Association of Left Ventricular Diastolic Dysfunction With Cardiovascular Outcomes in Patients With Pre-dialysis Chronic Kidney Disease: Findings From KNOW-CKD Study

Background

The impact of left ventricular diastolic dysfunction (LVDD) on cardiovascular (CV) outcomes in patients with pre-dialysis chronic kidney disease (CKD) has been rarely unveiled. We here investigated the association of LVDD with CV outcomes and all-cause mortality in patients with pre-dialysis CKD.

Methods

A total of 2,135 patients with pre-dialysis CKD from the Korean Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD) cohort were dichotomized by the absence or presence of LVDD, which was defined as the ratio of the early transmitral blood flow velocity to early diastolic velocity of the mitral annulus (E/e′) > 14.

Results

Cox regression analysis revealed that LVDD was significantly associated with increased risk of composite CV events [adjusted hazard ratio (HR) 2.194, 95% confidence interval (CI) 1.486–3.240] and all-cause mortality (adjusted HR 1.830, 95% CI 1.168–2.869). Restricted cubic splines visualized stringent linear correlations of E/e′ with both composite CV events and all-cause mortality. In the sensitivity analysis only including the subjects with left ventricular ejection fraction ≥ 50%, LVDD was still significantly associated with adverse CV outcomes (adjusted HR 1.984, 95% CI 1.325–3.000) and all-cause mortality (adjusted HR 1.727, 95% CI 1.083–2.754), suggesting that the impact of LVDD on the outcomes in patients with CKD is independent of LV systolic function. Subgroup analyses revealed that the associations were not modified by various clinical contexts, such as age, sex, burden of comorbid conditions, body mass index, estimated glomerular filtration rate, and albuminuria.

Conclusion

LVDD is independently associated with adverse CV outcomes and all-cause mortality in patients with pre-dialysis CKD.

Abdominal Aortic Calcification and Cardiovascular Outcomes in Chronic Kidney Disease: Findings from KNOW-CKD Study

To investigate the association between abdominal aortic calcification score (AACS) assessed by plain radiograph of the lateral abdomen and the risk of cardiovascular (CV) events in patients with pre-dialysis chronic kidney disease (CKD), a total of 2090 pre-dialysis CKD patients from the Korean Cohort Study for Outcome in Patients with Chronic Kidney Disease (KNOW-CKD) were categorized by AACS into 0, 1–2, 3–4, 5–6, and ≥7. The primary outcome of the study was the composite CV events, defined as a composite of non-fatal CV events and all-cause death. The risk of composite CV events was significantly higher in the subjects with AACS ≥ 7 (adjusted hazard ratio (HR) 1.888, 95% confidence interval (CI) 1.219 to 2.923), compared to that of the subjects with AACS 0. The risks of fatal and non-fatal CV events (adjusted HR 1.052, 95% CI 1.030 to 1.073) and all-cause death (adjusted HR 1.949, 95% CI 1.073 to 3.539) were also significantly higher in the subjects with AACS ≥ 7. In conclusion, AACS assessed by plain radiograph is independently associated with adverse CV outcomes in patients with pre-dialysis CKD. A simple radiographic examination of the lateral abdomen may help CV risk stratification in this population.

Association of Body Weight Variability With Progression of Coronary Artery Calcification in Patients With Predialysis Chronic Kidney Disease

Background

We investigated whether high body weight variability (BWV) is associated with a higher prevalence of coronary artery calcification (CAC) or more rapid progression of CAC in patients with predialysis chronic kidney disease (CKD).

Methods

A total of 1,162 subjects from a nationwide prospective cohort of predialysis CKD were analyzed. The subjects were divided into the tertile (T1, T2, and T3) by BWV. CAC was assessed at the baseline and a 4-year follow-up by CT scan. Rapid progression of coronary artery calcification was defined as an increase in coronary artery calcium score (CACS) more than 200 Agatston units during a 4-year follow-up.

Results

One-way ANOVA revealed that CACS change during the follow-up period is significantly higher in the subjects with high BWV, although CACS at the baseline and 4-year follow-up was not different among the tertile groups by BWV. Logistic regression analysis revealed that compared to low BWV (T1), both moderate (T2, adjusted odds ratio (OR) 2.118, 95% CI 1.075–4.175) and high (T3, adjusted OR 2.602, 95% CI 1.304–5.191) BWV was associated with significantly increased risk of rapid progression of CAC. Importantly, the association between BWV and progression of CAC remained robust even among the subjects without significant BW gain or loss during follow-up periods (T2, adjusted OR 2.007, 95% CI 1.011–3.984; T3, adjusted OR 2.054, 95% CI 1.003–4.207).

Conclusion

High BWV is independently associated with rapid progression of CAC in patients with predialysis CKD.

The Association between Health-Enhancing Physical Activity and Quality of Life in Patients with Chronic Kidney Disease: Propensity Score Matching Analysis

We investigate the association between health-enhancing physical activity and the quality of life in patients with non-dialysis chronic kidney disease. We performed data analysis on 1618 of 2238 patients from 2011 to 2016, obtained from the KoreaN Cohort Study for Outcome in Patients with Chronic Kidney Disease (KNOW-CKD). Health-related quality of life was measured using the Korean version 1.3 of Kidney Disease Quality of Life short-form questionnaire. Health-enhancing physical activity was defined as 150 min of moderate-intensity or 75 min of vigorous-intensity aerobic physical activity throughout the week. Propensity score matching analysis and linear regression was performed to estimate the effect of health-enhancing physical activity on health-related quality of life. The estimate of average treatment effects was 2.60 in the kidney component summary score, 4.45 in the physical component summary score, and 4.24 in the mental component summary score. In all component summary scores and most of their subscales, health-enhancing physical activity showed a significant association with health-related quality of life. Subgroup and sensitivity analyses also showed robust results. This study suggests that health-enhancing physical activity elevated quality of life in patients with non-dialysis chronic kidney disease. The results can contribute to encourage physical activity in patients with chronic kidney disease.

Association of High Serum Adiponectin Level With Adverse Cardiovascular Outcomes and Progression of Coronary Artery Calcification in Patients With Pre-dialysis Chronic Kidney Disease

Background: Serum adiponectin level predicts cardiovascular (CV) outcomes and progression of coronary artery calcification (CAC) in the general population, although the association has not been validated in patients with chronic kidney disease (CKD). In this study, we investigated the association of high serum adiponectin level with the risk of adverse CV outcomes and progression of CAC in patients with pre-dialysis CKD.

Methods: A total of 1,127 patients with pre-dialysis CKD from a nationwide prospective cohort of patients with pre-dialysis CKD in Korea were divided into the tertile by serum adiponectin level at the baseline. CV outcome of interest was fatal and non-fatal CV events and all-cause mortality. Progression of CAC was defined as coronary artery calcium score (CACS) change more than 200 during a 4-year follow-up.

Results: Cox regression analysis revealed that high serum adiponectin is associated with increased risk of fatal and non-fatal CV events (adjusted hazard ratio 2.799, 95% CI 1.348–5.811). In contrast, high serum adiponectin level was not significantly associated with all-cause mortality (adjusted hazard ratio 0.655, 95% CI 0.203–2.113). Binary logistic regression analysis revealed that high serum adiponectin level is also associated with increased risk of progression of CAC (adjusted odds ratio [OR] 2.078, 95% CI 1.014–4.260). Subgroup analyses demonstrated that the association of high serum adiponectin with increased risk of fatal and non-fatal CV events is not modified by age, gender, history of diabetes, estimated glomerular filtration rate (eGFR), or spot urine albumin-to-creatinine ratio (ACR).

Conclusions: High serum adiponectin level is associated with adverse CV outcomes and progression of CAC in patients with pre-dialysis CKD.

Nosocomial Outbreak of COVID-19 from a Kidney Transplant Patient: Necessity of a Longer Isolation Period in Immunocompromised Patients

BACKGROUND

Determination of the release from isolation for coronavirus disease 2019 (COVID-19) in immunocompromised patients who need additional hospitalization for treatment of non-COVID-19 related disease is important to prevent nosocomial transmission. However, there is insufficient evidence for an extended isolation period.

MATERIALS AND METHODS

In September 2021, when the Delta variant was dominant, a nosocomial outbreak of COVID-19 occurred in the nephrology ward of a tertiary hospital in Gwangju, Korea. We conducted epidemiological investigations and whole-genome sequencing (WGS) of this virus.

RESULTS

A man who underwent kidney transplantation was admitted to our hospital for the treatment of acute kidney injury. He was diagnosed with asymptomatic COVID-19 infection during a pre-admission screening test on September 1, 2021 and underwent isolation. After 10 days of isolation in the COVID-19-designated ward, he was transferred to the general nephrology ward. He underwent steroid pulse therapy (September 17 to September 23, >60 mg/day prednisolone) due to acute T-cell rejection. On September 28, 2021, the first patient with COVID-19 was identified in the nephrology ward, and a rapid-response team was activated to identify additional patients with COVID-19 and prevent the spread of COVID-19. Epidemiological investigations revealed that 12 patients, two caregivers, and three healthcare workers from the nephrology ward were diagnosed with COVID-19. The WGS of specimens from 14 nosocomial outbreak samples and released an index patient exhibited the same Delta variant originating from the B.1.617.2 lineage. This hospital-acquired COVID-19 outbreak in the nephrology ward resulted in two (11.7%) deaths in patients who underwent kidney transplantation.

CONCLUSION

We demonstrated that an immunocompromised patient can cause a nosocomial outbreak due to the prolonged shedding of infectious viruses. Prolonged isolation in patients under active immunosuppressive therapy may be necessary to prevent transmission, especially in the hospital setting.

Association between the progression of immunoglobulin A nephropathy and a controlled status of hypertension in the first year after diagnosis

BACKGROUND/AIMS

Hypertension is considered a risk factor in immunoglobulin A nephropathy (IgAN). However, after IgAN diagnosis, the relationship between early blood pressure control and renal prognosis remains unclear. This study aimed to analyze the association between the prognosis of IgAN patients and a controlled status of hypertension within the first year of IgAN diagnosis.

METHODS

We retrospectively analyzed 2,945 patients diagnosed with IgAN by renal biopsy. The patients were divided into 'normal,' 'new-onset,' 'well-controlled,' and 'poorly-controlled' groups using blood pressure data from two consecutive measurements performed within a year. The Kaplan-Meier survival analysis and Cox proportional-hazards regression model were used to survey the independent association between recovery from hypertension and the risk of IgAN progression. The primary endpoint was IgAN progression defined as the initiation of dialysis or kidney transplantation.

RESULTS

Before IgAN diagnosis, 1,239 patients (42.1%) had been diagnosed with hypertension. In the fully adjusted Cox proportional-hazards models, the risk of IgAN progression increased by approximately 1.7-fold for the prevalence of hypertension. In the subgroup analyses, the 'well-controlled' group showed a statistically significant risk of IgAN progression (hazard ratio [HR], 3.19; 95% confidence interval [CI], 1.103 to 9.245; p = 0.032). Moreover, the 'new-onset' and 'poorly-controlled' groups had an increased risk of IgAN progression compared to the 'normal' group (HR, 2.58; 95% CI, 1.016 to 6.545; p = 0.046 and HR, 3.85;95% CI, 1.541 to 9.603; p = 0.004, respectively).

CONCLUSION

Although hypertension was well-controlled in the first year after IgAN diagnosis, it remained a risk factor for IgAN progression.

Association between serum osteoprotegerin level and renal prognosis in nondialysis patients with chronic kidney disease in the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (the KNOW-CKD Study)

Background

Osteoprotegerin is an important regulator of bone metabolism and vascular calcification. The association between serum osteoprotegerin level and chronic kidney disease (CKD) progression has not been elucidated. We investigated the prognostic value of serum osteoprotegerin levels in nondialysis CKD patients.

Methods

We analyzed 2,082 patients enrolled in the Korean Cohort Study for Outcomes in Patients with CKD between 2011 and 2016. Patients were divided into quartiles by their serum osteoprotegerin levels. The primary outcome was the occurrence of ≥1 of the following: dialysis initiation, kidney transplantation, a two-fold increase in serum creatinine level from baseline, or a 50% decrease in the estimated glomerular filtration rate (eGFR). Cox proportional hazard regression models were used to investigate the prognostic value of the serum osteoprotegerin level to CKD progression.

Results

The median follow-up period was 48.9 months, and 641 patients (30.8%) experienced the primary outcome. The hazard ratio of serum osteoprotegerin for renal progression in the full extended Cox proportional hazard model was 1.064 (95% confidence interval, 1.041–1.088). Subgroup analyses by age, presence of diabetes, and eGFR showed significant results consistent with the overall analysis results.

Conclusion

Serum osteoprotegerin level is independently associated with renal prognosis and could have prognostic importance in CKD progression.

Association of Circulating Osteoprotegerin Level with Blood Pressure Variability in Patients with Chronic Kidney Disease

Circulating osteoprotegerin (OPG) is a biomarker for cardiovascular complications that are closely related to chronic kidney disease (CKD). To investigate the association between circulating OPG level with long-term visit-to-visit blood pressure variability (BPV) in patients with pre-dialysis CKD, a total of 1855 subjects with CKD from stage 1 to pre-dialysis stage 5 from a prospective cohort were analyzed. Long-term visit-to-visit BPV was determined by average real variability (ARV), standard deviation (SD), and coefficient of variation (CoV) of systolic and diastolic blood pressure (SBP and DBP). ARV of SBP (Adjusted β coefficient 0.143, 95% confidence interval 0.021 to 0.264) was significantly associated with serum OPG level. Although SD and CoV of SBP were not significantly associated with serum OPG level in multivariate linear regression analyses, restricted cubic spline visualized the linear correlation of serum OPG level with all of ARV, SD, and CoV. The association between serum OPG level and DBP variability was not significant. Subgroup analyses revealed that the association of serum OPG with BPV is more prominent in the subjects with Charlson comorbidity index ≤3 and in the subjects without history of diabetes mellitus. In conclusion, circulating OPG level is potentially associated with long-term visit-to-visit BPV in patients with pre-dialysis CKD.

Underweight and Weight Change Increases End-Stage Renal Disease Risk in Patients with Diabetes: A Nationwide Population-Based Cohort Study

Weight variability has known as a risk factor for cardiovascular events and mortality. However, its effect on end-stage renal disease (ESRD) development remains controversial. We investigated the relationship between weight change and ESRD risk. Overall, 97,029 patients with DM aged >20 years were selected from the Korean National Health Screening Program 2009–2012. Weight change was defined as differences in body weight from the index year to 2 years later. Newly diagnosed ESRD was observed until 2017 end. Over a 5.1-year median follow-up period, ESRD was newly diagnosed in 7932 (4.81%) DM patients. BMI < 18.5 kg/m² and waist circumferences <85/80 and >100/95 cm were ESRD risk factors. ESRD risk increased with increasing weight change; ≥10% weight loss (hazard ratio [HR], 1.247) followed by ≥10% weight gain (1.247) was associated with a higher HR than ≤5% weight change after adjusting for several confounding factors. The association between weight change and ESRD risk in a subgroup analysis was significantly stronger in patients aged <65 years, without proteinuria, with BMI ≥ 25, with DM duration <5 years, and prescribed less than 3 classes of DM medication. Underweight patients showed higher ESRD risks than overweight patients. Weight loss >10% was associated with the fastest decline in renal function.

Venous thromboembolism and severe hypernatremia in a patient with lithium-induced nephrogenic diabetes insipidus and acute kidney injury: a case report

We report a case of thromboembolism in a patient with hypernatremia resulting from lithiuminduced nephrogenic diabetes insipidus (NDI). A 49-year-old female patient on chronic lithium therapy due to bipolar disorder was transferred to the emergency department with signs of dehydration, altered mental status, and increased oxygen demand. She was admitted to a local psychiatric clinic first because of an exacerbation of a manic episode. When she was transferred to our clinic, her blood pressure was 130/80 mmHg, she was tachycardic (110 beats/min), had tachypnea (24 breaths/min), normal body temperature (36.5 ℃), and an oxygen saturation of 94% via a face mask (10 L/min). Laboratory results showed hypertonic hypernatremia (osmolality, 363 mOsm/kg; sodium, 171 mEq/L), low urine osmolality (osmolality, 231 mOsm/kg), and normal urine sodium (Na, 63 mEq/L). Her serum lithium concentration was above the therapeutic range (1.52 mmol/L). An increase in cardiac markers and changes in electrocardiogram were detected; therefore, echocardiography was performed, which showed right ventricular dysfunction and small left ventricular chamber size. Computed tomography of the chest and lower extremities showed pulmonary thromboembolism (PTE) and deep venous thrombosis (DVT). She was treated with hypotonic fluid to correct hypernatremia and intravenous heparin for thromboembolism. The size of the thromboembolism decreased, and hypernatremia was corrected. She was discharged with a direct oral anticoagulant (DOAC). Here, we report a case of severe hypernatremia and venous thromboembolism in lithium-induced NDI.

Predictive Model for High Coronary Artery Calcium Score in Young Patients with Non-Dialysis Chronic Kidney Disease

Cardiovascular disease is a major complication of chronic kidney disease. The coronary artery calcium (CAC) score is a surrogate marker for the risk of coronary artery disease. The purpose of this study is to predict outcomes for non-dialysis chronic kidney disease patients under the age of 60 with high CAC scores using machine learning techniques. We developed the predictive models with a chronic kidney disease representative cohort, the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD). We divided the cohort into a training dataset (70%) and a validation dataset (30%). The test dataset incorporated an external dataset of patients that were not included in the KNOW-CKD cohort. Support vector machine, random forest, XGboost, logistic regression, and multi-perceptron neural network models were used in the predictive models. We evaluated the model’s performance using the area under the receiver operating characteristic (AUROC) curve. Shapley additive explanation values were applied to select the important features. The random forest model showed the best predictive performance (AUROC 0.87) and there was a statistically significant difference between the traditional logistic regression model and the test dataset. This study will help identify patients at high risk of cardiovascular complications in young chronic kidney disease and establish individualized treatment strategies.

Association of Urinary Potassium Excretion with Blood Pressure Variability and Cardiovascular Outcomes in Patients with Pre-Dialysis Chronic Kidney Disease

Dietary potassium intake is a dilemma in patients with chronic kidney disease (CKD). We investigated the association of urine potassium excretion, a surrogate for dietary potassium intake, with blood pressure variability (BPV) and cardiovascular (CV) outcomes in patients with pre-dialysis CKD. A total of 1860 participants from a cohort of pre-dialysis CKD (KNOW-CKD) patients were divided into the quartiles by spot urine potassium-to-creatinine ratio. The first quartile (26.423 ± 5.731 mmol/gCr) was defined as low urine potassium excretion. Multivariate linear regression analyses revealed an independent association of low urine potassium excretion with high BPV (adjusted β coefficient 1.163, 95% confidence interval 0.424 to 1.901). Cox regression analyses demonstrated that, compared to high urine potassium excretion, low urine potassium excretion is associated with increased risk of CV events (adjusted hazard ratio 2.502, 95% confidence interval 1.162 to 5.387) but not with all-cause mortality. In conclusion, low urine potassium excretion is associated with high BPV and increased risk of CV events in patients with pre-dialysis CKD. The restriction of dietary potassium intake should be individualized in patients with pre-dialysis CKD.

Anti-fibrotic effect of 6-bromo-indirubin-3'-oxime (6-BIO) via regulation of activator protein-1 (AP-1) and specificity protein-1 (SP-1) transcription factors in kidney cells

PAI-1 and CTGF are overexpressed in kidney diseases and cause fibrosis of the lungs, liver, and kidneys. We used a rat model of unilateral ureteral obstruction (UUO) to investigate whether 6-BIO, a glycogen synthase kinase-3β inhibitor, attenuated fibrosis by inhibiting PAI-1 and CTGF in vivo. Additionally, TGFβ-induced cellular fibrosis was observed in vitro using the human kidney proximal tubular epithelial cells (HK-2), and rat interstitial fibroblasts (NRK49F). Expression of fibrosis-related proteins and signaling molecules such as PAI-1, CTGF, TGFβ, αSMA, SMAD, and MAPK were determined in HK-2 and NRK49F cells using immunoblotting. To identify the transcription factors that regulate the expression of PAI-1 and CTGF the promoter activities of AP-1 and SP-1 were analyzed using luciferase assays. Confocal microscopy was used to observe the co-localization of AP-1 and SP-1 to PAI-1 and CTGF. Expression of PAI-1, CTGF, TGFβ, and α-SMA increased in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Furthermore, UUO and TGFβ treatment induced the activation of P-SMAD2/3, SMAD4, P-ERK 1/2, P-P38, and P-JNK MAPK signaling pathways. PAI-1, CTGF, AP-1 and SP-1 promoter activity increased in response to TGFβ treatment. However, treatment with 6-BIO decreased the expression of proteins and signaling pathways associated with fibrosis in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Moreover, 6-BIO treatment attenuated the expression of PAI-1 and CTGF as well as the promoter activities of AP-1 and SP-1, thereby regulating the SMAD and MAPK signaling pathways, and subsequently exerting anti-fibrotic effects on kidney cells.

Hypertension as a risk factor for retinal vein occlusion in menopausal women: A nationwide Korean population-based study

Retinal vein occlusion (RVO) is an important cause of blindness. Hypertension is a well-known risk factor for RVO. Although the prevalence of hypertension increases in women after menopause, the relationship between blood pressure and RVO in women before and after menopause has not been studied in detail.We retrospectively analyzed 2,619,206 patients from the Korean National Health Insurance System database. A Cox proportional hazard regression model was used to evaluate the independent association between blood pressure and the risk of RVO development and identify differences between premenopausal and postmenopausal women.The incidence of RVO was higher among postmenopausal women than in premenopausal women. In the model adjusted for socioeconomic and clinical variables, there was an association between blood pressure and RVO development in premenopausal and postmenopausal women; however, this was stronger than premenopausal women.Both systolic and diastolic blood pressure are associated with an increased risk of RVO, and their effects are more potent in premenopausal women than postmenopausal women. Thus, comprehensive management of hypertension in premenopausal women is essential to reduce the risk of RVO.

Deep Learning-Based Software Improves Clinicians' Detection Sensitivity of Aneurysms on Brain TOF-MRA

BACKGROUND AND PURPOSE

The detection of cerebral aneurysms on MRA is a challenging task. Recent studies have used deep learning-based software for automated detection of aneurysms on MRA and have reported high performance. The purpose of this study was to evaluate the incremental value of using deep learning-based software for the detection of aneurysms on MRA by 2 radiologists, a neurosurgeon, and a neurologist.

MATERIALS AND METHODS

TOF-MRA examinations of intracranial aneurysms were retrospectively extracted. Four physicians interpreted the MRA blindly. After a washout period, they interpreted MRA again using the software. Sensitivity and specificity per patient, sensitivity per lesion, and the number of false-positives per case were measured. Diagnostic performances, including subgroup analysis of lesions, were compared. Logistic regression with a generalized estimating equation was used.

RESULTS

A total of 332 patients were evaluated; 135 patients had positive findings with 169 lesions. With software assistance, patient-based sensitivity was statistically improved after the washout period (73.5% versus 86.5%, P < .001). The neurosurgeon and neurologist showed a significant increase in patient-based sensitivity with software assistance (74.8% versus 85.2%, P = .03, and 56.3% versus 84.4%, P < .001, respectively), while the number of false-positive cases did not increase significantly (23 versus 30, P = .20, and 22 versus 24, P = .75, respectively).

CONCLUSIONS

Software-aided reading showed significant incremental value in the sensitivity of clinicians in the detection of aneurysms on MRA without a significant increase in false-positive findings, especially for the neurosurgeon and neurologist. Software-aided reading showed equivocal value for the radiologist.

Hyperuricemia is a risk factor for the progression to end-stage renal disease in minimal change disease

BACKGROUND

Minimal change disease (MCD) is one of the most common causes of nephrotic syndrome worldwide. Hyperuricemia increases the end-stage renal disease (ESRD) risk in glomerulonephritis. In this study, we aimed to determine the effect of high serum uric acid levels on the progression to ESRD in MCD.

METHODS

A total of 800 patients diagnosed with MCD by kidney biopsy were retrospectively analyzed. We determined the relationship of hyperuricemia with the progression to ESRD in MCD using the Cox proportional hazard model and Kaplan-Meier survival analysis. The primary outcome was defined as the initiation of dialysis or kidney transplantation.

RESULTS

A total of 42 patients (5.3%) progressed to ESRD during the follow-up period. In the restricted cubic spline curve, serum uric acid levels exhibited a positive correlation with ESRD progression in patients with MCD. In the fully adjusted model, the risk of MCD progression increased by 29% for every 1 mg/dL increase in the baseline serum uric acid level (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.09-1.54; p = 0.004). Falling into the high uric acid group (serum uric acid level > 7 mg/dL in men and > 6 mg/dL in women) was also a risk factor for progression of MCD to ESRD (HR, 3.40; 95% CI, 1.59-7.31; p < 0.001).

CONCLUSION

Our study shows that hyperuricemia is an independent risk factor for the progression to ESRD in patients with MCD.

Cumulative hypertension burden and risk of end-stage renal disease

Hypertension is the leading risk factor for end-stage renal disease (ESRD). However, the association between sustained exposure to increased blood pressure (BP) and ESRD is not well established. This study investigated whether the cumulative hypertension burden is a substantial risk factor for ESRD. The incidence of ESRD among 2,144,801 participants identified from the Korean National Health Insurance Service database who had documented BP assessment data in their annual health check-up data from between 2006 and 2010, was determined. Over a median follow-up of 7.2 years, ESRD was identified in 1758 participants. Hypertension burden was defined as the cumulative exposure to hypertension (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) during four consecutive follow-up periods and ranged from 0 to 4. The hypertension burden was as follows: 0 (n = 1,164,488), 77.6%; 1 (n = 292,377), 13.6%; 2 (n = 114,397), 5.3%; 3 (n = 52,671), 2.5%; and 4 (n = 20,886), 1.0%. Compared to the hypertension burden of 0, the adjusted hazard ratio for ESRD was 1.35, 1.54, 1.51, and 2.28 for hypertension burdens of 1, 2, 3, and 4, respectively. A positive dose-dependent relationship between hypertension burden and ESRD was found (P for interaction < 0.001). This association was maintained for sustained exposure to both systolic and diastolic hypertension burden. In conclusion, hypertension burden increases the risk of ESRD. Our study underlines the usefulness of a new assessment of the hypertension burden over a certain period for predicting the risk of ESRD in a large population-based cohort.

Risk of Kidney Failure in Patients With Cancer: A South Korean Population-Based Cohort Study

RATIONALE & OBJECTIVE

Reduced kidney function is associated with an increased risk of cancer; however, it is unclear if cancer increases the risk of kidney failure with replacement therapy (KFRT). We assessed the risk of KFRT among patients with various types of cancer collectively and with specific types of cancer.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING & PARTICIPANTS

A total of 2,473,095 participants with (n = 824,365) or without (n = 1,648,730) cancer registered in the Korean National Health Insurance Service database.

PREDICTORS

Cancer and cancer subtypes defined using International Classification of Diseases, 10th Revision, Clinical Modification, codes.

OUTCOMES

Primary outcome was KFRT defined as the initiation of hemodialysis or peritoneal dialysis or kidney transplantation.

ANALYTICAL APPROACH

For each patient with cancer, 2 controls matched for age, sex, estimated glomerular filtration rate, diabetes, and hypertension were included. To address the competing risk of death, a competing risk survival analysis was conducted using the Fine and Gray method.

RESULTS

Occurrence of KFRT was higher in patients with cancer than in controls without cancer (incidence rates of 1.07 vs 0.51 cases per 1,000 person-years). Competing risk analysis showed that cancer was significantly associated with an increased risk of KFRT after adjusting for other potential predictors (adjusted hazard ratio, 2.29 [95% CI, 2.20-2.39]). Multiple myeloma, leukemia, lymphoma, and kidney, ovarian, and liver cancer were most significantly associated with an increased KFRT risk, with multiple myeloma conferring the highest risk across age and sex groups. All subgroups of patients with cancer (based on age, sex, smoking, alcohol, exercise, obesity, and comorbid conditions) exhibited a higher risk of KFRT.

LIMITATIONS

Causal association between cancer and kidney outcomes could not be confirmed.

CONCLUSIONS

Patients with cancer, particularly those with multiple myeloma, exhibited an increased risk of KFRT after accounting for the competing risk of death.

P–153 Comparison outcome of vitrified human embryos stored in vapor phase liquid nitrogen (LN2) and direct LN2

Study question

Is vapor cryopreserved LN2 storage beneficial for clinical outcomes of vitrified human embryos that are frozen compared to vitrified human embryos having direct contact with LN2.

Summary answer

There are no significant differences compared to clinical outcomes of human embryos stored in LN2 vapor and direct store in LN2.

What is known already

There has been concerned about potential cross-contamination and biohazard issues of embryos for long term storage using direct LN2. This study aimed to compare clinical outcomes of human embryos transfer between vapor phase and liquid LN2.

Study design, size, duration

The embryo has undergone vitrification for long term storage with vapor or direct contact in LN2. After the thawing of the embryo, we checked on the survival rates. We transferred only one or two embryos per patient and kept analyzing the implantation and pregnancy rates

Participants/materials, setting, methods

This retrospective study was carried out from January 2018 to December 2019 with 3272cycles 4713embryos; vitrified for long term storage in vapor phase or direct contact with LN2. We compared the clinical outcomes of frozen embryo transfer cycles using vitrified for long term storage in vapor phase and direct contact with LN2. Clinical outcomes monitored were embryo survival, subsequent implantation and pregnancy after single or double embryo transfer

Main results and the role of chance

A total of 4713 fertilized human embryos are vitrified and then stored in LN2 vapor (n = 2520 cycles) or direct contact LN2 (n = 752 cycles). The study showed that the blastocyst stored in vapor able to retain full development. Survival was 97.8% (vapor) and 97.6% (direct contact LN2), and the vapor storage of human embryos had no significant difference in survival rates after a long term storage. For single blastocyst transfer, pregnancy and implantation rates were 51.5%, 52.4% in vapor, 54.6%, 54.9% in direct LN2; respectively (p=NS). In double blastocyst transfer, the pregnancy and implantation rates were 61.8%, 42.0% in vapor and 64.7%, 44.5% in direct LN2; respectively (p=NS). There were also no significant differences between two groups.

Limitations, reasons for caution

The study showed that the blastocyst stored in vapor can retain full development. A vapor storage system thus is safe and effective for long term vapor storage of vitrified human embryos.Within the limits of this study, there was no detection of an adverse effect of vapor storage.

Wider implications of the findings: Vapor storage systems thus represent a useful alternative for safe and effective long-term storage of vitrified human embryos that can avoid cross contamination chances from having direct contact with LN2.

Trial registration number

Not applicable

P–370 RPL-protease A as a potential biomarker for predicting recurrent pregnancy loss

Study question

Could the reduction of RPL-protease A be involved in the dysfunctional trophoblast for resulting in recurrent pregnancy loss (RPL).

Summary answer

Low expression of RPL-protease A may result in RPL and low serum RPL-protease A level may be a potential biomarker for predicting RPL.

What is known already

The RPL-protease A is expressed and secreted by placenta. The RPL-protease A is involved in the pathogenesis of pre-eclampsia, and the serum RPL-protease A level is higher in the patients with pre-eclampsia than that of normal groups. In our previous study, we identified that the RPL-protease A mRNA level was lower in the villi of patients with RPL than that of normal groups.

Study design, size, duration

Using the CRISPR/Cas9 system, the RPL-protease A gene knockout BeWo cell (BeWo KO) line was established, and the wild type (BeWo WT) and BeWo KO cells were applied to investigate the roles of RPL-protease A in trophoblasts. The human serum RPL-protease A levels were investigated by Western blot analysis and ELISA kit.

Participants/materials, setting, methods

The cell-cell fusion, cell counting analysis, invasion and scratch wound assays, cell cycle analysis, and immunocytochemical analysis were used to investigate cellular functions of RPL-protease A in trophoblast. The sera were obtained from 32 normal pregnant women and 60 women with RPL. The Western blot analysis and ELISA were used for detection of serum RPL-protease A levels.

Main results and the role of chance

The β-hCG was detected in fused BeWo WT cells, while the BeWo KO cells cannot fuse and did not express the β-hCG. The ability of invasion was decreased, but the capacity of migration and proliferation was higher in BeWo KO cells than BeWo WT cells. Cell fusion related factor (β-hCG), and cell invasion related factors (MMP–2 and MMP–9) were highly expressed in BeWo WT cells, and cell related factor (FAK), and cell proliferation related factors (ERK, p38, JNK, MKK3, MKK6, Raf, and Ras) were highly expressed in BeWo KO cells. The Western blot analysis and ELISA indicate that the serum RPL-protease A level was decreased in patients with RPL compared to that of normal groups.

Limitations, reasons for caution

The results of this study have the limitation of RPL-protease A functions in vitro.

Wider implications of the findings: The cellular functions of RPL-protease A in trophoblasts were investigated to explain the pathogenesis of RPL, and low serum RPL-protease A level can be used for a potential biomarker predicting RPL.

Trial registration number

Not applicable

Blood pressure prior to percutaneous coronary intervention is associated with the risk of end-stage renal disease: a nationwide population based-cohort study

Background

Hypertension is the most important modifiable risk factor for mortality and morbidity in chronic kidney disease and coronary artery syndrome. The effect of hypertension prior to percutaneous coronary intervention (PCI) on the development of end-stage renal disease (ESRD) is unknown.

Methods

We used nationally representative data from the Korean National Health Insurance System-140,164 subjects were enrolled during 2010-2015; they were free of ESRD at enrolment, underwent PCI, and were followed up until 2017. Blood pressure (BP) was measured within at least 2 years prior to PCI. The primary outcome was the development of ESRD.

Results

During a median follow-up of 5.4 years, 2,082 participants (1.5%) developed ESRD. The highest systolic BP group (>160 mmHg) showed a higher hazard ratio (3.69; 95% confidence interval, 2.61-5.23) than the reference group (110-119 mmHg). Similar results were observed in the highest diastolic BP group (>120 mmHg), which showed a higher hazard ratio than the reference group (70-79 mmHg). However, ESRD risk showed a J-shaped relationship with baseline systolic and diastolic BP at 113 and 74 mmHg in diabetes mellitus subgroup, respectively, after adjustment for potential confounders.

Conclusion

Our study showed that a high systolic or diastolic BP prior to PCI was independently associated with an increased incidence of ESRD.

Retroperitoneal emphysema caused by a renal abscess: a case report

We report a case of retroperitoneal emphysema caused by a renal abscess. A 45-year-old man with underlying type 2 diabetes mellitus visited the emergency department with right flank pain and a fever. On physical examination, right costovertebral tenderness in the ipsilateral flank was noted. Leukocytosis and high inflammatory marker levels were observed. Urinalysis showed pyuria and glucosuria. Urine culture was positive for Streptococcus agalactiae. A computed tomography scan of the abdomen showed a focal, lowattenuation lesion in the right kidney with a 3 cm, exophytic, high-attenuation lesion in the right kidney upper pole and gas-containing fluid collection within the retroperitoneal space. The diagnosis was retroperitoneal emphysema caused by a renal abscess. As the vital signs were stable and the patient refused puncture, we decided on a course of antibiotics alone with follow-up without percutaneous drainage or surgery. The patient improved without any complications. This is a rare case of a renal abscess penetrating the renal fascia and progressing to a posterior paranephric emphysema. The patient was treated with antibiotics alone and cured successfully. Early diagnosis and proper treatment are needed, and percutaneous drainage or urgent surgery would be beneficial for such cases depending on the patient's condition.