Impact of variability in estimated glomerular filtration rate on major clinical outcomes: A nationwide population-based study

BACKGROUND

The estimated glomerular filtration rate (eGFR), commonly estimated using the serum creatinine value, often fluctuates throughout the serial measurement. The clinical significance of GFR variation among the general population with normal renal function has not yet been demonstrated. Thus, we explored the impact of GFR variability on adverse clinical outcomes.

METHODS

A nationwide retrospective cohort study using the Korean National Health Insurance System database was performed. National health screening examinees who underwent creatinine measurement ≥3 times between 2012 and 2016 were considered. Those with eGFR under 60 mL/min/m2 were excluded. The fluctuation of eGFR was represented with variability independent of the mean (VIM) index; which was calculated by the standard deviation divided by the exponent of the regression coefficient of the mean. Then, the risks of myocardial infarction (MI), stroke and death were assessed according to the quartiles of the VIM.

RESULTS

Of total 3,538,500 participants, 0.29% of myocardial infarction (MI), 0.14% of stroke, 0.36% of deaths were observed during the median follow up of 3.27 years. Participants with the highest VIM index, which represents the highest eGFR variability, were significantly associated with an increased risk of MI (hazard ratio [HR]; 1.10, 95% confidence interval [95% CI]; 1.04-1.16), stroke (HR: 1.16; 95% CI 1.09-1.23), and death (HR: 1.18; 95% CI 1.12-1.24). The elevated risk of adverse events was consistent after the multivariate adjustment with potential confounding factors, except the risk of MI (HR 1.06; 95% 1.00-1.06).

CONCLUSIONS

Increased eGFR variability exhibited an association with major clinical outcomes, indicating that monitoring eGFR variability might be a useful parameter for predicting the adverse outcomes.

Association of the Serum Osteoprotegerin Level With Target Organ Damage in Patients at High Risk of Coronary Artery Disease

BACKGROUND

There is little data as to whether osteoprotegerin (OPG) is associated with target organ damage (TOD), so we evaluated the association in patients at high risk of coronary artery disease (CAD).Methods and Results:A total of 349 patients who underwent invasive coronary angiography (ICA) for suspected CAD were prospectively recruited. During the index admission, 6 TOD parameters were collected: extent of CAD, glomerular filtration rate (GFR), left ventricular mass index (LVMI), E/e', brachial-ankle pulse wave velocity (baPWV), and ankle-brachial index (ABI). Serum OPG levels were measured using enzyme-linked immunosorbent assay. The OPG level was significantly higher in patients with ≥1 TOD parameter than in those without (314±186 vs. 202±74 pg/mL, P<0.001). For each TOD parameter, the serum OPG level was significantly higher in patients with TOD than in those without (P<0.05 for each) except for ABI. In correlation analysis, OPG was significantly associated with GFR, LVMI, E/e', baPWV and ABI (P<0.05 for each). The OPG concentration increased proportionally with increasing TOD (P<0.001). Higher OPG concentrations (≥198 pg/mL) was significantly associated with the presence of TOD (odds ratio 3.22; 95% confidence interval 1.51-6.85; P=0.002) even after controlling for potential confounders.

CONCLUSIONS

Serum OPG level was significantly associated with a variety of TOD in patients undergoing ICA. OPG may be a useful marker for TOD and in the risk stratification of patients at high risk of CAD.

Association Between Moderate-to-Vigorous Physical Activity and the Risk of Major Adverse Cardiovascular Events or Mortality in People With Various Metabolic Syndrome Status: A Nationwide Population-Based Cohort Study Including 6 Million People

Background A population-scale evidence for the association between moderate-to-vigorous physical activity (MV-PA) and risks of major adverse cardiovascular event (MACE) or all-cause mortality in people with various metabolic syndrome (MetS) status is warranted. Methods and Results We performed a nationwide retrospective cohort study based on the claims database of South Korea. We included people who received ≥3 national health screenings from 2009 to 2013 without a previous MACE history. We determined the MetS status of 6 108 077 people: MetS-chronic (N=864 063), MetS-developed (N=348 163), MetS-recovery (N=348 313), and MetS-free (N=4 547 538). The exposure was self-reported MV-PA frequencies. The outcome was incident MACEs or all-cause mortality. The incidence rate ratios (IRR) were calculated with adjustments for clinical/demographic characteristics. During the median follow-up of 4.28 years, 78 770 and 51 840 people experienced MACEs or died, respectively. Those who engaged in MV-PA had a significantly lower risk of MACEs or all-cause mortality than those not engaged in MV-PA in every spectrum of MetS. Even among those who were free from MetS (for MACEs, IRR 0.94 [0.92-0.97], for all-cause mortality, IRR 0.85 [0.82-0.87]) or who had already recovered from MetS (for MACEs, IRR 0.89 [0.84-0.95], for all-cause mortality, IRR 0.74 [0.68-0.81]), 1 to 2 days per week of MV-PA were significantly associated with lower risk of the adverse outcomes when compared with not being engaged in MV-PA. Those who were engaged in MV-PA more frequently also had significantly lower risks of MACEs or all-cause mortality. Conclusions This nationwide study suggests that MV-PA may be recommended to the general population regardless of recent MetS status.

Effect of the similarity of gut microbiota composition between donor and recipient on graft function after living donor kidney transplantation

Graft outcomes of unrelated donor kidney transplant are comparable with those of related donor kidney transplant despite their genetic distance. This study aimed to identify whether the similarity of donor–recipient gut microbiota composition affects early transplant outcomes. Stool samples from 67 pairs of kidney transplant recipients and donors were collected. Gut microbiota differences between donors and recipients were determined using weighted UniFrac distance. Among the donor–recipient pairs, 30 (44.8%) pairs were related, while 37 (55.2%) were unrelated. The unrelated pairs, especially spousal pairs, had similar microbial composition, and they more frequently shared their meals than related pairs did. The weighted UniFrac distance showed an inverse correlation with the 6-month allograft function (p = 0.034); the correlation was significant in the unrelated pairs (p = 0.003). In the unrelated pairs, the microbial distance showed an excellent accuracy in predicting the estimated glomerular filtration rate of < 60 mL/min/1.73 m² at 6-months post-transplantation and was better than human leukocyte antigen incompatibility and rejection. The incidence of infection within 6 months post-transplantation increased in the recipients having dissimilar microbiota with donors compared to the other recipients. Thus, pre-transplantation microbial similarity in unrelated donors and recipients may be associated with 6-month allograft function.

Clinical outcomes of prolonged dual antiplatelet therapy after coronary drug-eluting stent implantation in dialysis patients

Background

End-stage renal disease yields susceptibility to both ischemia and bleeding. The optimal duration of dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation is not established in dialysis patients, who are usually excluded from randomized studies. Since recent studies implied the benefits of prolonged DAPT >12 months in chronic kidney disease, we investigated the effectiveness and safety of prolonged DAPT in dialysis patients with higher cardiovascular risks.

Methods

In this nationwide population-based study, we analyzed dialysis patients who underwent DES implantation from 2008 to 2015. Continued DAPT was compared with discontinued DAPT using landmark analyses, including free-of-event participants at 12 (n = 2246), 15 (n = 1925) and 18 months (n = 1692) after DES implantation. The primary outcome was major adverse cardiovascular events (MACEs): a composite of mortality, nonfatal myocardial infarction, coronary revascularization and stroke. Major bleeding was a safety outcome. Inverse probability of treatment weighting Cox regression was performed.

Results

Mean follow-up periods were 278.3-292.4 days, depending on landmarks. Overall, incidences of major bleeding were far lower than those of MACE. Continued DAPT groups showed lower incidences of MACE and higher incidences of major bleeding, compared with discontinued DAPT groups. In Cox analyses, continued DAPT reduced the hazards of MACE at the 12- [hazard ratio (HR) = 0.74, 95% confidence interval (CI) 0.61-0.90; P = 0.003], 15- (HR = 0.78, 95% CI 0.64-0.96; P = 0.019) and 18-month landmarks (HR = 0.79, 95% CI 0.63-0.99; P = 0.041), but without a significant increase in major bleeding at 12 (HR = 1.39, 95% CI 0.90-2.16; P = 0.14), 15 (HR = 1.13, 95% CI 0.75-1.70; P = 0.55) or 18 months (HR = 1.27, 95% CI 0.83-1.95; P = 0.27).

Conclusions

Prolonged DAPT reduced MACE without significantly increasing major bleeding in patients who were event-free at 12 months after DES implantation. In deciding on DAPT duration, prolonged DAPT should be considered in dialysis patients.

Comparative analysis of the tonsillar microbiota in IgA nephropathy and other glomerular diseases

Immunoglobulin A nephropathy (IgAN) involves repeated events of gross haematuria with concurrent upper airway infections. The mucosal immune system, especially the tonsil, is considered the initial site of inflammation, although the role of the tonsillar microbiota has not been established in IgAN. In this study, we compared the tonsillar microbiota of patients with IgAN (n = 21) and other glomerular diseases (n = 36) as well as, healthy controls (n = 23) from three medical centres in Korea. The microbiota was analysed from tonsil swabs using the Illumina MiSeq system based on 16S rRNA gene. Tonsillar bacterial diversity was higher in IgAN than in other glomerular diseases, although it did not differ from that of healthy controls. Principal coordinates analysis revealed differences between the tonsillar microbiota of IgAN and both healthy and disease controls. The proportions of Rahnella, Ruminococcus_g2, and Clostridium_g21 were significantly higher in patients with IgAN than in healthy controls (corrected p < 0.05). The relative abundances of several taxa were correlated with the estimated glomerular filtration rate, blood urea nitrogen, haemoglobin, and serum albumin levels. Based on our findings, tonsillar microbiota may be associated with clinical features and possible immunologic pathogenesis of IgAN.

Short or Long Sleep Duration and CKD: A Mendelian Randomization Study

BACKGROUND

Studies have found sleeping behaviors, such as sleep duration, to be associated with kidney function and cardiovascular disease risk. However, whether short or long sleep duration is a causative factor for kidney function impairment has been rarely studied.

METHODS

We studied data from participants aged 40-69 years in the UK Biobank prospective cohort, including 25,605 self-reporting short-duration sleep (<6 hours per 24 hours), 404,550 reporting intermediate-duration sleep (6-8 hours), and 35,659 reporting long-duration sleep (≥9 hours) in the clinical analysis. Using logistic regression analysis, we investigated the observational association between the sleep duration group and prevalent CKD stages 3-5, analyzed by logistic regression analysis. We performed Mendelian randomization (MR) analysis involving 321,260 White British individuals using genetic instruments (genetic variants linked with short- or long-duration sleep behavior as instrumental variables). We performed genetic risk score analysis as a one-sample MR and extended the finding with a two-sample MR analysis with CKD outcome information from the independent CKDGen Consortium genome-wide association study meta-analysis.

RESULTS

Short or long sleep duration clinically associated with higher prevalence of CKD compared with intermediate duration. The genetic risk score for short (but not long) sleep was significantly related to CKD (per unit reflecting a two-fold increase in the odds of the phenotype; adjusted odds ratio, 1.80; 95% confidence interval, 1.25 to 2.60). Two-sample MR analysis demonstrated causal effects of short sleep duration on CKD by the inverse variance weighted method, supported by causal estimates from MR-Egger regression.

CONCLUSIONS

These findings support an adverse effect of a short sleep duration on kidney function. Clinicians may encourage patients to avoid short-duration sleeping behavior to reduce CKD risk.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

Current findings of kidney biopsy including nephropathy associated with hypertension and diabetes mellitus in Korea

BACKGROUND/AIMS

This study aimed to investigate long-term temporal trends and outcomes of biopsy-proven kidney diseases in a multicenter kidney biopsy cohort, focusing on hypertension and diabetes, the leading causes of end-stage kidney disease (ESKD).

METHODS

The study included a total of 21,426 patients who underwent kidney biopsy from 1979 to 2018 in 18 hospitals in Korea. We selected subgroups of adults with diabetes (n = 2,813) or clinically presumed hypertensive nephrosclerosis (HT-N, n = 2,917). Clinical, demographic, and laboratory data were collected in conjunction with pathologic findings. The prevalence of pathologically confirmed kidney diseases over time and their associations with clinical outcomes were evaluated.

RESULTS

The prevalence of biopsy-proven diabetic nephropathy (DN) has increased significantly from 2.5% to 6.0% in the total cohort in the recent 30 years with an increase in the prevalence of diabetes. Approximately 68% of total diabetic patients had non-diabetic renal disease (NDRD); the proportion was retained since 2000s. DN showed a significantly higher risk of ESKD than NDRD (hazard ratio [HR], 1.59; 95% confidence interval [CI], 1.35 to 1.88). The prevalence of biopsy-proven HT-N remained < 2% in the total cohort for several decades. There was no difference in risks of ESKD between patients with or without biopsy-proven HT-N (HR, 0.93; 95% CI, 0.54 to 1.59).

CONCLUSION

In recent decades, the prevalence of diabetes and DN has significantly increased in the kidney biopsy cohort, showing an increased risk of ESKD. Despite the large numbers of patients meeting the clinical criteria of HT-N, most of those were diagnosed with pathologic diagnoses other than HT-N.

Biobanking for glomerular diseases: a study design and protocol for KOrea Renal biobank NEtwoRk System TOward NExt-generation analysis (KORNERSTONE)

Backgrounds

Glomerular diseases, a set of debilitating and complex disease entities, are related to mortality and morbidity. To gain insight into pathophysiology and novel treatment targets of glomerular disease, various types of biospecimens linked to deep clinical phenotyping including clinical information, digital pathology, and well-defined outcomes are required. We provide the rationale and design of the KOrea Renal biobank NEtwoRk System TOward Next-generation analysis (KORNERSTONE).

Methods

The KORNERSTONE, which has been initiated by Korea Centres for Disease Control and Prevention, is designed as a multi-centre, prospective cohort study and biobank for glomerular diseases. Clinical data, questionnaires will be collected at the time of kidney biopsy and subsequently every 1 year after kidney biopsy. All of the clinical data will be extracted from the electrical health record and automatically uploaded to the web-based database. High-quality digital pathologies are obtained and connected in the database. Various types of biospecimens are collected at baseline and during follow-up: serum, urine, buffy coat, stool, glomerular complementary DNA (cDNA), tubulointerstitial cDNA. All data and biospecimens are processed and stored in a standardised manner. The primary outcomes are mortality and end-stage renal disease. The secondary outcomes will be deterioration renal function, remission of proteinuria, cardiovascular events and quality of life.

Discussion

Ethical approval has been obtained from the institutional review board of each participating centre and ethics oversight committee. The KORNERSTONE is designed to deliver pioneer insights into glomerular diseases. The study design allows comprehensive, integrated and high-quality data collection on baseline laboratory findings, clinical outcomes including administrative data and digital pathologic images. This may provide various biospecimens and information to many researchers, establish the rationale for future more individualised treatment strategies for glomerular diseases.

Trial registration

NCT03929887.

Urinary cMet as a prognostic marker in immunoglobulin A nephropathy

The prediction of prognosis in patients with immunoglobulin A nephropathy (IgAN) is challenging. We investigated the correlation between urinary cMet (ucMet) levels and clinical parameters and examined the effects of cMet agonistic antibody (cMet Ab) in an in vitro IgAN model. Patients diagnosed with IgAN (n = 194) were divided into three groups representing undetectable (Group 1), below‐median (Group 2) and above‐median (Group 3) levels of ucMet/creatinine (ucMet/Cr). Stained kidney biopsy samples were graded according to cMet intensity. Primary‐cultured human mesangial cells were stimulated with recombinant tumour necrosis factor (TNF)‐α and treated with cMet Ab. Our results showed that ucMet/Cr levels positively correlated with proteinuria (P < .001). During the follow‐up, patients in Group 3 showed a significantly lower probability of complete remission (CR; uPCr < 300 mg/g) than those in groups 1 and 2, after adjusting for blood pressure, estimated glomerular filtration rate, and proteinuria, which influence clinical prognosis (HR 0.60, P = .038); moreover, ucMet/Cr levels were also associated with glomerular cMet expression. After TNF‐α treatment, the proliferation of mesangial cells and increased interleukin‐8 and intercellular adhesion molecule‐1 expression were markedly reduced by cMet Ab in vitro. In conclusion, ucMet/Cr levels significantly correlated with proteinuria, glomerular cMet expression, and the probability of CR. Further, cMet Ab treatment alleviated the inflammation and proliferation of mesangial cells. Hence, ucMet could serve as a clinically significant marker for treating IgAN.

Recalibration and validation of the Charlson Comorbidity Index in an Asian population: the National Health Insurance Service-National Sample Cohort study

Weights assigned to comorbidities in predicting mortality may vary based on the type of index disease and advances in the management of comorbidities. We aimed to develop a modified version of the Charlson Comorbidity Index (CCI) using an Asian nationwide database (mCCI-A), enabling the precise prediction of mortality rates in this population. The main data source used in this study was the National Health Insurance Service-National Sample Cohort (NHIS-NSC) obtained from the National Health Insurance database, which includes health insurance claims filed between January 1, 2002, and December 31, 2013, in Korea. Of the 1,025,340 individuals included in the NHIS-NSC, 570,716 patients who were hospitalized at least once were analyzed in this study. In total, 399,502 patients, accounting for 70% of the cohort, were assigned to the development cohort, and the remaining patients (n = 171,214) were assigned to the validation cohort. The mCCI-A scores were calculated by summing the weights assigned to individual comorbidities according to their relative prognostic significance determined by a multivariate Cox proportional hazard model. The modified index was validated in the same cohort. The Cox proportional hazard model provided reassigned severity weights for 17 comorbidities that significantly predicted mortality. Both the CCI and mCCI-A were correlated with mortality. However, compared with the CCI, the mCCI-A showed modest but significant increases in the c statistics. According to the analyses using continuous net reclassification improvement, the mCCI-A improved the net mortality risk reclassification by 44.0% (95% confidence intervals (CI), 41.6–46.5; p < 0.001). The mCCI-A facilitates better risk stratification of mortality rates in Korean inpatients than the CCI, suggesting that the mCCI-A may be a preferable index for use in clinical practice and statistical analyses in epidemiological studies.

An independent validation of the kidney failure risk equation in an Asian population

Predicting the risk of end-stage renal disease (ESRD) progression facilitates appropriate nephrology care of patients with chronic kidney disease (CKD). Previously, the kidney failure risk equations (KFREs) were developed and validated in several cohorts. The purpose of this study is to validate the KFREs in a Korean population and to recalibrate the equations. A total of 38,905 adult patients, including 13,244 patients with CKD stages G3–G5, who were referred to nephrology were recruited. Using the original KFREs (4-, 6- and 8-variable equations) and recalibration equations, we predicted the risk of 2- and 5-year ESRD progression. All analyses were conducted in CKD stages G3-G5 patients as well as the total population. In CKD stages G3–G5 patients, All the original 4-, 6- and 8-variable equations showed excellent areas under the receiver operating characteristic curve of 0.87 and 0.83 for the 2- and 5-year risk of ESRD, respectively. The results of net reclassification improvement, integrated discrimination index and Brier score showed that recalibration improved the prediction models in some cases. The original KFREs showed high discrimination in both CKD stages G3–G5 patients and the total population referred to nephrology in this large Korean cohort. KFREs can be implemented in Korean health systems and can guide nephrology referrals and other CKD-related treatment decisions.

Glomerular Hyperfiltration and Cancer: A Nationwide Population-Based Study

BACKGROUND

Glomerular hyperfiltration is associated with all-cause mortality. Herein, we evaluated the association between glomerular hyperfiltration and the development of cancer, the most common cause of death, in an Asian population.

METHODS

We retrospectively reviewed the National Health Insurance Service database of Korea for people who received national health screenings from 2012 to 2013. Glomerular hyperfiltration was defined as the 95th percentile and greater after stratification by sex and age decile. We performed a multivariate Cox regression analysis using glomerular hyperfiltration at the first health screening as the exposure variable and cancer development as the outcome variable to evaluate the impact of glomerular hyperfiltration on the development of cancer.

RESULTS

A total of 1,953,123 examinations for patients with a median follow-up time of 4.4 years were included in this study. Among the 8 different site-specific cancer categories, digestive organs showed significant associations between glomerular hyperfiltration and cancer. The population with glomerular hyperfiltration showed an increased risk for stomach cancer [adjusted hazard ratio (aHR) = 1.22], colorectal cancer (aHR = 1.16), and liver or intrahepatic malignancy (aHR = 1.35).

CONCLUSIONS

Glomerular hyperfiltration was associated with an increased risk for the development of cancer in specific organs, such as the stomach, colorectum, and liver and intrahepatic organ.

IMPACT

Glomerular hyperfiltration needs to be considered a significant sign of the need to evaluate the possibility of hidden adverse health conditions, including malignancies.

Fumarate modulates phospholipase A2 receptor autoimmunity-induced podocyte injury in membranous nephropathy

Downstream mechanisms that lead to podocyte injury following phospholipase A2 receptor (PLA2R) autoimmunity remain elusive. To help define this we compared urinary metabolomic profiles of patients with PLA2R-associated membranous nephropathy (MN) at the time of kidney biopsy with those of patients with minimal change disease (MCD) and to healthy individuals. Among the metabolites differentially expressed in patients with PLA2R-associated MN compared to healthy individuals, fumarate was the only significant differentially expressed metabolite in PLA2R-associated MN compared to MCD [fold-difference vs. healthy controls and vs. MCD: 1.76 and 1.60, respectively]. High urinary fumarate levels could predict the composite outcome of PLA2R-associated MN. Fumarate hydratase, which hydrolyzes fumarate, colocalized with podocalyxin, and its expression was lower in glomerular sections from patients with PLA2R-associated MN than in those from healthy individuals, patients with non-PLA2R-associated MN or MCD. Podocytes stimulated with IgG purified from serum with a high anti-PLA2R titer (MN-IgG) decreased expression of fumarate hydratase and increased fumarate levels. These changes were coupled to alterations in the expression of molecules involved in the phenotypic profile of podocytes (WT1, ZO-1, Snail, and fibronectin), an increase in albumin flux across the podocyte layer and the production of reactive oxygen species in podocytes. However, overexpression of fumarate hydratase ameliorated these alterations. Furthermore, knockdown of fumarate hydratase exhibited synergistic effects with MN-IgG treatment. Thus, fumarate may promote changes in the phenotypic profiles of podocytes after the development of PLA2R autoimmunity. These findings suggest that fumarate could serve as a potential target for the treatment of PLA2R-associated MN.

Reduced risk for chronic kidney disease after recovery from metabolic syndrome: A nationwide population-based study

Background

Metabolic syndrome (MetS) is linked to various chronic comorbidities, including chronic kidney disease (CKD). However, few large studies have addressed whether recovery from MetS is associated with reduction in the risks of such comorbidities.

Methods

This nationwide population-based study in Korea screened 10,664,268 people who received national health screening ≥ 3 times between 2012 and 2016. Those with a history of major cardiovascular events or preexisting CKD were excluded. We classified study groups into four, according to the course of MetS state, as defined by the harmonizing criteria. The main study outcome was incidental CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m² which was persistent until the last health exams). The study outcomes were investigated using multivariable logistic regression analysis, which was adjusted for clinical variables and the previous severity of MetS.

Results

Four study groups included 6,315,301 subjects: 4,537,869 people without MetS, 1,034,605 with chronic MetS, 438,287 who developed MetS, and 304,540 who recovered from preexisting MetS. Those who developed MetS demonstrated higher risk of CKD (adjusted odds ratio [OR], 1.26 [1.23-1.29]) than did those who did not develop MetS. In contrast, MetS-recovery was associated with decreased risk of CKD (adjusted OR, 0.84 [0.82-0.86]) than that in people with chronic MetS. Among the MetS components, change in hypertension was associated with the largest difference in CKD risk.

Conclusion

Reducing or preventing MetS may reduce the burden of CKD on a population-scale. Clinicians should consider the clinical importance of altering MetS status for risk of CKD.

Comparison of dietary intake patterns in hemodialysis patients by nutritional status: A cross-sectional analysis

Background

Although appropriate dietary adjustments in hemodialysis (HD) patients are important, most HD patients have difficulty adhering to dietary therapy due to the stress of a restricted-food diet or loss of appetite, which eventually leads to malnutrition and other complications. The dietary intake of HD patients stratified by nutritional status has not yet been studied.

Methods

In total, 111 HD patients from five dialysis centers were stratified into 2 groups based on the Subjective Global Assessment: the well-nourished group and the poorly nourished group. The 7-day dietary intake and food behaviors of the two groups were compared. Logistic regression analysis was performed to reveal the factors associated with poorly nourished status.

Results

The 7-day dietary survey showed a lower intake of total calories and protein and a higher intake of sodium and potassium than in the standard recommendations, but there were no differences between groups. The poorly nourished group ate fried food significantly more frequently than the well-nourished group. Moreover, higher hip and waist circumferences were significantly associated with poorly nourished status.

Conclusion

We found differences in the dietary intake patterns and food behaviors between well- and poorly nourished HD patients. Further research is needed to design customized nutritional education, consultations, and dietary management for HD patients.

The effects of vascular access types on the survival and quality of life and depression in the incident hemodialysis patients

Background

Although arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD), the association between vascular access types and quality of life is not well-known. We investigated the relationships between HD vascular access types and all-cause mortality, health-related quality of life (HRQOL) and the degree of depression in a large prospective cohort.

Methods

A total of 1461 patients who newly initiated HD were included. The initial vascular access types were classified into AVF, arteriovenous graft (AVG), and central venous catheter (CVC). The primary outcomes were all-cause mortality and HRQOL and depression. The secondary outcome was all-cause hospitalization. Kidney Disease Quality of Life Short Form 36 (KDQOL-36) and Beck’s depression inventory (BDI) scores were measured to assess HRQOL and depression.

Results

Among 1461 patients, we identified 314 patients who started HD via AVF, 76 via AVG, and 1071 via CVC. In the survival analysis, patients with AVF showed significantly better survival compared with patients with other accesses (p < .001). The AVF and AVG group had higher KDQOL-36 score and lower BDI score than CVC group at 3 months and 12 months after the initiation of HD. The frequency of hospitalization was higher in patients with AVG compared to those with AVF (AVF 0.7 vs. AVG 1.1 times per year) (p = .024).

Conclusions

The patients with AVF had better survival rate and low hospitalization rate, and the patients with AVF or AVG showed both higher HRQOL and lower depression scores than those with CVC.

P0762THE SERUM URIC ACID HAS A INDEPENDENT ASSOCIATION WITH 1-YEAR RENAL OUTCOMES IN CHRONIC KIDNEY DISEASE PATIENT WITH HYPERTENSION

Background and Aims

Serum uric acid (UA) is associated with renal disease. Hyperuricemia can be a risk of hypertension, intrarenal vascular disease and renal injury. We investigate the serum UA has an association with renal disease progression in patients with chronic kidney disease (CKD) with hypertension.

Method

We recruited 270 CKD patients with hypertension from 4 centers in Korea through the APrODiTe study and followed for 1 year. Serum UA was evaluated as a continuous value and groups divided by quartiles. The renal outcomes were an increase in random urine protein/creatinine ratio (PCR) than baseline value or estimated glomerular filtration rate (eGFR) deterioration which means a decrease in eGFR ≥ 5 (ml/min/1.73m2).

Results

Baseline serum UA was 6.58 ± 1.73 mg/dl and 6.52 ± 3.59 mg/dl after 1 year. For proteinuria progression, a 1 mg/dl higher serum UA has independent correlation in multivariate regression (odds ratio (OR): 1.272; 95% confidence interval (CI): 1.031-1.568; P = 0.024). The higher quartile of serum UA showed a correlation with the odd ratio than lower quartile (OR: 2.243; 95% CI: 0.862-5.837; P = 0.098, OR:3.417; 95% CI: 1.275-9.152; P= 0.015, OR: 2.754; 95% CI: 1.013-7.488; P &lt; 0.047). In subgroup analysis, the patients with late CKD stage (3-5) showed serum UA has a positive correlation with proteinuria progression (OR: 1.311; 95% CI: 1.022-1.682; P= 0.033) and the top quartile group was correlated with the increased odds ratio compared to lower quartile (OR: 3.811; 95% CI: 1.153-12.59; P = 0.028). For eGFR deterioration, the higher quartile of UA was positively correlated with the odd ratio in only univariate analysis.

Conclusion

Serum UA level has an independent correlation with proteinuria progression in especially late CKD patient with hypertension. Whereas for eGFR deterioration, serum UA did not show a significant correlation.

P1000URINE MYO-INOSITOL AS A NOVEL PROGNOSTIC BIOMARKER FOR DIABETIC KIDNEY DISEASE

Background and Aims

Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease (CKD) and end-stage kidney disease (ESRD). Metabolomics has been increasingly applied to identify the cause of CKD, as it can present epigenetics and suggest corresponding treatment options. Only a few metabolomics studies were conducted in DKD patients, and the results are inconclusive. We investigated the association between urine metabolites and renal disease progression and mortality in DKD, using 800 MHz NMR spectroscopy based targeted metabolomics profiling.

Method

Prospectively stored urine samples from consecutive patients with DKD stage 1 to 5 (n=208) and their healthy controls (n=26) were analyzed. Cross-sectional associations were evaluated between eGFR or urine protein creatinine ratio (UPCR) and 26 urinary metabolites. Multivariable adjusted Cox models were conducted for the risk prediction of ESRD and mortality. The receiver-operating characteristic (ROC) analyses were used to assess the additive effect of each metabolite to predict the progression to ESRD.

Results

ESRD occurred in 103 (44.0%) patients and 65 (27.8%) deaths occurred during median 4.5 years (IQR, 2.06–6.58) follow-up period. The median fold change in 9 metabolites (glucose, mannose, myo-inositol, glycerol, lactate, fumarate, creatine, taurine and choline) in patient group revealed a trend corresponding to DKD stages. Linear regression showed that myo-inositol had a strongest association with eGFR. The relationship between the competitive metabolites and outcomes (ESRD and mortality) was investigated by multivariate Cox models after adjusting for the baseline covariates. Of these, 4 metabolites (myo-inositol, glycerol, fumarate, oxoisocaproate) had predictive values for ESRD, and among them, only myo-inositol retained predictive significance in mortality (adjusted HR 1.004, 95% confidence interval 1.002-1.006, P &lt; 0.001). At ROC analysis, urinary myo-inositol had additive effect to serum creatinine concentration and UPCR in the prediction for ESRD progression (NRI = 2.9%, P = 0.03; IDI = 35.1%, P = 0.02).

Conclusion

These results suggest that myo-inositol can be a predictive biomarker for the risk of ESRD progression and mortality in DKD. Further studies are needed to elucidate the pathophysiological roles of myo-inositol in DKD.

P0502BIOBANKING FOR GLOMERULAR DISEASES: A STUDY DESIGN AND PROTOCOL FOR KOREA RENAL BIOBANK NETWORK SYSTEM TOWARD NEXT-GENERATION ANALYSIS (KORNERSTONE)

Background and Aims

Glomerular diseases, a set of debilitating and complex disease entities, are related to mortality and morbidity. To gain insight into pathophysiology and novel treatment targets of glomerular disease, various types of biospecimens linked to deep clinical phenotyping including clinical information, digital pathology, and well-defined outcomes are required. We provide the rationale and design of the KOrea Renal biobank NEtwoRk System TOward Next-generation analysis (KORNERSTONE).

Method

The KORNERSTONE, which has been initiated by Korea Centres for Disease Control and Prevention, is designed as a multi-centre, prospective cohort study and biobank for glomerular diseases. Clinical data, questionnaires will be collected at the time of kidney biopsy and subsequently every one year after kidney biopsy. All of the clinical data will be extracted from the electrical health record and automatically uploaded to the web-based database. High-quality digital pathologies are obtained and

connected in the database. Various types of biospecimens are collected at baseline and during follow-up: serum, urine, buffy coat, stool, glomerular complementary DNA (cDNA), tubulointerstitial cDNA. All data and biospecimens are processed and stored in a standardised manner. The primary outcomes are mortality and end-stage renal disease. The secondary outcomes will be deterioration renal function, remission of proteinuria, cardiovascular events and quality of life.

Disussion

Ethical approval has been obtained from the institutional review board of each participating centre and ethics oversight committee. The KORNERSTONE is designed to deliver pioneer insights into glomerular diseases. The study design allows comprehensive, integrated and high-quality data collection on baseline laboratory findings, clinical outcomes including administrative data and digital pathologic images. This may provide various biospecimens and information to many researchers, establish the rationale for future more individualised treatment strategies for glomerular diseases.

Conclusion

In conclusion, we describe the objectives and clinical protocol for the KORNERSTONE. As the first large-scale glomerulonephropathy cohort study with the integration of clinical data, biospecimens and digital pathologic images in Korea, the KORNERSTONE will help to clarify the natural course, complication profiles, and novel treatment targets of the Asian population with glomerular disease.