Hospitalization among adults with chronic kidney disease: results from the KoreaN cohort study for Outcomes in patients With Chronic Kidney Disease (KNOW-CKD) study.

Background: Chronic kidney disease (CKD) patients are hospitalized for various conditions. Hospitalization increases the readmission rate and mortality rate, seriously deteriorating patients' quality of life. Consequently, it is crucial to analyze the reasons for hospitalization in CKD patients from a broader perspective according to CKD grade. Methods: This is a prospective cohort study of CKD patients entitled the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD). A total of 2,238 patients were examined, and the reasons for hospitalization were classified into 16 disease categories. The incidence rate ratio (IRR) according to CKD stage was compared using negative bimodal regression analysis. Results: The all-cause hospitalization incidence was 184.96 per 1,000 person-years. The most common reason for hospitalization was circulatory system disease, followed by infection and digestive system disease. Among hospitalizations for acute kidney injury, endocrine-nutrition-metabolic-related illness, blood-related disease, and diseases of the nervous system and sensory organs, IRR increased as CKD grade advanced. The incidence of ophthalmologic surgery during hospitalization increased according to the CKD stage. The IRR of KNOW-CKD patients was 6.19 (95% confidence interval, 5.92-6.48; p < 0.001) compared with the general population. Conclusion: This in-depth analysis of hospitalizations among CKD patients confirmed that CKD patients were hospitalized for various reasons, such as metabolic, ophthalmic, and hematologic diseases. Early detection and intervention regarding causative diseases of CKD are important to reduce the hospitalization burden and improve patients' quality of life.

Molecular incompatibility between pig CD200 and human CD200 receptor in in vitro xenogeneic immune responses.

Overexpression of human CD200 (hCD200) in porcine endothelial cells (PECs) has been reported to suppress xenogeneic immune responses of human macrophages against porcine endothelial cells. The current study aimed to address whether the above-mentioned beneficial effect of hCD200 is mediated by overcoming the molecular incompatibility between porcine CD200 (pCD200) and hCD200 receptor or simply by increasing the expression levels of CD200 without any molecular incompatibility across the two species. We overexpressed hCD200 or pCD200 using lentiviral vectors with V5 marker in porcine endothelial cells and compared their suppressive activity against U937-derived human macrophage-like cells (hMCs) and primary macrophages. In xenogeneic coculture of porcine endothelial cells and human macrophage-like cells or macrophages, hCD200-porcine endothelial cells suppressed phagocytosis and cytotoxicity of human macrophages to a greater extent than pCD200-porcine endothelial cells. Secretion of tumor necrosis factor-α, interleukin-1ß, and monocyte chemoattractant protein-1 from human macrophages and expression of M1 phenotypes (inducible nitric oxide synthase, dectin-1, and CD86) were also suppressed by hCD200 to a greater extent than pCD200. Furthermore, in signal transduction downstream of CD200 receptor, hCD200 induced Dok2 phosphorylation and suppressed IκB phosphorylation to a greater extent than pCD200. The above data supported the possibility of a significant molecular incompatibility between pCD200 and human CD200 receptor, suggesting that the beneficial effects of hCD200 overexpression in porcine endothelial cells could be mediated by overcoming the molecular incompatibility across the species barrier rather than by simple overexpression effects of CD200.

Inhibition of ribonucleotide reductase subunit M2 enhances the radiosensitivity of metastatic pancreatic neuroendocrine tumor.

Ribonucleotide Reductase (RNR) is a rate-limiting enzyme in the production of deoxyribonucleoside triphosphates (dNTPs), which are essential substrates for DNA repair after radiation damage. We explored the radiosensitization property of RNR and investigated a selective RRM2 inhibitor, 3-AP, as a radiosensitizer in the treatment of metastatic pNETs. We investigated the role of RNR subunit, RRM2, in pancreatic neuroendocrine (pNET) cells and responses to radiation in vitro. We also evaluated the selective RRM2 subunit inhibitor, 3-AP, as a radiosensitizer to treat pNET metastases in vivo. Knockdown of RNR subunits demonstrated that RRM1 and RRM2 subunits, but not p53R3, play significant roles in cell proliferation. RRM2 inhibition activated DDR pathways through phosphorylation of ATM and DNA-PK protein kinases but not ATR. RRM2 inhibition also induced Chk1 and Chk2 phosphorylation, resulting in G1/S phase cell cycle arrest. RRM2 inhibition sensitized pNET cells to radiotherapy and induced apoptosis in vitro. In vivo, we utilized pNET subcutaneous and lung metastasis models to examine the rationale for RNR-targeted therapy and 3-AP as a radiosensitizer in treating pNETs. Combination treatment significantly increased apoptosis of BON (human pNET) xenografts and significantly reduced the burden of lung metastases. Together, our results demonstrate that selective RRM2 inhibition induced radiosensitivity of metastatic pNETs both in vitro and in vivo. Therefore, treatment with the selective RRM2 inhibitor, 3-AP, is a promising radiosensitizer in the therapeutic armamentarium for metastatic pNETs.

Long-term Kidney Transplant Survival Across the Globe.

BACKGROUND: The outcomes after kidney transplantation (KT), including access, wait time, and other issues around the globe, have been studied. However, issues do vary from one country to another. METHODS: We obtained data from several countries from North America, South America, Europe, Asia, and Australia, including the number of patients awaiting KT from 2015, transplant rate per million population (pmp), proportion of living donor and deceased donor (LD/DD) KT, and posttransplant survival. We also sought opinions on key difficulties faced by each of these countries with respect to KT and long-term survival. RESULTS: Variation in access to KT across the globe was noted. Countries with the highest rates of KT pmp included the United States (79%) and Spain (71%). A higher proportion of LD transplants was noted in Japan (93%), India (85%), Singapore (63%), and South Korea (63%). A higher proportion of DD KTs was noted in Spain (90%), Brazil (90%), France (85%), Italy (85%), Finland (85%), Australia-New Zealand (80%), and the United States (77%). The 5-y graft survival for LD was highest in South Korea (95%), Singapore (94%), Italy (93%), Finland (93%), and Japan (93%), whereas for DD, it was South Korea (93%), Italy (88%), Japan (86%), and Singapore (86%). The common issues surrounding KTs are access and a limited number of LDs and DDs. Key issues identified for long-term survival were increasing age of donors and recipients, higher recipient comorbidity, and posttransplant events, such as alloimmune injury to the kidney, infection, cancer, and suboptimal adherence to therapy. CONCLUSIONS: A unified approach is necessary to improve issues surrounding KT as the demand continues to increase.

Comparison between characteristics of immunoglobulin M nephropathy and other glomerular diseases.

Background: Immunoglobulin M (IgM) nephropathy (IgMN) is characterized by the IgM deposition in the kidney's mesangium. We assessed the impact of electron-dense deposits (EDDs) on IgMN and compared it to other kidney diseases. Methods: We enrolled 63 adult patients with IgMN who underwent renal biopsy from May 2003 to June 2017. We compared clinicopathological features of IgMN based on EDD presence; compared characteristics to 91 minimal change disease (MCD), 103 focal segmental glomerulosclerosis (FSGS), and 469 immunoglobulin A nephropathy (IgAN) patients. Renal events were defined as a >50% decrease in estimated glomerular filtration rate (eGFR), eGFR of <15 mL/min/1.73 m2, or end-stage renal disease development. Results: IgMN patients with EDDs had increased mesangial cellularity, matrix accumulation, prominent immunofluorescent staining, and more diffuse podocyte effacement than those without EDD. Clinical characteristics and renal outcomes did not differ significantly based on EDD presence. During 79.5 ± 58.8 months of follow-up, renal events developed in 46.2% and 46.0% of IgMN cases with and without EDD. IgMN (46.0%) and FSGS cases (40.8%) had similar frequencies of renal events and higher frequency than MCD (18.7%) or IgAN cases (26.4%). IgMN cases had more severe manifestations than MCD and IgAN; higher blood pressure, lower proteinuria, and eGFR levels at biopsy than MCD cases; higher blood pressure, proteinuria, frequency of acute kidney injury, and lower eGFR levels. Conclusion: Clinical characteristics of IgMN did not differ based on EDD presence. Therefore, IgMN should be defined based on IF findings. IgMN shared clinical characteristics with FSGS but had more severe than MCD and IgAN.

Circulating osteoprotegerin levels and cardiovascular outcomes in patients with pre-dialysis chronic kidney disease: results from the KNOW-CKD study.

While the relationship between circulating osteoprotegerin (OPG) and cardiovascular events is well-established in the general population, its association with cardiovascular risks in chronic kidney disease (CKD) patients remains less robust. This study hypothesized that elevated circulating OPG levels might be associated with an increased risk of major adverse cardiac events (MACE) in CKD patients, a total of 2,109 patients with CKD stages 1 through pre-dialysis 5 from the KNOW-CKD cohort were categorized into quartiles based on serum OPG levels. The primary outcome of the study was 3-point MACE, defined as a composite of nonfatal myocardial infarction, nonfatal stroke, or cardiac death. The median follow-up duration was 7.9 years. The cumulative incidence of 3-point MACE significantly varied across serum OPG levels in Kaplan-Meier curve analysis (P < 0.001, log-rank test), with the highest incidence observed in the 4th quartile. Cox regression analysis indicated that, relative to the 1st quartile, the risk of 3-point MACE was significantly higher in the 3rd (adjusted hazard ratio 2.901, 95% confidence interval 1.009 to 8.341) and the 4th quartiles (adjusted hazard ratio 4.347, 95% confidence interval 1.410 to 13.395). In conclusion, elevated circulating OPG levels are associated with adverse cardiovascular outcomes in pre-dialysis CKD patients.

DeepPhe-CR: Natural Language Processing Software Services for Cancer Registrar Case Abstraction.

PURPOSE: Manual extraction of case details from patient records for cancer surveillance is a resource-intensive task. Natural Language Processing (NLP) techniques have been proposed for automating the identification of key details in clinical notes. Our goal was to develop NLP application programming interfaces (APIs) for integration into cancer registry data abstraction tools in a computer-assisted abstraction setting. METHODS: We used cancer registry manual abstraction processes to guide the design of DeepPhe-CR, a web-based NLP service API. The coding of key variables was performed through NLP methods validated using established workflows. A container-based implementation of the NLP methods and the supporting infrastructure was developed. Existing registry data abstraction software was modified to include results from DeepPhe-CR. An initial usability study with data registrars provided early validation of the feasibility of the DeepPhe-CR tools. RESULTS: API calls support submission of single documents and summarization of cases across one or more documents. The container-based implementation uses a REST router to handle requests and support a graph database for storing results. NLP modules extract topography, histology, behavior, laterality, and grade at 0.79-1.00 F1 across multiple cancer types (breast, prostate, lung, colorectal, ovary, and pediatric brain) from data of two population-based cancer registries. Usability study participants were able to use the tool effectively and expressed interest in the tool. CONCLUSION: The DeepPhe-CR system provides an architecture for building cancer-specific NLP tools directly into registrar workflows in a computer-assisted abstraction setting. Improved user interactions in client tools may be needed to realize the potential of these approaches.

Outcomes of minimal change disease without nephrotic range proteinuria.

Minimal change disease (MCD) is characterized by edema and nephrotic range proteinuria (NS). However, the fate of MCD without nephrotic proteinuria requires elucidation. We retrospectively reviewed 79 adults diagnosed with primary MCD at their initial renal biopsy at a tertiary hospital between May 2003 and June 2017. Clinicopathologic features were compared between patients with and without NS. The frequency of flaring to nephrotic proteinuria and renal outcomes were assessed during follow-up. There were 20 and 59 patients in the Non-NS and NS groups, respectively. The Non-NS group had a lower frequency of acute kidney injury (AKI) during the follow-up period [5.0% vs. 59.3%, p <0.001]. The response rate to steroid treatment was 100% in the Non-NS group and 92.3% in the NS group (p = 1.000). Except for one patient, the Non-NS group was treated with steroids when their proteinuria increased to a nephrotic level. There were no differences in the frequency of the first relapse or the number of relapses among patients with initial remission from nephrotic range proteinuria. At the final visit, the complete remission rate was 73.4%. The estimated glomerular filtration rate during follow-up was significantly better in the NS group than the Non-NS group, given the higher rates of AKI at renal biopsy. The rates of renal events, end-stage renal disease, and mortality did not differ between the groups. Adult MCD patients with nephrotic and non-nephrotic range proteinuria showed similar outcomes. Accordingly, this population must be carefully managed, regardless of the amount of proteinuria at renal biopsy.

DeepPhe-CR: Natural Language Processing Software Services for Cancer Registrar Case Abstraction.

Objective: The manual extraction of case details from patient records for cancer surveillance efforts is a resource-intensive task. Natural Language Processing (NLP) techniques have been proposed for automating the identification of key details in clinical notes. Our goal was to develop NLP application programming interfaces (APIs) for integration into cancer registry data abstraction tools in a computer-assisted abstraction setting. Methods: We used cancer registry manual abstraction processes to guide the design of DeepPhe-CR, a web-based NLP service API. The coding of key variables was done through NLP methods validated using established workflows. A container-based implementation including the NLP wasdeveloped. Existing registry data abstraction software was modified to include results from DeepPhe-CR. An initial usability study with data registrars provided early validation of the feasibility of the DeepPhe-CR tools. Results: API calls support submission of single documents and summarization of cases across multiple documents. The container-based implementation uses a REST router to handle requests and support a graph database for storing results. NLP modules extract topography, histology, behavior, laterality, and grade at 0.79-1.00 F1 across common and rare cancer types (breast, prostate, lung, colorectal, ovary and pediatric brain) on data from two cancer registries. Usability study participants were able to use the tool effectively and expressed interest in adopting the tool. Discussion: Our DeepPhe-CR system provides a flexible architecture for building cancer-specific NLP tools directly into registrar workflows in a computer-assisted abstraction setting. Improving user interactions in client tools, may be needed to realize the potential of these approaches. DeepPhe-CR: https://deepphe.github.io/.

Predictive performance of the new race-free Chronic Kidney Disease Epidemiology Collaboration equations for kidney outcome in Korean patients with chronic kidney disease.

BACKGROUND: The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations without a race coefficient have gained recognition across the United States. We aimed to test whether these new equations performed well in Korean patients with chronic kidney disease (CKD). METHODS: This study included 2,149 patients with CKD G1-G5 without kidney replacement therapy from the Korean Cohort Study for Outcome in Patients with CKD (KNOW-CKD). The estimated glomerular filtration rate (eGFR) was calculated using the new CKD-EPI equations with serum creatinine and cystatin C. The primary outcome was 5-year risk of kidney failure with replacement therapy (KFRT). RESULTS: When we adopted the new creatinine equation [eGFRcr (NEW)], 81 patients (23.1%) with CKD G3a based on the current creatinine equation (eGFRcr) were reclassified as CKD G2. Accordingly, the number of patients with eGFR of <60 mL/min/1.73 m2 decreased from 1,393 (64.8%) to 1,312 (61.1%). The time-dependent area under the receiver operating characteristic curve for 5-year KFRT risk was comparable between the eGFRcr (NEW) (0.941; 95% confidence interval [CI], 0.922-0.960) and eGFRcr (0.941; 95% CI, 0.922-0.961). The eGFRcr (NEW) showed slightly better discrimination and reclassification than the eGFRcr. However, the new creatinine and cystatin C equation [eGFRcr-cys (NEW)] performed similarly to the current creatinine and cystatin C equation. Furthermore, eGFRcr-cys (NEW) did not show better performance for KFRT risk than eGFRcr (NEW). CONCLUSION: Both the current and the new CKD-EPI equations showed excellent predictive performance for 5-year KFRT risk in Korean patients with CKD. These new equations need to be further tested for other clinical outcomes in Koreans.

Comparison of cardiovascular event predictability between the 2009 and 2021 Chronic Kidney Disease Epidemiology Collaboration equations in a Korean chronic kidney disease cohort: the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease.

BACKGROUND: The 2009 Chronic Kidney Disease Epidemiology Collaboration creatinine-based estimated glomerular filtration rate (eGFRcr) equation contains a race component that is not based on biology and may cause a bias in results. Therefore, the 2021 eGFRcr and creatinine-cystatin C-based eGFR (eGFRcr-cysC) equations were developed with no consideration of race. This study compared the cardiovascular event (CVE) and all-cause mortality and CVE combined predictability among the three eGFR equations in Korean chronic kidney disease (CKD) patients. METHODS: This study included 2,207 patients from the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease. Receiver operating characteristic (ROC) and net reclassification improvement (NRI) index were used to compare the predictability of the study outcomes according to the 2009 eGFRcr, 2021 eGFRcr, and 2021 eGFRcr-cysC equations. RESULTS: The overall prevalence of CVE and all-cause mortality were 9% and 7%, respectively. There was no difference in area under the curve of ROC for CVE and mortality and CVE combined among all three equations. Compared to the 2009 eGFRcr, both the 2021 eGFRcr (NRI, 0.013; 95% confidence interval [CI], - 0.002 to 0.028) and the eGFRcr-cysC (NRI, -0.001; 95% CI, -0.031 to 0.029) equations did not show improved CVE predictability. Similar findings were observed for mortality and CVE combined predictability with both the 2021 eGFRcr (NRI, -0.019; 95% CI, -0.039-0.000) and the eGFRcr-cysC (NRI, -0.002; 95% CI, -0.023 to 0.018). CONCLUSION: The 2009 eGFRcr equation was not inferior to either the 2021 eGFRcr or eGFRcr-cysC equation in predicting CVE and the composite of mortality and CVE in Korean CKD patients.

Metformin Use and Long-term Clinical Outcomes in Kidney Transplant Recipients.

RATIONALE & OBJECTIVE: Metformin has been recommended for some patients with advanced chronic kidney disease. However, the value of metformin in kidney transplant recipients (KTRs) with pretransplant diabetes mellitus (DM) or posttransplant DM is uncertain. We investigated the clinical effects of metformin in KTRs. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: A total of 1,995 KTRs with diabetes from 6 tertiary referral centers in the Republic of Korea. EXPOSURE: Metformin usage was defined as the use of metformin for>90 days after kidney transplantation; 1,193 KTRs were metformin users, and 802 KTRs did not use metformin. Changing usage of metformin among those exposed for >90 days was also characterized. OUTCOME: Primary outcomes were all-cause mortality and death-censored graft failure (DCGF). Secondary outcomes were biopsy-proven acute rejection (BPAR) and lactic acidosis events. ANALYTICAL APPROACH: Survival analyses were conducted using multivariable Cox regression and competing risk analyses using Fine and Gray models. Changes in metformin use over time were modeled using a time-varying covariate. Metformin usage, mean daily dose, and hemoglobin A1c (HbA1c) changes were considered in the landmark analysis to address time-varying confounding. RESULTS: Metformin use was associated with a lower risk of DCGF (adjusted hazard ratio [AHR], 0.47 [95% CI, 0.23-0.96], P=0.038); there was no significant association with all-cause mortality (AHR, 0.94 [95% CI, 0.32-2.76], P=0.915) or BPAR (AHR 0.98 [95% CI, 0.62-1.54], P=0.942). In the subgroup analysis, metformin usage was associated with a reduced risk of all-cause mortality and a lower risk of DCGF for both pretransplantation DM and posttransplant DM groups. Metformin usage was associated with a lower risk of BPAR in the posttransplant DM group, although it was less effective in the pretransplantation DM group. There was no confirmed case of metformin-associated lactic acidosis (MALA) in the present cohort. A higher dose of metformin was correlated with lower risks of DCGF and BPAR. LIMITATIONS: Data on newer antidiabetic drugs such as SGLT2 inhibitors are limited, and there is potential limited generalizability to other populations. CONCLUSIONS: Metformin usage may benefit KTRs, as evidenced by its association with a reduced risk of DCGF and the absence of MALA events. Randomized controlled trials are needed to validate these observational findings.

Local data commons: the sleeping beauty in the community of data commons.

BACKGROUND: Public Data Commons (PDC) have been highlighted in the scientific literature for their capacity to collect and harmonize big data. On the other hand, local data commons (LDC), located within an institution or organization, have been underrepresented in the scientific literature, even though they are a critical part of research infrastructure. Being closest to the sources of data, LDCs provide the ability to collect and maintain the most up-to-date, high-quality data within an organization, closest to the sources of the data. As a data provider, LDCs have many challenges in both collecting and standardizing data, moreover, as a consumer of PDC, they face problems of data harmonization stemming from the monolithic harmonization pipeline designs commonly adapted by many PDCs. Unfortunately, existing guidelines and resources for building and maintaining data commons exclusively focus on PDC and provide very little information on LDC. RESULTS: This article focuses on four important observations. First, there are three different types of LDC service models that are defined based on their roles and requirements. These can be used as guidelines for building new LDC or enhancing the services of existing LDC. Second, the seven core services of LDC are discussed, including cohort identification and facilitation of genomic sequencing, the management of molecular reports and associated infrastructure, quality control, data harmonization, data integration, data sharing, and data access control. Third, instead of commonly developed monolithic systems, we propose a new data sharing method for data harmonization that combines both divide-and-conquer and bottom-up approaches. Finally, an end-to-end LDC implementation is introduced with real-world examples. CONCLUSIONS: Although LDCs are an optimal place to identify and address data quality issues, they have traditionally been relegated to the role of passive data provider for much larger PDC. Indeed, many LDCs limit their functions to only conducting routine data storage and transmission tasks due to a lack of information on how to design, develop, and improve their services using limited resources. We hope that this work will be the first small step in raising awareness among the LDCs of their expanded utility and to publicize to a wider audience the importance of LDC.

Dominant predictors of early post-transplant outcomes based on the Korean Organ Transplantation Registry (KOTRY).

Data for Asian kidney transplants are very limited. We investigated the relative importance of prognostic markers in Asian kidney transplants by using Korean Organ Transplantation Registry (KOTRY) cohort. Prediction models were developed by data-driven variable selection approach. The relative importance of the selected predictors was measured by dominance analysis. A total of 4854 kidney transplant donor-recipient pairs were analyzed. Overall patient survival rates were 99.8%, 98.8%, and 91.8% at 1, 3, and 5 years, respectively. Death-censored graft survival rates were 98.4%, 97.0%, and 95.8% at 1, 3, and 5 years. Biopsy-proven acute rejection free survival rates were 90.1%, 87.4%, and 87.03% at 1, 3, and 5 years. The top 3 dominant predictors for recipient mortality within 1 year were recipient cardiovascular disease history, deceased donor, and recipient age. The dominant predictors for death-censored graft loss within 1 year were acute rejection, deceased donor, and desensitization. The dominant predictors to acute rejection within 1 year were donor age, HLA mismatched numbers, and desensitization. We presented clinical characteristics of patients enrolled in KOTRY during the last 5 years and investigated dominant predictors for early post-transplant outcomes, which would be useful for clinical decision-making based on quantitative measures.

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.

Renal outcomes of laparoscopic versus open surgery in patients with rectal cancer: a propensity score analysis.

BACKGROUND: A laparoscopic approach is widely used in abdominal surgery. Although several studies have compared surgical and oncological outcomes between laparoscopic surgery (LS) and open surgery (OS) in rectal cancer patients, there have been few studies on postoperative renal outcomes. METHODS: We conducted a retrospective cohort study involving 1,633 patients who underwent rectal cancer surgery between 2003 and 2017. Postoperative acute kidney injury (AKI) was diagnosed according to the serum creatinine criteria of the Kidney Disease: Improving Global Outcomes classification. RESULTS: Among the 1,633 patients, 1,072 (65.6%) underwent LS. After matching propensity scores, 395 patients were included in each group. The incidence of postoperative AKI in the LS group was significantly lower than in the OS group (9.9% vs. 15.9%; p = 0.01). Operation time, estimated blood loss, and incidence of transfusion in the LS group were significantly lower than those in the OS group. Cox proportional hazard models revealed that LS was associated with decreased risk of postoperative AKI (hazard ratio [HR], 0.599; 95% confidence interval [CI], 0.402-0.893; p = 0.01) and postoperative transfusion was associated with increased risk of AKI (HR, 2.495; 95% CI, 1.529-4.072; p < 0.001). In the subgroup analysis, the incidence of postoperative AKI in patients with middle or high rectal cancer who underwent LS was much lower than in those who underwent OS (HR, 0.373; 95% CI, 0.197-0.705; p = 0.002). CONCLUSION: This study showed that LS may have a favorable effect on the development of postoperative AKI in patients with rectal cancer.

Privacy-Preserving Deep Learning NLP Models for Cancer Registries.

Population cancer registries can benefit from Deep Learning (DL) to automatically extract cancer characteristics from the high volume of unstructured pathology text reports they process annually. The success of DL to tackle this and other real-world problems is proportional to the availability of large labeled datasets for model training. Although collaboration among cancer registries is essential to fully exploit the promise of DL, privacy and confidentiality concerns are main obstacles for data sharing across cancer registries. Moreover, DL for natural language processing (NLP) requires sharing a vocabulary dictionary for the embedding layer which may contain patient identifiers. Thus, even distributing the trained models across cancer registries causes a privacy violation issue. In this paper, we propose DL NLP model distribution via privacy-preserving transfer learning approaches without sharing sensitive data. These approaches are used to distribute a multitask convolutional neural network (MT-CNN) NLP model among cancer registries. The model is trained to extract six key cancer characteristics - tumor site, subsite, laterality, behavior, histology, and grade - from cancer pathology reports. Using 410,064 pathology documents from two cancer registries, we compare our proposed approach to conventional transfer learning without privacy-preserving, single-registry models, and a model trained on centrally hosted data. The results show that transfer learning approaches including data sharing and model distribution outperform significantly the single-registry model. In addition, the best performing privacy-preserving model distribution approach achieves statistically indistinguishable average micro- and macro-F1 scores across all extraction tasks (0.823,0.580) as compared to the centralized model (0.827,0.585).

The tacrolimus metabolism affect post-transplant outcome mediating acute rejection and delayed graft function: analysis from Korean Organ Transplantation Registry data.

Tacrolimus is a key drug in kidney transplantation (KT) with a narrow therapeutic index. The association between the tacrolimus metabolism rate and KT outcomes have not been investigated in large-scale multi-center studies. The Korean Organ Transplantation Registry (KOTRY) datasets were used. A total of 3456 KT recipients were analyzed. The tacrolimus metabolism rate was defined as blood trough concentration of tacrolimus (C0 ) divided by the daily dose (D). The patients were grouped into fast, intermediate, or slow metabolizers by the C0 /D measured 6 months after transplantation. The slow metabolism group was associated with a 2.7 ml/min/1.73 m2 higher adjusted estimated glomerular filtration rate (eGFR) at 6 months [95% confidence interval (C.I.) 1.2-4.3, P = 0.001], less acute rejection (AR) within 6 months [Odds ratio (OR) 0.744, 95% C.I. 0.585-0.947, P = 0.016], and less interstitial fibrosis and tubular atrophy [OR 0.606, 95% C.I. 0.390-0.940, P = 0.025]. Fast tacrolimus metabolism affected the 6-month post-KT eGFR through mediation of AR [natural indirect effect (NIE) -0.434, 95% C.I. -0.856 to -0.012, P = 0.044) and delayed graft function (DGF; NIE -0.119, 95% C.I. -0.231 to -0.007, P = 0.038). Slow tacrolimus metabolism was associated with better post-KT eGFR. AR and DGF were found to be significant mediators.

Efficacy and Safety of a Balanced Salt Solution Versus a 0.9% Saline Infusion for the Prevention of Contrast-Induced Acute Kidney Injury After Contrast-Enhanced Computed Tomography.

RATIONALE & OBJECTIVE: We aimed to elucidate whether a balanced salt solution decreases the occurrence of contrast-induced acute kidney injury (CI-AKI) after contrast-enhanced computed tomography (CE-CT) as compared to 0.9% saline solution. STUDY DESIGN: A randomized clinical trial. SETTING & PARTICIPANTS: The study was performed in 14 tertiary hospitals in South Korea. Patients with estimated glomerular filtration rates (eGFRs) < 45 or <60 mL/min/1.73 m2 and additional risk factors (age ≥ 60 years or diabetes) who were undergoing scheduled CE-CT were included from December 2016 to December 2018. INTERVENTION: An open-label intervention was performed. The study group received a balanced salt solution and the control group received 0.9% saline solution as prophylactic fluids for CE-CT. OUTCOMES: The primary outcome was CI-AKI, defined by creatinine level elevation ≥ 0.5 mg/dL or 25% from baseline within 48 to 72 hours after CE-CT. Secondary outcomes included AKI defined based on the KDIGO (Kidney Disease: Improving Global Outcomes) guideline, eGFR changes, death, or requiring dialysis within 6 months after CE-CT. RESULTS: 493 patients received the study fluids. The control and study groups included 251 and 242 patients, respectively. The occurrence of CI-AKI in the study (10 [4.2%]) and control (17 [6.8%]) groups was not significantly different (P = 0.27). No significant difference was present for the secondary outcomes; AKI by the KDIGO definition (study: 19 [7.9%], control: 27 [10.8%]; P = 0.33), death/dialysis (study: 11 [4.7%], control: 9 [3.7%]; P = 0.74), and eGFR changes (study: 0.1 ± 0.2 mg/dL, control: 0.3 ± 2.8 mg/dL; P = 0.69). LIMITATIONS: This study failed to meet target enrollment. CONCLUSIONS: The risk for CI-AKI was similar after administration of a balanced salt solution and after use of 0.9% saline solution during CE-CT in higher-risk patients. FUNDING: This study was funded by CJ Healthcare (CS2015_0046). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02799368.

Peripheral blood transcriptome analysis and development of classification model for diagnosing antibody-mediated rejection vs accommodation in ABO-incompatible kidney transplant.

The major obstacle to successful ABO blood group-incompatible kidney transplantation (ABOi KT) is antibody-mediated rejection (AMR). This study aimed to investigate transcriptional profiles through RNA sequencing and develop a minimally invasive diagnostic tool for discrimination between accommodation and early acute AMR in ABOi KT. Twenty-eight ABOi KT patients were selected: 18 with accommodation and 10 with acute AMR at the 10th day posttransplant protocol biopsy. Complete transcriptomes of their peripheral blood were analyzed by RNA sequencing. Candidate genes were selected by bioinformatics analysis, validated with quantitative polymerase chain reaction, and used to develop a classification model to diagnose accommodation. A total of 1385 genes were differentially expressed in accommodation compared with in AMR with P-adjusted < .05. Functional annotation and gene set enrichment analysis identified several immune-related and immunometabolic pathways. A 5-gene classification model including COX7A2L, CD69, CD14, CFD, and FOXJ3 was developed by logistic regression analysis. The model was further validated with an independent cohort and discriminated between accommodation and AMR with 92.7% sensitivity, 85.7% specificity, and 91.7% accuracy. Our study suggests that a classification model based on peripheral blood transcriptomics may allow minimally invasive diagnosis of acute AMR vs accommodation and subsequent patient-tailored immunosuppression in ABOi KT.