Real-world evidence of constipation and laxative use in the Korean population with chronic kidney disease from a common data model.

Constipation is a highly prevalent gastrointestinal disorder in patients with chronic kidney disease (CKD). However, our understanding of its epidemiology and management in CKD is limited. We aimed to explore real-world data on constipation and laxative use in patients with CKD in a nationwide population-based cohort from the Korean Health Insurance Review and Assessment-National Patient Sample database. This study analyzed retrospective health claims data in Korea from 2012 to 2017 that were transformed into the Observational Medical Outcomes Partnership Common Data Model. The pooled proportion of constipation diagnoses was 30.5% in all patients with CKD and 15.9%, 16.5%, 17.4%, 29.9%, and 43.3% in patients with CKD stages 1-5, respectively, suggesting a higher prevalence in advanced CKD. Patients receiving peritoneal dialysis or hemodialysis had the highest prevalence of constipation, while transplant recipients showed a prevalence comparable to that of patients with early CKD. Patients with CKD had a significantly higher risk of constipation than age- and sex-matched non-CKD individuals (range of odds ratio [OR]:1.66-1.90). Laxative prescribing patterns differed by CKD severity. Osmotic agents were prescribed in more than half of patients with advanced CKD, while magnesium salts and bulking agents were prescribed less frequently. The CKD patients with constipation were more likely to be prescribed constipation-inducing medications, including antipsychotic and neurological medications. Our findings provide real-world constipation and laxative prescription status in the Korean CKD population, revealing a significantly higher risk of constipation and different laxative prescribing patterns in patients with CKD.

The Effect of Induction Therapy on Antibody-Mediated Rejection in Kidney Transplantation: A Network Meta-Analysis Using Recent Data.

BACKGROUND: Various induction regimens are available for kidney transplantation (KT); however, which is superior remains unclear. Moreover, although the induction regimens are effective and important for reducing side effects, their respective relationships with antibody-mediated rejection (AMR) after transplantation remain unclear. Therefore, this study aimed to elucidate the most effective induction regimen for AMR reduction through network analysis. METHODS: We performed a comprehensive search of databases, including basiliximab, alemtuzumab, antithymocyte globulin (ATG), and daclizumab as induction regimens for KT from inception to September 1, 2022. Using a network meta-analysis, we investigated the priorities of 5 induction regimens for patient survival, graft failure, and graft rejection after ABO-incompatible KT. RESULTS: In total, 25 studies comprising 1768 people were included in this network meta-analysis. The primary outcome was the AMR rate of other induction regimens compared with that of basiliximab, whereas the secondary outcomes were heart failure, stroke, hospitalization, peripheral artery disease, myocardial infarction, anemia, leukopenia, herpes zoster, or adverse events. Notably, ATG reduced the AMR rate by 59% (odds ratio, 0.41; 95% credible interval, 0.20-0.90), whereas the other drugs did not show statistical significance. Furthermore, secondary outcomes did not significantly differ between the induction regimens. CONCLUSION: ATG is widely used in KT induction regimens. Our results showed that ATG reduced the risk of AMR in KT recipients when compared with other induction drugs; therefore, it appears to be an efficient choice of induction regimen to reduce AMR after KT.

High-Dose Intravenous Immunoglobulin to Treat Anti-Thymocyte Globulin Induction-Related BK Virus and Cytomegalovirus Infection in Patients with ABO-Incompatible Kidney Transplantation.

BACKGROUND: ABO-incompatible (ABOi) transplantation is a novel method transplantation method that carries a heightened risk of infection caused by the use of high immunosuppressant doses. This elevated risk is particularly concerning for viral infections, such as cytomegalovirus (CMV) and the BK virus (BKV) increases. Herein, we present a case where high-dose intravenous immunoglobulin (IVIG) was effective in treating viral infections after transplantation. METHODS: A 41-year-old man underwent an ABOi transplantation. The initial isoagglutinin titer was 1:32. The patient received 200 mg of rituximab, and 3 rounds of plasmapheresis were performed. Subsequently, renal function remained normal; however, 7 months later, the renal function declined, and BK nephropathy and CMV infection were diagnosed through biopsy and serologic tests. The FK level was reduced, and mycophenolate mofetil was discontinued. Although ciprofloxacin and leflunomide were administered, their effects were minimal. Therefore, high-dose IVIG (1 g/kg) was administered 5 times over 5 weeks, which led to a reduction in BK viral load and CMV infectivity in the serum. CONCLUSIONS: High-dose IVIG may serve as a promising alternative treatment to mitigate early transplant rejection and BKV and CMV infections.

Association between circulating ECM-associated molecules and cardiovascular outcomes in hemodialysis patients: a multicenter prospective cohort study.

Hemodialysis patients are susceptible to cardiovascular remodeling, which increases the risk of cardiovascular morbidity and mortality. Circulating extracellular matrix (ECM)-associated molecules increase during cardiovascular remodeling and can be potential biomarkers of adverse cardiovascular outcomes. However, their clinical significance in patients undergoing hemodialysis remain unclear. This study aimed to elucidate the association between circulating ECM-associated molecules and cardiovascular outcomes in patients undergoing hemodialysis. To this end, we measured levels of plasma matrix metalloproteinase (MMP)-2, MMP-9, tenascin-C, and thrombospondin-2 in 372 patients with hemodialysis. Plasma MMP-2 levels were significantly higher in patients with future cardiovascular events than in those without future cardiovascular events (P = 0.004). All measured molecules had significant correlations with amino-terminal pro-brain natriuretic peptide levels, but the correlation coefficient was the strongest for plasma MMP-2 (rho = 0.317, P < 0.001). High plasma MMP-2 levels were predictive of left ventricular (LV) diastolic dysfunction (adjusted odds ratio per a standard deviation increase = 1.48, 95% confidence interval [CI] = 1.05-2.08) and were independently associated with an increased risk of composite cardiovascular events (adjusted hazard ratio per a standard deviation increase = 1.30, 95% CI = 1.04-1.63). In conclusion, high plasma MMP-2 levels are associated with LV diastolic dysfunction and an increased risk of adverse cardiovascular outcomes in hemodialysis patients.

Effect of Plasmapheresis on the Efficacy of Rituximab in Antibody-Mediated Rejection Patients.

BACKGROUND: Rituximab and plasmapheresis (PP) suppress and eliminate antibody production in patients experiencing antibody-mediated rejection (AMR). Herein, we discuss a case where rituximab was less effective after PP for treating AMR. CASE: A 55-year-old male patient underwent kidney transplantation. His renal function remained normal for 1 year. Subsequently, renal function declined, and (donor-specific antibodies showed positive results. A biopsy of the transplanted kidney revealed AMR. On the day of the biopsy, the medical staff administered 200 mg of rituximab, followed by IV immunoglobulin (IVIg) and PP the next day. The time interval between PP + IVIg treatment and rituximab was 12 h. As a result, the B-cell markers CD19 and CD20 did not decrease sufficiently, and the patient's creatinine and glomerular filtration rate muscles did not recover adequately. CONCLUSION: We report a case in which PP was administered shortly after rituximab injection, resulting in insufficient B-cell inhibition due to the removal of rituximab.

The impact of C-reactive protein-to-albumin ratio on mortality in patients with acute kidney injury requiring continuous renal replacement therapy: A multicenter retrospective study.

INTRODUCTION: C-reactive protein-to-albumin ratio (CAR) is a prognostic marker in various diseases that represents patients' inflammation and nutritional status. Here, we aimed to investigate the prognostic value of CAR in critically ill patients with severe acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). METHODS: We retrospectively collected data from eight tertiary hospitals in Korea from 2006-2021. The patients were divided into quartiles according to CAR levels at the time of CRRT initiation. Cox regression analyses were performed to investigate the effect of CAR on in-hospital mortality. The mortality prediction performance of CAR was evaluated using the area under the curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI). RESULTS: In total, 3995 patients who underwent CRRT were included, and the in-hospital mortality rate was 67.3% during the follow-up period. The 7-day, 30-day, and in-hospital mortality rates increased toward higher CAR quartiles (all P < 0.001). After adjusting for confounding variables, the higher quartile groups had an increased risk of in-hospital mortality (quartile 3: adjusted hazard ratio [aHR], 1.26, 95% confidence interval [CI], 1.10-1.43, P < 0.001; quartile 4: aHR, 1.22, 95% CI, 1.07-1.40, P = 0.003). CAR combined with APACHE II or SOFA scores significantly increased the predictive power compared to each severity score alone for the AUC, NRI, and IDI (all P < 0.05). CONCLUSIONS: A high CAR is associated with increased in-hospital mortality in critically ill patients requiring CRRT. The combined use of CAR and severity scores provides better predictive performance for mortality than the severity score alone.

The effects of muscle mass and quality on mortality of patients with acute kidney injury requiring continuous renal replacement therapy.

This study examined the effects of muscle mass on mortality in patients with acute kidney injury requiring continuous renal replacement therapy. It was conducted in eight medical centers between 2006 and 2021. The data of 2200 patients over the age of 18 years with acute kidney injury who required continuous renal replacement therapy were retrospectively collected. Skeletal muscle areas, categorized into normal and low attenuation muscle areas, were obtained from computed tomography images at the level of the third lumbar vertebra. Cox proportional hazards models were used to investigate the association between mortality within 1, 3, and 30 days and skeletal muscle index. Sixty percent of patients were male, and the 30-day mortality rate was 52%. Increased skeletal muscle areas/body mass index was associated with decreased mortality risk. We also identified a 26% decreased risk of low attenuation muscle area/body mass index on mortality. We established that muscle mass had protective effects on the mortality of patients with acute kidney injury requiring continuous renal replacement therapy. This study showed that muscle mass is a significant determinant of mortality, even if the density is low.

Synergistic Renoprotective Effect of Melatonin and Zileuton by Inhibition of Ferroptosis via the AKT/mTOR/NRF2 Signaling in Kidney Injury and Fibrosis.

According to recent evidence, ferroptosis is a major cell death mechanism in the pathogenesis of kidney injury and fibrosis. Despite the renoprotective effects of classical ferroptosis inhibitors, therapeutic approaches targeting kidney ferroptosis remain limited. In this study, we assessed the renoprotective effects of melatonin and zileuton as a novel therapeutic strategy against ferroptosis-mediated kidney injury and fibrosis. First, we identified RSL3-induced ferroptosis in renal tubular epithelial HK-2 and HKC-8 cells. Lipid peroxidation and cell death induced by RSL3 were synergistically mitigated by the combination of melatonin and zileuton. Combination treatment significantly downregulated the expression of ferroptosis-associated proteins, 4-HNE and HO-1, and upregulated the expression of GPX4. The expression levels of p-AKT and p-mTOR also increased, in addition to that of NRF2 in renal tubular epithelial cells. When melatonin (20 mg/kg) and zileuton (20 mg/kg) were administered to a unilateral ureteral obstruction (UUO) mouse model, the combination significantly reduced tubular injury and fibrosis by decreasing the expression of profibrotic markers, such as α-SMA and fibronectin. More importantly, the combination ameliorated the increase in 4-HNE levels and decreased GPX4 expression in UUO mice. Overall, the combination of melatonin and zileuton was found to effectively ameliorate ferroptosis-related kidney injury by upregulating the AKT/mTOR/ NRF2 signaling pathway, suggesting a promising therapeutic strategy for protection against ferroptosis-mediated kidney injury and fibrosis.

Dynamic nature and prognostic value of the neutrophil-to-lymphocyte ratio in critically ill patients with acute kidney injury on continuous renal replacement therapy: A multicenter cohort study.

Introduction: Patients with acute kidney injury (AKI) receiving renal replacement therapy constitute the subgroup of AKI with the highest risk of mortality. Despite recent promising findings on the neutrophil-to-lymphocyte ratio (NLR) in AKI, studies have not yet addressed the clinical implication of the NLR in this population. Therefore, we aimed to examine the prognostic value of NLR in critically ill patients requiring continuous renal replacement therapy (CRRT), especially focusing on temporal changes in NLR. Methods: We enrolled 1,494 patients with AKI who received CRRT in five university hospitals in Korea between 2006 and 2021. NLR fold changes were calculated as the NLR on each day divided by the NLR value on the first day. We performed a multivariable Cox proportional hazard analysis to assess the association between the NLR fold change and 30-day mortality. Results: The NLR on day 1 did not differ between survivors and non-survivors; however, the NLR fold change on day 5 was significantly different. The highest quartile of NLR fold change during the first 5 days after CRRT initiation showed a significantly increased risk of death (hazard ratio [HR], 1.65; 95% confidence intervals (CI), 1.27-2.15) compared to the lowest quartile. NLR fold change as a continuous variable was an independent predictor of 30-day mortality (HR, 1.14; 95% CI, 1.05-1.23). Conclusion: In this study, we demonstrated an independent association between changes in NLR and mortality during the initial phase of CRRT in AKI patients receiving CRRT. Our findings provide evidence for the predictive role of changes in the NLR in this high-risk subgroup of AKI.

Changes in CT-Based Morphological Features of the Kidney with Declining Glomerular Filtration Rate in Chronic Kidney Disease.

Chronic kidney disease (CKD) progression involves morphological changes in the kidney, such as decreased length and thickness, with associated histopathological alterations. However, the relationship between morphological changes in the kidneys and glomerular filtration rate (GFR) has not been quantitatively and comprehensively evaluated. We evaluated the three-dimensional size and shape of the kidney using computed tomography (CT)-derived features in relation to kidney function. We included 257 patients aged ≥18 years who underwent non-contrast abdominal CT at the Inha University Hospital. The features were quantified using predefined algorithms in the pyRadiomics package after kidney segmentation. All features, except for flatness, significantly correlated with estimated GFR (eGFR). The surface-area-to-volume ratio (SVR) showed the strongest negative correlation (r = -0.75, p < 0.0001). Kidney size features, such as volume and diameter, showed moderate to high positive correlations; other morphological features showed low to moderate correlations. The calculated area under the receiver operating characteristic (ROC) curve (AUC) for different features ranged from 0.51 (for elongation) to 0.86 (for SVR) for different eGFR thresholds. Diabetes patients had weaker correlations between the studied features and eGFR and showed less bumpy surfaces in three-dimensional visualization. We identified alterations in the CKD kidney based on various three-dimensional shape and size features, with their potential diagnostic value.

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis.

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

Potassium Channel Syndrome Caused by Nicorandil in Chronic Kidney Disease: A Case Report and Literature Review.

Nicorandil is an anti-anginal drug that is commonly used in the treatment of ischemic heart disease. Nicorandil acts as a nitrate donor and ATP-sensitive potassium channel agonist, inducing coronary artery vasodilation. Potassium efflux through ATP-sensitive potassium channels activated by nicorandil can cause refractory hyperkalemia, particularly in patients with chronic kidney disease (CKD). Here, we report the case of an 85-year-old man who presented with severe refractory hyperkalemia, despite proper medical management. His serum potassium level increased from 4.96 to 7.21 mEq/L 7 days after restarting nicorandil. Hyperkalemia resolved shortly after discontinuation of nicorandil, which was presumed to be the offending drug. Previously, a few cases reported nicorandil-induced hyperkalemia called potassium channel syndrome in patients with CKD, and hyperkalemia can be reversed by ceasing nicorandil or using sulfonyl urea drugs. Given that CKD patients may have several contributing factors to this adverse event, clinicians should be aware of the risk of nicorandil-induced hyperkalemia, and medication review and drug discontinuation should be considered.

Three-Dimensional Kidney-on-a-Chip Assessment of Contrast-Induced Kidney Injury: Osmolality and Viscosity.

Increased viscosity of concentrated contrast media (CM) in the renal tubules can perturb renal hemodynamics and have a detrimental effect on tubular epithelial cells. However, the effects of viscosity on contrast-induced nephropathy (CIN) remain poorly understood. Conventional in vitro culture studies do not reflect the rheological properties of CM. Therefore, we investigated the effects of CM viscosity on renal tubules using a kidney-on-a-chip and two different types of CM. Renal proximal tubule epithelial cells (RPTEC) were cultured in a three-dimensional microfluidic culture platform under bidirectional fluid shear stress. We treated the RPTEC with two types of CM: low- (LOCM, iopromide) and iso-osmolar contrast media (IOCM, iodixanol). Renal tubular cell injury induced by LOCM and IOCM was examined under different iodine concentrations (50-250 mgI/mL) and shear-stress conditions. LOCM showed a significant dose-dependent cytotoxic effect, which was significantly higher than that of IOCM under static and low-to-moderate shear stress conditions. However, high shear-stress resulted in reduced cell viability in IOCM; no difference between IOCM and LOCM was found under high shear-stress conditions. The cytotoxic effects were pronounced at a mean shear stress of 1 dyn/cm2 or higher. The high viscosity of IOCM slowed the fluid flow rate and augmented fluid shear-stress. We suggest an alternative in vitro model of CIN using the three-dimensional kidney-on-a-chip. Our results indicate a vital role of viscosity-induced nephrotoxicity under high shear-stress conditions, contrary to the findings of conventional in vitro studies.

Three-Dimensional Visualization With Tissue Clearing Uncovers Dynamic Alterations of Renal Resident Mononuclear Phagocytes After Acute Kidney Injury.

Traditional histologic methods are limited in detecting dynamic changes in immune cells during acute kidney injury (AKI). Recently, optical tissue clearing combined with multiphoton microscopy (MPM) or light sheet fluorescence microscopy (LSFM) has become an emerging method for deep tissue evaluation and three-dimensional visualization. These new approaches have helped expand our understanding of tissue injury and repair processes, including tracing the changes in immune cells. We designed this study to investigate the morphological and functional alterations of renal mononuclear phagocytes (MNPs) in lipopolysaccharide (LPS)-induced AKI using renal clearing in CD11c-YFP mice. We also evaluated the effect of the NLRP3 inhibitor MCC950 to determine whether NLRP3 inhibition attenuates the activation of CD11c+ cells in an LPS-induced AKI model. Transverse sectioned whole mouse kidney imaging by LSFM showed that CD11c+ cells were mainly distributed in the cortex, especially the tubulointerstitial area. The number of CD11c+ cells was significantly more densely interspersed, particularly in periglomerular and perivascular lesions, in the saline-treated LPS-exposed kidney than in the control kidney. Deep imaging of the kidney cortex by MPM demonstrated an increased number of CD11c+ cells in the saline-treated LPS group compared with the control group. This quantitative alteration of CD11c+ cells in AKI was accompanied by morphological changes at high resolution, showing an increased number and level of dendrites. These morphological and behavioral changes in the saline-treated LPS group were accompanied by increased MHC class II and CD86 on CD11c-YFP+ cells. MCC950 attenuated the activation of CD11c+ cells after AKI and improved renal function. In conclusion, wide and deep three-dimensional visualization using MPM or LSFM combined with kidney clearing uncovers dynamic changes of renal MNPs, which are directly linked to renal function in AKI.

Multiple Gouty Arthritis With Tophi Formation in a Patient With End-Stage Kidney Disease Treated After Kidney Transplant.

BACKGROUND: Hyperuricemia is a common condition in patients with chronic kidney disease and end-stage kidney disease. It occurs even after kidney transplant because of the use of calcineurin inhibitors and transplanted kidney failure. We describe the case of a patient with end-stage kidney disease who had multiple gouty arthritis with tophi formation despite receiving appropriate treatment but was successfully cured after kidney transplant. CASE REPORT: A 36-year-old male patient undergoing hemodialysis treatment was treated with febuxostat for multiple gouty arthritis and underwent tophi removal twice. He received a deceased donor kidney transplant 10 years after dialysis treatment. He received immunosuppressants (basiliximab, tacrolimus, mycophenolate mofetil) and steroids. Results of renal biopsy performed on days 7 and 21 postoperation showed no specific findings and normal renal function. The uric acid level before transplant was 3.1 mg/dL, and when renal function was normal, it reached 6-7 mg/dL and remained stable. Although hyperuricemia was still present, the tophi disappeared 3 months after transplant. It is presumed that the high-dose steroids interfered with the activation of inflammatory responses during tophi formation, which may have caused the tophi to disappear. It is also presumed that the patient adhered to the diet well after transplant, which suppressed tophi formation. CONCLUSIONS: Our findings suggest that disappearance of multiple tophi and arthritis in patients undergoing hemodialysis can be achieved with kidney transplant, especially when uric acid-lowering drugs are not effective.

Cancer Diagnosis During Kidney Donor Evaluation.

Donor evaluation is important to ensure that life threatening diseases like cancer can be prevented from getting passed on to the recipient. The donor patient described in our report showed normal parameters in blood and urine biochemistry analysis. Additionally, kidney ultrasonography and renal artery CT showed no indications of any abnormalities. However, endoscopic analysis performed later turned out to be valuable in detection of a protruding mass of 22 to 25 cm in size at the anal verge, and positron emission tomography revealed liver metastasis. Thus, our study highlights that endoscopic techniques can be really valuable in cancer detection and medical centers must consider including these tests in their donor evaluation diagnostic procedures.

Acute Anti-A/B Antibody-Mediated Rejection After ABO-Incompatible Kidney Transplantation Treated With Bortezomib and Plasmapheresis: A Case Report.

BACKGROUND: ABO-incompatible kidney transplantation (KTP) is effective for avoiding transplantation-related issues. It is a viable alternative to ABO-compatible KTP, as both techniques have similar patient and graft survival rates. However, anti-A/B antibody-mediated rejection (AMR) can occur, resulting in poor long-term graft survival. CASE: A 45-year-old man with end-stage renal disease presented with a serum creatinine level of 10.2 mg/dL. We decided to perform KTP with spousal donation. He had panel-reactive antibody class I and II and cross matching test negativity, a 3/6 mismatch on human leukocyte antigen typing, an ABO antibody titer of 1:256, and no donor-specific antibodies. The patient and donor blood types were O+ and A+, respectively. The anti-A/B antibody titer was reduced preoperatively with rituximab (200 mg/body), plasmapheresis, and intravenous immunoglobulin (0.2 mg/kg). Basiliximab and methylprednisolone were used for induction immunosuppression, and tacrolimus, mycophenolate mofetil, and prednisolone were used for maintenance immunosuppression. KTP was successful, and graft function was initially normal. On postoperative day (POD) 5, the serum creatinine level and anti-A/B antibody titer increased from 0.9 mg/dL to 1.9 mg/dL and 1:16 to 1:64, respectively. Graft biopsy revealed acute AMR and tubular injury. We started steroid pulse therapy, plasmapheresis, and subcutaneous bortezomib (2.6 mg, twice a day, every 3 days) with no side effects. The serum creatinine level decreased from 5.7 mg/dL to 1.5 mg/dL on POD 28. Graft biopsy showed no rejection, and normal function was maintained for 40 months. CONCLUSIONS: Acute, early anti-A/B AMR was successfully treated with plasmapheresis and bortezomib.

Effect of estimating equations for glomerular filtration rate on novel surrogate markers for renal outcome.

BACKGROUNDS: Recently, alternative surrogate endpoints such as a 30% or 40% decline in estimated glomerular filtration rate (eGFR) or eGFR slope over 2 to 3 years have been proposed for predicting renal outcomes. However, the impact of GFR estimation methods on the accuracy and effectiveness of surrogate markers is unknown. METHODS: We retrospectively enrolled participants in health screening programs at three hospitals from 1995 to 2009. We defined two different participant groups as YR1 and YR3, which had available 1-year or 3-year eGFR values along with their baseline eGFR levels. We compared the effectiveness of eGFR percentage change or slope to estimate end-stage renal disease (ESRD) risk according to two estimating equations (modified Modification of Diet in Renal Disease equation [eGFRm] and Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation [eGFRc]) for GFR. RESULTS: In the YR1 and YR3 groups, 9,971 and 10,171 candidates were enrolled and ESRD incidence during follow-up was 0.26% and 0.19%, respectively. The eGFR percentage change was more effective than eGFR slope in estimating ESRD risk, regardless of the method of estimation. A 40% of decline in eGFR was better than 30%, and a 3-year baseline period was better than a 1-year period for prediction accuracy. Although some diagnostic indices from the CKD-EPI equation were better, we found no significant differences in the discriminative ability and hazard ratios for incident ESRD between eGFRc and eGFRm in either eGFR percentage change or eGFR slope. CONCLUSION: There were no significant differences in the prediction accuracy of GFR percentage change or eGFR slope between eGFRc and eGFRm in the general population.

Real-Time Clinical Decision Support Based on Recurrent Neural Networks for In-Hospital Acute Kidney Injury: External Validation and Model Interpretation.

BACKGROUND: Acute kidney injury (AKI) is commonly encountered in clinical practice and is associated with poor patient outcomes and increased health care costs. Despite it posing significant challenges for clinicians, effective measures for AKI prediction and prevention are lacking. Previously published AKI prediction models mostly have a simple design without external validation. Furthermore, little is known about the process of linking model output and clinical decisions due to the black-box nature of neural network models. OBJECTIVE: We aimed to present an externally validated recurrent neural network (RNN)-based continuous prediction model for in-hospital AKI and show applicable model interpretations in relation to clinical decision support. METHODS: Study populations were all patients aged 18 years or older who were hospitalized for more than 48 hours between 2013 and 2017 in 2 tertiary hospitals in Korea (Seoul National University Bundang Hospital and Seoul National University Hospital). All demographic data, laboratory values, vital signs, and clinical conditions of patients were obtained from electronic health records of each hospital. We developed 2-stage hierarchical prediction models (model 1 and model 2) using RNN algorithms. The outcome variable for model 1 was the occurrence of AKI within 7 days from the present. Model 2 predicted the future trajectory of creatinine values up to 72 hours. The performance of each developed model was evaluated using the internal and external validation data sets. For the explainability of our models, different model-agnostic interpretation methods were used, including Shapley Additive Explanations, partial dependence plots, individual conditional expectation, and accumulated local effects plots. RESULTS: We included 69,081 patients in the training, 7675 in the internal validation, and 72,352 in the external validation cohorts for model development after excluding cases with missing data and those with an estimated glomerular filtration rate less than 15 mL/min/1.73 m2 or end-stage kidney disease. Model 1 predicted any AKI development with an area under the receiver operating characteristic curve (AUC) of 0.88 (internal validation) and 0.84 (external validation), and stage 2 or higher AKI development with an AUC of 0.93 (internal validation) and 0.90 (external validation). Model 2 predicted the future creatinine values within 3 days with mean-squared errors of 0.04-0.09 for patients with higher risks of AKI and 0.03-0.08 for those with lower risks. Based on the developed models, we showed AKI probability according to feature values in total patients and each individual with partial dependence, accumulated local effects, and individual conditional expectation plots. We also estimated the effects of feature modifications such as nephrotoxic drug discontinuation on future creatinine levels. CONCLUSIONS: We developed and externally validated a continuous AKI prediction model using RNN algorithms. Our model could provide real-time assessment of future AKI occurrences and individualized risk factors for AKI in general inpatient cohorts; thus, we suggest approaches to support clinical decisions based on prediction models for in-hospital AKI.

Effect of rituximab dose on induction therapy in ABO-incompatible living kidney transplantation: A network meta-analysis.

BACKGROUND: Rituximab is an induction immunosuppressant essential for ABO-incompatible kidney transplantation (ABOi KT). However, studies on its dosing, which differs among countries and transplant centers, are lacking. Therefore, we retrospectively investigated the effectiveness of the induction dose of rituximab against patient mortality, graft failure, and adverse events. METHODS: We included the studies referring to at least 2 of eligible induction doses (200 mg, 200-500 mg, or 500 mg) of rituximab during ABOi KT and relevant outcomes such as patient survival, graft failure, and bacterial and viral infections. We performed direct and indirect network meta-analyses using Bayesian models and ranked different rituximab doses using generation mixed treatment comparison. Publications were retrieved using CENTRAL, MEDLINE, EMBASE, and Science Citation Index Expanded databases from 1970 to February 2020 and analyzed. The GRADE of network meta-analysis approach specified 4 levels of certainty for a given result: high, moderate, low, and very low. RESULTS: Among the 4256 patients from 21 trials, glomerular filtration rate, graft loss, antibody-mediated rejection, T-cell mediated rejection, fungal infection, bacterial infection, and CMV infection did not differ among ABOi groups treated with different rituximab doses. The effect on mortality was significantly higher in rituximab 200 to 500 mg, and rituximab 500 mg groups (odds ratios [OR] 3.5, 95% CrI: 1.3-9.8, and OR 3.0, 95% CrI 1.1-9.8), but not in rituximab 20 mg group (OR 0.45, 95% CrI 0.036-2.5). The incidence of BK virus was significantly lower in the rituximab 200-mg group than in the other groups. DISCUSSION: In ABO-incompatible kidney transplantation, low-dose rituximab is more efficacious than higher doses and reduces serious infection risks. Additional randomized controlled trials might be needed to confirm these findings due to small sample size.