients (total n = 138; 65 ICU, 73 non-ICU) requiring RRT for AKI and chosen to receive IRRT were included. Patient and RRT characteristics as well as outcomes at 90 days, 1 year, and 3 years were registered.

RESULTS

Characteristics of ICU and non-ICU patients differed markedly. Pre-existing chronic kidney disease (CKD) and chronic heart failure were significantly more common among non-ICU patients. At 1 year, RRT dependence was significantly more common in the non-ICU group. At 3 years, there was no significant difference between the groups either in RRT dependence or mortality.

CONCLUSION

Outcome of AKI patients treated with IRRT is dismal with regard to 3-year kidney function and mortality. Although pre-existing CKD emerged as a major risk factor for end-stage renal disease after AKI, the poor kidney survival was also seen in patients without prior CKD.

Renal complications and subsequent mortality in acute critically ill patients without pre-existing renal disease

BACKGROUND

Most studies of long-term renal outcomes after acute critical illness have enrolled patients with pre-existing renal dysfunction. We assessed renal outcomes in patients who did not have pre-existing renal disease and who were admitted to hospital for acute critical illness.

METHODS

We identified adults who did not have pre-existing renal disease and who were admitted to hospital for acute critical illness between 2000 and 2011, from the Taiwan National Health Insurance Research Database. Each patient was matched 1:2 with controls without acute critical illness, according to age, sex and index date. A subset was further matched 1:1 with controls using propensity scores. Outcomes included acute kidney injury, chronic kidney disease and end-stage renal disease.

RESULTS

We evaluated 33 613 patients with acute critical illness matched to 63 148 controls, of whom 14 218 were propensity matched to 14 218 controls. Patients with acute critical illness had incidence rates per 10 000 person-years of 9.45 for acute kidney injury, 78.3 for chronic kidney disease and 21.0 for end-stage renal disease. In the propensity-matched cohort, patients with acute critical illness had significantly higher risks of acute kidney injury (adjusted hazard ratio [aHR] 2.92, 95% confidence interval [CI] 1.78-4.77), chronic kidney disease (aHR 1.81, 95% CI 1.57-2.08), and end-stage renal disease (aHR 3.60, 95% CI 2.50-5.18). Acute critical illness conferred higher mortality risk among patients who subsequently developed end-stage renal disease (aHR 3.37, 95% CI 2.07-5.49) or chronic kidney disease (aHR 2.16, 95% CI 1.67-2.80).

INTERPRETATION

Patients with acute critical illness and without pre-existing renal disease have a higher risk of adverse renal outcomes and subsequent mortality. A resolved episode of critical illness has implications for future renal function surveillance, even in patients without pre-existing renal disease.

Mortality and long-term dialysis requirement among elderly continuous renal replacement therapy patients in a tertiary referral intensive care unit

Background

Elderly patients are frequently considered poor candidates for continuous renal replacement therapy in intensive care units, but with little evidence base.

Methods

We gathered data regarding patients requiring continuous renal replacement therapy at our institution's intensive care unit during 2012-2014, and compared outcomes between patients of 75 years or older, and younger patients.

Results

Older patients had similar intensive care unit mortality to younger patients (41.5% vs. 36.1%, p = 0.21), but higher hospital mortality (54.2% vs. 44.0%, p = 0.02), and one-year mortality (63.6% vs. 50.6%, p = 0.005). There were no significant differences in dialysis-dependence rates between older and younger patients at intensive care unit discharge (31.9% vs. 35.8%, p = 0.50), and hospital discharge (18.5% vs. 24.2%, 0.32). Rates of new dialysis-dependence between older and younger patients at time of hospital discharge were similar (10.2% vs. 6.0%, p = 0.20).

Conclusions

Intensivists should not withhold continuous renal replacement therapy based on age alone. Other factors should be considered in triage of patients for intensive care unit and continuous renal replacement therapy.

Protein carbonyl concentration as a biomarker for development and mortality in sepsis-induced acute kidney injury

The objective of the present study was to evaluate protein carbonyl concentration as a predictor of AKI development in patients with septic shock and of renal replacement therapy (RRT) and mortality in patients with SAKI. This was a prospective observational study of 175 consecutive patients over the age of 18 years with septic shock upon Intensive Care Unit (ICU) admission. After exclusion of 46 patients (27 due to AKI at ICU admission), a total of 129 patients were enrolled in the study. Demographic information and blood samples were taken within the first 24 h of the patient’s admission to determine serum protein carbonyl concentrations. Among the patients who developed SAKI, the development of AKI was evaluated, along with mortality and need for RRT. The mean age of the patients was 63.3 ± 15.7 years, 47% were male and 51.2% developed SAKI during ICU stay. In addition, protein carbonyl concentration was shown to be associated with SAKI. Among 66 patients with SAKI, 77% died during the ICU stay. Protein carbonyl concentration was not associated with RRT in patients with SAKI. However, the ROC curve analysis revealed that higher levels of protein carbonyl were associated with mortality in these patients. In logistic regression models, protein carbonyl level was associated with SAKI development (OR: 1.416; 95% CI: 1.247–1.609; P<0.001) and mortality when adjusted by age, gender, and APACHE II score (OR: 1.357; 95% CI: 1.147–1.605; P<0.001). In conclusion, protein carbonyl concentration is predictive of AKI development and mortality in patients with SAKI, with excellent reliability.

Timing of renal replacement therapy and long-term risk of chronic kidney disease and death in intensive care patients with acute kidney injury

Background

The optimal time to initiate renal replacement therapy (RRT) in intensive care unit (ICU) patients with acute kidney injury (AKI) is unclear. We examined the impact of early RRT on long-term mortality, risk of chronic kidney disease (CKD), and end-stage renal disease (ESRD).

Methods

This cohort study included all adult patients treated with continuous RRT in the ICU at Aarhus University Hospital, Skejby, Denmark (2005–2015). Data were obtained from a clinical information system and population-based registries. Early treatment was defined as RRT initiation at AKI stage 2 or below, and late treatment was defined as RRT initiation at AKI stage 3. Inverse probability of treatment (IPT) weights were computed from propensity scores. The IPT-weighted cumulative risk of CKD (estimated glomerular filtration rate < 60 ml/minute/1.73 m²), ESRD, and mortality was estimated and compared using IPT-weighted Cox regression.

Results

The mortality, CKD, and ESRD analyses included 1213, 303, and 617 patients, respectively. The 90-day mortality in the early RRT group was 53.6% compared with 46.0% in the late RRT group (HR 1.24, 95% CI 1.03–1.48). The 90-day to 5-year mortality was 37.7% and 41.5% in the early and late RRT groups, respectively (HR 0.95, 95% CI 0.70–1.29). The 5-year risk of CKD was 35.9% in the early RRT group and 44.9% in the late RRT group (HR 0.74, 95% CI 0.46–1.18). The 5-year risk of ESRD was 13.3% in the early RRT group and 16.7% in the late RRT group (HR 0.79, 95% CI 0.47–1.32).

Conclusions

Early initiation was associated with increased 90-day mortality. In patients surviving to day 90, early initiation was not associated with a major impact on long-term mortality or risk of CKD and ESRD. Despite potential residual confounding due to the observational design, our findings do not support that early RRT initiation is superior to late initiation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1903-y) contains supplementary material, which is available to authorized users.

Impact of acute kidney injury on long-term mortality and progression to chronic kidney disease among critically ill children

Objectives:

To determine the 2-year outcome of acute kidney injury (AKI) following admission to pediatric critical care units (PICU).

Methods:

A retrospective cohort study was conducted between January 2012 and December 2013. We followed 131 children admitted to PICU, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia with a diagnosis of AKI, based on pRIFLE (pediatric risk, injury, failure, loss, and end-stage renal disease), for 2 years. During the study period, 46 children died and 38 of survivors completed the follow-up. Factors affecting long-term progression to chronic kidney disease were also evaluated.

Results:

The 2-year mortality was more than 40%. The main determinant of the 2-year mortality was the pediatric risk of mortality (PRISM) score, which increased the risk of mortality by 6% per each one score (adjusted odds ratio, 1.06: 95% confidence interval: 1.00-1.11). By the end of the 2 years, 33% of survivors had reduction in the glomerular filtration rate and proteinuria, and 73% were hypertensive. Patients with more severe renal impairment at admission, based on the pRIFLE criteria, had higher mortality rate. This association, however, was not independent since it was influenced by baseline disease severity (PRISM score).

Conclusion:

Large proportion of patients admitted to PICU with AKI either died during the first 2 months of follow-up or developed long-term complications. The severity of AKI, however, was not an independent risk factor for mortality.

Outcomes in patients with acute kidney injury reviewed by Critical Care Outreach: What is the role of the National Early Warning Score?

Introduction

This study investigated outcomes in critically unwell acute kidney injury patients and the role of the National Early Warning Score and other factors in identifying patients who experience negative outcomes.

Methods

Retrospective cohort study investigating 64 patients seen by Critical Care Outreach between November 2014 and February 2015. Mortality at one year was analysed using multivariate regression; all other statistical tests were non-parametric.

Results

Forty-four per cent of patients required escalation to higher level care, 56% failed to survive beyond one year and 30% of those who did survive had a deterioration in renal function. Previous acute kidney injury significantly predicted mortality but the National Early Warning Score did not. A subgroup of patients developed Stage 3 acute kidney injury before a rise in National Early Warning Score.

Conclusions

Acute kidney injury in the Critical Care Outreach patient population is associated with high morbidity and mortality. Previous acute kidney injury and acute kidney injury stage may be superior to the National Early Warning Score at identifying patients in need of Critical Care Outreach review.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Renal recovery after acute kidney injury

Acute kidney injury (AKI) is a frequent complication of critical illness and carries a significant risk of short- and long-term mortality, chronic kidney disease (CKD) and cardiovascular events. The degree of renal recovery from AKI may substantially affect these long-term endpoints. Therefore maximising recovery of renal function should be the goal of any AKI prevention and treatment strategy. Defining renal recovery is far from straightforward due in part to the limitations of the tests available to assess renal function. Here, we discuss common pitfalls in the evaluation of renal recovery and provide suggestions for improved assessment in the future. We review the epidemiology of renal recovery and of the association between AKI and the development of CKD. Finally, we stress the importance of post-discharge follow-up of AKI patients and make suggestions for its incorporation into clinical practice. Summary key points are that risk factors for non-recovery of AKI are age, CKD, comorbidity, higher severity of AKI and acute disease scores. Second, AKI and CKD are mutually related and seem to have a common denominator. Third, despite its limitations full recovery of AKI may best be defined as the absence of AKI criteria, and partial recovery as a fall in AKI stage. Fourth, after an episode of AKI, serial follow-up measurements of serum creatinine and proteinuria are warranted to diagnose renal impairment and prevent further progression. Measures to promote recovery are similar to those preventing renal harm. Specific interventions promoting repair are still experimental.

Incidence, timing and outcome of AKI in critically ill patients varies with the definition used and the addition of urine output criteria

Background

Acute kidney injury (AKI) is a serious complication of critical illness with both attributed morbidity and mortality at short-term and long-term. The incidence of AKI reported in critically ill patients varies substantially with the population evaluated and the definitions used. We aimed to assess which of the AKI definitions (RIFLE, AKIN or KDIGO) with or without urine output criteria recognizes AKI most frequently and quickest. Additionally, we conducted a review on the comparison of incidence proportions of varying AKI definitions in populations of critically ill patients.

Methods

We included all patients with index admissions to our intensive care unit (ICU) from January 1^st, 2014 until June 11^th, 2014 to determine the incidence and onset of AKI by RIFLE, AKIN and KDIGO during the first 7 days of ICU admission. We conducted a sensitive search using PubMed evaluating the comparison of RIFLE, AKIN and KDIGO in critically ill patients

Results

AKI incidence proportions were 15, 21 and 20% respectively using serum creatinine criteria of RIFLE, AKIN and KDIGO. Adding urine output criteria increased AKI incidence proportions to 35, 38 and 38% using RIFLE, AKIN and KDIGO definitions. Urine output criteria detected AKI in patients without AKI at ICU admission in a median of 13 h (IQR 7–22 h; using RIFLE definition) after admission compared to a median of 24 h using serum creatinine criteria (IQR24-48 h). In the literature a large heterogeneity exists in patients included, AKI definition used, reference or baseline serum creatinine used, and whether urine output in the staging of AKI is used.

Conclusion

AKIN and KDIGO criteria detect more patients with AKI compared to RIFLE criteria. Addition of urine output criteria detect patients with AKI 11 h earlier than serum creatinine criteria and may double AKI incidences in critically ill patients. This could explain the large heterogeneity observed in literature.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0487-8) contains supplementary material, which is available to authorized users.

Long-term outcome of severe acute kidney injury survivors followed by nephrologists in a developing country

AIM

This study aimed to evaluate the long-term outcome of patients after a severe episode of acute kidney injury (AKI) on survival and progression to chronic kidney disease (CKD) and to identify risk factors associated with these outcomes.

METHODS

We performed a prospective study that evaluated the long-term outcome of 509 AKI stage 3 patients who were followed by nephrologists in a Brazilian University Hospital from 2004 to 2013.

RESULTS

Age was 60.2 years (47.5-71) and the follow-up time was 25 months (12-44). The late mortality was 38.1% and age (HR 2.89, 95% CI=1.88 to 4.46, P < 0.0001), diabetes (HR 1.46, 95% CI=1 0.02 to 2.16, P < 0.047), liver disease (HR 2.95, 95% CI=1.19 to 7.3, P = 0.02) and creatinine (Cr) at the time of hospital discharge (HR 1.21, 95% CI=1.04 to 1.41, P = 0.01) were associated with poor long-term survival. At the moment of hospital discharge, 52.1% of patients had complete recovery of renal function, 39.7% had partial recovery and 8.3% had not recovered renal function. After 36 months, 43.5% of patients progressed to CKD, and 5.3% needed for chronic dialysis. Factors associated with progression to CKD were age (HR 1.02, 95% CI=1.008 to 1.035, P = 0.009), CKD (HR 1.05 95% CI=1.007 to 1.09, P = 0.04), diabetes (HR 1.12, CI 1.008-1.035, P = 0.009) and number of AKI episodes (HR 1.65, 95% CI=1.19 to 2.2, P = 0.0023).

CONCLUSION

This study showed that AKI patients have high mortality after hospital discharge and age, diabetes, liver disease, and Cr value at the time of discharge were factors associated with long-term mortality. The risk factors for this progression to CKD were age, the presence of diabetes and the number of AKI episodes.

The Danish Nephrology Registry

Aim of database

The Danish Nephrology Registry’s (DNR) primary function is to support the Danish public health authorities’ quality control program for patients with end-stage renal disease in order to improve patient care. DNR also supplies epidemiological data to several international organizations and supports epidemiological and clinical research.

Study population

The study population included patients treated with dialysis or transplantation in Denmark from January 1, 1990 to January 1, 2016, with retrospective data since 1964.

Main variables

DNR registers patient data (eg, age, sex, renal diagnosis, and comorbidity), predialysis specialist treatment, details of eight dialysis modalities (three hemodialysis and five peritoneal dialysis), all transplantation courses, dialysis access at first dialysis, treatment complications, and biochemical variables. The database is complete (<1% missing data). Patients are followed until death or emigration.

Descriptive data

DNR now contains 18,120 patients, and an average of 678 is added annually. Data for each transplantation course include donor details, tissue type, time to onset of graft function, and cause of graft loss. Registered complications include peritonitis in peritoneal dialysis patients, causes of peritoneal dialysis technique failure, and transplant rejections. Fifteen biochemical variables are registered, mainly describing anemia control, mineral and bone disease, nutritional and uremia status. Date and cause of death are also included. Six quality indicators are published annually, and have been associated with improvements in patient results, eg, a reduction in dialysis patient mortality, improved graft survival, and earlier referral to specialist care. Approximately, ten articles, mainly epidemiological, are published each year.

Conclusion

DNR contains a complete description of end-stage renal disease patients in Denmark, their treatment, and prognosis. The stated aims are fulfilled.

Erythrocyte superoxide dismutase as a biomarker of septic acute kidney injury

Background

Oxidative stress is a key feature of sepsis and could be a common pathophysiological pathway between septic shock and acute kidney injury (AKI) Our objective was to evaluate the erythrocyte superoxide dismutase (SOD1) activity as predictor of AKI in patients with septic shock.

Methods

This is a prospective observational study that evaluated 175 consecutive patients over the age of 18 years with septic shock upon intensive care unit (ICU) admission. However, 43 patients were excluded (27 due to AKI at ICU admission). Thus, 132 patients were enrolled in the study. At the time of the patients’ enrollment, demographic information was recorded. Blood samples were taken within the first 24 h of the patient’s admission to determine the erythrocyte SOD1 activity. All patients were followed throughout the ICU stay, and the development of AKI was evaluated. In addition, we also evaluated 17 control subjects.

Results

The mean age of patients with septic shock was 63.2 ± 15.7 years, 53 % were male and the median ICU stay was 8 days (4–16). Approximately 50.7 % developed AKI during the ICU stay. The median erythrocyte SOD1 activity was 2.92 (2.19–3.92) U/mg Hb. When compared to control subjects, septic shock patients had a higher serum malondialdehyde concentration and lower erythrocyte SOD1 activity. In univariate analysis, erythrocyte SOD1 activity was lower in patients who developed AKI. The ROC curve analysis revealed that lower erythrocyte SOD1 activity was associated with AKI development (AUC 0.686; CI 95 % 0.595–0.777; p < 0.001) at the cutoff of <3.32 U/mg Hb. In the logistic regression models, SOD1 activity higher than 3.32 U/mg Hb was associated with protection of AKI development when adjusted by hemoglobin, phosphorus and APACHE II score (OR 0.309; CI 95 % 0.137–0.695; p = 0.005) and when adjusted by age, gender, chronic kidney disease, admission category (medical or surgery) and APACHE II score (OR 0.129; CI 95 % 0.033–0.508; p = 0.003).

Conclusions

In conclusion, our data suggest that erythrocyte SOD1 activity could play a role as an early marker of septic AKI and could be seen as a new research avenue in the field of biomarker in AKI. However, our study did not show a strong correlation between SOD activity and AKI. Nevertheless, these original data do warrant further research in order to confirm or not this hypothesis.

Long term end-stage renal disease and death following acute renal replacement therapy in the ICU

INTRODUCTION

In ICU the need for acute renal replacement therapy (RRT) associates with high mortality and risk of end-stage renal disease (ESRD), but there are limited long-term data. We investigated these outcomes and their risk factors.

METHODS

Retrospective analysis of all adult patients admitted to a general, university hospital ICU 2005-2012, excluding chronic dialysis patients. ESRD was defined as need of RRT > 90 days or kidney transplant.

RESULTS

Of 5766 patients included, 1004 (16%) received acute RRT; their 30-day mortality was 42% vs. 16% for those not requiring acute RRT (adjusted hazard ratio (HR) 1.13 (0.96-1.32)). The 90-day mortality was 55% for patients receiving acute RRT vs. 22% for those who did not (adjusted HR 1.32 (1.15-1.51)) and 1-year mortality was 63% vs. 30%, respectively, (adjusted HR 1.31 (1.16-1.48)). The 7-year risk of ESRD for ICU patients surviving 90 days was 10% for patients who received acute RRT vs. 0.5% among those who did not (adjusted HR 5.9 (2.9-12.4)). Independent risk factors for ESRD included pre-existing kidney disease, pre-existing peripheral vascular disease and use of acute RRT in ICU.

CONCLUSIONS

The need of acute RRT was associated with markedly increased long term risk of death and ESRD; in contrast its use was not associated with 30-day mortality. In addition to acute RRT, decreased kidney function and peripheral vascular disease before ICU admission were risk factors for ESRD. It seems warranted offering medical follow-up to patients after acute RRT in ICU.

Improving outcomes of acute kidney injury survivors

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common problem in critically ill patients, with long-term health implications that extend beyond hospital discharge. Though they are at a high risk of adverse events, AKI survivors may not be receiving adequate postdischarge medical attention. This review discusses recently published data regarding health outcomes after AKI, the current state of post-AKI care, and potential opportunities to improve outpatient care after AKI.

RECENT FINDINGS

In addition to predisposing to de-novo chronic kidney disease or an exacerbation of previously existing chronic kidney disease, a prior episode of AKI has been linked to subsequent cardiac events, cerebrovascular events, and the need for hospital readmission. Despite this, a population-wide study in Ontario showed that only 40% of patients surviving an episode of dialysis-requiring AKI visited a nephrologist within 90 days of hospital discharge. This care gap is important since outpatient contact with a nephrologist during this critical period was associated with enhanced survival.

SUMMARY

AKI is associated with a number of long-term health effects, and new strategies may be needed to address this emerging public health issue. An ambulatory program dedicated to the postdischarge care of AKI survivors may confer a variety of benefits. Future research is needed to evaluate this model of care.