End-stage Renal Disease Registry Research Articles

Major changes and improvements of dialysis therapy in Korea: review of end-stage renal disease registry

The Korean Society of Nephrology (KSN) launched a nationwide end-stage renal disease (ESRD) patient registry in 1985 called the Insan Prof. Byung-Suk Min Memorial ESRD Patient Registry. KSN members voluntarily participate in this registry, which has been collecting data through the Internet since 2000. The KSN ESRD patient registry data were reviewed to elucidate the major changes and improvements in dialysis therapy in Korea. The data review revealed: a rapid increase in the number of patients with ESRD; an increase in the number of patients with diabetic nephropathy; a decrease in the proportion of patients undergoing peritoneal dialysis; an increase in the role of private dialysis clinics; an increase in the number of elderly patients undergoing dialysis and the number of patients undergoing long-term dialysis; a decrease in mean blood pressure and an increase in pulse pressure; improvement in anemia treatment; improvement in dialysis adequacy; and improvement in the survival of patients undergoing dialysis. In conclusion, improvements have been made in blood pressure control, anemia treatment, and dialysis adequacy despite increases in the number of elderly patients, diabetic patients, and patients on long-term dialysis during the last two decades in Korea.

The essential of 2012 results from the French Renal Epidemiology and Information Network (REIN) ESRD registry

The French Renal Epidemiology and Information Network (REIN) registry began in 2002 to provide a tool for public health decision support, evaluation and research related to renal replacement therapies (RRT) for end-stage renal disease (ESRD). It is relying on a network of nephrologists, epidemiologists, patients and public health representatives. Continuous registration covers all dialysis and transplanted patients. In 2012, in France, 10,048 patients started a RRT (154 per million inhabitants). Elders provided majority of new patients (median age at RRT start: 70 years old). New patients had a high and age increasing rate of comorbidities, especially diabetes (42% of the new patients) and cardiovascular comorbidities (>50% of the new patients). Like previous years, incidence is stabilized. On December 31, 2012, 73,491 patients were receiving a RRT in France (1127 per million inhabitants, 56% on dialysis and 44% living with a functional renal transplant). More than 50% of patients were undergoing in-center hemodialysis with significant variations among regions. An increase in medical satellite unit hemodialysis but a decrease in self-care unit hemodialysis rates were noticed across the time, whereas peritoneal dialysis remained stable at 7%. Five years after starting RRT, the overall survival rate was 51% but only 16% among patients over 85 years. Mortality rate was highly dependent on treatment and age; transplanted patients aged 60–69 had a 27/1000 patients-year mortality rate versus 133 for a dialysis patient. Patients who started dialysis had a probability of first wait-listing of 4.8% at the start of dialysis (pre-emptive registrations) and 27% at 72 months. Whatever their diabetes status was, patients older than 60 had poor access to the waiting list. Seventeen percent of the patients received a first renal transplant within 15.4 month median time; 3% had received a pre-emptive graft. Ten years after the start of the French ESRD registry, this report provides a comprehensive and nation-wide overview of dialysis and transplantation cares in France, including overseas.

The Association between Body Mass Index and Mortality on Peritoneal Dialysis: A Prospective Cohort Study

Previous studies have demonstrated that increased body mass index (BMI) is associated with decreased mortality in hemodialysis (HD) patients. However, the association between BMI and survival has not been well established in patients undergoing peritoneal dialysis (PD). The aim of the study was to determine the association between BMI and mortality in the PD population using the Clinical Research Center (CRC) registry for end-stage renal disease (ESRD) cohort in Korea. Prevalent patients with PD were selected from the CRC registry for ESRD, a prospective cohort study on dialysis patients in Korea. Patients were categorized into four groups by quartiles of BMI. Cox regression analysis was used to calculate the adjusted hazard ratio (HR) of mortality with a BMI of quartile 2 (21.4 - 23.5 kg/m(2)) as the reference. A total of 900 prevalent patients undergoing PD were included. The median follow-up period was 24 months. The multivariate Cox proportional hazard model showed that the lowest quartile of BMI was associated with higher mortality (HR 3.00, 95% confidence interval (CI), 1.26 - 7.15). However, the higher quartiles of BMI were not associated with mortality compared with the reference category of BMI quartile 2 (Quartile 3: HR 1.11, 95% CI, 0.43 - 2.85, Quartile 4: HR 1.64, 95% CI, 0.66 - 4.06) after adjustment for clinical variables. Lower BMI was a significant risk factor for death, but increased BMI was not associated with mortality in Korean PD patients.

Trends in Anemia Care in Older Patients Approaching End-Stage Renal Disease in the United States (1995-2010)

Anemia is common in patients with advanced chronic kidney disease. Whereas the treatment of anemia in patients with end-stage renal disease (ESRD) has attracted considerable attention, relatively little is known about patterns and trends in the anemia care received by patients before they start maintenance dialysis or undergo preemptive kidney transplantation. To determine the trends in anemia treatment received by Medicare beneficiaries approaching ESRD. Closed cohort study in the United States using national ESRD registry data (US Renal Data System) of patients 67 years or older who initiated maintenance dialysis or underwent preemptive kidney transplantation between 1995 and 2010. All eligible patients had uninterrupted Medicare (A+B) coverage for at least 2 years before ESRD. Time, defined as calendar year of incident ESRD. Use of erythropoiesis-stimulating agents (ESA), intravenous iron supplements, and blood transfusions in the 2 years prior to ESRD; hemoglobin concentration at the time of ESRD. We used multivariable modified Poisson regression to estimate utilization prevalence ratios (PRs). Records of 466,803 patients were analyzed. The proportion of patients with incident ESRD receiving any ESA in the 2 years before increased from 3.2% in 1995 to a peak of 40.8% in 2007; thereafter, ESA use decreased modestly to 35.0% in 2010 (compared with 1995; PR, 9.85 [95% CI, 9.04-10.74]). Among patients who received an ESA, median time from first recorded ESA use to ESRD increased from 120 days in 1995 to 337 days in 2010. Intravenous iron administration increased from 1.2% (1995) to 12.3% (2010; PR, 9.20 [95% CI, 7.97-10.61]). The proportion of patients receiving any blood transfusions increased monotonically from 20.6% (1995) to 40.3% (2010; PR, 1.88 [95% CI, 1.82-1.95]). Mean hemoglobin concentrations were 9.5 g/dL in 1995, increased to a peak of 10.3 g/dL in 2006, and then decreased moderately to 9.9 g/dL in 2010. Between 1995 and 2010, older adults approaching ESRD were increasingly more likely to be treated with ESAs and to receive intravenous iron supplementation, but also more likely to receive blood transfusions.

Educational programs improve the preparation for dialysis and survival of patients with chronic kidney disease

Preparation for end-stage renal disease (ESRD) is widely acknowledged to be suboptimal in the United States. We sought to determine whether participation in a kidney disease screening and education program resulted in improved ESRD preparation and survival in 595 adults who developed ESRD after participating in the National Kidney Foundation Kidney Early Evaluation Program (KEEP), a community-based screening and education program. Non-KEEP patients were selected from a national ESRD registry and matched to KEEP participants based on demographic and clinical characteristics. The main outcomes were pre-ESRD nephrologist care, placement of permanent vascular access, use of peritoneal dialysis, pre-emptive transplant wait listing, transplantation, and mortality after ESRD. Participation in KEEP was associated with significantly higher rates of pre-ESRD nephrologist care (76.0% vs. 69.3%), peritoneal dialysis (10.3% vs. 6.4%), pre-emptive transplant wait listing (24.2% vs. 17.1%), and transplantation (9.7% vs. 6.4%) but not with higher rates of permanent vascular access (23.4% vs. 20.1%). Participation in KEEP was associated with a lower risk for mortality (hazard ratio 0.80), but this was not statistically significant after adjusting for ESRD preparation. Thus, participation in a voluntary community kidney disease screening and education program was associated with higher rates of ESRD preparation and survival.

The impact of high-flux dialysis on mortality rates in incident and prevalent hemodialysis patients

Background/AimsThe effect of high-flux (HF) dialysis on mortality rates could vary with the duration of dialysis. We evaluated the effects of HF dialysis on mortality rates in incident and prevalent hemodialysis (HD) patients.MethodsIncident and prevalent HD patients were selected from the Clinical Research Center registry for end-stage renal disease (ESRD), a Korean prospective observational cohort study. Incident HD patients were defined as newly diagnosed ESRD patients initiating HD. Prevalent HD patients were defined as patients who had been receiving HD for > 3 months. The primary outcome measure was all-cause mortality.ResultsThis study included 1,165 incident and 1,641 prevalent HD patients. Following a median 24 months of follow-up, the mortality rates of the HF and low-flux (LF) groups did not significantly differ in the incident patients (hazard ratio [HR], 1.046; 95% confidence interval [CI], 0.592 to 1.847; p = 0.878). In the prevalent patients, HF dialysis was associated with decreased mortality compared with LF dialysis (HR, 0.606; 95% CI, 0.416 to 0.885; p = 0.009).ConclusionsHF dialysis was associated with a decreased mortality rate in prevalent HD patients, but not in incident HD patients.

Mortality risk factors associated with familial Mediterranean fever among a cohort of 1.25 million adolescents

ObjectiveThere are limited data on long-term comorbidities and mortality among patients with familial Mediterranean fever (FMF). Our objective was to evaluate comorbidities and death rates among individuals with FMF.MethodsWe studied...

Obesity and Future Risk of End-stage Renal Disease

Vivante A, Golan E, Tzur D, et al. Body mass index in 1.2 million adolescents and risk for end-stage renal disease. Arch Intern Med. 2012; 172( 21): 1644- 1650; doi: 10.1001/2013.jamainternmed.85[OpenUrl][1][CrossRef][2][PubMed][3][Web of Science][4] Investigators from Israel sought to examine whether there was an association between obesity and treated end-stage renal disease (ESRD). They retrospectively analyzed data on nearly 1.2 million 17-year-olds who underwent a medical examination 1 year prior to conscription into military service between 1967 and 1997, and linked this cohort to the Israeli ESRD registry. Baseline measurements of height, weight, blood pressure (BP), and dipstick urinalysis were obtained during the examination. Individuals who had hematuria or proteinuria were excluded from the study. Body mass index (BMI) subgroups for age and sex were classified according to the 2000 US Centers for Disease Control and Prevention definitions. A BMI between the 85th and 94th percentile (24.90-28.19 for males and 25.20-29.59 for females) was categorized as overweight while a BMI … [1]: {openurl}?query=rft.jtitle%253DArch%2BIntern%2BMed%26rft.volume%253D172%26rft.spage%253D1644%26rft_id%253Dinfo%253Adoi%252F10.1001%252F2013.jamainternmed.85%26rft_id%253Dinfo%253Apmid%252F23108588%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=10.1001/2013.jamainternmed.85&link_type=DOI [3]: /lookup/external-ref?access_num=23108588&link_type=MED&atom=%2Faapgrand%2F29%2F3%2F32.atom [4]: /lookup/external-ref?access_num=000311513000008&link_type=ISI

Body Mass Index in 1.2 Million Adolescents and Risk for End-Stage Renal Disease

The relationship between adolescent body mass index (BMI) and future risk for end-stage renal disease (ESRD) is not fully understood, nor is it known the extent to which this association is limited to diabetic ESRD. We evaluated the association between BMI in adolescence and the risk for all-cause, diabetic, and nondiabetic ESRD. Medical data about 1 194 704 adolescents aged 17 years who had been examined for fitness for military service between January 1, 1967, and December 31, 1997, were linked to the Israeli ESRD registry in this nationwide population-based retrospective cohort study. Incident cases of treated ESRD between January 1, 1980, and May 31, 2010, were included. Cox proportional hazards models were used to estimate the hazard ratio (HR) for treated ESRD among study participants for their BMI at age 17 years, defined in accord with the US Centers for Disease Control and Prevention BMI for age and sex classification. During 30 478 675 follow-up person-years (mean [SD], 25.51 [8.77] person-years), 874 participants (713 male and 161 female) developed treated ESRD, for an overall incidence rate of 2.87 cases per 100 000 person-years. Compared with adolescents of normal weight, overweight adolescents (85th to 95th percentiles of BMI) and obese adolescents (≥95th percentile of BMI) had an increased future risk for treated ESRD, with incidence rates of 6.08 and 13.40 cases per 100 000 person-years, respectively. In a multivariate model adjusted for sex, country of origin, systolic blood pressure, and period of enrollment in the study, overweight was associated with an HR of 3.00 (95% CI, 2.50-3.60) and obesity with an HR of 6.89 (95% CI, 5.52-8.59) for all-cause treated ESRD. Overweight (HR, 5.96; 95% CI, 4.41-8.06) and obesity (HR, 19.37; 95% CI, 14.13-26.55) were strong and independent risk factors for diabetic ESRD. Positive associations of overweight (HR, 2.17; 95% CI, 1.71-2.74) and obesity (HR, 3.41; 95% CI, 2.42-4.79) with nondiabetic ESRD were also documented. Overweight and obesity in adolescents were associated with significantly increased risk for all-cause treated ESRD during a 25-year period. Elevated BMI constitutes a substantial risk factor for diabetic and nondiabetic ESRD.

A New Approach for Measuring Gender Disparity in Access to Renal Transplantation Waiting Lists

Gender inequity in access to renal transplantation waiting lists, in favor of men, has long since been demonstrated in a number of studies. Discrepancies between the results of the available studies might be explained by different analytical approaches or different national contexts. In this study we analyzed French end-stage renal disease registry data using a novel model to determine whether the female gender is associated with a lower probability of being listed on the transplant waiting list or with a longer time from dialysis start until registration, or both. The effect of gender on access to the national renal transplantation waiting list was assessed in 9497 men and 5386 women aged 18 to 74 years who started dialysis between 2002 and 2009. We used a semiparametric regression cure model adjusted for age, work status, and 11 comorbidities or disabilities. Women were younger and less likely to work or have associated comorbidities. At the study endpoint, 33.8% of the men and 34.1% of the women were placed on the renal transplantation waiting list. After taking potential confounders into account, our model shows that women demonstrated a lower probability of being registered on the national transplant waiting list (odds ratio=0.69; 95% confidence interval, 0.62-0.78) and a longer time from dialysis start to registration (hazard ratio=0.89; 95% confidence interval, 0.84-0.95) than men. This disparity affects predominantly older women who do not work or have diabetes and is more pronounced in some geographic areas. These poorly understood gender-based inequities require further consideration.

Brief Report: Renal replacement therapy in Korea, 2010

The Korean Society of Nephrology (KSN) launched the official End-Stage Renal Disease (ESRD) Patient Registry in 1985 and the Internet online registry program was opened in 2001. The ESRD Registry Committee of KSN has collected data on dialysis therapy in Korea through the online registry program in the KSN Internet website. The increasing number of elderly people and diabetic patients in Korea has resulted in a very rapid increase in the number of ESRD patients. The total number of ESRD patients was 58,860 (hemodialysis [HD], 39,509; peritoneal dialysis [PD], 7309; and functioning kidney transplant [KT], 12,042). The prevalence of ESRD was 1144.4 patients per million population (PMP), and the proportion of renal replacement therapy was HD, 67.1%; PD, 12.4%; and KT, 20.5%. The number of new ESRD patients in 2010 was 9335 (HD, 7204; PD, 867; and KT, 1264; the incidence rate was 181.5 PMP). The primary causes of ESRD were diabetic nephropathy (45.2%), hypertensive nephrosclerosis (19.2%), and chronic glomerulonephritis (11.3%). The mean urea reduction ratio was 67.9% in male HD patients and 73.9% in female HD patients. The mean Kt/V was 1.394 in male patients and 1.659 in female patients. Five-year survival rates of male and female dialysis patients were 64.9% and 67.3%, respectively.

Trends in Timing of Initiation of Chronic Dialysis in the United States

During the past decade, a trend has been observed in the United States toward initiation of chronic dialysis at higher levels of estimated glomerular filtration rate. This likely reflects secular trends in the composition of the dialysis population and a tendency toward initiation of dialysis earlier in the course of kidney disease. The goal of this study was to generate model-based estimates of the magnitude of changes in the timing of dialysis initiation between 1997 and 2007. We used information from a national registry for end-stage renal disease on estimated glomerular filtration rate at initiation among patients who received their first chronic dialysis treatment in 1997 or 2007. We used information regarding predialysis estimated glomerular filtration rate slope from an integrated health care system. After accounting for changes in the characteristics of new US dialysis patients from 1997 to 2007, we estimate that chronic dialysis was initiated a mean of 147 days earlier (95% confidence interval, 134-160) in the later compared with the earlier year. Differences in timing were consistent across a range of patient subgroups but were most pronounced for those aged 75 years or older; the mean difference in timing in that subgroup was 233 days (95% confidence interval, 206-267). Chronic dialysis appears to have been initiated substantially earlier in the course of kidney disease in 2007 compared with 1997. In the absence of strong evidence to suggest that earlier initiation of chronic dialysis is beneficial, these findings call for careful evaluation of contemporary dialysis initiation practices in the United States.

Persistent Asymptomatic Isolated Microscopic Hematuria in Israeli Adolescents and Young Adults and Risk for End-Stage Renal Disease

Few data are available on long-term outcomes among adolescents and young adults with persistent asymptomatic isolated microscopic hematuria. To evaluate the risk of end-stage renal disease (ESRD) in adolescents and young adults with persistent asymptomatic isolated microscopic hematuria. Nationwide, population-based, retrospective cohort study using medical data from 1,203,626 persons aged 16 through 25 years (60% male) examined for fitness for military service between 1975 and 1997 were linked to the Israeli treated ESRD registry. Incident cases of treated ESRD from January 1, 1980, to May 31, 2010, were included. Cox proportional hazards models were used to estimate the hazard ratio (HR) of treated ESRD among those diagnosed as having persistent asymptomatic isolated microscopic hematuria. Treated ESRD onset, defined as the date of initiation of dialysis treatment or the date of renal transplantation, whichever came first. Persistent asymptomatic isolated microscopic hematuria was diagnosed in 3690 of 1,203,626 eligible individuals (0.3%). During 21.88 (SD, 6.74) years of follow-up, treated ESRD developed in 26 individuals (0.70%) with and 539 (0.045%) without persistent asymptomatic isolated microscopic hematuria, yielding incidence rates of 34.0 and 2.05 per 100,000 person-years, respectively, and a crude HR of 19.5 (95% confidence interval [CI], 13.1-28.9). A multivariate model adjusted for age, sex, paternal country of origin, year of enrollment, body mass index, and blood pressure at baseline did not substantially alter the risk associated with persistent asymptomatic isolated microscopic hematuria (HR, 18.5 [95% CI, 12.4-27.6]). A substantially increased risk for treated ESRD attributed to primary glomerular disease was found for individuals with persistent asymptomatic isolated microscopic hematuria compared with those without the condition (incidence rates, 19.6 vs 0.55 per 100,000 person-years, respectively; HR, 32.4 [95% CI, 18.9-55.7]). The fraction of treated ESRD attributed to microscopic hematuria was 4.3% (95% CI, 2.9%-6.4%). Presence of persistent asymptomatic isolated microscopic hematuria in persons aged 16 through 25 years was associated with significantly increased risk of treated ESRD for a period of 22 years, although the incidence and absolute risk remain quite low.

Growing a peritoneal dialysis program: A single‐center experience

Growing a peritoneal dialysis program: A single‐center experience

Insights from the Chronic Kidney Disease in Children (CKiD) study.

Over the last 5 years, the Chronic Kidney Disease in Children (CKiD) prospective cohort study has enrolled close to 600 children ages 1 to 16 years with mild to moderate chronic kidney disease (CKD). The main purpose of this interim report is to review the initial cross-sectional data and conclusions derived from the clinical studies conducted within CKiD in the context of findings from other pediatric CKD and end-stage renal disease (ESRD) registry and cohort studies. In particular, special emphasis was placed on studying four aspects of chronic kidney disease in children, including the identification of risk factors related to disease progression, the impact of CKD on neurocognition and quality of life (QoL), the cardiovascular morbidity associated with CKD, and identifying the causes and effects of growth failure in the context of mild to moderate kidney failure.

Epidemiology of chronic kidney disease in children

In the past 30 years there have been major improvements in the care of children with chronic kidney disease (CKD). However, most of the available epidemiological data stem from end-stage renal disease (ESRD) registries and information on the earlier stages of pediatric CKD is still limited. The median reported incidence of renal replacement therapy (RRT) in children aged 0–19 years across the world in 2008 was 9 per million of the age-related population (4–18 years). The prevalence of RRT in 2008 ranged from 18 to 100 per million of the age-related population. Congenital disorders, including congenital anomalies of the kidney and urinary tract (CAKUT) and hereditary nephropathies, are responsible for about two thirds of all cases of CKD in developed countries, while acquired causes predominate in developing countries. Children with congenital disorders experience a slower progression of CKD than those with glomerulonephritis, resulting in a lower proportion of CAKUT in the ESRD population compared with less advanced stages of CKD. Most children with ESRD start on dialysis and then receive a transplant. While the survival rate of children with ERSD has improved, it remains about 30 times lower than that of healthy peers. Children now mainly die of cardiovascular causes and infection rather than from renal failure.Electronic supplementary materialThe online version of this article (doi:10.1007/s00467-011-1939-1) contains supplementary material, which is available to authorized users

Adherence to clinical practice guidelines and outcomes in diabetic patients

To examine the level of adherence to clinical practice guidelines and its relationship to outcomes in patients with diabetes. Retrospective cohort study. A tertiary teaching hospital in Korea. Patients aged ≥18 years with diabetes (n = 4994) who visited the study hospital once or more during 2004. The outcomes were mortality from the database of the Statistics Korea and end-stage renal disease (ESRD) incidence from ESRD registry in the Korean Society of Nephrology until December 2009. Testing rates for blood pressure, eye examination, HbA1c, renal function and lipid profiles were 93.9, 32.8, 84.9, 33.5 and 45.9%, respectively. The percentage of patients achieving each treatment goal was 27.8% for blood pressure, 44.2% for HbA1c and 49.4% for low-density lipoprotein (LDL) cholesterol. There were 11.7% patients with composite outcome (death and/or ESRD). Male gender, level of HbA1c (<7%), presence of HbA1c data, checking eye examination, presence of data on urine albumin-to-creatinine ratio (UACR) and having anti-platelet medication were associated with better outcome. The adherence to recommendations was unsatisfactory, especially in checking eye examination, testing UACR and LDL cholesterol, and achieving a target goal for each parameter. Guideline adherence was positively related to better prognosis. Active strategies to apply the guidelines to clinical practice should be developed to improve patient outcomes.

Quantifying the benefit of early living-donor renal transplantation with a simulation model of the Dutch renal replacement therapy population

Early living-donor transplantation improves patient- and graft-survival compared with possible cadaveric renal transplantation (RTx), but the magnitude of the survival gain is unknown. For patients starting renal replacement therapy (RRT), we aimed to quantify the survival benefit of early living-donor transplantation compared with dialysis and possible cadaveric transplantation and to estimate the population benefit from increasing the early transplantation rate. We used a decision-analytic computer-simulation model, with a lifetime time horizon, simulating patients starting RRT, using data from the Dutch End-Stage Renal Disease Registry and published data. We compared the (quality adjusted) life expectancy (LE) of 'early living-donor RTx' and 'dialysis' (with possible cadaveric RTx if available). LE and quality-adjusted LE benefits of the early living-donor RTx compared with the dialysis strategy for 40-year-old patients ranged from 7.5 to 9.9 life years (LYs) [6.7-8.8 quality-adjusted life years (QALYs)] depending on the primary renal disease. For 70-year-old patients, the benefit was 4.3-6.0 LYs (4.3-6.0 QALYs). Increasing the early transplantation rate from currently 5.8 to 22.2% (the highest in Europe) would increase average LE by 1.2 LYs and total LE for annual incident cases in the Netherlands by >1800 LYs. Efforts to increase early living-donor RTx could potentially substantially increase LE for patients starting RRT, especially in younger patients.

Validation of a case definition to define chronic dialysis using outpatient administrative data

BackgroundAdministrative health care databases offer an efficient and accessible, though as-yet unvalidated, approach to studying outcomes of patients with chronic kidney disease and end-stage renal disease (ESRD). The objective of this study is to determine the validity of outpatient physician billing derived algorithms for defining chronic dialysis compared to a reference standard ESRD registry.MethodsA cohort of incident dialysis patients (Jan. 1 - Dec. 31, 2008) and prevalent chronic dialysis patients (Jan 1, 2008) was selected from a geographically inclusive ESRD registry and administrative database. Four administrative data definitions were considered: at least 1 outpatient claim, at least 2 outpatient claims, at least 2 outpatient claims at least 90 days apart, and continuous outpatient claims at least 90 days apart with no gap in claims greater than 21 days. Measures of agreement of the four administrative data definitions were compared to a reference standard (ESRD registry). Basic patient characteristics are compared between all 5 patient groups.Results1,118,097 individuals formed the overall population and 2,227 chronic dialysis patients were included in the ESRD registry. The three definitions requiring at least 2 outpatient claims resulted in kappa statistics between 0.60-0.80 indicating "substantial" agreement. "At least 1 outpatient claim" resulted in "excellent" agreement with a kappa statistic of 0.81.ConclusionsOf the four definitions, the simplest (at least 1 outpatient claim) performed comparatively to other definitions. The limitations of this work are the billing codes used are developed in Canada, however, other countries use similar billing practices and thus the codes could easily be mapped to other systems. Our reference standard ESRD registry may not capture all dialysis patients resulting in some misclassification. The registry is linked to on-going care so this is likely to be minimal. The definition utilized will vary with the research objective.

History of nephrology and renal replacement therapy in Korea

Korea has a long tradition of Eastern (Korean) medicine. Modern nephrology in Korea began in the 20th century after the Second World War. The first nephrology report was presented in 1949 at the third annual meeting of the Korean Society of Internal Medicine. The first hemodialysis was performed in 1952 during the Korean War, the first acute peritoneal dialysis in 1957, the first kidney biopsy in 1959, the first kidney transplantation in 1969 and the first continuous ambulatory peritoneal dialysis in 1981. National Health Insurance was launched in 1976 with a limited coverage, which was gradually expanded to cover all Korean nationals in 1989. The Korean Society of Nephrology (KSN) was inaugurated in 1980. The KSN End-Stage Renal Disease (ESRD) Registry was started in 1985. Brain death legislation was enacted, and the Korean network for organ sharing launched in 2000. During 2009, a total of 8,906 patients or 175.9 patients per million population (PMP) began renal replacement therapy (RRT), and at the end of the year a total of 56,396 patients or 1,113.6 patients PMP were on RRT in Korea. The prevalence of ESRD continues to grow in Korea while its incidence is stable or declining as compared with the previous year.