Chronic Kidney Disease In Korea Research Articles

Comparing predictions among competing risks models with rare events: application to KNOW-CKD study—a multicentre cohort study of chronic kidney disease

A prognostic model to determine an association between survival outcomes and clinical risk factors, such as the Cox model, has been developed over the past decades in the medical field. Although the data size containing subjects’ information gradually increases, the number of events is often relatively low as medical technology develops. Accordingly, poor discrimination and low predicted ability may occur between low- and high-risk groups. The main goal of this study was to evaluate the predicted probabilities with three existing competing risks models in variation with censoring rates. Three methods were illustrated and compared in a longitudinal study of a nationwide prospective cohort of patients with chronic kidney disease in Korea. The prediction accuracy and discrimination ability of the three methods were compared in terms of the Concordance index (C-index), Integrated Brier Score (IBS), and Calibration slope. In addition, we find that these methods have different performances when the effects are linear or nonlinear under various censoring rates.

Epigenome-wide association study of diabetic chronic kidney disease progression in the Korean population: the KNOW-CKD study

Since the etiology of diabetic chronic kidney disease (CKD) is multifactorial, studies on DNA methylation for kidney function deterioration have rarely been performed despite the need for an epigenetic approach. Therefore, this study aimed to identify epigenetic markers associated with CKD progression based on the decline in the estimated glomerular filtration rate in diabetic CKD in Korea. An epigenome-wide association study was performed using whole blood samples from 180 CKD recruited from the KNOW-CKD cohort. Pyrosequencing was also performed on 133 CKD participants as an external replication analysis. Functional analyses, including the analysis of disease-gene networks, reactome pathways, and protein–protein interaction networks, were conducted to identify the biological mechanisms of CpG sites. A phenome-wide association study was performed to determine the associations between CpG sites and other phenotypes. Two epigenetic markers, cg10297223 on AGTR1 and cg02990553 on KRT28 indicated a potential association with diabetic CKD progression. Based on the functional analyses, other phenotypes (blood pressure and cardiac arrhythmia for AGTR1) and biological pathways (keratinization and cornified envelope for KRT28) related to CKD were also identified. This study suggests a potential association between the cg10297223 and cg02990553 and the progression of diabetic CKD in Koreans. Nevertheless, further validation is needed through additional studies.

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.

Incidence of and risk factors for short stature in children with chronic kidney disease: results from the KNOW-Ped CKD.

Preserving optimal growth has long been a significant concern for children with chronic kidney disease (CKD). We aimed to examine the incidence of and risk factors for short stature in Asian pediatric patients with CKD. We analyzed growth status by height, weight, and body mass index (BMI) standard deviation scores (SDSs) for 432 participants in the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease. The median height, weight, and BMI SDSs were - 0.94 (interquartile range (IQR) - 1.95 to 0.05), - 0.58 (IQR - 1.46 to 0.48), and - 0.26 (IQR - 1.13 to 0.61), respectively. A high prevalence of short stature (101 of 432 patients, 23.4%) and underweight (61 of 432 patients, 14.1%) was observed. In multivariable logistic regression analysis, CKD stages 4 and 5 (adjusted odds ratio (aOR) 2.700, p = 0.001), onset before age 2 (aOR 2.928, p < 0.0001), underweight (aOR 2.353, p = 0.013), premature birth (aOR 3.484, p < 0.0001), LBW (aOR 3.496, p = 0.001), and low household income (aOR 1.935, p = 0.030) were independent risk factors associated with short stature in children with CKD. Children with CKD in Korea were shorter and had lower body weight and BMI than the general population. Short stature in children with CKD was most independently associated with low birth weight, followed by premature birth, onset before age 2, CKD stages 4 and 5, underweight, and low household income. Among these, underweight is the only modifiable factor. Therefore, we suggest children with CKD should be carefully monitored for weight, nutritional status, and body composition to achieve optimal growth.

SAT-256 AWARESS AND PREVALENCE OF CHRONIC KIDNEY DISEASE: THE KOREAN NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY (KHANES) 1998-2016

In Korea, the number of incident end stage renal disease (ESRD) patients doing renal replacement therapy has increased by 300% from 20 years ago to 16,068 in 2016, the number of patients undergoing RRT is 93,884 in 2016, an increase of about 400% compared to 20 years ago. Early recognition and treatment of chronic kidney disease (CKD) is essential to slow progression to end-stage renal failure. The purpose of this study was to investigate the awareness of CKD in Korea from 1998 to 2016 and to evaluate the prevalence of CKD during the period compared to the past.

SP057Association between asymptomatic hyperuricemia and apparent treatment resistant hypertension in chronic kidney disease in Korea : KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD)

SP057Association between asymptomatic hyperuricemia and apparent treatment resistant hypertension in chronic kidney disease in Korea : KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD)

Metronidazole therapy as initial treatment of Clostridium difficile infection in patients with chronic kidney disease in Korea.

The risk of metronidazole treatment failure in Clostridium difficile infection (CDI) patients with chronic kidney disease (CKD) or end-stage renal disease in Korea has not been established. We evaluated 481 patients who had been admitted to two secondary hospitals with a diagnosis of, and treatment for, CDI during 2010-2016. CDI patients were divided into three groups according to CKD status: non-CKD (n = 363), CKD (n = 55) and those requiring dialysis (n = 63). Logistic regression analyses were performed to examine the association of CKD status with treatment failure. CDI patients receiving dialysis tended to have increased odds of metronidazole and overall treatment failure compared to non-CKD patients; adjusted odds ratios and 95% confidence intervals were 2.09 (1.03-4.21) and 2.18 (1.11-4.32) for metronidazole and overall treatment failure, respectively. However, CKD patients did not have increased odds of metronidazole or overall treatment failure compared to non-CKD patients, even where severe CDI was more prevalent in CKD patients. The incidence of symptomatic ileus or toxic megacolon did not differ among groups. Our results suggest that initial metronidazole therapy may be considered in CDI patients with non-dialysis CKD, but should not be considered in CDI patients undergoing dialysis.

Klotho and Postmenopausal Hormone Replacement Therapy in Women with Chronic Kidney Disease.

Kidney function is highly susceptible to age-related changes, with chronic kidney disease (CKD) serving as an important cause of morbidity and mortality in older patients. The prevalence of CKD in Korea is higher among the elderly, relative to the general population, with the most significant increases seen following the onset of menopause. Under normal conditions, estrogen attenuates renal superoxide production and protects the kidney from oxidative damage. As estrogen levels are known to decrease by as much as 80% during menopause, this represents a significant risk for older women. Postmenopausal hormone replacement therapy (HRT) modulates the renin-angiotensin system, thereby reducing the progressive deterioration of renal function. Use of estrogen-based HRT has been shown to ameliorate renal function in postmenopausal women, and delay CKD progression. Renal expression of klotho, an important suppressor of aging, is markedly decreased in CKD patients, making it a promising candidate for use as a prognostic biomarker in CKD. Here, we review the key links between renal function, sex, age, and estrogen levels during menopause, and discuss the use of postmenopausal HRT in CKD attenuation.

Economic burden of chronic kidney disease in Korea using national sample cohort.

Determining the cost of a disease is one of the approaches to estimate the burden of the disease. This study was aimed to estimate the socioeconomic burden of chronic kidney disease (CKD) by CKD stages and treatment strategies in Korea. This was a population-based study designed to estimate the cost of CKD according to CKD stages and treatment strategies from a societal perspective in Korea using multiple data sources. Costs of CKD stages III, IV, and V, hemodialysis (HD), and peritoneal dialysis (PD) were estimated with a prevalence-based method. Costs of kidney transplantation (KT) and post kidney transplantation were estimated using an incidence-based method. Costs consisted of direct medical cost, productivity loss cost due to hospitalization and outpatient visit, caregiver cost, and transportation cost. Direct medical cost per year per patient with CKD stages III, IV, and V were 1205, 1963, and 8035 Euros, respectively. Direct medical cost per year per patient receiving HD and PD was 34,554 and 25,806 Euros, respectively. Medical cost per year per KT patient was 68,798 Euros. Direct medical cost which accounted for 70% of the total cost of CKD IV and 87% of the total cost of post KT. Cost associated with productivity loss was approximately 8-20%. Our findings could be useful for evaluating cost-effectiveness of various CKD interventions including the screening strategy. This study also emphasizes a remarkable increase in the socioeconomic burden associated with the progression of CKD in patients.

Prevalence of Chronic Kidney Disease in Korea: the Korean National Health and Nutritional Examination Survey 2011-2013.

Chronic kidney disease is a leading public health problem related to poor quality of life and premature death. As a resource for evidence-informed health policy-making, we evaluated the prevalence of chronic kidney disease using the data of non-institutionalized adults aged ≥ 20 years (n = 15,319) from the Korean National Health and Nutrition Examination Survey in 2011–2013. Chronic kidney disease was defined as a urine albumin-to-creatinine ratio ≥ 30 mg/g or an estimated glomerular filtration rate < 60 mL/min/1.73 m2 using the Chronic Kidney Disease-Epidemiology Collaboration equation. The total prevalence estimate of chronic kidney disease for adults aged ≥ 20 years in Korea was 8.2%. By disease stage, the prevalence of chronic kidney disease was as follows: stage 1, 3.0%; stage 2, 2.7%; stage 3a, 1.9%; stage 3b, 0.4%; and stages 4–5, 0.2%. When grouped into three risk categories according to the 2012 Kidney Disease: Improving Global Outcomes guidelines, the proportions for the moderately increased risk, high risk, and very high risk categories were 6.5%, 1.2%, and 0.5%, respectively. Factors including older age, diabetes, hypertension, cardiovascular disease, body mass indexes of ≥ 25 kg/m2 and < 18.5 kg/m2, and rural residential area were independently associated with chronic kidney disease. Based on this comprehensive analysis, evidence-based screening strategies for chronic kidney disease in the Korean population should be developed to optimize prevention and early intervention of chronic kidney disease and its associated risk factors.

Influence of frailty on health-related quality of life in pre-dialysis patients with chronic kidney disease in Korea: a cross-sectional study.

BackgroundChronic kidney disease (CKD) is a progressive and lifelong condition with multiple medical comorbidities. Patients with CKD experience frailty more frequently and have lower health-related quality of life than do those with other chronic diseases. The purpose of this study was to examine the prevalence of frailty and investigate the contribution of frailty to quality of life in pre-dialysis CKD patients in Korea.MethodsUsing a cross-sectional survey design, data were collected at an outpatient CKD clinic in a general hospital in Korea. The frailty criterion was modified from previous studies. The Short Form-36 Health Survey version 2 was used to measure physical and mental component summary scores. Data were analyzed using chi-square, t-tests, and hierarchical linear regression.ResultsOf the 168 CKD patients, 63 (37.5 %) were frail. Frail patients were significantly older and had lower physical and mental quality of life than those who were non-frail. In hierarchical regression evaluating the influence of frailty on physical and mental quality of life, the initial model was significantly improved when frailty was included. Frail patients had lower physical and mental quality of life.ConclusionsFrailty affected both physical and mental quality of life in pre-dialysis patients with CKD. More attention should be paid to the potential role of early detection and prevention of frailty to improve patients’ quality of life.

Relationship between symptom clusters and quality of life in patients at stages 2 to 4 chronic kidney disease in Korea

PurposeThis study was conducted to identify the relationship between symptom clusters and quality of life (QOL) in patients with stages 2 to 4 chronic kidney disease (CKD) in Korea. MethodsUsing self-reported questionnaires, data were collected from 143 patients who underwent treatment for CKD at one hospital in Korea. The 17-item Patient Outcome Scale was used to measure symptoms, and the 36-item Short Form Health Survey Instrument Version 2 (SF-36v2) was used to measure the QOL. Data were analyzed using factor analysis to draw symptom clusters. ResultsAmong five symptom clusters, the energy insufficiency and pain cluster was found to have the highest prevalence and greatest severity. The severity of symptom clusters showed negative correlations with both physical and mental component summary (PCS and MCS) scores. Elderly patients scored low on PCS, whereas younger patients in their 30s and 40s scored low on MCS. Negative correlations were found between symptom clusters and PCS as well as MCS. The severity of symptoms and QOL had stronger relationships with subjective perception of symptoms and psychological factors than with objective clinical indicators. ConclusionAs the effects of physical and psychological symptoms on the QOL in patients with stages 2 to 4 CKD were identified in this study, nurses should develop strategic nursing plans focused on symptom clusters and patients' subjective perception of symptoms rather than objective clinical indicators in order to improve the QOL in patients with CKD.

25-Hydroxyvitamin D Status Based on Estimated Glomerular Filtration Rate in Patients with Chronic Kidney Disease

Background/Aims: Accumulating data suggest that vitamin D deficiency is prevalent in patients with chronic kidney disease (CKD). However, comprehensive data are lacking for Koreans. The aim of this study was to survey vitamin D deficiency among patients with CKD in Korea and to identify the relationships among various factors. Methods: We conducted a retrospective cohort study of 444 patients who were divided into four subgroups by estimated glomerular filtration rate (eGFR) for comparisons of mean 25-hydroxyvitamin D [25(OH)D] level and other parameters. In addition, non-dialyzed patients were categorized into four groups based on 25(OH)D levels (<10, 10-19, 20-29, and ≥ 30 ng/mL), and risk factors for severe vitamin D deficiency (<10 ng/mL) were investigated. Results: Of patients with an eGFR ≥ 60 mL/min/1.73 m2, 43% (34/79) showed severe 25(OH)D deficiency, and the mean 25(OH)D level was 11.7±5.3 ng/mL. In CKD3 group, 53.2% (41/77) showed severe 25(OH)D deficiency, with a mean level of 11.3±7.2 ng/mL. In CKD4 group, 53.3% (49/92) had severe 25(OH)D deficiency, with a mean level of 11.0±6.2 ng/mL. Approximately 71% (139/196) of patients in CKD5 group showed severe deficiency, and the mean level was 9.2±5.9 ng/mL. Severe 25(OH)D deficiency was affected by winter season, renal function, diabetes, and low-density lipoprotein cholesterol. The serum parathyroid hormone level was inversely correlated with the 25(OH)D level, such that 25(OH)D < 20 ng/mL were associated with a steep increase in parathyroid hormone. Conclusions: Vitamin D deficiency is highly prevalent in the Korean population. Few patients met a sufficient 25(OH)D concentration, even in the early stages of CKD. Our data suggest that 25(OH)D level of 20 ng/mL is a threshold for a rapid increase in parathyroid hormone levels. (Korean J Med 2012;83:740-751)

The Prevalence of Chronic Kidney Disease (CKD) and the Associated Factors to CKD in Urban Korea: A Population-based Cross-sectional Epidemiologic Study

Chronic kidney disease (CKD) is a worldwide problem. This study was designed to survey the prevalence and risk factors for CKD in Korea. The 2,356 subjects were selected in proportion to age, gender, and city. Subjects 35 yr of age or older were selected from 7 cities. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) Study equation, with albuminuria defined as a urine albumin to creatinine ratio of 30 mg/g or more. The overall prevalence of CKD was 13.7%. The prevalences of CKD according to stage were 2.0% stage 1, 6.7% stage 2, 4.8% stage 3, 0.2% stage 4, and 0.0% stage 5. The prevalences of microalbuminuria and macroalbuminuria were 8.6% and 1.6%, respectively. The prevalence of eGFR less than 60 mL/min/1.73 m2 was 5.0%. Age, body mass index (BMI), hypertension, diabetes mellitus, systolic blood pressure (SBP), diastolic blood pressure (DBP), and fasting blood glucose were independent factors related to the presence of CKD. In conclusions, Korea, in which the prevalence of CKD is increasing, should prepare a policy for early detection and appropriate treatment of CKD. The present data will be helpful in taking those actions.

Study of the Association of -667 Aquaporin-2 (AQP-2) A/G Promoter Polymorphism with the Incidence and Clinical Course of Chronic Kidney Disease in Korea

Background. Impaired urinary concentration is uniformly present with advanced disease in chronic renal failure. Aquaporin-2 (AQP-2) is known to be expressed in the renal collecting duct cells and participates in urinary concentration in response to vasopressin. Recently, the study of AQP expression in various forms of chronic kidney disease (CKD) demonstrated a reduction in AQP-2 expression associated with a loss of nephrons and the presence of chronic interstitial fibrosis. No information on aquaporin genetic variations in CKD is available to date. The aim of our study was to evaluate the possible impact of aquaporin-2 genotype on the development and clinical course of CKD. Methods. Blood samples from 259 patients with CKD and 106 ethnicity-, age-, and sex-matched healthy controls were collected, and genomic DNA was extracted. AQP-2 -667 genotype was assessed by PCR, followed by restriction fragment length polymorphism analysis. Results. There were no significant differences in genotype and allele frequencies between the patients and healthy controls (p = 0.3936, p = 0.2941, respectively). In all, 79 (30.5%) patients had the AQP-2 -667 wild-type A/A, 123 (47.5%) were heterozygous for the G allele, and 57 (22.0%) patients showed homozygosity. After subclassification of CKD according to underlying disease, no significant differences were observed between those patients and controls (p = 0.72 for diabetic nephropathy, p = 0.52 for hypertensive nephropathy, p = 0.27 for chronic glomerulonephritis, and p = 0.80 for unknown etiology). Genotype and allele frequencies of the AQP-2 gene polymorphism (rs3759126) of hypertensive patients in pre-ESRD did not show a noticeable difference compared with normal blood pressure patients in pre-ESRD (p = 0.50). No correlation was found to exist between the AQP-2 gene polymorphism (rs3759126) and serum electrolyte levels in pre-ESRD patients (p = 0.38 for serum sodium level and p = 0.44 for serum potassium level). Conclusion. Our data indicate that no association exists between the -667 AQP-2 A/G polymorphism and susceptibility to CKD or its clinical course.