A comparison of the epidemiology of kidney replacement therapy between Europe and the United States: 2021 data of the ERA Registry and the USRDS.

BACKGROUND AND HYPOTHESIS: This paper compares the most recent data on the incidence and prevalence of kidney replacement therapy (KRT), kidney transplantation rates, and mortality on KRT from Europe to those from the United States (US), including comparisons of treatment modalities (haemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KTx)). METHODS: Data were derived from the annual reports of the European Renal Association (ERA) Registry and the United States Renal Data System (USRDS). The European data include information from national and regional renal registries providing the ERA Registry with individual patient data. Additional analyses were performed to present results for all participating European countries together. RESULTS: In 2021, the KRT incidence in the US (409.7 per million population (pmp)) was almost 3-fold higher than in Europe (144.4 pmp). Despite the substantial difference in KRT incidence, approximately the same proportion of patients initiated HD (Europe: 82%, US: 84%), PD (14%; 13% respectively), or underwent pre-emptive KTx (4%; 3% respectively). The KRT prevalence in the US (2436.1 pmp) was 2-fold higher than in Europe (1187.8 pmp). Within Europe, approximately half of all prevalent patients were living with a functioning graft (47%), while in the US, this was one third (32%). The number of kidney transplantations performed was almost twice as high in the US (77.0 pmp) compared to Europe (41.6 pmp). The mortality of patients receiving KRT was 1.6-fold higher in the US (157.3 per 1000 patient years) compared to Europe (98.7 per 1000 patient years). CONCLUSIONS: The US had a much higher KRT incidence, prevalence, and mortality compared to Europe, and despite a higher kidney transplantation rate, a lower proportion of prevalent patients with a functioning graft.

Increasing numbers and improved overall survival of patients on kidney replacement therapy over the last decade in Europe: an ERA Registry study.

BACKGROUND: The aim of this study was to describe the trends in the incidence, prevalence and survival of patients on kidney replacement therapy (KRT) for end-stage kidney disease (ESKD) across Europe from 2008 to 2017. METHODS: Data from renal registries in 9 countries and 16 regions that provided individual patient data to the ERA Registry from 2008 to 2017 were included. These registries cover 34% of the general population in Europe. Crude and standardized incidence and prevalence per million population (pmp) were determined. Trends over time were studied using Joinpoint regression. Survival probabilities were estimated using Kaplan-Meier analysis and hazard ratios (HRs) using Cox regression analysis. RESULTS: The standardized incidence of KRT was stable [annual percentage change (APC): -1.48 (-3.15; 0.21)] from 2008 (146.0 pmp) to 2011 (141.6 pmp), followed by a slight increase [APC: 1.01 (0.43; 1.60)] to 148.0 pmp in 2017, although trends in incidence varied across countries. This increase was primarily due to a rise in the incidence of KRT in men older than 65 years. Moreover, as a cause of kidney failure, diabetes mellitus is increasing. The standardized prevalence increased from 2008 (990.0 pmp) to 2017 (1166.8 pmp) [APC: 1.82 (1.75; 1.89)]. Patient survival on KRT improved in the time period 2011-13 compared with 2008-[adjusted HR: 0.94 (0.93; 0.95)]. CONCLUSION: This study showed an overall increase in the incidence and prevalence of KRT for ESKD as well as an increase in the KRT patient survival over the last decade in Europe.

Switch from Hemodialysis to Peritoneal Dialysis: Does the Time Spent on Hemodialysis Impact Outcomes in Peritoneal Dialysis?

INTRODUCTION: Switch from hemodialysis (HD) to peritoneal dialysis (PD) is unfrequent, but incentive strategies to perform PD can lead to an increase of these transitions. However, data on transitioning from HD to PD are scarce. We hypothesized that time spent on HD before transfer to PD would impact PD outcomes. METHODS: This registry-based, nationwide study analyzed patients transferred from HD to PD. Patients who began HD between January 2008 and December 2016 were included. Cox and Fine and Gray regression models were used to explore the relationship between time spent on HD before PD and outcomes in PD: PD cessation for death or retransfer to HD (composite endpoint); for death; and for retransfer to HD. RESULTS: Over the study period, 1,985 of the 77,587 HD starters (3%) were transferred to PD. The median time spent on HD before transfer to PD was 1.94 months (interquartile range [IQR] 1.02-4.01). The median survival time on PD after this transition was 20 months (IQR 18-21). Time spent on HD before PD was associated with increased risk of death or retransfer to HD (cause-specific hazard ratio [cs-HR] 1.01, 95% confidence interval [CI]: 1-1.02 for a 1-month increase) and death (cs-HR 1.02, 95% CI: 1.01-1.03) but not with retransfer to HD censored on death (cs-HR 1.00, 95% CI: 0.99-1.01). The results were similar when considering competing events. DISCUSSION/CONCLUSION: Switch from HD to PD is rare in France. Time spent on HD before transfer is associated with patient survival but not with retransfer to HD.

Impact of nephrology care trajectories pre-CKD stage 5 on initiation of kidney replacement therapy in children.

BACKGROUND: To improve pre-emptive kidney transplantation (PKT) in children and limit starting dialysis in an emergency, we aimed to describe nephrology care trajectories pre-CKD stage 5. METHODS: We included all children in France who, between 2010 and 2016, started kidney replacement therapy (KRT): standard dialysis (reference group) and emergency dialysis or PKT. We identified four pre-CKD stage 5 nephrology care trajectories before KRT that were extracted from the national exhaustive medical-administrative database and used logistic regression to explore associations between patient characteristics, care trajectories, and KRT initiation. RESULTS: Six hundred forty-three pediatric patients started KRT in France; 406 started dialysis and 30.5% emergency dialysis. The "optimal" care trajectory encompassed 179 patients, 82.7% with at least 18 months nephrology follow-up. Conversely, the "no care" trajectory encompassed 118 patients with no nephrology follow-up before KRT. The "severe" trajectory encompassed 128 patients; 93% hospitalized more than once a year and 18% in an intensive care unit. Finally, the "irregular" trajectory encompassed 127 patients, 77% and 46% with irregular laboratory monitoring and CKD drug delivery, respectively. With the "optimal" trajectory as the reference, probability of emergency dialysis was higher with the "irregular" and "no care" trajectories (odds ratio 3.02 [95% confidence interval 1.18-7.66] and 26.5 [10.8-64.8], respectively), and PKT was reduced with the "severe" trajectory (0.43 [0.23-0.82]). CONCLUSION: We identified a group of patients with irregular follow-up who may benefit the most from interventions aiming at improving adherence to treatment and earlier diagnosis of their CKD to improve access to PKT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinical Trial Emulation by Matching Time-dependent Propensity Scores: The Example of Estimating Impact of Kidney Transplantation.

BACKGROUND: No study to our knowledge has examined the use of observational data to emulate a clinical trial whereby patients at the time of kidney transplant proposal are randomly assigned to an awaiting transplantation or transplantation group. The main methodologic issue is definition of the baseline for dialyzed patients assigned to awaiting transplantation, resulting in the inability to use common propensity score-based approaches. We aimed to use time-dependent propensity score to better appraise the benefit of transplantation. METHODS: We studied 23,231 patients included in the French registry and on a transplant waiting list from 2005 to 2016. The main outcome was time to death. By matching on time-dependent propensity score, we obtained 10,646 pairs of recipients (transplantation group) versus comparable patients remaining on dialysis (awaiting transplantation group). RESULTS: The baseline exposure, that is, pseudo-randomization, was matching time. Median follow-up time was 3.5 years. At 10 years' follow-up, the restricted mean survival time was 8.8 years [95% confidence interval (CI) = 8.7, 8.9] in the transplantation group versus 8.2 years (95% CI = 8.1, 8.3) in the awaiting transplantation group. The corresponding life expectancy gain was 6.8 months (95% CI = 5.5, 8.2), and this corresponded to one prevented death at 10 years for 13 transplantations. CONCLUSIONS: Our study has estimated the life expectancy gain due to kidney transplantation. It confirms transplantation as the best treatment for end-stage renal disease. Furthermore, we demonstrated that this simple method should also be considered for estimating marginal effects of time-dependent exposures.

Impact of the dialysate acid component on haemodialysis mortality rates.

BACKGROUND: No prospective study has evaluated the long-term effect on mortality of the new acid concentrates added to bicarbonate dialysate. The aim of this pharmacoepidemiological study was to evaluate the association between hydrochloric or citric acid-based dialysate and mortality on haemodialysis (HD). METHODS: This study included 117 796 patients with 3 723 887 months on HD recorded in the national French Renal Epidemiology and Information Network registry. Dialysate acid components were retrospectively reconstructed for each facility. All patients on HD were associated each month with an exposure based on that at their facility of treatment. We took each patient's time-varying exposure into account to calculate the monthly mortality rates for each exposure. Incidence rate ratios (IRRs) for mortality were calculated with a Poisson regression, with acetic acid as the reference. Regressions were adjusted for initial clinical characteristics (age, gender, previous cardiovascular events, active malignancy, diabetes, pulmonary disease, mobility), dialysis technique and location (in-centre, outpatient centre, self-care unit) and ESRD vintage, updated monthly. RESULTS: The crude mortality rate per 1000 patient-months with citric acid {11.5 [95% confidence interval (CI) 11.1-12.0]} was lower than with either acetic acid [12.9 (95% CI 12.8-13.1)] or hydrochloric acid [12.8 (95% CI 12.2-13.5)]. For the 2014-17 period, the IRR for mortality with citric acid [adjusted IRR 0.94 (95% CI 0.90-0.99)] and with hydrochloric acid [adjusted IRR 0.86 (95% CI 0.79-0.94)] were significantly lower than with acetic acid. CONCLUSION: This post-marketing study of long-term exposure to dialysate acidifiers at the patient level found the use of citric and hydrochloric acid-based dialysates, compared with acetic acid, was associated with lower mortality.

Is self-care dialysis associated with social deprivation in a universal health care system? A cohort study with data from the Renal Epidemiology and Information Network Registry.

BACKGROUND: Socioeconomic status is associated with dialysis modality in developed countries. The main objective of this study was to investigate whether social deprivation, estimated by the European Deprivation Index (EDI), was associated with self-care dialysis in France. METHODS: The EDI was calculated for patients who started dialysis in 2017. The event of interest was self-care dialysis 3 months after dialysis initiation [self-care peritoneal dialysis (PD) or satellite haemodialysis (HD)]. A logistic model was used for the statistical analysis, and a counterfactual approach was used for the causal mediation analysis. RESULTS: Among the 9588 patients included, 2894 (30%) were in the most deprived quintile of the EDI. A total of 1402 patients were treated with self-care dialysis. In the multivariable analysis with the EDI in quintiles, there was no association between social deprivation and self-care dialysis. Compared with the other EDI quintiles, patients from Quintile 5 (most deprived quintile) were less likely to be on self-care dialysis (odds ratio 0.81, 95% confidence interval 0.71-0.93). Age, sex, emergency start, cardiovascular disease, chronic respiratory disease, cancer, severe disability, serum albumin and registration on the waiting list were associated with self-care dialysis. The EDI was not associated with self-care dialysis in either the HD or in the PD subgroups. CONCLUSIONS: In France, social deprivation estimated by the EDI is associated with self-care dialysis in end-stage renal disease patients undergoing replacement therapy.

Setting reasonable objectives for improving preemptive kidney transplantation rates in children.

BACKGROUND: This study aims to develop a method to estimate the potential of preemptive kidney transplantation (PKT) by identifying patients who were transplanted after a dialysis period (non-preemptive kidney transplantation (NPKT)) despite being medically suitable for PKT. METHODS: All children (< 18 years old) starting kidney replacement therapy (KRT) in France, between 2010 and 2016 and transplanted before December 31, 2017, were included. A propensity score (PS) of receiving PKT was estimated by multivariate logistic regression based on recipient medical characteristics. Healthcare use during the 24 months prior to KRT initiation was extracted from the French National Health Insurance database, and a pre-KRT follow-up of more than 18 months was considered sufficient to allow preemptive transplantation. RESULTS: Among 643 patients who started KRT, 149 (23.2%) were preemptively transplanted. Using PS stratification, among 391 NPKT patients, we identified 145 patients (37%) suitable for PKT, according to clinical characteristics. Mean age was 12.3 years, 67% were males, and 56% had urological abnormalities. Among those 145 patients, we identified 79 NPKT patients who started on dialysis despite early referral to a nephrologist (more than 18 months prior to KRT initiation). CONCLUSIONS: This method estimates a potential of 228 (149 + 79) PKT (35%) among pediatric patients in France. A similar method could be used in adults or in other countries. Estimation of the rate of patients with CKD stage 5 medically suitable for PKT will be of interest for health policy makers when setting up objectives for improvement in preemptive kidney transplant access.

Linking disease registries and nationwide healthcare administrative databases: the French renal epidemiology and information network (REIN) insight.

BACKGROUND: Record linkage is increasingly used in health research worldwide. Combining the patient information available in healthcare, administrative and clinical databases broadens the research perspectives, particularly for chronic diseases. Recent guidelines highlight the need for transparency on the used record linkage processes and the extracted data to be used by researchers. METHODS: Therefore, the aim of this study was to describe the deterministic iterative approach used to link the French Epidemiology and Information Network (REIN), a French national End-Stage Renal Disease registry, with the Système National des Données de Santé (SNDS), a French nationwide medico-administrative healthcare database. RESULTS: Among the 22,073 patients included in the REIN registry who started renal replacement therapy between 2014 and 2015 in France, 19,223 (87.1%) were matched with patients in the SNDS database. Comparison of matched and unmatched patients confirmed the absence of any major selection bias. Then, the record linkage was evaluated using the comorbidity status (diabetes). CONCLUSIONS: This fast and efficient method of record linkage with pseudonymized data and without unique and direct identifier might inspire other research teams. It also opens the path for new research on chronic kidney disease.

Access to the waiting list and to kidney transplantation for people living with HIV: A national registry study.

We compared access to a kidney transplantation (KT) waiting list (WL) and to KT between people living with HIV (PLHIV) and HIV-uninfected controls. Using the REIN (the national Renal Epidemiology and Information Network registry), we included all PLHIV initiating dialysis in France throughout 2006-2010 and HIV-uninfected controls matched for age, sex, year of dialysis initiation, and the existence of a diabetic nephropathy. Patients were prospectively followed until December 2015. We used a competitive risk approach to assess the cumulative incidence of enrollment on WL and of KT, with death as a competing event (subdistribution hazard ratio adjusted on comorbidities, asdHR). There were 255 PLHIV in the REIN (median age 47 years) of whom 180 (71%) were also found in the French Hospital Database on HIV (FHDH-ANRS CO4) including 126 (70%) known to be on antiretroviral therapy with HIV viral suppression (VS). Five years after dialysis initiation, 65%, and 76%, of treated PLHIV with VS, and of HIV-uninfected controls were enrolled on a WL (asdHR 0.68; 95% CI 0.50-0.91). Access to KT was also less frequent and delayed for treated PLHIV with VS (asdHR 0.75, 95% CI, 0.52-1.10). PLHIV continue to face difficulties to access KT.

2017 Annual Report Digest of the Renal Epidemiology Information Network (REIN) registry.

The French Renal Epidemiology and Information Network (REIN) registry started in 2002 with the goal to provide a tool to evaluate renal replacement therapy (RRT) practices and outcomes, to provide data for research and to support public health decisions related to end-stage renal disease ESRD. This summary presents the incidence and prevalence of RRT including kidney transplantation and wait-listing activity in 2017, and patients' survival and trends over 5 years. In 2017, 11 543 patients started RRT for ESRD, that is, incidence of 172 pmp. Between 2012 and 2017, the incidence of RRT increased by 1% per year [CI 95% (0.0; +2.0)]. On 31 December 2017, 87 275 patients were receiving RRT, that is, prevalence of 1294 pmp, 55% on dialysis, 45% with a functioning transplant. In 2017, 3782 kidney transplantations have been performed including 16% from a living donor, 13% being retransplantations and 15% pre-emptive transplantations. The median time on the waiting list was 19.7 months when only taking into account active waiting periods on the list. In 2017, 5280 new patients were registered on the renal transplant waiting list (i.e. 78.7 pmp). The number of patients considered as 'inactive' represented 45% of the patients on the list.

Twenty years of the French Renal Epidemiology and Information Network.

Background: The French Renal Epidemiology and Information Network (REIN) is 20 years old. It is not just a national data registry, but rather an epidemiological and informational network serving patients with chronic kidney disease, nephrology teams and health services. Methods: The past 10-year trends of the incidence and prevalence of renal replacement therapy by dialysis or kidney transplantation and waitlist activity are presented. To detect potential significant changes in trends from 2012 and 2021, a Joinpoint regression model was used. Results: The overall incidence of treated end-stage kidney disease (ESKD) was 169 per million population (pmp) in 2021. It was stable despite an increase in the incidence of diabetes. We found a decreasing trend in the proportion of patients starting dialysis in an emergency but an increase in those starting haemodialysis (HD) with a temporary catheter. Peritoneal dialysis decreased by 1.7% each year, whereas home HD, although involving only 1% of dialysis patients, increased by 10% each year. For patients not treated at home, the median time to drive from the patient's home to the dialysis unit was 17 min. The proportion of patients on the transplantation waitlist at the start of dialysis increased from 7% to 12%. Among the 111 263 new ESKD patients from 2012 to 2021, 8% received a first transplant at 1 year and 20% at 5 years. Among kidney transplant recipients, the mean time on the waitlist increased from 13.8 to 22.6 months. Living donor transplants increased in frequency, representing 15% of kidney transplants. Conclusions: Data from the REIN registry allow for the evaluation of needs and provide a planning tool for French authorities. The progressive implementation of automatic data retrieval from dialysis informatics charts might alleviate the burden of data collection. Furthermore, the research activity the REIN engenders, resulting in renewed confidence by health authorities in the dynamism of French nephrology, allows for an optimistic outlook for the REIN.

Transfers from home to facility-based dialysis: comparisons of HHD, assisted PD and autonomous PD.

Background: Home dialysis therapies such as peritoneal dialysis (PD) and home hemodialysis (HHD) are beneficial for quality of life and patient empowerment. The short technique survival time partly explains their low prevalence. We aimed to assess the risk of transfer to facility-based hemodialysis in patients treated with autonomous PD, assisted PD and HHD. Methods: This was a retrospective study using data from the REIN registry of patients starting home dialysis in France from 2002 to 2019. The risks of transfer to facility-based hemodialysis (HD) were compared between three modalities of home dialysis (HHD, nurse-assisted PD, autonomous PD) using survival models with a propensity score (PS)-matched and unmatched cohort of patients. Results: The study included 17 909 patients: 628 in the HHD group, 10 214 in the autonomous PD group, and 7067 in the assisted PD group. During the follow-up period, there were 5347 transfers to facility-based HD. The observed number of transfers was 2458 (13.7%) at 1 year and 5069 (28.3) at 5 years after the start of home dialysis, including 3272 (32%) on autonomous PD, 1648 (23.3%) on assisted PD, and 149 (23.7) on HHD. Owing to clinical characteristics differences, only 38% of HHD patients could be matched to patients from the others group. In the PS-matched cohort, the adjusted Cox model showed no difference in the risk of transfer for assisted PD (cs-HR 1.04, 95% CI 0.75-1.44) or HHD (cs-HR 1.07, 95% CI 0.77-1.48) compared with autonomous PD. Conclusions: Unlike results from other countries, where nurse assistance is not fully available for PD-associated care, there was no difference in technique survival between autonomous PD, nurse-assisted PD, and HHD in France. This discrepancy may be attributed to our inclusion of a broader spectrum of patients who derive significant benefits from assisted PD.

Multiple air pollutant exposure is associated with higher risk of all-cause mortality in dialysis patients: a French registry-based nationwide study.

Background: Little is known about the effect of combined exposure to different air pollutants on mortality in dialysis patients. This study aimed to investigate the association of multiple exposures to air pollutants with all-cause and cause-specific death in dialysis patients. Materials and methods: This registry-based nationwide cohort study included 90,373 adult kidney failure patients initiating maintenance dialysis between 2012 and 2020 identified from the French REIN registry. Estimated mean annual municipality levels of PM2.5, PM10, and NO2 between 2009 and 2020 were combined in different composite air pollution scores to estimate each participant's exposure at the residential place one to 3 years before dialysis initiation. Adjusted cause-specific Cox proportional hazard models were used to estimate hazard ratios (HRs) per interquartile range (IQR) greater air pollution score. Effect measure modification was assessed for age, sex, dialysis care model, and baseline comorbidities. Results: Higher levels of the main air pollution score were associated with a greater rate of all-cause deaths (HR, 1.082 [95% confidence interval (CI), 1.057-1.104] per IQR increase), regardless of the exposure lag. This association was also confirmed in cause-specific analyses, most markedly for infectious mortality (HR, 1.686 [95% CI, 1.470-1.933]). Sensitivity analyses with alternative composite air pollution scores showed consistent findings. Subgroup analyses revealed a significantly stronger association among women and fewer comorbid patients. Discussion: Long-term multiple air pollutant exposure is associated with all-cause and cause-specific mortality among patients receiving maintenance dialysis, suggesting that air pollution may be a significant contributor to the increasing trend of CKD-attributable mortality worldwide.

Prevalence of chronic kidney disease in France: methodological considerations and pitfalls with the use of Health claims databases.

Background: Health policy-making require careful assessment of chronic kidney disease (CKD) epidemiology to develop efficient and cost-effective care strategies. The aim of the present study was to use the RENALGO-EXPERT algorithm to estimate the global prevalence of CKD in France. Methods: An expert group developed the RENALGO-EXPERT algorithm based on healthcare consumption. This algorithm has been applied to the French National Health claims database (SNDS), where no biological test findings are available to estimate a national CKD prevalence for the years 2018-2021. The CONSTANCES cohort (+219 000 adults aged 18-69 with one CKD-EPI eGFR) was used to discuss the limit of using health claims data. Results: Between 2018 and 2021, the estimated prevalence in the SNDS increased from 8.1% to 10.5%. The RENALGO-EXPERT algorithm identified 4.5% of the volunteers in the CONSTANCES as CKD. The RENALGO-EXPERT algorithm had a positive predictive value of 6.2% and negative predictive value of 99.1% to detect an eGFR<60 ml/min/1.73 m². Half of 252 false positive cases (ALGO+, eGFR > 90) had been diagnosed with kidney disease during hospitalization, and the other half based on healthcare consumption suggestive of a 'high-risk' profile; 95% of the 1661 false negatives (ALGO-, eGFR < 60) had an eGFR between 45 and 60 ml/min, half had medication and two-thirds had biological exams possibly linked to CKD. Half of them had a hospital stay during the period but none had a diagnosis of kidney disease. Conclusions: Our result is in accordance with other estimations of CKD prevalence in the general population. Analysis of diverging cases (FP and FN) suggests using health claims data have inherent limitations. Such an algorithm can identify patients whose care pathway is close to the usual and specific CKD pathways. It does not identify patients who have not been diagnosed or whose care is inappropriate or at early stage with stable GFR.

The ERA Registry Annual Report 2021: a summary.

Background: The European Renal Association (ERA) Registry collects data on kidney replacement therapy (KRT) in patients with end-stage kidney disease (ESKD). This paper is a summary of the ERA Registry Annual Report 2021, including a comparison across treatment modalities. Methods: Data was collected from 54 national and regional registries from 36 countries, of which 35 registries from 18 countries contributed individual patient data and 19 registries from 19 countries contributed aggregated data. Using this data, incidence and prevalence of KRT, kidney transplantation rates, survival probabilities and expected remaining lifetimes were calculated. Result: In 2021, 533.2 million people in the general population were covered by the ERA Registry. The incidence of KRT was 145 per million population (pmp). In incident patients, 55% were 65 years or older, 64% were male, and the most common primary renal disease (PRD) was diabetes (22%). The prevalence of KRT was 1040 pmp. In prevalent patients, 47% were 65 years or older, 62% were male, and the most common PRDs were diabetes and glomerulonephritis/sclerosis (both 16%). On 31 December 2021, 56% of patients received haemodialysis, 5% received peritoneal dialysis, and 39% were living with a functioning graft. The kidney transplantation rate in 2021 was 37 pmp, a majority coming from deceased donors (66%). For patients initiating KRT between 2012-2016, 5-year survival probability was 52%. Compared to the general population, life expectancy was 65% and 68% shorter for males and females receiving dialysis, and 40% and 43% shorter for males and females living with a functioning graft.

Renal replacement therapy registries--time for a structured data quality evaluation programme.

Registries in the area of renal replacement therapy (RRT) are intended to be a tool for epidemiological research, health care planning and improvement of quality of care. In this perspective, the value of a population-based RRT registry and its ability to achieve its goals rely heavily on the quality of its data and on quality control procedures. Data quality is of crucial importance to prevent 'garbage coming out from garbage going in'. Regular evaluations of the data quality within these registries are needed to assess various aspects of data quality like completeness, prevention of duplicates, data validity, comparability, timeliness, usefulness and responsiveness of different items and accuracy of reporting and interpretation. In this technical note, we will discuss the purposes of RRT registries and the importance of different aspects of data quality in relation to those purposes. In addition, we discuss how these data quality aspects can be assessed and, where possible, how data quality may be improved.

REIN: a tool to evaluate pratices / REIN : un outil au service de l'évaluation des pratiques

On the occasion of the 20th anniversary of the REIN (French Renal Epidemiology and Information Network), a summary work on the contributions of the national French ESKD register was carried out. On the issue of its role in practices evaluation, the following key messages were retained. The evaluation of our practices allows improving them as proposed by the concept of the Edward Deming wheel (Plan, Do, Check, Act). Measurement also allows setting goals and targets. Where there are recommendations available, the REIN indicators allow comparison with the identified targets. The REIN registry is an interesting tool to observe the deployment and impact of the recommendations in dialysis units and to evaluate the professional practices taking into account the patients' characteristics and the changes in the recommendations. Finally, the treatment indicators analysed using REIN data show the great diversity of practices from one region to another, the result of habits, training of nephrologists, the history of the care offered and sometimes the geography of the region and its population.

À l'occasion des 20 ans du REIN (Réseau Épidémiologie et Information en Néphrologie), un travail de synthèse sur les apports du registre a été mené. Sur la question de REIN comme outil pour l'évaluation des pratiques, les messages clés suivants ont été retenus. L'évaluation de nos pratiques permet de les améliorer comme proposé par le concept de la roue d'Edward Deming (Plan, Do, Check, Act). Se mesurer permet également de fixer des objectifs et des cibles. Lorsque des recommandations sont disponibles, les indicateurs REIN permettent de se comparer aux cibles identifiées. Le registre REIN est un outil intéressant pour observer le déploiement et l'impact des recommandations dans les unités de dialyse et évaluer les pratiques professionnelles en tenant compte des caractéristiques des patients et de l'évolution des recommandations. Enfin, les indicateurs de prise en charge analysés à l'aide des données REIN montrent la grande diversité des pratiques d'une région à l'autre, fruit des habitudes, de la formation des néphrologues, de l'historique de l'offre de soins et parfois de la géographie de la région et de sa population.

REIN: a tool for the benefit of renal transplantation / REIN : un outil au service de l'accès à la greffe

On the occasion of the 20th anniversary of the REIN (French Renal Epidemiology and Information Network), a summary work on the contributions of the national French ESKD register was carried out. On the issue of access to renal transplantation for ESKD patients, the following key messages were retained. The registry of the REIN includes data about kidney transplant and dialysis. It thus allows evaluating the access to kidney transplant in France based on the needs of the population with stage 5 CKD treated by renal replacement therapy. The data produced by the registry is complementary to the data in the report of the Agence de la biomédecine (Agency of Biomedicine) based on the activity of the transplant centres and the population of registered patients waiting for a transplant. The proportion of preemptive transplant (transplant without prior recourse to dialysis) as well as that of preemptive registration (before starting dialysis) have increased since 2012 but remain low. The proportion of preemptive transplant as the first replacement therapy remains low and stable over time at around 3 to 4%. The access to the waiting list and the transplant varies depending on the age and co-morbidities of the patients (diabetes, obesity) as well as on the region. The rates of registration on the kidney transplant waiting list at the time of initiation of dialysis and at 1 year from the start have been increasing since 2012, irrespective of the patients' characteristics, though it remains low in elderly, diabetic and severely obese patients. This is partly the result related to the publication of the HAS (French National Authority for Health) recommendations in 2015 and the publications on the disparities in access to transplants established thanks to the REIN registry. The causes of non-registration at the time of initiation of dialysis have changed over time with some patients not registering for contraindication steadily decreasing since 2012. Thanks to several studies conducted using data from the registry, the variations in access to the list could be explained, partly, by the health condition of the dialysis population as well as by the socio-economic context and differences in practices according to dialysis networks. The median waiting time for a kidney transplant has been gradually increasing since 2012, with a delta of about 8 months between 2012 and 2020. However, the waiting time between the initiation of dialysis and the transplant has increased less significantly. The probability of receiving a first kidney transplant depends on the age, diabetic status and obesity of the patient, and has remained stable over time.

À l'occasion des 20 ans du REIN (Réseau Épidémiologie et Information en Néphrologie), un travail de synthèse sur les apports du registre a été mené. Sur la question de l'accès à la greffe rénale des patients avec une maladie rénale stade 5, les messages clés suivants ont été retenus. Le registre du REIN intègre les données de la greffe rénale et de la dialyse. Il permet ainsi d'évaluer l'accès à la greffe rénale en France à partir des besoins de la population MRC au stade 5 traitée par suppléance. Les données produites par le registre sont complémentaires des données du rapport de l'Agence de la biomédecine basées sur l'activité des centres de greffe et la population des patients inscrits en attente de greffe. La part de la greffe préemptive (greffe sans recours préalable à la dialyse) ainsi que celle de l'inscription préemptive (avant le démarrage de la dialyse) ont augmenté depuis 2012 mais restent faibles. La proportion de greffe préemptive comme premier traitement de suppléance reste faible et stable dans le temps aux alentours de 3 à 4 %. L'accès à la liste d'attente et à la greffe varie selon l'âge et les comorbidités des patients (diabète, obésité) mais aussi selon la région. Les taux d'inscription sur liste d'attente de greffe rénale au moment de l'initiation de la dialyse et à 1 an du début augmentent depuis 2012, quelles que soient les caractéristiques des patients même si elle reste faible chez les patients âgés, diabétiques et présentant une obésité sévère. Ceci est en partie le résultat lié à la publication des recommandations HAS en 2015 et aux publications sur les disparités d'accès à la greffe établies grâce au registre REIN. Les causes de non-inscription au moment de l'initiation de la dialyse ont évolué dans le temps avec une proportion de patients non inscrits pour contre-indication en baisse constante depuis 2012. Grâce à plusieurs études menées à partir des données du registre, les variations d'accès à la liste ont pu être expliquées, en partie, par l'état de santé de la population dialysée mais aussi par le contexte socioéconomique et des différences de pratiques selon les filières de prise en charge. Le temps d'attente médian avant une greffe rénale augmente progressivement depuis 2012 avec un delta d'environ 8 mois entre 2012 et 2020 ; cependant, le temps d'attente entre l'initiation de la dialyse et la greffe a augmenté de façon moins importante. La probabilité de recevoir une première greffe rénale dépend de l'âge, du statut diabétique et de l'obésité du patient et est restée stable au cours du temps.

Interactive tool for visualizing disparities in access to the waiting list and home dialysis / Outil interactif de visualisation des disparités dans l'accès à la liste d'attente et à la dialyse à domicile

Healthcare professionals and patient associations want to identify any disparities within the different regions, particularly in access to the waiting list for a kidney transplant and to home dialysis. An application containing the results of two REIN studies on these two issues was created to meet this need. It is now available for consultation on the professional portal of the Biomedicine Agency.

Un des besoins des professionnels de santé et des associations de patients est d'identifier au sein des différentes régions les éventuelles disparités, notamment dans l'accès à la liste d'attente pour une greffe rénale et à la dialyse à domicile. Une application reprenant les résultats de deux études du Réseau épidémiologique et information en néphrologie (REIN) portant sur ces deux problématiques a été créée pour répondre à ce besoin. Elle est désormais disponible à la consultation sur le portail des professionnels de l'Agence de la biomédecine.