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Background/aims: The obesity paradox has been known in end-stage renal disease (ESRD). However, the effect of body mass index (BMI) or waist circumference (WC) prior to percutaneous coronary intervention (PCI) on the development of ESRD is not clear., Methods: Using nationally representative data from the Korean National Health Insurance System, we enrolled 140,164 subjects without ESRD at enrolment who underwent PCI between 2010 and 2015, and were followed-up until 2017. Patients were stratified into five levels based on their baseline BMI and six levels based on their WC with 5-cm increments. BMI and WC were measured 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 (1.49%) participants developed ESRD. The underweight group (hazard ratio [HR], 1.331; 95% confidence interval [CI], 0.955 to 1.856) and low WC (< 80/< 75) (HR, 1.589; 95% CI, 1.379 to 1.831) showed the highest ESRD risk and the BMI 25 to 30 group showed the lowest ESRD risk (HR, 0.604; 95% CI, 0542 to 0.673) in all participants after adjusting for all covariates. In the subgroup analysis for diabetes mellitus (DM) duration, WC < 85/80 cm (men/women) increased ESRD risk in only the DM group (DM < 5 years and DM ≥ 5 years) compared to the reference group (85-90/80-85 of WC), but not the normal or impaired fasting glucose group., Conclusion: Low WC prior to PCI showed an increased ESRD risk in patients with DM undergoing PCI as compared to those without DM.

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., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Abstract: 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., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background/aims: This study aimed to investigate whether urinary angiotensinogen (UAGT) excretion was associated with elevated blood pressure in patients with chronic kidney disease (CKD) and to evaluate the relationship among blood pressure, intra-renal renin-angiotensin system (RAS) activity, and dietary sodium in patients with CKD., Methods: Participants from the Korean Cohort Study for Outcome in Patients with Chronic Kidney Disease (KNOW-CKD) were included. Of the total cohort of 2,238 individuals with CKD, we included 1,955 participants who underwent complete 24-hour urinary sodium (24-hour UNa) analysis. They were categorized into three groups according to three tertiles of their 24-hour UNa, reflecting daily salt intake. To measure intra-renal RAS activity, the UAGT excretion was assayed with an enzyme-linked immunosorbent assay., Results: Elevated 24-hour UNa levels, logarithm of UAGT-to-creatinine ratio (UAGT/Cr), increased waist-to-hip ratio, and decreased estimated glomerular filtration rate were the risk factors for increased systolic blood pressure. Systolic blood pressure showed a positive correlation with 24-hour UNa levels and logarithm of UAGT/Cr., Conclusion: UAGT and urinary sodium excretion are independent determinants of systolic blood pressure in patients with CKD. These findings suggest that increased systolic blood pressure in CKD patients is associated with both increased dietary sodium levels and intra-renal RAS activity. The risk of elevated systolic blood pressure in the 3rd tertile of both the UAGT/Cr and 24-hour UNa groups was about 2.3 times higher than that in the reference group.

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.

Abstract: 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., Competing Interests: The authors have no conflict of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

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.

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.

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.

Chronic underhydration and malnutrition can be associated with irreversible renal damage. This study investigated the association of meal frequency and breakfast skipping with chronic kidney disease (CKD) in South Korea. Participants (4370 participants from the Korean National Health and Nutrition Examination Survey VI 2013-2014) were divided into two groups based on meal frequency: ≥ 15 or < 15 meals/week. They were further divided into four groups based on the frequency of breakfast, lunch, and dinner consumed in the previous year. The data were analyzed with complex samples logistic regression. We found that 9.6% of the participants ( n = 412) had CKD, which was associated with gender, body mass index, serum fasting glucose, daily calorie intake, hypertension, diabetes, and cerebrovascular accident. Participants consuming <15 meals/week had a higher risk of CKD than those who consumed ≥15 meals/week (adjusted odds ratio [OR] 1.531, 95% confidence interval [CI] 1.209-1.938). Participants who rarely had breakfast showed a higher risk of CKD than those who had breakfast 5-7 times/week (adjusted OR 1.572, 95% CI 1.108-2.231). Our findings suggest that <15 meals/week or skipping breakfast is associated with a higher risk of CKD in the general South Korean population, especially for men or persons aged 42-64 years.

The impact of health-related quality of life (HRQOL) on outcomes remains unclear in chronic kidney disease (CKD) patients despite its importance in socioeconomic aspects and individual health. We aim to identify the relationship between HRQOL and progression of CKD in pre-dialysis patients. A total 1622 patients with CKD were analyzed in the KoreaN cohort Study for Outcomes in patients With Chronic Kidney Disease, a prospective cohort study. CKD progression was defined as one or more of the following: initiation of dialysis or transplantation, a two-fold increase in baseline serum creatinine levels, or a 50% decline in the estimated glomerular filtration rate during the follow-up period. The group with CKD progression had lower scores of HRQOL than the group without CKD progression. A fully adjusted Cox proportional hazard ratio model showed that each low baseline physical and mental component summary score was associated with a higher risk of CKD progression. In Kaplan-Meier survival analysis using propensity score matched data, only low physical component summary scores showed statistical significance with CKD progression. Our study highlights low physical component summary score for an important prognostic factor of CKD progression. Risk-modification interventions for high-risk patients may provide benefits to individuals.

Background: Obstructive sleep apnea (OSA) is known to be associated with metabolic dysregulation and incident cardiovascular diseases. However, its association with end-stage renal disease (ESRD) has not been clarified. This study aimed to evaluate longitudinally whether OSA is an independent risk factor for ESRD., Methods: This retrospective nationwide population-based cohort study included data on 67,359 patients with OSA and 336,795 age-, sex- and years of the enrollment-matched controls without OSA obtained from the Korean National Health Insurance Service database from 2009 to 2014. The study population was followed up from baseline to the date of ESRD diagnosis or until 2016. A Cox proportional-hazards model with multivariable adjustment was used to evaluate the association between OSA and incident ESRD., Results: A significantly higher incident ESRD risk (adjusted hazard ratio: 1.29, 95% confidence interval 1.02-1.62) was observed for patients older than 40 years with OSA than for matched controls, when adjusted for age, sex, income status, smoking, alcohol consumption, body mass index, diabetes, hypertension, dyslipidemia, estimated glomerular filtration rate, and proteinuria. The OSA group remained predictive of higher risk of ESRD incidence in subgroups of age ≥ 65 years, female sex, hypertension, dyslipidemia, proteinuria, and chronic kidney disease., Conclusion: OSA was associated with a higher risk of incident ESRD. Understanding the association between OSA and ESRD might provide further insights to establish national health care policy.

Recent data suggest that visit-to-visit variability of blood pressure (BP) is associated with cardiovascular events. We evaluated the role of BP variability as a determinant of end-stage renal disease (ESRD). Using nationally representative data from the Korean National Health Insurance System, 8 199 089 subjects had been enrolled during 2009 to 2010 who were free of ESRD and underwent ≥3 health examinations during 2005 to 2010 were followed to the end of 2017. BP variability was measured using the coefficient of variation, SD, and variability independent of the mean. The primary outcome was the development of ESRD, defined as a combination of the relevant disease code and the initiation of renal replacement therapy. The χ 2 test, t test, and log-rank test were used in the statistical analysis. There were 16 567 cases of ESRD during a median follow-up of 7.89±0.88 years. The highest quartile of systolic or diastolic BP showed a higher incident rate of ESRD compared with the other 3 quartiles. It was augmented in patients with the highest quartile of both systolic and diastolic BP variabilities. Among patients with the highest quartile of systolic and diastolic BP variabilities, the uncontrolled hypertension group (>140/90 mm Hg) taking antihypertensive medication showed the highest incidence rate of ESRD. These results were consistent when modeling variability of BP using coefficient of variation, SD, and variability independent of the mean and in various sensitivity analyses. Systolic and diastolic BP variabilities were independently associated with an increased incidence of ESRD, and it was augmented when both variabilities were present together.

Systemic lupus erythematosus (SLE) is known to be one of the leading causes of end-stage renal disease (ESRD). The aim of this study was to estimate the incidence rate of ESRD and the risk for progression to ESRD in SLE patients compared to the general population.A total of 21,253 SLE patients were extracted from the Korean National Health Insurance Service database between 2008 and 2013. Age-and sex-matched controls (n = 106,265) were randomly sampled in a 5:1 ratio from non-SLE individuals. Both cohorts were followed up for development of ESRD until 2015.During the median 7.53 years of follow-up, 533 (2.51%) cases of ESRD were newly developed in SLE patients and 145 (0.14%) cases in matched controls (incidence rate: 4.075 and 0.219 per 1000 person-year, respectively). SLE patients were at higher risk for ESRD development compared to matched controls (hazard ratio [HR], 9.84; 95% confidence interval [CI] 8.10-11.96) after multivariate adjustment. In subgroup analysis, the risk for ESRD was higher in male (HR, 7.76; 95% CI 5.07-11.90) and female patients with SLE (HR, 10.48; 95% CI 8.41-13.07) than in matched controls. When analyzed by age group, the younger the age, the higher the risk of ESRD versus non-SLE matched controls; this result was also significant after adjustment. In subgroup analysis according to comorbidities, the SLE group had a significantly higher risk of ESRD than the non-SLE group in almost all subgroups.SLE was associated with an increased incidence of ESRD.

This study examined the characteristics of biochemical parameters, bone diseases, and vascular calcification in Korean patients with chronic kidney disease (CKD) not yet on dialysis. Serum levels of fibroblast growth factor 23 (FGF23), intact parathyroid hormone (iPTH), 25-hydroxyvitamin D3 (25D), and 1,25-dihydroxyvitamin D3 (1,25D); lumbar spine, total hip, and femur neck bone mineral densities; and brachial-to-ankle pulse wave velocity (baPWV) representing vascular calcification were measured at baseline for 2,238 CKD patients in the KoreaN Cohort Study for Outcomes in Patients With CKD (KNOW-CKD). Increases in serum FGF23 and iPTH preceded changes in serum calcium and phosphate, similar to Western populations. However, the 25D and 1,25D levels decreased earlier than serum FGF23 or iPTH increased, with a decreased estimated glomerular filtration rate (eGFR) in Korean CKD patients. Vitamin D deficiency occurred in 76.7% of patients with CKD stage 1. Bone mineral densities were lowest in CKD stage 5 (lumbar spine, -0.64 ± 1.67; total hip, -0.49 ± 1.21; femur neck, -1.02 ± 1.25). Osteoporosis was more prevalent in patients with higher CKD stages. The mean baPWV, abdominal aortic calcification (AAC), and coronary calcium score also increased, with declined eGFR. In conclusion, a decline in serum vitamin D levels was observed in early CKD stages before significant increases of FGF23 and iPTH in the Korean CKD population compared with that in Western populations. Increased bone disease and vascular calcification occurred in early-stage CKD., Competing Interests: The authors have no potential conflicts of interest to disclose.

Background: Adiponectin, a peptide hormone secreted from adipocytes, exerts anti-diabetic, anti-atherogenic, and anti-inflammatory properties. We aimed to determine the relationship between serum adiponectin levels and albuminuria, and evaluate determinant factors for serum adiponectin in patients with chronic kidney disease (CKD)., Methods: In total, 1442 CKD patients were included and divided into three groups according to their albumin-to-creatinine ratios: patients with normoalbuminuria (N = 228), microalbuminuria (N = 444), and macroalbuminuria (N = 761). Serum adiponectin was specifically assayed with a commercially available enzyme-linked immunosorbent assay kit., Results: Serum adiponectin was significantly higher in patients with macroalbuminuria than in those without macroalbuminuria (9.7 ± 6.0, 12.4 ± 9.0, and 14.9 ± 11.0 μg/mL in patients with normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively). Univariate linear regression analysis showed that the serum adiponectin concentrations were correlated with age, the albumin-to-creatinine ratio, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, whereas they were negatively correlated with body mass index, the estimated glomerular filtration rate, and serum albumin and triglyceride levels. The stepwise regression multiple analysis showed that sex; the estimated glomerular filtration rate; body mass index; total cholesterol, high-density lipoprotein cholesterol, and triglyceride levels; and logarithm of the albumin-to-creatinine ratio were independently associated with the logarithm of serum adiponectin levels (r = 0.55, p < 0.001)., Conclusion: Serum adiponectin concentrations are higher in patients with increasing albuminuria, and these levels are associated with renal insufficiency and lipid profiles.

Background: This study aimed to compare the changes in kidney function and the association of tumor size and renal outcomes between patients with renal cell carcinoma (RCC) who underwent radical nephrectomy (RN) and those who underwent partial nephrectomy (PN)., Methods: A retrospective cohort study was conducted for 557 patients with an RCC of ≤7 cm in diameter and normal contralateral kidney function who underwent PN or RN. PN was performed for 218 (39%) patients. Renal outcomes included the incidence of acute kidney injury (AKI), new-onset chronic kidney disease (CKD), and a ≥25% decline in eGFR 1 year after surgery., Results: Serial changes in eGFR were compared during the 3 years of follow-up. Postoperative eGFR was significantly lower in patients undergoing RN than in those undergoing PN. The incidence of AKI and new-onset CKD was significantly higher in patients after RN (70.1% vs. 24.3%, respectively; P<0.001) than after PN (55.7% vs. 6.2%, respectively; P<0.001). According to the multivariable logistic regression analysis, RN was an independent risk factor for a ≥25% decline in kidney function after 1 year regardless of the tumor size, even after adjusting for various covariates., Conclusions: Compared to PN, RN for even a moderate sized RCC leads to an increased incidence of AKI and new-onset CKD, and is a significant risk factor for kidney function decline. Therefore, PN should be considered as the choice of surgical treatment for RCCs that are ≤7 cm in diameter in order to preserve renal function postoperatively.

Potassium plays a key role in normal myocardial function, and current guidelines recommend that serum potassium levels be maintained from 4.0 to 5.0 mEq/L in patients with acute myocardial infarction (AMI). However, the impact of serum potassium levels on long-term mortality has not been evaluated. We retrospectively studied 1,924 patients diagnosed with AMI. The average serum potassium levels measured throughout the hospitalization were obtained and statistically analyzed. Patients were categorized into 5 groups to determine the relation between mean serum potassium and long-term mortality: <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, and ≥5 mEq/L. The long-term mortality was lowest in the group of patients with potassium levels of 3.5 to <4.0 mEq/L, whereas mortality was higher in the patients with potassium levels≥4.5 or <3.5 mEq/L. In a multivariate Cox-proportional regression analysis, the mortality risk was greater for serum potassium levels of >4.5 mEq/L (hazard ratio [HR] 1.71, 95% confidence interval [CI] 1.04 to 2.81 and HR 4.78, 95% CI 2.14 to 10.69, for patients with potassium levels of 4.5 to <5.0 mEq/L and ≥5.0, respectively) compared with patients with potassium levels of 3.5 to <4.0 mEq/L. The mortality risk was also higher for patients with potassium levels<3.5 mEq/L (HR 1.55, 95% CI 0.94 to 2.56). In contrast to the association with long-term mortality, there was no relation between serum potassium levels and the occurrence of ventricular arrhythmias. The results of the current analysis suggest that there is a need for change in our current concepts of the ideal serum potassium levels in patients with AMI., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Postoperative acute kidney injury (AKI), a serious surgical complication, is common after cardiac surgery; however, reports on AKI after noncardiac surgery are limited. We sought to determine the incidence and predictive factors of AKI after gastric surgery for gastric cancer and its effects on the clinical outcomes., Methods: We conducted a retrospective study of 4718 patients with normal renal function who underwent partial or total gastrectomy for gastric cancer between June 2002 and December 2011. Postoperative AKI was defined by serum creatinine change, as per the Kidney Disease Improving Global Outcomes guideline., Results: Of the 4718 patients, 679 (14.4%) developed AKI. Length of hospital stay, intensive care unit admission rates, and in-hospital mortality rate (3.5% versus 0.2%) were significantly higher in patients with AKI than in those without. AKI was also associated with requirement of renal replacement therapy. Multivariate analysis revealed that male gender; hypertension; chronic obstructive pulmonary disease; hypoalbuminemia (<4 g/dl); use of diuretics, vasopressors, and contrast agents; and packed red blood cell transfusion were independent predictors for AKI after gastric surgery. Postoperative AKI and vasopressor use entailed a high risk of 3-month mortality after multiple adjustments., Conclusions: AKI was common after gastric surgery for gastric cancer and associated with adverse outcomes. We identified several factors associated with postoperative AKI; recognition of these predictive factors may help reduce the incidence of AKI after gastric surgery. Furthermore, postoperative AKI in patients with gastric cancer is an important risk factor for short-term mortality.

This study aimed to evaluate the effects of percutaneous coronary intervention (PCI) on short- and long-term major adverse cardiac events (MACE) in elderly (>75 yr old) acute myocardial infarction (AMI) patients with renal dysfunction. As part of Korea AMI Registry (KAMIR), elderly patients with AMI and renal dysfunction (GFR<60 mL/min) received either medical (n=439) or PCI (n=1,019) therapy. Primary end point was in-hospital death. Secondary end point was MACE during a 1 month and 1 yr follow-up. PCI group showed a significantly lower incidence of in-hospital death (20.0% vs 14.3%, P=0.006). Short-term and long-term MACE rates were higher in medical therapy group (31.9% vs 19.0%; 57.7% vs 31.3%, P<0.001), and this difference was mainly attributed to cardiac death (29.3% vs 17.6%; 51.9% vs 25.0%, P<0.001). MACE-free survival time after adjustment was also higher in PCI group on short-term (hazard ratio, 0.67; confidence interval, 0.45-0.98; P=0.037) and long-term follow-up (hazard ratio, 0.61, confidence interval, 0.45-0.83; P=0.002). In elderly AMI patients with renal dysfunction, PCI therapy yields favorable in-hospital and short-term and long-term MACE-free survival.

Limited information is available regarding the impact of acute kidney injury (AKI) during hospitalization on clinical outcomes after myocardial infarction (MI), and the effect of transient kidney injury (KI) on long-term mortality has not been validated. We retrospectively analyzed 2,289 patients diagnosed with MI. AKI patients were classified into a transient KI group and a persistent KI group based on serum creatinine levels at discharge. The end point of the study was 3-year mortality after MI. We included 2,110 patients of whom 237 patients (11%) developed AKI during hospitalization. Of these 237 patients, 154 (65%) had transient KI, and 83 (35%) had persistent KI. Multivariate analysis showed that age, left ventricular ejection fraction, estimated glomerular filtration rate on admission, and Killip class were significantly associated with developing AKI during hospitalization. The adjusted hazard ratios for 3-year mortality were 1.71 (95% confidence interval: 1.08-2.70) for AKI patients with transient KI and 2.21 (95% confidence interval: 1.34-3.64) for AKI patients with persistent KI, compared with no AKI. In conclusion, AKI was associated with an increased risk of death for patients who experienced MIs and survived during hospitalization. Although renal function had completely recovered in many AKI patients at discharge, these transient KI patients are also at a great risk of death after MI., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background and Objectives: CKD is a well known poor prognostic factor in myocardial infarction (MI). This study evaluated the prognostic significance of CKD, particularly in association with increasing age, in MI patients., Design, Setting, Participants, & Measurements: This study was based on a retrospective cohort, the Korean Acute Myocardial Infarction Registry. Patients with a discharge diagnosis of MI were analyzed to investigate the association of CKD with mortality risk according to age. A total of 11,268 patients (mean age 63.0±12.6 years) were included and followed for 1 year., Results: In the full cohort, 26% of patients had CKD (n=2929). The prevalence of CKD was higher with advancing age. Eight hundred sixty-one patients (7.6%) died and the interaction for 1-year mortality between age strata and estimated GFR (eGFR) strata was significant (P<0.001). Within each age category, the absolute 1-year mortality was higher in patients with a low eGFR. However, the adjusted relative mortality risk for a low eGFR was lower with increasing age (adjusted hazard ratio [95% confidence interval] for 1-year mortality at eGFR <30 ml/min per 1.73 m(2): 4.84 [1.93-12.15], 4.53 [2.42-8.47], 3.51 [2.42-5.09], and 3.30 [2.41-4.52] for patients aged <55, 55-64, 65-74, and ≥75 years compared with those with eGFR ≥60 ml/min per 1.73 m(2), respectively)., Conclusions: For all age categories, the overall mortality was significantly higher as eGFR declined. The association of a lower eGFR with mortality was weaker with increasing age, indicating that the prognostic significance of CKD in MI patients is age dependent.

The clinical course and medical treatment of patients with congestive heart failure (CHF) complicating acute myocardial infarction (AMI) are not well established, especially in patients with concomitant renal dysfunction. We performed a retrospective analysis of the prospective Korean Acute Myocardial Infarction Registry to assess the medical treatments and clinical outcomes of patients with CHF (Killip classes II or III) complicated by AMI, in the presence or absence of renal dysfunction. Of 13,498 patients with AMI, 2769 (20.5%) had CHF on admission. Compared to CHF patients with preserved renal function, in-hospital mortality and major adverse cardiac events were increased both at 1 month and at 1 year after discharge in patients with renal dysfunction (1154; 41.7%). Postdischarge use of aspirin, betablockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, or angiotensin II receptor blockers and statins significantly reduced the 1-year mortality rate for CHF patients with renal dysfunction; such reduction was not observed for those without renal dysfunction, except in the case of aspirin. Patients with CHF complicating AMI, which is accompanied by renal dysfunction, are at higher risk for adverse cardiovascular outcomes than patients without renal dysfunction. However, they receive fewer medications proven to reduce mortality rates.

Background: A limited number of studies have investigated the impact of gender on renal function and clinical outcomes after ST-segment elevated myocardial infarction (STEMI), and these studies have provided discrepant results., Methods and Results: This study was based on a retrospective cohort, the Korean Acute Myocardial Infarction Registry (KAMIR). Patients (n = 7,679) with a discharge diagnosis of STEMI were analyzed to investigate association of gender with renal function and clinical outcomes. Compared to men, women were older and exhibited more comorbidity, including impaired renal function. Women showed higher mortality compared to men (1-month mortality,5.6% in men vs. 12.6% in women, p < 0.001; 1-year mortality, 6.8% in men vs. 14.4% in women, p < 0.001). The risk of death proportionally increased as estimated glomerular filtration rate (eGFR) decreased in both genders. After adjusting for potential confounders, hazard ratios for women did not significantly differ from those for men at each eGFR level.The interaction test showed no significant interaction between gender and eGFR in 1-month mortality and 1-year mortality., Conclusions: Impaired renal function was an independent prognostic factor after STEMI in both genders, and the impact of impaired renal function on prognosis after STEMI did not significantly differ between genders.

Background/aims: Blood pressure (BP) variability is known as a poor prognostic factor for cardiovascular outcomes. This study assessed the prognostic significance of BP variability in association with increasing age in hemodialysis patients., Methods: We retrospectively analyzed 2,174 patients on hemodialysis from March 2005 to December 2012. The impact of intradialytic and interdialytic BP variability on all-cause mortality according to age groups was analyzed., Results: Kaplan-Meier survival curves for 5-year cumulative mortality showed higher mortality in patients with higher intradialytic systolic and diastolic BP variability as well as interdialytic systolic and diastolic BP variability (log-rank p=0.006, <0.001, 0.018 and < 0.001) in patients aged <55 years, but not in older age groups. Cox proportional analysis revealed that 5-year mortality was associated with intradialytic diastolic BP variability in patients aged <55 years (HR, 2.03 CI, 1.24-3.32)., Conclusion: The overall mortality was associated with BP variability in patients aged <55 years, but not in older ages. This result suggests that younger hemodialysis patients with BP variability require further medical attention and intervention to reduce BP variability.

Aim: Renal dysfunction has been associated with many types of neuropathy and the incidence of myocardial infarction (MI) presenting without chest pain can be expected to be higher in patients with renal dysfunction. We evaluated clinical outcomes of painless MI patients and relationship between renal dysfunction and painless MI., Methods and Results: Study population consisted of 9,735 patients (63 ± 13 years, men 70.7 %), whose discharge diagnosis by cardiac enzyme and electrocardiogram was MI. The study subjects were divided into two groups according to presence of chest pain (painful MI group, n = 8,249; painless MI group, n = 1486). Rates of in-hospital death, 1-month and 12-month composite MACE, cardiac death, and non-cardiac death were significantly higher in painless MI patients. In a multivariate logistic analysis, compared with glomerular filtration rate (GFR) > 90 mL/min/1.73 m(2), odds ratio of painless MI was increased proportionally in patients with GFR of 30-59, 15-29 and <15 mL/min/1.73 m(2) (odds ratio [OR] 1.25, 95 % confidence interval [CI] 1.05-1.49; OR 1.88, CI 1.39-2.53; OR 2.32, CI 1.65-3.26) In addition, the concomitant presence of renal dysfunction and diabetes mellitus significantly affected the prevalence of painless MI., Conclusion: Poorer outcomes of painless MI patients and the increased probability of painless MI proportional to declining GFR indicate that the possibility of painless MI should be considered in patients with renal dysfunction, particularly concomitant with diabetes mellitus.

Background: The presence of chronic kidney disease is an independent prognostic factor in patients with myocardial infarction (MI). We compared the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation and the Modification of Diet in Renal Disease (MDRD) study equation with regard to prognostic value in patients with MI., Methods: This study analyzed a retrospective cohort of 11 050 consecutive patients who had MI and were enrolled in the Korea Acute Myocardial Infarction Registry from November 2005 to August 2008. We applied the CKD-EPI equation and the MDRD study equation to determine the estimated glomerular filtration rate (eGFR) in a cohort of patients with MI., Results: The mean eGFR(CKD-EPI) was slightly higher than that of eGFR(MDRD) (73.16 versus 72.23 mL/min/1.73 m(2); P < 0.001). The prevalence of eGFR(CKD-EPI) <60 mL/min/1.73 m(2) was 26.9%, whereas that of eGFR(MDRD) was 28.5%. The area under the receiver operating characteristic curve was significantly larger for predicting the 1-year major adverse cardiovascular event (MACE) and 1-year all-cause mortality with CKD-EPI equation (0.648 versus 0.641, 0.768 versus 0.753, respectively; P < 0.001). The net reclassification index for improvement in risk of 1-year MACE and 1-year all-cause mortality were 4.09% (P< 0.001) and 9.25% (P< 0.001), respectively., Conclusions: The application of the eGFR(CKD-EPI) demonstrated better predictive values for clinical outcomes than eGFR(MDRD) in a cohort of patients with MI.

Background: The clinical outcomes of ST-segment elevation myocardial infarction (STEMI) are poor in patients with renal insufficiency. This study investigated changes in the likelihood that patients received optimal medical care throughout the entire process of myocardial infarction management, on the basis of their glomerular filtration rate (GFR)., Methods: This study analyzed 7,679 patients (age, 63 ± 13 years; men 73.6%) who had STEMI and were enrolled in the Korea Acute Myocardial Infarction Registry (KAMIR) from November 2005 to August 2008. The study subjects were divided into 5 groups corresponding to strata used to define chronic kidney disease stages., Results: Patients with lower GFR were less likely to present with typical chest pain. The average symptom-to-door time, door-to-balloon time, and symptom-to-balloon time were longer with lower GFR than higher GFR. Primary reperfusion therapy was performed less frequently and the results of reperfusion therapy were poorer in patients with renal insufficiency; these patients were less likely to receive adjunctive medical treatment, such as treatment with aspirin, clopidogrel, β-blocker, angiotensin-converting enzyme (ACE) inhibitor/angiotensin-receptor blocker (ARB), or statin, during hospitalization and at discharge. Patients who received less intense medical therapy had worse clinical outcomes than those who received more intense medical therapy., Conclusions: Patients with STEMI and renal insufficiency had less chance of receiving optimal medical care throughout the entire process of MI management, which may contribute to worse outcomes in these patients.

The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) reduce major adverse cardiac events (MACE) and mortality in patients with acute coronary syndrome. We investigated the effectiveness of statin therapy in reducing MACE in patients with acute myocardial infarction (AMI) and renal dysfunction (RD). In the present retrospective study of 12,853 patients with AMI, the patients were categorized into 4 groups: group I, statin therapy and no RD (estimated glomerular filtration rate ≥60 ml/min/1.73 m(2)); group II, neither statin therapy nor RD; group III, statin therapy and RD; group IV, no statin therapy but RD. The primary end points were death and complications during the hospital course. The secondary end points were MACE during 1 year of follow-up after AMI. Significant differences in the composite MACE during 12 months of follow-up were observed among the 4 groups (group I, 11.7%; group II, 19.0%; group III, 26.7%; and group IV, 45.5%; p <0.001). In a Cox proportional hazards model, mortality at 12 months increased stepwise from group II to IV compared to group I. Moreover, MACE-free survival in the severe RD group (estimated glomerular filtration rate <30 mL/min/1.73 m(2)) was also greater in the statin-treated group. In conclusion, statin therapy reduced MACE at 1 year of follow-up in patients with AMI regardless of RD., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Patients with chronic kidney disease have had conflicting results between drug-eluting stents (DES) and bare-metal stents (BMS). The aim of the present study was to determine whether DES is preferable for the treatment of acute myocardial infarction (AMI) with renal insufficiency, and to elucidate the impact of diabetes mellitus (DM) on outcomes of each stent., Methods and Results: As a part of the Korea Acute Myocardial Infarction Registry (KAMIR), 2,175 AMI patients with renal insufficiency (glomerular filtration rate <60ml/min) comprising 208 patients with BMS and 1,967 DES implantation were selected. Primary outcome was major adverse cardiac event (MACE), defined as a composite of mortality, nonfatal myocardial infarction, and target lesion revascularization. In the overall population, the MACE rate at 1 year was significantly higher in the BMS group than that of DES (44% vs. 26%, P<0.05), which was mainly due to death rather than repeat intervention (44% vs. 26%, P<0.05). In the diabetic group with DES implantation, the MACE rate was higher compared with the DES group without DM, mainly due to repeat intervention (5% vs. 8%, P<0.05)., Conclusions: In AMI patients with renal insufficiency, DES implantation exhibits a favorable 1-year clinical outcome than BMS implantation, and subgroup analysis for diabetic subjects showed worse outcomes in the DM group with implanted DES.