BACKGROUND: The clinical importance of hypokalemia is likely underrecognized in Chinese dialysis patients, and whether its clinical effect was mediated by serum albumin is not fully elucidated. This study aimed to explore the association between serum potassium and mortality in dialysis patients of a Chinese nationwide multicenter cohort, taking albumin as a consideration. METHODS: This was a prospective nation-wide multicenter cohort study. Restricted cubic splines were used to test the linearity of serum potassium and relationships with all-cause (AC) and cardiovascular (CV) mortality and a subsequent two-line piecewise linear model was fitted to approach the nadir. A mediation analysis was performed to examine relations of albumin to potassium and mortalities. RESULTS: A total of 10,027 patients were included, of whom 6605 were peritoneal dialysis and 3422 were hemodialysis patients. In the overall population, the mean age was 51.7 ± 14.8 years, 55.3%(5546/10,027) were male, and the median dialysis vintage was 13.60 (4.70, 39.70) months. Baseline serum potassium was 4.30 ± 0.88 mmol/L. After a median follow-up period of 26.87 (14.77, 41.50) months, a U-shape was found between potassium and mortality, and a marked increase in risk at lower potassium but a moderate elevation in risk at higher potassium were observed. The nadir for AC mortality risk was estimated from piecewise linear models to be a potassium concentration of 4.0 mmol/L. Interestingly, the significance of the association between potassium and mortality was attenuated when albumin was introduced into the extended adjusted model. A subsequent significant mediation by albumin for potassium and AC and CV mortalities were found ( P < 0.001 for both), indicating that hypokalemia led to higher mortality mediated by low serum albumin, which was a surrogate of poor nutritional status and inflammation. CONCLUSIONS Associations between potassium and mortalities were U-shaped in the overall population. The nadir for AC mortality risk was at a potassium of 4.0 mmol/L. Serum albumin mediated the association between potassium and AC and CV mortalities.
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; East Asian People ; Hypokalemia/etiology* ; Kidney Failure, Chronic/mortality* ; Potassium/blood* ; Prospective Studies ; Renal Dialysis ; Serum Albumin/analysis*

BACKGROUND: The purpose of this study was to determine whether components of the ProVent model can predict the high medical costs in Korean patients requiring at least 21 days of mechanical ventilation (prolonged mechanical ventilation [PMV]). METHODS: Retrospective data from 302 patients (61.6% male; median age, 63.0 years) who had received PMV in the past 5 years were analyzed. To determine the relationship between medical cost per patient and components of the ProVent model, we collected the following data on day 21 of mechanical ventilation (MV): age, blood platelet count, requirement for hemodialysis, and requirement for vasopressors. RESULTS: The mortality rate in the intensive care unit (ICU) was 31.5%. The average medical costs per patient during ICU and total hospital (ICU and general ward) stay were 35,105 and 41,110 US dollars (USD), respectively. The following components of the ProVent model were associated with higher medical costs during ICU stay: age <50 years (average 42,731 USD vs. 33,710 USD, p=0.001), thrombocytopenia on day 21 of MV (36,237 USD vs. 34,783 USD, p=0.009), and requirement for hemodialysis on day 21 of MV (57,864 USD vs. 33,509 USD, p<0.001). As the number of these three components increased, a positive correlation was found betweeen medical costs and ICU stay based on the Pearson's correlation coefficient (γ) (γ=0.367, p<0.001). CONCLUSION: The ProVent model can be used to predict high medical costs in PMV patients during ICU stay. The highest medical costs were for patients who required hemodialysis on day 21 of MV.
Humans ; Intensive Care Units ; Male ; Mortality ; Platelet Count ; Renal Dialysis ; Respiration, Artificial ; Retrospective Studies ; Thrombocytopenia

BACKGROUND: Kidney transplantation is an effective renal replacement therapy for patients with end-stage renal disease (ESRD). In this study, we assessed the impact of the baseline characteristics and comorbidities of ESRD patients on the probability of deceased donor kidney transplantation (DDKT) and evaluated the morbidity and mortality during the time spent waiting. METHODS: The study population consisted of 544 ESRD patients on the waiting list for DDKT at Chungnam National University Hospital in South Korea between February 2000 and October 2015. The patients were observed from the date of transplantation list registration to the date of transplantation. Baseline characteristics and comorbidities were investigated together with new-onset comorbidities that occurred during the waiting time. RESULTS: Diabetes mellitus (39.0%), hypertension (25.2%), and glomerulonephritis (21.3%) were the three most common causes of ESRD in this study, and coronary artery disease (9.4%) was the most common comorbidity. The 115 patients (19.3%) who underwent DDKT had a mean waiting time of 1,711 days (768–2,654 days or 4.68 years [2.10–7.27]). Blood groups other than type O, peritoneal dialysis, and nondiabetic ESRD were significantly associated with a higher likelihood of DDKT. Infection was the leading cause of death and the most common comorbidity that arose during the waiting time. Patients who experienced cardiovascular events during the waiting time showed a lower transplant rate compared with those who did not. CONCLUSION: The prevalence of comorbidities was high in renal transplantation candidates. During the often-long waiting time, new comorbidities may occur, with long-term sequelae limiting access to kidney transplantation or resulting in death.
Blood Group Antigens ; Cause of Death ; Chungcheongnam-do ; Comorbidity ; Coronary Artery Disease ; Diabetes Mellitus ; Glomerulonephritis ; Humans ; Hypertension ; Kidney Failure, Chronic ; Kidney Transplantation ; Kidney ; Korea ; Mortality ; Peritoneal Dialysis ; Prevalence ; Renal Replacement Therapy ; Tissue Donors ; Waiting Lists

BACKGROUND: Unlike patterns observed in the general population, obesity is associated with better survival among hemodialysis patients, which could be explained by reverse causation or illness-related weight loss. However, the time-varying effect of body mass index (BMI) on hemodialysis survival has not been investigated. Therefore, this study investigated the time-varying effect of BMI on mortality after starting hemodialysis. METHODS: In the present study, we examined Korean Society of Nephrology data from 16,069 adult patients who started hemodialysis during or after the year 2000. Complete survival data were obtained from Statistics Korea. Survival analysis was performed using Cox regression and a non-proportional hazard fractional polynomial model. RESULTS: During the median follow-up of 8.6 years, 9,272 patients (57.7%) died. Compared to individuals with normal BMI (18.5–24.9 kg/m²), the underweight group (< 18.5 kg/m²) had a higer mortality hazard ratio (HR, 1.292; 95% confidence interval [CI], 1.203–1.387; P < 0.001) and the overweight group (25.0–29.9 kg/m²) had a lower mortality HR (0.904; 95% CI, 0.829–0.985; P = 0.022). The underweight group had increasing HRs during the first 3 to 7 years after starting hemodialysis, which varied according to age group. The young obese group (< 40 years old) had a U-shaped temporal trend in their mortality HRs, which reflected increased mortality after 7 years. CONCLUSION: The obese hemodialysis group had better survival during the early post-dialysis period, although the beneficial effect of obesity disappeared 7 years after starting hemodialysis. The young obese group also had an increased mortality HR after 7 years.
Adult ; Body Mass Index ; Follow-Up Studies ; Humans ; Korea ; Models, Statistical ; Mortality ; Nephrology ; Obesity ; Overweight ; Renal Dialysis ; Thinness ; Weight Loss

The End-stage Renal Disease Registry Committee of the Korean Society of Nephrology collects data on the dialysis therapy in Korea through an internet-based registry program and reports it annually. In this article, the method and clinical implications of the mortality hazard ratio analyses of various clinical parameters in the 2017 registry report have been described, with the inclusion of data on four additional parameters. The mortality risk based on clinical parameters was analyzed only for hemodialysis patients. The number of registered patients with laboratory data was 13,943 (8,446 male and 5,497 female patients), and death was reported in 3,139 patients. Analysis of the effects of various clinical parameters on mortality was performed using non-linear Cox proportional hazard model with the R statistics program. For all clinical parameters, univariate and adjusted multivariate hazard ratio analyses were performed. Analysis of the mortality hazard ratio showed that low body mass index, low hemoglobin, low serum albumin, low serum phosphorus, and low urea reduction ratio were associated with a significantly increased mortality risk, whereas paradoxically high serum creatinine levels were associated with low mortality risk.
Body Mass Index ; Creatinine ; Dialysis ; Female ; Humans ; Kidney Failure, Chronic ; Korea ; Male ; Methods ; Mortality ; Nephrology ; Phosphorus ; Proportional Hazards Models ; Renal Dialysis ; Serum Albumin ; Urea

The life expectancy of end-stage renal disease patients undergoing regular hemodialysis (HD) remains significantly lower than in the general population. Reducing excess mortality by improving renal replacement options is an unmet medical need. Online post-dilution hemodiafiltration (HDF) has been promoted as the gold standard, offering improved clinical outcomes, based on numerous observational studies that suggest a reduced mortality risk and lower morbidity with HDF compared with standard HD. However, most randomized controlled trials (RCTs) have failed to demonstrate a significant beneficial effect of HDF on all-cause mortality. The effects on secondary outcomes were often negligible or absent. Unfortunately, these RCTs were characterized by a moderate to high risk of bias. In post-hoc analyses of the largest RCTs and meta-analysis of individual participant data from four RCTs, HDF patients receiving the highest convection volume consistently and dose-dependently saw superior outcomes. However, as these studies were not designed a priori to clarify this issue, and there are no indisputable mechanisms underlying reduced mortality risks, we cannot exclude the possibility that the health status of patients (with vascular access as a proxy) may affect outcomes more than the convective technique itself. There is currently insufficient evidence to support the contention that high-volume HDF confers relevant benefits to patients over standard HD. The conflicting data of published RCTs reduce confidence in the superiority of high-volume convective therapy. Hopefully, ongoing large RCTs (for example, CONVINCE) may supply an indisputable answer to the crucial question of high-volume HDF.
Bias (Epidemiology) ; Convection ; Hemodiafiltration ; Humans ; Kidney Failure, Chronic ; Life Expectancy ; Mortality ; Renal Dialysis

BACKGROUND: Cardiovascular diseases of chronic dialysis patients are often undertreated because of their higher surgical risk. This study aimed to assess mortality and morbidity after open heart surgery in chronic dialysis patients compared to those with normal renal function and identify risk factors for postoperative outcomes. METHODS: We retrospectively analyzed 2,432 patients who underwent open heart surgery from 2002 to 2017 and collected data from 116 patients (38 patients on dialysis and 78 age-, sex-, and diabetes mellitus status-matched control patients with normal kidney function). We assessed comorbidities, New York Heart Association (NYHA) class, laboratory data, surgical methods, and postoperative outcomes. RESULTS: The dialysis group had more comorbidities, higher NYHA classes, and greater need for urgent surgeries compared to the control group. They exhibited significantly higher postoperative mortality (18.4% vs. 2.6%, P = 0.005) and more overall complications (65.8% vs. 25.6%, P < 0.001). Dialysis itself significantly increased relative risk for in-hospital mortality after adjustment. EuroSCORE II was not as useful as in the general population. Multivariate logistic regression analysis demonstrated that total (adjusted odds ratio [AOR], 10.7; P = 0.029) and in-hospital death risk (AOR, 14.7; P = 0.033), the durations of postoperative hospitalization (AOR, 4.6; P = 0.034), CRRT (AOR 36.8; P = 0.004), and ventilator use (AOR, 7.6; P = 0.022) were significantly increased in the dialysis group. CONCLUSION: The dialysis group exhibited a higher risk for mortality and overcall complications after open heart surgery compared to the patients with normal renal function. Therefore, the benefit of surgical treatment must be balanced against potential risks.
Cardiovascular Diseases ; Comorbidity ; Diabetes Mellitus ; Dialysis ; Heart ; Hospital Mortality ; Hospitalization ; Humans ; Kidney ; Kidney Failure, Chronic ; Logistic Models ; Mortality ; Odds Ratio ; Renal Insufficiency ; Retrospective Studies ; Risk Factors ; Thoracic Surgery ; Ventilators, Mechanical

BACKGROUND: Controversies exist whether arteriovenous fistula (AVF) placement is preferred over arteriovenous graft (AVG) for elderly patients. Current guidelines did not offer specific recommendations. Thus, this study was conducted to analyze the all-cause mortality and primary patency associated with various vascular access (VA) types according to age group. METHODS: This retrospective observational study investigated the Korean insurance claims data of chronic kidney disease patients who began hemodialysis between January 2008 and December 2016. We investigated all-cause mortality associated with initial VA in incident hemodialysis patients and primary patency between AVF and AVG according to age group. RESULTS: The proportion of patients with a tunneled dialysis catheter (TDC) that was first placed for VA increased from 18.4% in 2008 to 52.3% in 2016. Incident hemodialysis patients with a TDC or AVG for the initial VA had significantly higher mortality risk than patients with an AVF, except for patients over 85 years, who showed no significant difference in all-cause mortality regardless of VA type. In the patency analysis on initial AV access, AVG had significantly poorer primary patency than AVF in all age groups. CONCLUSION: AVF had better patency than AVG in all age groups; however, the benefit of AVF attenuated in the older age groups. The mortality rate between AVF and AVG was not significantly different in patients over 85 years. Therefore, a “patient-first” approach should be emphasized over a “fistula-first” approach in AV access creation for incident hemodialysis patients older than 85 years.
Administrative Claims, Healthcare ; Aged ; Arteriovenous Fistula ; Catheters ; Dialysis ; Humans ; Insurance ; Mortality ; National Health Programs ; Observational Study ; Renal Dialysis ; Renal Insufficiency, Chronic ; Retrospective Studies ; Transplants

BACKGROUND: Mortality is higher in patients with chronic kidney disease (CKD) than in the general population, but little information is available on CKD-related mortality that is representative of the Korean population. Our objective was to investigate mortality risk in Korean patients with CKD. METHODS: We identified patients with incident CKD who had not undergone dialysis or kidney transplantation between January 1, 2003 and December 31, 2007 in Korea using the database of the Korean National Health Insurance Service-National Sample Cohort, and stratified the population into the following three groups: group 1 (n = 1,473), controls; group 2 (n = 2,212), patients with diabetes or hypertension, but without CKD; and group 3 (n = 2,212), patients with CKD. We then monitored them for all-cause mortality until December 2013. RESULTS: A total of 1,473 patients were included in this analysis. During the follow-up period, 941 patients in group 3 died (134 deaths/1,000 person-years) compared with 550 deaths in the group 2 (34 deaths/1,000 person-years) and 459 deaths in group 1 (30 deaths/1,000 person-years). The rate ratio for mortality rate was 4.5, and the hazard ratio for mortality was 4.88 (95% confidence interval [CI], 4.36–5.47, P < 0.001) in patients in group 3 compared with age- and sex-matched controls (group 1). The rate ratio for mortality rate was 4.0, and the hazard ratio for mortality was 4.36 (95% CI, 3.92–4.85, P < 0.001) in patients in group 3 compared with patients in group 2. CONCLUSION: In this nationally representative sample cohort, excess mortality was observed in Korean patients with incident CKD.
Cohort Studies ; Diabetes Mellitus ; Dialysis ; Follow-Up Studies ; Humans ; Hypertension ; Kidney Transplantation ; Korea ; Mortality ; National Health Programs ; Renal Insufficiency ; Renal Insufficiency, Chronic

OBJECTIVE: To investigate the associations between mean arterial pressure (MAP) and mortality in patients with peritoneal dialysis (PD). METHODS: A total of 1737 patients with terminal renal diseases under PD in the First Affiliated Hospital of Zhejiang University from 2008 to 2016 were enrolled. Patients were followed up for 33.0(19.3, 52.4) months. The mean arterial pressure over the first 3 months of PD therapy were calculated. All-cause death and cardiovascular death were assessed using Cox regression models adjusted for demographics, laboratory measurements, comorbid conditions and antihypertensive medications. RESULTS: During the follow-up, 208 patients died, among which 95(45.7%) patients died of cardiovascular causes. Compared with patients with MAP >95-<120 mmHg, patients with MAP ≤ 95 mmHg were associated with significantly higher risk of all-cause death (=1.40,95%:1.01-1.93,<0.05); patients with MAP ≥ 120 mmHg were associated with significantly higher risk of all-cause (=2.12,95%:1.32-3.40, <0.01) and cardiovascular morality (=2.55, 95%:1.38-4.70, <0.01). MAP presents a U-shaped association with all-cause mortality and a J-shaped association with cardiovascular mortality. CONCLUSIONS Both high MAP and low MAP are associated with higher risk of mortality in PD patients.
Arterial Pressure ; Humans ; Kidney Failure, Chronic ; mortality ; pathology ; Peritoneal Dialysis ; Renal Dialysis ; Risk Factors