Trends in the incidence and prevalence of end-stage renal disease with hemodialysis in entire Korean population: A nationwide population-based study

Data on the overall epidemiology and temporal trends of end-stage renal disease (ESRD) requiring hemodialysis in Korea are scarce. We aimed to estimate the prevalence and incidence of ESRD requiring hemodialysis in Korea between 2002 and 2017.Using the National Health Insurance Service database, we analyzed data from the entire Korean population between 2002 and 2017. Hemodialysis patients were identified using rare incurable disease codes (V001) or prescription of medical fee codes of hemodialysis (O7020 and O7021). We only included patients who had been maintained on hemodialysis for more than 90 days from the date of dialysis initiation, to exclude patients who required short-term dialysis for acute kidney injury, conversion to peritoneal dialysis, or kidney transplantation.During the 16-year follow-up, the number of hemodialysis patients in Korea has steadily increased from 11,215 in 2002 to 67,486 in 2017. The mean age of these patients has gradually increased from 55.57 ± 13.31 years in 2002 to 62.13 ± 13.23 years in 2017. In 2017, the crude prevalence rate of hemodialysis was 1303.4 per million population. Overall, the number of men tended to be somewhat higher than that of women, and the proportion of men increased slightly from 55.56% in 2002 to 58.45% in 2017. The proportion of diabetic patients increased rapidly from 23.84% to 47.84%, and the percentage of dyslipidemic patients rose from 18.9% to 86.7%. The number of incident hemodialysis patients increased significantly from 4406 in 2003 to 12,134 in 2014, and then decreased to 8090 in 2017. In the incident cases of hemodialysis, the observed increase in the proportion of male patients and in diabetes and dyslipidemia were similar to that of prevalent patients. The more recent era of hemodialysis initiation, the better 5-year survival rates were observed.The prevalence and incidence of hemodialysis in Korea gradually increased between 2002 and 2017. The proportion of men, and patients with diabetes and dyslipidemia requiring hemodialysis also increased continuously. The survival rate of hemodialysis patients was gradually improving. These findings may serve as a reference for future epidemiological studies on hemodialysis in Korea.

Chronic Kidney Disease Risk of Isolated Systolic or Diastolic Hypertension in Young Adults: A Nationwide Sample Based-Cohort Study

Background

Hypertension among young adults is common. However, the effect of isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), or systolic and diastolic hypertension (SDH) among young adults on chronic kidney disease (CKD) development is unknown.

Methods and Results

From a nationwide health screening database, we included 3 030 884 participants aged 20 to 39 years who were not taking antihypertensives at baseline examination in 2009 to 2010. Participants were categorized as having normal blood pressure (BP), elevated BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH. The primary outcome was incident CKD. A total of 5853 (0.19%) CKD events occurred. With normal BP as the reference, multivariable‐adjusted hazard ratios (HRs) (95% CIs) for CKD were 1.14 (95% CI, 1.04–1.26), elevated BP; 1.19 (95% CI, 1.10–1.28), stage 1 IDH; 1.24 (95% CI, 1.08–1.42), stage 1 ISH; 1.39 (95% CI, 1.28–1.51), stage 1 SDH; 1.88 (95% CI, 1.63–2.16), stage 2 IDH; 1.84 (95% CI, 1.54–2.19), stage 2 ISH; 2.70 (95% CI, 2.44–2.98), stage 2 SDH. The HRs for CKD were attenuated in the patients who were antihypertensive and began medication within 1 year of medical checkup than in those without antihypertensives.

Conclusions

Among Korean young adults, those with elevated BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH were associated with a higher CKD risk than those with normal BP. The CKD risk in ISH and IDH groups was similar but lower than that in the SDH group. Antihypertensives attenuated the risk of CKD in young adults with hypertension.

The critical role of FXR is associated with the regulation of autophagy and apoptosis in the progression of AKI to CKD

Autophagy is important for cells to break down and recycle cellular proteins, remove damaged organelles, and especially, for recovery from acute kidney injury (AKI). Despite research on the role and cellular mechanism of autophagy in AKI, the role of autophagy in the progression to chronic kidney disease (CKD) remains poorly understood. Here, using farnesoid X receptor (FXR) knockout (KO) mice, we determined whether FXR prevents the progression of AKI to CKD after renal ischemic-reperfusion (such as I/R) injury through the regulation of renal autophagy and apoptosis. FXR regulated genes that participate in renal autophagy under feeding and fasting conditions, such as hepatic autophagy, and the activation of FXR by agonists, such as GW4064 and INT-747, attenuated the increased autophagy and apoptosis of hypoxia-induced human renal proximal tubule epithelial (HK2) cells. The expression levels of autophagy-related and apoptosis-related proteins in FXR KO mice were increased compared with those in wild-type (WT) mice. We also showed that the increase in reactive oxidative species (ROS) in hypoxia-treated HK2 cells was attenuated by treatment with FXR agonist or by FXR overexpression, and that the level of ROS was elevated in FXR-deficient cells and mice. At 28 days after I/R injury, the autophagy levels were still elevated in FXR KO mice, and the expression levels of fibrosis-related proteins and ROS deposits were higher than those in WT mice. In conclusion, the regulation of renal autophagy and apoptosis by FXR may be a therapeutic target for the early stages of kidney damage, and the progression of AKI to CKD.

Kidney-accumulating olmesartan-loaded nanomicelles ameliorate the organ damage in a murine model of Alport syndrome

ACE inhibitors or angiotensin II receptor blockers (ACEi/ARBs) have been a cornerstone of the management in kidney disease, but their use is often limited by undesired systemic effects, such as symptomatic hypotension. To minimize the extra-renal effects of ACEi/ARBs, we formulated hydrophobically modified glycol chitosan (HGC) nanomicelles releasing olmesartan (HGC-Olm) that specifically accumulated in the kidney, and investigated whether kidney-specific delivery of olmesartan by HGC nanomicelles could ameliorate organ damage in Col4a3^-/- mouse, a murine model of progressive chronic kidney disease mimicking human Alport syndrome. Ex vivo tracing demonstrated that intravenously injected HGC-Olm nanomicelles were specifically delivered to the kidney, with sustained release of olmesartan for more than 48 h. Contrary to the conventional delivery of olmesartan via oral route, injection of HGC-Olm nanomicelles did not alter blood pressure in Col4a3^-/- mice. Immunohistochemistry revealed that HGC nanomicelles were diffusely distributed from the cortex and glomeruli to the outer medulla, sparing the inner medulla. Phenotypic analysis showed that the attenuation of kidney fibrosis in the kidney of Col4a3^-/- mice by HGC-Olm nanomicelles was comparable to that noted with conventionally delivered olmesartan. Therefore, our results suggest that HGC-Olm nanomicelles could be a safe and effective alternative drug delivery system for kidney diseases.

Obesity, Abdominal Obesity and Chronic Kidney Disease in Young Adults: A Nationwide Population-Based Cohort Study

Obesity has become a pandemic. It is one of the strongest risk-factors of new-onset chronic kidney disease (CKD). However, the effects of obesity and abdominal obesity on the risk of developing CKD in young adults has not been elucidated. From a nationwide health screening database, we included 3,030,884 young adults aged 20–39 years without CKD during a baseline examination in 2009–2010, who could follow up during 2013–2016. Patients were stratified into five levels based on their baseline body mass index (BMI) and six levels based on their waist circumference (WC; 5-cm increments). The primary outcome was the development of CKD. During the follow up, until 2016, 5853 (0.19%) participants developed CKD. Both BMI and WC showed a U-shaped relationship with CKD risk, identifying the cut-off values as a BMI of 21 and WC of 72 cm in young adults. The obesity group (odd ratio [OR] = 1.320, 95% confidence interval [CI]: 1.247–1.397) and abdominal obesity group (male WC ≥ 90, female WC ≥ 85) (OR = 1.208, 95%CI: 1.332–1.290) showed a higher CKD risk than the non-obesity or non-abdominal obesity groups after adjusting for covariates. In the CKD risk by obesity composite, the obesity displayed by the abdominal obesity group showed the highest CKD risk (OR = 1.502, 95%CI: 1.190–1.895), especially in those under 30 years old. During subgroup analysis, the diabetes mellitus (DM) group with obesity or abdominal obesity paradoxically showed a lower CKD risk compared with the non-obesity or non-abdominal obesity group. Obesity and abdominal obesity are associated with increased risk of developing CKD in young adults but a decreased risk in young adults with diabetes.

Effect of body mass index and abdominal obesity on mortality after percutaneous coronary intervention: a nationwide, population-based study

BACKGROUND/AIMS

We investigated the impact of obesity on the clinical outcomes following percutaneous coronary intervention (PCI).

METHODS

We included South Koreans aged > 20 years who underwent the Korean National Health Screening assessment between 2009 and 2012. Obesity was defined using the body mass index (BMI), according to the World Health Organization's recommendations. Abdominal obesity was defined using the waist circumference (WC), as defined by the Korean Society for Obesity. The odds and hazard ratios in all-cause mortality were calculated after adjustment for multiple covariates. Patients were followed up to the end of 2017.

RESULTS

Among 130,490 subjects who underwent PCI, the mean age negatively correlated with BMI. WC, hypertension, diabetes, dyslipidemia, fasting glucose, total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels correlated with the increased BMI. The mortality rates were higher in the lower BMI and WC groups than the higher BMI and WC groups. The non-obese with abdominal obesity group showed a mortality rate of 2.11 per 1,000 person-years. Obese with no abdominal obesity group had the lowest mortality rate (0.88 per 1,000 person-years). The mortality showed U-shaped curve with a cut-off value of 29 in case of BMI and 78 cm of WC.

CONCLUSION

The mortality showed U-shaped curve and the cut-off value of lowest mortality was 29 in case of BMI and 78 cm of WC. The abdominal obesity may be associated with poor prognosis in Korean patients who underwent PCI.

Angiotensin-converting enzyme 2 and kidney diseases in the era of coronavirus disease 2019

In the decades since the discovery of angiotensin-converting enzyme 2 (ACE2), its protective role in terms of antagonizing activation of the classical renin-angiotensin system (RAS) axis has been recognized in clinical and experimental studies on kidney and cardiovascular diseases. The effects of ACE inhibitor/angiotensin type 1 receptor blockers (ACEi/ARBs) on ACE2-angiotensin-(1-7) (Ang- (1-7))-Mas receptor (MasR) axis activation has encouraged the use of such blockers in patients with kidney and cardiovascular diseases, until the emergence of coronavirus disease 2019 (COVID-19). The previously unchallenged functions of the ACE2-Ang-(1-7)-MasR axis and ACEi/ARBs are being re-evaluated in the era of COVID-19; the hypothesis is that ACEi/ARBs may increase the risk of severe acute respiratory syndrome coronavirus 2 infection by upregulating the human ACE2 receptor expression level. In this review, we examine ACE2 molecular structure, function (as an enzyme of the RAS), and distribution. We explore the roles played by ACE2 in kidney, cardiovascular, and pulmonary diseases, highlighting studies that defined the benefits imparted when ACEi/ARBs activated the local ACE2- Ang-(1-7)-MasR axis. Finally, the question of whether ACEi/ARBs therapies should be stopped in COVID-19-infected patients will be reviewed by reference to the available evidence.

Parental educational status independently predicts the risk of prevalent hypertension in young adults

Identification of individuals at risk of hypertension development based on socio-economic status have been inconclusive, due to variable definitions of low socio-economic status. We investigated whether educational status of individuals or their parents predicts prevalent hypertension in young adult population, by analyzing data of more than 37,000 non-institutionalized subjects from Korea National Health and Nutrition Examination Survey 2008 to 2017. Although low educational status of individual subjects was robustly associated with elevation of systolic blood pressure and increased prevalence of hypertension in general population, its impact on prevalent hypertension differed across age subgroups, and was remarkably attenuated in young adults. Parental educational status was significantly associated with prevalent hypertension in young adults, but not or only marginally in elderly population. Low parental educational status was also associated with high sodium intake in young adults, irrespective of subject’s own educational status. These collectively indicate that parental educational status, rather than individual’s own educational status, better and independently predicts prevalent hypertension in young adults, and that young adults with low parental educational status are prone to intake more sodium, possibly contributing to the increased risk of hypertension development. We expect that our findings could help define young individuals at risk of high sodium intake and hypertension.

Genetic identification of inherited cystic kidney diseases for implementing precision medicine: a study protocol for a 3-year prospective multicenter cohort study

Background

Inherited cystic kidney disease is a spectrum of disorders in which clusters of renal cysts develop as the result of genetic mutation. The exact methods and pipelines for defining genetic mutations of inherited cystic kidney disease are not clear at this point. This 3-year, prospective, multicenter, cohort study was designed to set up a cohort of Korean patients with inherited cystic kidney disease, establish a customized genetic analysis pipeline for each disease subtype, and identify modifying genes associated with the severity of the disease phenotype.

Methods/design

From May 2020 to May 2022, we aim to recruit 800 patients and their family members to identify pathogenic mutations. Patients with more than 3 renal cysts in both kidneys are eligible to be enrolled. Cases of simple renal cysts and acquired cystic kidney disease that involve cyst formation as the result of renal failure will be excluded from this study. Demographic, laboratory, and imaging data as well as family pedigree will be collected at baseline. Renal function and changes in total kidney volume will be monitored during the follow-up period. Genetic identification of each case of inherited cystic kidney disease will be performed using a targeted gene panel of cystogenesis-related genes, whole exome sequencing (WES) and/or family segregation studies. Genotype-phenotype correlation analysis will be performed to elucidate the genetic effect on the severity of the disease phenotype.

Discussion

This is the first nationwide cohort study on patients with inherited cystic kidney disease in Korea. We will build a multicenter cohort to describe the clinical characteristics of Korean patients with inherited cystic kidney disease, elucidate the genotype of each disease, and demonstrate the genetic effects on the severity of the disease phenotype.

Trial registration

This cohort study was retrospectively registered at the Clinical Research Information Service (KCT0005580) operated by the Korean Center for Disease Control and Prevention on November 5th, 2020.

Atypical hemolytic uremic syndrome after childbirth: a case report

We report a case of atypical hemolytic uremic syndrome (HUS) that occurred after childbirth. A 33-year-old female was admitted to the emergency room, complaining of abdominal pain six days after giving birth to twins. The patient was diagnosed with hemoperitoneum due to hepatic hemangioma rupture and a left lateral hepatectomy was performed. Angioembolization was performed for the accompanying uterine artery bleeding. After that, her kidney function worsened after the 12th day postpartum. Microangiopathic anemia, thrombocytopenia and renal dysfunction were observed. Shiga toxin-producing Escherichia coli was negative in the stool. Plasma ADMATS 13 activity was normal. After transfer to the nephrology department with suspected atypical HUS, the patient underwent fresh frozen plasma (FFP) transfusion with three hemodialysis sessions. The patient improved without additional dialysis, but a renal biopsy was performed because of persistent proteinuria. Renal pathologic findings were compatible with thrombotic microangiopathy. A genetic test for atypical HUS revealed variants of uncertain significance in the complement factor H related (CFHR) 4 gene and the presence of CFHR3-CFHR1 copy number gain. The CFHR3-CFHR1 copy number gain found in this case is a rare causative mutation of atypical HUS. This case suggests that genetic testing of atypical HUS should include analysis of CFH-CFHR rearrangements as well as general screening for complement-associated genes.

Incidence and risk factors for osteoporotic fractures in patients with systemic lupus erythematosus versus matched controls

BACKGROUND/AIMS

Despite recent improvements in the quality of life of patients with systemic lupus erythematosus (SLE), osteoporosis, and osteoporotic fractures are one of the major complications of SLE. Furthermore, limited data are available on the incidence and predictor of osteoporotic fractures in Korean patients with SLE. Herein, we aimed to assess the incidence and risk factors for osteoporotic fractures in Korean SLE patients compared to those without SLE.

METHODS

SLE patients aged ≥ 40 years (n = 10,434; mean age, 51.3 ± 9.1 years; women, 89.7%) were selected from the Korean National Health Insurance Service database, spanning a period from 2008 to 2014. Age- and sex-matched controls (n = 52,170) were randomly sampled in a 5:1 ratio from non-SLE individuals. The primary outcome was the first occurrence of osteoporotic fracture.

RESULTS

The incidence of osteoporotic fractures was significantly higher in the SLE patients (19.085 per 1,000 person-years) than in matched controls (6.530 per 1,000 person-years). According to the multivariable Cox proportional analysis, patients with SLE exhibited a higher osteoporotic fracture rate than the control group (hazards ratio, 2.964; 95% confidence interval, 2.754 to 3.188), even after adjustment for confounding variables. In the subgroup analysis, male SLE patients or SLE patients aged 40 to 65 years were associated with a higher osteoporotic fracture rate than women SLE patients or SLE patients aged ≥ 65 years, respectively.

CONCLUSION

We found a 2.964-fold increased risk of osteoporotic fracture in SLE patients compared to age- and sex-matched non-SLE controls. Male or middle-aged SLE patients had a relatively higher fracture risk among patients with SLE.

A Case Report of Very Severe Hyperphosphatemia (19.3 mg/dL) in a Uremic Patient Taking Honey and Persimmon Vinegar

We report a case of severe hyperphosphatemia in advanced CKD with poor compliance. A 55-year-old male patient with underlying type 2 diabetes mellitus, hypertension, and chronic kidney disease presented emergently with general weakness and altered mental status. The creatinine level was 14 mg/dL (normal range: 0.5-1.3 mg/dL) 2 months prior to consultation, and he was advised initiation of hemodialysis, which he refused. Subsequently, the patient stopped taking all prescribed medications and self-medicated with honey and persimmon vinegar with the false belief it was detoxifying. At the time of admission, he was delirious, and his laboratory results showed blood urea nitrogen level of 183.4 mg/dL (8-23 mg/dL), serum creatinine level of 26.61 mg/dL (0.5-1.3 mg/dL), serum phosphate level of 19.3 mg/dL (2.5-5.5 mg/dL), total calcium level of 4.3 mg/dL (8.4-10.2 mg/dL), vitamin D (25(OH)D) level of 5.71 ng/mL (30-100 ng/mL) and parathyroid hormone level of 401 pg/ml (9-55 pg/mL). Brain computed tomography revealed non-traumatic spontaneous subdural hemorrhage, presumably due to uremic bleeding. Emergent hemodialysis was initiated, and hyperphosphatemia and hypocalcemia were rectified; calcium acetate and cholecalciferol were administered. The patient’s general condition and laboratory results improved following dialysis. Strict dietary restrictions with patient education were implemented. Multifaceted interventions, including dietary counseling, administration of phosphate-lowering drugs, and lifestyle modifications, should be implemented when encountering patients with CKD, considering the extent of the patient’s adherence.

Idiopathic membranous nephropathy in older patients: Clinical features and outcomes

Background

Various factors can affect renal and patient outcome in idiopathic membranous nephropathy (iMN). We aimed to identify predictors of renal and patient survival in patients with iMN, with a special focus on outcomes among older patients.

Methods

We retrieved data on 1,776 patients (mean age 53.0 ± 14.7 years; 1,075 [60.5%] males) diagnosed with iMN from the Korean GlomeruloNEphritis sTudy (KoGNET), a database compiled from 18 centers in Korea.

Results

The cohort included 428 (24.1%) patients over 65 years old. Compared to younger patients, this group had lower hemoglobin and serum albumin levels, a higher incidence of nephrotic-range proteinuria, and higher prevalences of hypertension and diabetes. At last follow-up, complete or partial remission rates were not significantly different between the older and younger groups. Older age (HR: 0.98, 95%CI: 0.97–0.99), elevated hemoglobin (HR: 0.82, 95%CI: 0.72–0.93), high serum albumin (HR: 0.66, 95%CI: 0.44–0.99), and a high estimated glomerular filtration rate (HR: 0.96, 95%CI: 0.95–0.97) at biopsy were good predictors of renal outcomes. Significant risk factors for patient survival were older age (HR: 1.04, 95%CI: 1.01–1.10) and hypertension at biopsy (HR: 2.76, 95%CI: 1.30–5.90).

Conclusions

Older patients with iMN had favorable renal outcomes, but poor patient survival, compared to younger patients. Prognostic information on outcomes in this study might be helpful for optimizing the management of patients with iMN.

A late-onset male Fabry disease patient with somatic mosaicism of a classical GLA mutation: a case report

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A gene (GLA). Male patients of FD develop early sign and symptoms in childhood or adolescence. However, "de novo somatic mosaicism" is rare and might be developed a relatively mild phenotype despite carrying a classic type. A 34-year-old male patient visited with foamy urine. Renal biopsy findings were consistent with FD. Leukocyte α-galactosidase activity was markedly reduced at 5.3 nmol/hr/mg (normal range, 25-126). Sequence analysis of the patient's GLA gene identified mosaicism for the mutation GLA[NM_000169.2] c.820=/G>C. This mutation results in a substitution of the amino acid in position 274 from glycine to arginine. However, no family members showed FD-related symptoms, and the daughter of the patient was also tested for paternity and was identified as a real biological daughter, but DNA sequence analysis for FD showed no mutations. Based on these results, we diagnosed the patients as de novo mutation with somatic mosaicism. Next generation sequencing turned out that 58% of the readings had the mutated allele in buccal cells, 84% in blood, and 85% in urine, when 100% should be expected in a hemizygous affected male confirming the presence of somatic mosaicisms. The patient has been on treatment for enzyme replacement therapy (agalsidase-β, 1.0 mg/kg biweekly) for past 9 years and has maintained normal renal function (serum creatinine 1.0 mg/dL) with mild albuminuria (123 mg/g Cr). Therefore, this case suggests somatic mosaicism is one of important phenotype modifiers.

Treatment of hyperlipidemia with proprotein convertase subtilisin/kexin type 9 inhibitor in a patient with nephrotic syndrome: a case report

We report the case of a patient with nephrotic syndrome and toxic epidermal necrolysis (TEN) caused by statin use. The associated hyperlipidemia was controlled using proprotein convertase subtilisin/ kexin type 9 (PCSK9) inhibitors. This is a unique case of treating hyperlipidemia with PCSK9 inhibitor in patient with nephrotic syndrome with TEN. A 54-year-old woman was admitted owing to generalized edema. She had massive proteinuria and was diagnosed with minimal change disease through kidney biopsy. Statins were used for treatment of hyperlipidemia associated with nephrotic syndrome; however, she developed a skin rash, which progressed to TEN. After discontinuation of statins, her skin symptoms improved; however, hyperlipidemia persisted. Because statins could not be administered, we injected evolocumab, a PCSK9 inhibitor, every 2 weeks. Since then, hyperlipidemia has been well controlled without any side effects. Thus, PCSK9 inhibitors may be a good alternative to control hyperlipidemia in patients with statin intolerance or serious side effects.

Extremely Severe Hypernatremia Caused by Wrong Belief in a Patient with Cervical Cancer

A 56-year old female patient who was undergoing follow-up for cervical cancer in our oncology center was presented to the emergency center with anxiety and excessive thirst. The initial serum sodium level of the patient exceeded 200mEq/L, rising up to 238mEq/L during hospitalization. The extremely severe hypernatremia was caused by patient's wrong belief that bay salt would cure the cancer. The patient was treated with hypotonic solution and finally with appropriate hydration, she was fully recovered without any neurological complications.

Association of Hypertension and Blood Pressure With Kidney Cancer Risk: A Nationwide Population-Based Cohort Study

Data regarding health behavior-related factors and systolic or diastolic blood pressure to evaluate the association between blood pressure and kidney cancer are lacking. Using nationally representative data from the Korean National Health Insurance System, 9 746 445 participants without kidney cancer between January 1, 2006 and December 31, 2009 were followed up until December 31, 2017 to obtain data regarding cancer incidence. Participants were categorized, according to blood pressure, as normal (<120/80 mm Hg), elevated (120-129/<80 mm Hg), and hypertensive (≥130/80 mm Hg) with or without antihypertensive medication, according to the 2017 American College of Cardiology and American Heart Association blood pressure guidelines. Kidney cancer was noted in 11 083 participants during the 8-year follow-up. Participants with hypertension were at higher risk for kidney cancer than those without hypertension. Participants with hypertension using medication had a higher cancer risk than those not using medication and those with elevated blood pressure. The risk of kidney cancer significantly increased with higher systolic or diastolic blood pressure, in a dose-dependent manner, even after adjusting for antihypertensive medication use. Therefore, hypertension and high systolic or diastolic blood pressure, compared with normal blood pressure, were associated with an increased risk of kidney cancer.

P0376EFFECTS OF HYPERURICEMIA ON THE PROGNOSIS OF IGA NEPHROPATHY AND ITS SEX DIFFERENCE

Background and Aims

Hyperuricemia is a potential risk factor for immunoglobulin A nephropathy (IgAN) progression, but its sex-specific effects on IgAN progression remain unclear. This study aimed to determine the effect of serum uric acid on IgAN progression and whether its effect varied according to sex.

Method

A total of 4339 patients were retrospectively analyzed at a university medical school. We assessed the effect of serum uric acid on IgAN progression using Kaplan–Meier survival analyses and Cox proportional hazards models. The study’s primary end point was IgAN progression that was defined as a 50% decline in the estimated glomerular filtration rate or the initiation of dialysis.

Results

On average, the serum uric acid levels were higher in the men than in the women. In the fully adjusted Cox proportional hazards model that considered all subjects, the risk of IgAN progression increased by about 25.6% for every 1 mg/dL increase in the baseline uric acid level. The serum uric acid level was an independent risk factor for IgAN progression in both sexes, but its effect was more pronounced in the women (hazard ratio [HR], 1.383; confidence interval [CI],1.263 to 1.514; P&lt;0.001) than in the men (HR, 1.181; CI, 1.097 to 1.272; P&lt;0.001) (Pinteraction &lt;0.001). A sensitivity analysis involving serum uric acid quartiles generated consistent and robust results.

Conclusion

The serum uric acid level was an independent risk factor for IgAN progression, and its effect was more pronounced among the women compared with that among the men.

P0378SERUM URIC ACID IS ASSOCIATED WITH PROGNOSIS OF LUPUS NEPHRITIS IN FEMALE BUT NOT IN MALE

Background and Aims

Lupus nephritis (LN) is one of the major complications of systemic lupus erythematosus. Early intervention in lupus nephritis is known to benefit patients' prognosis. Recent studies have found an association between hyperuricemia and lupus nephritis, but the sex-specific role of uric acid in lupus nephritis remains unclear. The purpose of this study is to elucidate the relationship between lupus nephritis and hyperuricemia, and to investigate sex differences.

Method

We retrospectively analyzed 394 patients who diagnosed with LN by renal biopsy. We assessed the effect of serum uric acid on progression of LN using Kaplan–Meier survival analyses and Cox proportional hazards models. The study’s primary end point was LN progression that was defined as the initiation of dialysis.

Results

The male had a higher mean of serum uric acid level than female. In the overall patient analysis, every 1 mg / dL increase in baseline uric acid level increased the risk of LN progression by about 16.9%. The serum uric acid level was an independent risk factor for LN progression in female (hazard ratio [HR], 1.177; confidence interval [CI],1.024 to 1.353; P&lt;0.001) but not in male (HR, 1.0351; CI, 0.661 to 1.622; P = 0.880). A sensitivity analysis involving serum uric acid tertile generated consistent and robust results.

Conclusion

The serum uric acid level was an independent risk factor for LN progression in female but no in male.

Trend of prevalence and incidence of systemic lupus erythematosus in South Korea, 2005 to 2015: a nationwide population-based study

BACKGROUND/AIMS

The aim of this study was to evaluate the trend of incidence and prevalence of systemic lupus erythematosus (SLE) in South Korea from 2005 to 2015.

METHODS

From 2005 to 2015, individuals with SLE were identified from the National Health Insurance database, which records information on almost all Koreans. SLE was defined according to the International Classification of Diseases, 10th revision (ICD-10), code M32. The incidence was calculated per 100,000 person-years. The prevalence was calculated per 100,000 people and stratified by year, age group, sex, region, and income.

RESULTS

The annual prevalence of SLE increased slightly from 21.25/100,000 people in 2005 to 35.45/100,000 people in 2015. In contrast, the annual incidence of SLE decreased slightly from 5.42/100,000 person-years in 2005 to 3.6/100,000 person-years in 2015. The prevalence and incidence of SLE were 10- and 6-fold higher in women than in men, respectively. The peak age of prevalence and incidence was 30 to 39 years in 2005; in 2015, the peak age of prevalence was 30 to 49 years and of incidence was 20 to 49 years. Regional variation was observed in both incidence and prevalence of SLE. Jeju province showed the highest prevalence of SLE (44.54/100,000 person-years), and Gwangju province showed the highest incidence of SLE (6.98/100,000 person-years) in 2015. The income status did not affect the prevalence or incidence of SLE except in patients without income who received medical aid.

CONCLUSION

The incidence of SLE has declined, but the prevalence has increased in Korea in recent years. Peak age of SLE trend to right shift in Korea.