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.

Trends and Specific Causes of Cardiovascular Mortality after Kidney Transplantation in Finland

BACKGROUND

Cardiovascular diseases are an important cause of mortality in patients who have undergone kidney transplantation, but the knowledge on trends of cardiovascular mortality and specific causes of cardiovascular death among these patients is scarce.

METHODS

Our aim was to compare the cardiovascular mortality rates after kidney transplantation in Finland between 1990-1999, 2000-2009, and 2010-2019 using data from the Finnish Registry for Kidney Diseases. We analyzed 1-year and long-term cardiovascular mortality rates as well as the specific causes of cardiovascular death and the trends in them.

RESULTS

In total, 4946 patients underwent first kidney transplantation in 1990-2019. During the follow-up time (median 8.3 years, interquartile range 4.0-14.5), there were 1392 deaths, of which 582 were cardiovascular deaths. In an unadjusted Cox regression model, the risk of long-term cardiovascular mortality was similar in the different periods. However, when adjusted for age, sex, duration of dialysis, and cause of kidney disease, the long-term cardiovascular mortality risk was significantly lower in 2000-2009 and 2010-2019 (hazard ratio 0.60 [95% confidence interval, 0.49 to 0.73] and hazard ratio 0.51 [95% confidence interval, 0.39 to 0.66], respectively) compared with 1990-1999. The results were similar regarding 1-year cardiovascular mortality. The distribution of different causes of cardiovascular death remained unchanged during the study period, with coronary artery disease accounting for 47% of deaths. During the first year after transplantation, pulmonary embolisms and arrhythmias were more common than in the long term.

CONCLUSIONS

Cardiovascular disease remained the most common cause of death in kidney transplant recipients, but adjusted cardiovascular mortality risk has decreased significantly during the past three decades. Coronary artery disease was the most frequent cause of cardiovascular death, and the proportion of coronary artery disease-related cardiovascular deaths increased after the first year after transplantation.

Effect of comorbidities on healthcare expenditures for patients on kidney replacement therapy considering the treatment modality and duration in a French cohort

End-stage kidney disease (ESKD) is associated with a substantial economic burden. In France, the cost of care for such patients represents 2.5% of the total French healthcare expenditures but serves less than 1% of the population. These patients' healthcare expenditures are high because of the specialized and complex treatment needed as well as the presence of multiple comorbidities. This study aims to describe and assess the effect of comorbidities on healthcare expenditures (direct medical cost and non-medical costs including transportation and compensatory allowances) for patients with ESKD in France while considering the modality and duration of renal replacement therapy (RRT). This study included adults who started RRT for the first time between 2012 and 2014 in France and were followed for 5 years. Generalized linear models were built to predict mean monthly cost (MMC) by integrating first the time duration in the cohort, then patient characteristics and finally the duration of use of each treatment modalities. Comorbidities with the highest effect on MMC were inability to walk (+ 1435€), active cancer (+ 593€), HIV positivity (+ 507€) and diabetes (+ 396€). These effects vary according to age or treatment modalities. This study confirms the importance of considering patient characteristics, comorbidities and type of RRT when assessing healthcare expenditures for patients with ESKD.

Infection-Related Hospitalizations After Simultaneous Pancreas-Kidney Transplantation Compared to Kidney Transplantation Alone

The total burden of infections after transplantation has not been compared in detail between recipients of simultaneous pancreas-kidney transplantation (SPK) and kidney transplantation alone (KTA). We compared infection-related hospitalizations and bacteremias after transplantation during 1- and 5-year follow-up among 162 patients undergoing SPK. The control group consisted of 153 type 1 diabetics undergoing KTA with the inclusion criteria of donor and recipient age < 60, and BMI < 30. During the first year, SPK patients had more infection-related hospitalizations (0.54 vs. 0.31 PPY, IRR 1.76, p = <0.001) and bacteremias (0.11 vs. 0.01 PPY, IRR 17.12, p = <0.001) compared to KTA patients. The first infection-related hospitalizations and bacteremias occurred later during follow-up in KTA patients. SPK was an independent risk factor for infection-related hospitalization and bacteremia during the first year after transplantation, but not during the 5-year follow-up. Patient survival did not differ between groups, however, KTA patients had inferior kidney graft survival. SPK patients are at greater risk for infection-related hospitalizations and bacteremias during the first year after transplantation compared to KTA patients, however, at the end of the follow-up the risk of infection was similar between groups.

Incidence and outcomes of kidney replacement therapy for end-stage kidney disease due to primary glomerular disease in Europe: findings from the ERA Registry

BACKGROUND AND HYPOTHESIS

Primary glomerular disease (PGD) is a major cause of end-stage kidney disease (ESKD) leading to kidney replacement therapy (KRT). We aimed to describe incidence (trends) in individuals starting KRT for ESKD due to PGD and to examine their survival and causes of death.

METHODS

We used data from the European Renal Association (ERA) Registry on 69 854 patients who started KRT for ESKD due to PGD between 2000 and 2019. ERA primary renal disease codes were used to define six PGD subgroups. We examined age and sex standardized incidence, trend of the incidence, and survival.

RESULTS

The standardized incidence of KRT for ESKD due to PGD was 16.6 per million population (pmp), ranging from 8.6 pmp in Serbia to 20.0 pmp in France. IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) had the highest incidence of 4.6 pmp and 2.6 pmp, respectively. Histologically non-examined PGDs represented over 50% of cases in Serbia, Bosnia and Herzegovina, and Romania and were also common in Greece, Estonia, Belgium, and Sweden. The incidence declined from 18.6 pmp in 2000 to 14.5 pmp in 2013, after which it stabilized. All PGD subgroups had five-year survival probabilities above 50%, with crescentic glomerulonephritis having the highest risk of death (adjusted hazard ratio: 1.8 [95% confidence interval: 1.6-1.9]) compared with IgAN. Cardiovascular disease was the most common cause of death (33.9%).

CONCLUSION

The incidence of KRT for ESKD due to PGD showed large differences between countries and was highest and increasing for IgAN and FSGS. Lack of kidney biopsy facilities in some countries may have affected accurate assignment of the cause of ESKD. The recognition of the incidence and outcomes of KRT among different PGD subgroups may contribute to a more individualized patient care approach.

Tuberculosis in Kidney Transplant Recipients: A Nationwide Cohort in a Low Tuberculosis Incidence Country

Background

World Health Organization recommends tuberculosis (TB) preventive treatment for risk groups such as patients preparing for organ transplantation. Pretransplant screening or treatment of latent TB infection has not been routine practice in Finland.

Methods

In this nationwide registry study, we assessed the risk of TB among kidney transplant recipients compared to the general population. TB cases were identified by data linkage of the national infectious disease and the national transplant registries between 1995 and 2019. Standardized incidence ratios were calculated with adjustment for age, sex, and annual TB dynamics.

Results

A total of 4101 kidney transplants in 3900 recipients with a follow-up of 37 652 patient-years were included. Eighteen TB cases were detected. Patients diagnosed with TB were older (median age 64 y, interquartile range 56-66) at transplantation than those without TB (median 51 y, interquartile range 41-60, P < 0.001). The standardized incidence ratio of TB was 6.9 among kidney transplant recipients compared to general population during the whole study period 1995-2019 but decreased from 12.5 in 1995-2007 to 3.2 in 2008-2019. The standardized incidence ratio was 44.2 during the first year after transplantation. Significant differences in 5-y graft losses were not detected between TB patients and those without TB.

Conclusions

The standardized incidence ratio of TB in kidney transplant recipients has decreased over the years, but these patients remain at risk of TB, especially during the first posttransplant year. Cost-benefit analysis is required to address feasibility of latent TB infection screening among transplant candidates in countries with low incidence of TB.

Severe infections in peritoneal dialysis and home hemodialysis patients: An inception cohort study

OBJECTIVES

Infections are the most common non-cardiovascular cause of death among dialysis patients. Earlier studies have shown similar or higher risk of infectious complications in peritoneal dialysis (PD) compared to hemodialysis (HD) patients, but comparisons to home HD patients have been rare. We investigated the risk of severe infections after start of continuous ambulatory PD (CAPD) and automated PD (APD) as compared to home HD.

METHODS

All adult patients (n = 536), who were on home dialysis at day 90 from starting kidney replacement therapy (KRT) between 2004 and 2017 in Helsinki healthcare district, were included. We defined severe infection as an infection with C-reactive protein of 100 mg/l or higher. Cumulative incidence of first severe infection was assessed considering death as a competing risk. Hazard ratios were estimated using Cox regression with propensity score adjustment.

RESULTS

The risk of getting a severe infection during the first year of dialysis was 35% for CAPD, 25% for APD and 11% for home HD patients. During five years of follow-up, the hazard ratio of severe infection was 2.8 [95% CI 1.6-4.8] for CAPD and 2.2 [95% CI 1.4-3.5] for APD in comparison to home HD. Incidence rate of severe infections per 1000 patient-years was 537 for CAPD, 371 for APD, and 197 for home HD patients. When excluding peritonitis, the incidence rate was not higher among PD than home HD patients.

CONCLUSIONS

CAPD and APD patients had higher risk of severe infections than home HD patients. This was explained by PD-associated peritonitis.

Predicting mortality after start of long-term dialysis-International validation of one- and two-year prediction models

BACKGROUND

Mortality prediction is critical on long-term kidney replacement therapy (KRT), both for individual treatment decisions and resource planning. Many mortality prediction models already exist, but as a major shortcoming most of them have only been validated internally. This leaves reliability and usefulness of these models in other KRT populations, especially foreign, unknown. Previously two models were constructed for one- and two-year mortality prediction of Finnish patients starting long-term dialysis. These models are here internationally validated in KRT populations of the Dutch NECOSAD Study and the UK Renal Registry (UKRR).

METHODS

We validated the models externally on 2051 NECOSAD patients and on two UKRR patient cohorts (5328 and 45493 patients). We performed multiple imputation for missing data, used c-statistic (AUC) to assess discrimination, and evaluated calibration by plotting average estimated probability of death against observed risk of death.

RESULTS

Both prediction models performed well in the NECOSAD population (AUC 0.79 for the one-year model and 0.78 for the two-year model). In the UKRR populations, performance was slightly weaker (AUCs: 0.73 and 0.74). These are to be compared to the earlier external validation in a Finnish cohort (AUCs: 0.77 and 0.74). In all tested populations, our models performed better for PD than HD patients. Level of death risk (i.e., calibration) was well estimated by the one-year model in all cohorts but was somewhat overestimated by the two-year model.

CONCLUSIONS

Our prediction models showed good performance not only in the Finnish but in foreign KRT populations as well. Compared to the other existing models, the current models have equal or better performance and fewer variables, thus increasing models' usability. The models are easily accessible on the web. These results encourage implementing the models into clinical decision-making widely among European KRT populations.

Sex differences in COVID-19 mortality risk in patients on kidney function replacement therapy

In the general population with COVID-19, the male sex is an established risk factor for mortality, in part due to a more robust immune response to COVID-19 in women. Because patients on kidney function replacement therapy (KFRT) have an impaired immune response, especially kidney transplant recipients due to their use of immunosuppressants, we examined whether the male sex is still a risk factor for mortality among patients on KFRT with COVID-19. From the European Renal Association COVID-19 Database (ERACODA), we examined patients on KFRT with COVID-19 who presented between February 1st, 2020, and April 30th, 2021. 1204 kidney transplant recipients (male 62.0%, mean age 56.4 years) and 3206 dialysis patients (male 61.8%, mean age 67.7 years) were examined. Three-month mortality in kidney transplant recipients was 16.9% in males and 18.6% in females (p = 0.31) and in dialysis patients 27.1% in males and 21.9% in females (p = 0.001). The adjusted HR for the risk of 3-month mortality in males (vs females) was 0.89 (95% CI 65, 1.23, p = 0.49) in kidney transplant recipients and 1.33 (95% CI 1.13, 1.56, p = 0.001) in dialysis patients (p_interaction = 0.02). In a fully adjusted model, the aHR for the risk of 3-month mortality in kidney transplant recipients (vs. dialysis patients) was 1.39 (95% CI 1.02, 1.89, p = 0.04) in males and 2.04 (95% CI 1.40, 2.97, p < 0.001) in females (p_interaction = 0.02). In patients on KFRT with COVID-19, the male sex is not a risk factor for mortality among kidney transplant recipients but remains a risk factor among dialysis patients. The use of immunosuppressants in kidney transplant recipients, among other factors, may have narrowed the difference in the immune response to COVID-19 between men and women, and therefore reduced the sex difference in COVID-19 mortality risk.

MO874: Incidence of Severe Infections in Home Haemodialysis and Peritoneal Dialysis Patients

BACKGROUND

Dialysis patients have a more than ten-fold risk of dying from infections compared with general population. In earlier studies, the risk of infections was similar in peritoneal dialysis (PD) and haemodialysis (HD), but comparison to home HD has not been performed. Our aim was to study the incidence of severe infections after start of home HD as compared with continuous ambulatory PD (CAPD) and automated PD (APD).

METHODS

We included all 536 adult patients, who were on home dialysis at day 90 from start of kidney replacement therapy (KRT) between 2004 and 2017 in Helsinki healthcare district. Severe infections were identified from patients’ laboratory data as a plasma C-reactive protein over 100 mg/L and confirmed from the patient data system. The cumulative incidence of the first severe infection was estimated considering death as a competing risk event. Hazard ratios of first severe infection were assessed using Cox regression with propensity score adjustment. Incidence rate (IR) and ratios (IRR) of all severe infection episodes were calculated.

RESULTS

The probability of getting a severe infection during the first year of dialysis was 35% for CAPD, 25% for APD and 11% for home HD patients. During a 5-year follow-up, the hazard ratio of severe infection was 2.8 [95% confidence interval (95% CI) 1.6–4.8] for CAPD and 2.2 (95% CI 1.4–3.5) for APD in comparison to home HD with adjustment for propensity scores. IR of infections/100 patient-years was 54 for CAPD, 37 for APD and 20 for home HD patients. The IR of peritonitis was 37 for CAPD and 25 for APD patients. When infection episodes caused by peritonitis were excluded, the IR of severe infections was not higher among PD than home HD patients.

CONCLUSION

The risk of severe infection was considerably lower among home HD than PD patients. This difference was mainly explained by the peritonitis episodes among the PD patients.

Bone volume, mineral density, and fracture risk after kidney transplantation

Background

Disordered mineral metabolism reverses incompletely after kidney transplantation in numerous patients. Post-transplantation bone disease is a combination of pre-existing chronic kidney disease and mineral disorder and often evolving osteoporosis. These two frequently overlapping conditions increase the risk of post-transplantation fractures.

Material and methods

We studied the prevalence of low bone volume in bone biopsies obtained from kidney transplant recipients who were biopsied primarily due to the clinical suspicion of persistent hyperparathyroidism between 2000 and 2015 at the Hospital District of Helsinki and Uusimaa. Parameters of mineral metabolism, results of dual-energy x-ray absorptiometry scans, and the history of fractures were obtained concurrently.

One hundred nine bone biopsies taken at a median of 31 (interquartile range, IQR, 18–70) months after transplantation were included in statistical analysis. Bone turnover was classified as high in 78 (72%) and normal/low in 31 (28%) patients. The prevalence of low bone volume (n = 47, 43%) was higher among patients with low/normal turnover compared to patients with high turnover [18 (58%) vs. 29 (37%), P = 0.05]. Thirty-seven fragility fractures in 23 (21%) transplant recipients corresponding to fracture incidence 15 per 1000 person-years occurred during a median follow-up 9.1 (IQR, 6.3–12.1) years. Trabecular bone volume did not correlate with incident fractures. Accordingly, low bone mineral density at the lumbar spine correlated with low trabecular bone volume, but not with incident fractures. The cumulative corticosteroid dose was an important determinant of low bone volume, but not of incident fractures.

Conclusions

Despite the high prevalence of trabecular bone loss among kidney transplant recipients, the number of fractures was limited. The lack of association between trabecular bone volume and fractures suggests that the bone cortical compartment and quality are important determinants of bone strength and post-transplantation fracture.

Clinical Prediction of High-Turnover Bone Disease After Kidney Transplantation

Bone histomorphometric analysis is the most accurate method for the evaluation of bone turnover, but non-invasive tools are also required. We studied whether bone biomarkers can predict high bone turnover determined by bone histomorphometry after kidney transplantation. We retrospectively evaluated the results of bone biopsy specimens obtained from kidney transplant recipients due to the clinical suspicion of high bone turnover between 2000 and 2015. Bone biomarkers were acquired concurrently. Of 813 kidney transplant recipients, 154 (19%) biopsies were taken at a median of 28 (interquartile range, 18-70) months after engraftment. Of 114 patients included in the statistical analysis, 80 (70%) presented with high bone turnover. Normal or low bone turnover was detected in 34 patients (30%). For discriminating high bone turnover from non-high, alkaline phosphatase, parathyroid hormone, and ionized calcium had the areas under the receiver operating characteristic curve (AUCs) of 0.704, 0.661, and 0.619, respectively. The combination of these markers performed better with an AUC of 0.775. The positive predictive value for high turnover at a predicted probability cutoff of 90% was 95% while the negative predictive value was 35%. This study concurs with previous observations that hyperparathyroidism with or without hypercalcemia does not necessarily imply high bone turnover in kidney transplant recipients. The prediction of high bone turnover can be improved by considering alkaline phosphatase levels, as presented in the logistic regression model. If bone biopsy is not readily available, this model may serve as clinically available tool in recognizing high turnover after engraftment.

Incidence of sexually transmitted INFECTIONS is lower among kidney transplant recipients compared to the general population- a nationwide cohort study

AIM

The burden of sexually transmitted infections (STI) among solid-organ transplant recipients is currently unknown. We studied the risk of STIs among kidney transplant recipients compared with the general population in a nationwide cohort.

METHODS

Between 2002 and 2019, all microbiological findings of Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum (syphilis), and human immunodeficiency virus among kidney transplant recipients <65 years and transplanted between 1995 and 2017 in our country were captured from statutory national registries. Data from the general population of Finland, population 5.5 million, were used for comparisons. Incidence of STIs and age and sex-adjusted standardized incidence ratios (SIR) were calculated.

RESULTS

Altogether 3612 transplantations, with a total follow-up of 27 069 person-years were included. A total of 30 STIs microbiological findings of STI were confirmed in 25 patients: C. trachomatis (N = 27), N. gonorrhoeae (N = 2), and syphilis (N = 1). No hospitalizations associated with STIs were detected. The risk of STI after kidney transplantation was significantly lower compared to the general population (SIR, 0.57, 95% CI 0.39-0.80). The lower risk of STIs was more pronounced in female patients (SIR 0.40, 95% CI 0.20-0.74), whereas in male patients the difference was statistically not significant (SIR 0.69, 95% CI 0.44-1.04)). Of the confirmed STI cases, 30% were detected in patients who received their transplants during adolescence.

CONCLUSIONS

Within the Finnish kidney transplant population, the age and sex-adjusted incidence of sexually transmitted infections is not higher compared to the general population. Highest frequency of infections was seen among patients transplanted during adolescence. This article is protected by copyright. All rights reserved.

The ERA Registry Annual Report 2019: summary and age comparisons

Background

Data on renal replacement therapy (RRT) for end-stage renal disease were collected by the European Renal Association (ERA) Registry via national and regional renal registries in Europe and countries bordering the Mediterranean Sea. This article provides a summary of the 2019 ERA Registry Annual Report, including data from 34 countries and additional age comparisons.

Methods

Individual patient data for 2019 were provided by 35 registries and aggregated data by 17 registries. Using these data, the incidence and prevalence of RRT, the kidney transplantation activity and the survival probabilities were calculated.

Results

In 2019, a general population of 680.8 million people was covered by the ERA Registry. Overall, the incidence of RRT was 132 per million population (p.m.p.). Of these patients, 62% were men, 54% were ≥65 years of age and 21% had diabetes mellitus as primary renal disease (PRD), and 84% had haemodialysis (HD), 11% had peritoneal dialysis (PD) and 5% had pre-emptive kidney transplantation as an initial treatment modality. The overall prevalence of RRT on 31 December 2019 was 893 p.m.p., with 58% of patients on HD, 5% on PD and 37% living with a kidney transplant. The overall kidney transplant rate was 35 p.m.p. and 29% of the kidney grafts were from a living donor. The unadjusted 5-year survival probability was 42.3% for patients commencing dialysis, 86.6% for recipients of deceased donor grafts and 94.4% for recipients of living donor grafts in the period 2010–14. When comparing age categories, there were substantial differences in the distribution of PRD, treatment modality and kidney donor type, and in the survival probabilities.

Incidence of Kidney Replacement Therapy and Subsequent Outcomes Among Patients With Systemic Lupus Erythematosus: Findings From the ERA Registry

RATIONALE AND OBJECTIVE

There is a dearth of data characterizing patients requiring kidney replacement therapy (KRT) for kidney failure due to systemic lupus erythematosus (SLE) and their clinical outcomes. The aim of this study was to describe trends in incidence and prevalence of KRT among these patients as well as to compare their outcomes to patients treated with KRT for diseases other than SLE.

STUDY DESIGN

Retrospective cohort study based on kidney registry data.

SETTING & PARTICIPANTS

Patients recorded in 14 registries of patients receiving kidney replacement therapy that provided data to the European Renal Association (ERA) Registry between 1992 and 2016.

PREDICTOR

SLE as cause of kidney failure.

OUTCOMES

Incidence and prevalence of KRT, patient survival while receiving KRT, patient and graft survival after kidney transplantation, and specific causes of death.

ANALYTICAL APPROACH

Kaplan-Meier methods and Cox regression models were fit to compare patient survival between the SLE and non-SLE groups, overall KRT, dialysis and patient and graft survival after kidney transplantation.

RESULTS

In total, 1826 patients commenced KRT for kidney failure due to SLE, representing an incidence of 0.80 per million population (pmp) per year. The incidence remained stable during the study period (annual percent change=0.1 [95%CI: -0.6 ; 0.8]). Patient survival among patients with SLE receiving KRT was similar to survival within the comparator group (HR=1.11 [95%CI: 0.99-1.23]). After kidney transplantation, the risk of death was greater among patients with SLE than among patients within the comparator group (HR=1.25 [95%CI: 1.02-1.53]), while the risk of all-cause graft failure was similar (HR=1.09 [95%CI: 0.95-1.27]). Ten-year patient overall survival on KRT, and patient and graft survival after kidney transplantation improved over the study period (HR=0.71 [95%CI: 0.56-0.91], 0.43 [0.27-0.69] and 0.60 [0.43-0.84], respectively). Patients with SLE receiving KRT were significantly more likely to die from infections (24.8%) than patients in the comparator group (16.9%, p<0.001).

LIMITATIONS

No data were available on extrarenal manifestations of SLE, drug treatments, comorbidities, kidney transplant characteristics, or relapses of SLE.

CONCLUSION

The prognosis of patients with SLE receiving KRT has improved over time. Survival of patients with SLE requiring KRT was similar when compared to patients requiring KRT due to other causes of kidney failure. Survival following kidney transplantation was worse among patients with SLE.

Primary kidney disease modifies the effect of comorbidities on kidney replacement therapy patients' survival

Background

Comorbidities are associated with increased mortality among patients receiving long-term kidney replacement therapy (KRT). However, it is not known whether primary kidney disease modifies the effect of comorbidities on KRT patients’ survival.

Methods

An incident cohort of all patients (n = 8696) entering chronic KRT in Finland in 2000–2017 was followed until death or end of 2017. All data were obtained from the Finnish Registry for Kidney Diseases. Information on comorbidities (coronary artery disease, peripheral vascular disease, left ventricular hypertrophy, heart failure, cerebrovascular disease, malignancy, obesity, underweight, and hypertension) was collected at the start of KRT. The main outcome measure was relative risk of death according to comorbidities analyzed in six groups of primary kidney disease: type 2 diabetes, type 1 diabetes, glomerulonephritis (GN), polycystic kidney disease (PKD), nephrosclerosis, and other or unknown diagnoses. Kaplan-Meier estimates and Cox regression were used for survival analyses.

Results

In the multivariable model, heart failure increased the risk of death threefold among PKD and GN patients, whereas in patients with other kidney diagnoses the increased risk was less than twofold. Obesity was associated with worse survival only among GN patients. Presence of three or more comorbidities increased the age- and sex-adjusted relative risk of death 4.5-fold in GN and PKD patients, but the increase was only 2.5-fold in patients in other diagnosis groups.

Conclusions

Primary kidney disease should be considered when assessing the effect of comorbidities on survival of KRT patients as it varies significantly according to type of primary kidney disease.

Similar survival on home hemodialysis and automated peritoneal dialysis: an inception cohort study

BACKGROUND

Several studies have shown superior survival of patients on home hemodialysis (HD) compared to peritoneal dialysis (PD), but patients on automated PD (APD) and continuous ambulatory PD (CAPD) have not been considered separately. As APD allows larger fluid volumes and may be more efficient than CAPD, we primarily compared patient survival between APD and home HD.

METHODS

All adult patients who started kidney replacement therapy (KRT) between 2004 and 2017 in the district of Helsinki-Uusimaa in Finland, and who were on one of the home dialysis modalities at 90 days from starting KRT, were included. We used intention-to-treat analysis.Survival of home HD, APD and CAPD patients was studied using Kaplan-Meier curves and Cox regression with adjustment for propensity scores that were based on extensive data on possible confounding factors.

RESULTS

The probability of surviving 5 years was 90% for home HD, 88% for APD and 56% for CAPD patients. After adjustment for propensity score, the hazard ratio of death was 1.1 [95% CI 0.52-2.4] for APD and 1.6 [95% CI 0.74-3.6] for CAPD in comparison to home HD. Censoring at the time of kidney transplantation or at transfer to in-center hemodialysis did not change the results. Characteristics of home HD and APD patients at the start of dialysis were similar, whereas patients on CAPD had higher median age and more comorbidities, and received kidney transplantation less frequently.

CONCLUSIONS

Home HD and APD patients had comparable characteristics and their survival appeared similar.

Epidemiology of laboratory-confirmed influenza among kidney transplant recipients compared to the general population-A nationwide cohort study

Seasonal influenza causes morbidity and mortality after organ transplantation. We quantified the detection of laboratory-confirmed influenza among kidney transplant recipients compared to the general population in a nationwide cohort. All laboratory-confirmed cases of influenza and hospitalizations due to influenza among all kidney transplant recipients in our country between 1995 and 2017 were captured with database linkage from statutory national registries. Data from the general population of Finland, population 5.5 million, were used for comparisons. Annual incidences of influenza and hospitalizations due to influenza, and standardized incidence ratios (SIR) were calculated. Altogether 3904 kidney transplant recipients with a total follow-up of 37 175 patient-years were included. Incidence of laboratory-confirmed influenza was 9.0 per 1000 patient years in 2003-2019, and 18.0 per 1000 patient years during 2015-2019. The risk of laboratory-confirmed influenza was significantly higher among kidney transplant recipients compared to the general population (SIR 5.1, 95% CI 4.5-5.7). SIR for hospitalization due to influenza was 4.4 (95% CI 3.4-4.7). Mortality of the hospitalized patients was 9%, and 5% of the patients with laboratory-confirmed influenza. Detection of laboratory-confirmed influenza is increased fivefold and risk of hospitalization due to influenza more than fourfold among kidney transplant recipients compared to the general population.

Effect of comorbidities on survival in patients >80 years of age at onset of renal replacement therapy: data from the ERA-EDTA Registry

BACKGROUND

The number of elderly patients on renal replacement therapy (RRT) is increasing. The survival and quality of life of these patients may be lower if they have multiple comorbidities at the onset of RRT. The aim of this study was to explore whether the effect of comorbidities on survival is similar in elderly RRT patients compared with younger ones.

METHODS

Included were 9333 patients ≥80 years of age and 48 352 patients 20-79 years of age starting RRT between 2010 and 2015 from 15 national or regional registries submitting data to the European Renal Association-European Dialysis and Transplantation Association Registry. Patients were followed until death or the end of 2016. Survival was assessed by Kaplan-Meier curves and the relative risk of death associated with comorbidities was assessed by Cox regression analysis.

RESULTS

Patients ≥80 years of age had a greater comorbidity burden than younger patients. However, relative risks of death associated with all studied comorbidities (diabetes, ischaemic heart disease, chronic heart failure, cerebrovascular disease, peripheral vascular disease and malignancy) were significantly lower in elderly patients compared with younger patients. Also, the increase in absolute mortality rates associated with an increasing number of comorbidities was smaller in elderly patients.

CONCLUSIONS

Comorbidities are common in elderly patients who enter RRT, but the risk of death associated with comorbidities is less than in younger patients. This should be taken into account when assessing the prognosis of elderly RRT patients.

A roadmap for optimizing chronic kidney disease patient care and patient-oriented research in the Eastern European nephrology community

Chronic kidney disease (CKD) is a major health problem because of its high prevalence, associated complications and high treatment costs. Several aspects of CKD differ significantly in the Eastern European nephrology community compared with Western Europe because of different geographic, socio-economic, infrastructure, cultural and educational features. The two most frequent aetiologies of CKD, DM and hypertension, and many other predisposing factors, are more frequent in the Eastern region, resulting in more prevalent CKD Stages 3-5. Interventions may minimize the potential drawbacks of the high prevalence of CKD in Eastern Europe, which include several options at various stages of the disease, such as raising public, medical personnel and healthcare authorities awareness; early detection by screening high-risk populations; preventing progression and CKD-related complications by training health professionals and patients; promoting transplantation or home dialysis as the preferred modality; disseminating and implementing guidelines and guided therapy and encouraging/supporting country-specific observational research as well as international collaborative projects. Specific ways to significantly impact CKD-related problems in every region of Europe through education, science and networking are collaboration with non-nephrology European societies who have a common interest in CKD and its associated complications, representation through an advisory role within nephrology via national nephrology societies, contributing to the training of local nephrologists and stimulating patient-oriented research. The latter is mandatory to identify country-specific kidney disease-related priorities. Active involvement of patients in this research via collaboration with the European Kidney Patient Federation or national patient federations is imperative to ensure that projects reflect specific patient needs.

The ERA-EDTA Registry Annual Report 2018: a summary

Background

The European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) Registry collects data on kidney replacement therapy (KRT) via national and regional renal registries in Europe and countries bordering the Mediterranean Sea. This article summarizes the 2018 ERA-EDTA Registry Annual Report, and describes the epidemiology of KRT for kidney failure in 34 countries.

Methods

Individual patient data on patients undergoing KRT in 2018 were provided by 34 national or regional renal registries and aggregated data by 17 registries. The incidence and prevalence of KRT, the kidney transplantation activity and the survival probabilities of these patients were calculated.

Results

In 2018, the ERA-EDTA Registry covered a general population of 636 million people. Overall, the incidence of KRT for kidney failure was 129 per million population (p.m.p.), 62% of patients were men, 51% were ≥65 years of age and 20% had diabetes mellitus as cause of kidney failure. Treatment modality at the onset of KRT was haemodialysis (HD) for 84%, peritoneal dialysis (PD) for 11% and pre-emptive kidney transplantation for 5% of patients. On 31 December 2018, the prevalence of KRT was 897 p.m.p., with 57% of patients on HD, 5% on PD and 38% living with a kidney transplant. The transplant rate in 2018 was 35 p.m.p.: 68% received a kidney from a deceased donor, 30% from a living donor and for 2% the donor source was unknown. For patients commencing dialysis during 2009-13, the unadjusted 5-year survival probability was 42.6%. For patients receiving a kidney transplant within this period, the unadjusted 5-year survival probability was 86.6% for recipients of deceased donor grafts and 93.9% for recipients of living donor grafts.

Young deceased donor kidneys show a survival benefit over older donor kidneys in transplant recipients aged 20-50 years: a study by the ERA-EDTA Registry

BACKGROUND

Updated survival outcomes of young recipients receiving young or old deceased donor kidneys are required when considering accepting a deceased donor kidney.

METHODS

We examined outcomes in 6448 European kidney allografts donated from younger (≥20-<50 years) and older (≥50-<70 years) deceased donors when transplanted into very young (≥20-<35 years) or young (≥35-<50 years) adult recipients. Outcomes of first kidney transplantations during 2000-13 and followed-up to 2015 were determined via competing risk, restricted mean survival and Cox regression methods.

RESULTS

The 10-year cumulative incidence of graft failure was lowest in very young {22.0% [95% confidence interval (95% CI) 19.1-24.9]} and young [15.3% (95% CI 13.7-16.9)] recipients of younger donor kidneys and highest in very young [36.7% (95% CI 31.9-41.5)] and young [29.2% (95% CI 25.1-33.2)] recipients of older donor kidneys. At the 10-year follow-up, younger donor kidneys had a 1 year (very young) or 9 months (young) longer mean graft survival time compared with older donor kidneys. Graft failure risk in younger donor kidneys was 45% [very young adjusted hazard ratio (aHR) 0.55 (95% CI 0.44-0.68)] and 40% [young aHR 0.60 (95% CI 0.53-0.67)] lower compared with older donor kidneys. A 1-year increase in donor age resulted in a 2% [very young aHR 1.02 (95% CI 1.00-1.04)] or 1% [young aHR 1.01 (95% CI 1.00-1.01)] increase in the 10-year risk of death.

CONCLUSIONS

Younger donor kidneys show survival benefits over older donor kidneys in adult recipients ages 20-50 years. Updated survival outcomes from older deceased donors are necessary due to advances in transplantation medicine and the increasing role these donors play in organ transplantation.

Donor Age, Cold Ischemia Time, and Delayed Graft Function

BACKGROUND AND OBJECTIVES

Increased donor age is one of the most important risk factors for delayed graft function (DGF), and previous studies suggest that the harmful effect of cold ischemia time is increased in kidneys from older donors. Our aim was to study the association of increased donor age and cold ischemia time with the risk of delayed graft function in a large cohort kidney transplants from the current era.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Scientific Registry of Transplant Recipients was used for this observational, retrospective registry analysis to identify all deceased donor kidney transplantations in the United States between 2010 and September 2018, who were on dialysis pretransplantation (n=90,810). The association of donor age and cold ischemia time with the risk of DGF was analyzed in multivariable models adjusted for recipient characteristics (age, race, sex, diabetes, calculated panel-reactive antibodies, pretransplant dialysis duration) and donor characteristics (cause of death, sex, race, body mass index, creatinine, donation after circulatory death status, history of hypertension, and HLA mismatch).

RESULTS

Cold ischemia time and donor age were independently associated with the risk of DGF, but the risk of DGF was not statistically significantly lower in donor age categories between 50 and 64 years, compared with donors ≥65 years. The harmful association of cold ischemia time was not higher in kidneys from older donors in any age category, not even among donation after circulatory death donors. When donor risk was assessed with kidney donor profile index, although a statistically significant interaction with cold ischemia time was found, no practically meaningful increase in cold-ischemia susceptibility of kidneys with a high kidney donor profile index was found.

CONCLUSIONS

We were unable to demonstrate an association between donor age and DGF. The association of longer cold ischemia time with the risk of DGF was not magnified in older or more marginal donors.

P1452PATIENT SURVIVAL ON HOME DIALYSIS MODALITIES

Background and Aims

Many studies have compared survival of patients on peritoneal dialysis and hemodialysis, but knowledge on survival differences between various types of home dialysis is limited. Therefore, our study aimed to assess the associated survival in CAPD, APD and home HD.

Method

During 2004 to 2017, 1640 patients aged 18 years or older started RRT in Helsinki University Hospital. Patients who were on one of the home dialysis modalities at 90 days (n=536), have been studied. The follow up endpoint was either death or the end of 2019. A research database was established and extensive data were systematically collected from the patient files, comprising 35 different comorbidities, laboratory results, primary renal disease, and renal replacement therapy-related factors. Study design was intention-to-treat, and patients were analyzed in the home dialysis modality group they were at 90 days after onset of RRT. Patient survival was compared between patients on CAPD, APD, and home HD using Kaplan-Meier curves and Cox regression.

Results

Characteristics of home HD and APD patients at the start of dialysis and proportion of patients who received a kidney transplant during follow-up were similar (Table), whereas patients on CAPD had higher median age, more comorbidities, and received a kidney transplant less frequently. The probability of surviving 5 years was 56% for CAPD, 88% for APD, and 90% for home HD patients (Figure). Relative risk of death associated with APD was 0.96 (95% CI 0.60–1.5), and that of CAPD was 3.7 (2.4–5.7) as compared to home HD. After adjustment for age and number of comorbidities, the relative risks were 0.82 (0.39–1.7) and 2.5 (1.2–5.0), respectively. Additional adjustments for other possible confounding factors listed in the Table did not change the results. Censoring for kidney transplantation did not alter the conclusion.

Conclusion

APD and home HD patients had similar characteristics and comparable survival. CAPD patients were older, had more often comorbid conditions, and their prognosis was worse even after adjustment for confounders.

Changes in clinical indicators related to the transition from dialysis to kidney transplantation-data from the ERA-EDTA Registry

Background

Kidney transplantation should improve abnormalities that are common during dialysis treatment, like anaemia and mineral and bone disorder. However, its impact is incompletely understood. We therefore aimed to assess changes in clinical indicators after the transition from chronic dialysis to kidney transplantation.

Methods

We used European Renal Association–European Dialysis and Transplant Association Registry data and included adult dialysis patients for whom data on clinical indicators before and after transplantation (2005–15) were available. Linear mixed models were used to quantify the effect of transplantation and of time after transplantation for each indicator.

Results

In total, 16 312 patients were included. The mean age at transplantation was 50.1 (standard deviation 14.2) years, 62.9% were male and 70.2% were on haemodialysis before transplantation. Total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol and triglycerides increased right after transplantation but decreased thereafter. All other indicators normalized or approached the target range soon after transplantation and these improvements were sustained for the first 4 years of follow-up. In patients with higher estimated glomerular filtration rate (eGFR) levels (30–60 and >60 mL/min/1.73 m²), the improvement of haemoglobin, ferritin, ionized calcium, phosphate, parathyroid hormone, HDL cholesterol, triglycerides, albumin and C-reactive protein levels was more pronounced than in patients with a lower eGFR (<30 mL/min/1.73 m²).

Conclusions

Except for total cholesterol, LDL cholesterol and triglycerides, all clinical indicators improved after transplantation. These improvements were related to eGFR. Nevertheless, values remained out of range in a considerable proportion of patients and anaemia and hyperparathyroidism were still common problems. Further research is needed to understand the complex relationship between eGFR and the different clinical indicators.

Nephrology and Public Policy Committee propositions to stimulate research collaboration in adults and children in Europe

The strengths and the limitations of research activities currently present in Europe are explored in order to outline how to proceed in the near future. Epidemiological and clinical research and public policy in Europe are generally considered to be comprehensive and successful, and the European Renal Association – European Dialysis and Transplant Association (ERA-EDTA) is playing a key role in the field of nephrology research. The Nephrology and Public Policy Committee (NPPC) aims to improve the current situation and translation into public policy by planning eight research topics to be supported in the coming 5 years by ERA-EDTA.

Sex Differences in Kidney Replacement Therapy Initiation and Maintenance

BACKGROUND AND OBJECTIVES

More men than women undergo kidney replacement therapy (KRT) despite a larger number of women being affected by CKD. The aim of this multinational European study was to explore whether there might be historic and geographic trends in sex-specific incidence and prevalence of various KRT modalities.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We assessed sex-specific differences in KRT incidence and prevalence using data from nine countries reporting to the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry for at least 40 years, during the period 1965-2015. Sex distribution data were compared with the European general population (Eurostat). Statistical methodology included basic descriptive statistics, incidence and prevalence calculations per million population (pmp), as well as their male-to-female ratios. Analyses were stratified by age group and diabetic status.

RESULTS

We analyzed data from 230,378 patients receiving KRT (38% women). For all KRT modalities, the incidence and prevalence rates were consistently higher in men than women. For example, the KRT incidence increased from 8 pmp in 1965-1974 to 98 pmp in 2005-2015 in women, whereas it rose from 12 to 173 pmp in men during the same period. Male-to-female ratios, calculated for incident and prevalent KRT patients, increased with age (range 1.2-2.4), showing consistency over decades and for individual countries, despite marked changes in primary kidney disease (diabetes more prevalent than glomerulonephritis in recent decades). The proportion of kidney transplants decreased less with age in incident and prevalent men compared with women on KRT. Stratified analysis of patients who were diabetic versus nondiabetic revealed that the male-to-female ratio was markedly higher for kidney transplantation in patients with diabetes.

CONCLUSIONS

Since the beginning of KRT programs reporting to the ERA-EDTA Registry since the 1960s, fewer women than men have received KRT. The relative difference between men and women initiating and undergoing KRT has remained consistent over the last five decades and in all studied countries.

Changes in co-morbidity pattern in patients starting renal replacement therapy in Europe-data from the ERA-EDTA Registry

Background

Patients starting renal replacement therapy (RRT) for end-stage renal disease often present with one or more co-morbidities. This study explored the prevalence of co-morbidities in patients who started RRT in Europe during the period from 2005 to 2014.

Methods

Using data from patients aged 20 years or older from all 11 national or regional registries providing co-morbidity data to the European Renal Association - European Dialysis and Transplant Association Registry, we examined the prevalence of the following co-morbidities: diabetes mellitus (DM) (primary renal disease and/or co-morbidity), ischaemic heart disease (IHD), congestive heart failure (CHF), peripheral vascular disease (PVD), cerebrovascular disease (CVD) and malignancy.

Results

Overall, 70% of 7578 patients who initiated RRT in 2014 presented with at least one co-morbidity: 39.0% presented with DM, 25.0% with IHD, 22.3% with CHF, 17.7% with PVD, 16.4% with malignancy and 15.5% with CVD. These percentages differed substantially between countries. Co-morbidities were more common in men than in women, in older patients than in younger patients, and in patients on haemodialysis at Day 91 when compared with patients on peritoneal dialysis. Between 2005 and 2014 the prevalence of DM and malignancy increased over time, whereas the prevalence of IHD and PVD declined.

Conclusions

More than two-thirds of patients initiating RRT in Europe have at least one co-morbidity. With the rising age at the start of RRT over the last decade, there have been changes in the co-morbidity pattern: the prevalence of cardiovascular co-morbidities decreased, while the prevalence of DM and malignancy increased.

Outpatient Kidney Biopsy: A Single Center Experience and Review of Literature

BACKGROUND

A kidney biopsy is an important tool in managing kidney diseases. Bleeding is the most significant complication. The biopsy can be performed as an inpatient or an outpatient procedure with a shorter post-biopsy bed rest and monitoring period. It is cost-effective, but raises some questions about patient safety. At Helsinki University Hospital, the majority of elective kidney biopsies have been performed as outpatient procedures since 2010. The aim of this study was to retrospectively evaluate the safety and risk factors of this protocol.

METHODS

We collected data from all patients undergoing an elective outpatient biopsy of a native or transplanted kidney following the outpatient protocol between January 2011 and February 2016. We recorded the data on the biopsy procedure and complications: bleeding (hematoma or macrohematuria), severe pain, death, or "other" (infection, accidental puncture of another organ). A complication was classified as major, if it required interventions such as transfusion or radiological or surgical intervention.

RESULTS

Over a 5-year period, 824 (448 native and 326 transplant kidney) patients were biopsied. In total, 94 (11.4%) had a complication, but only 4 patients (0.5%) had a major complication; no deaths were recorded. All major and 70 minor complications emerged during post-biopsy monitoring (4-6 h). Patients with complications were younger (p = 0.001), female (p < 0.001), and had lower hemoglobin (p = 0.001) than those without. Transplant biopsies were associated with fewer complications than native kidney biopsies (p= 0.002).

CONCLUSIONS

In selected patients, an outpatient kidney biopsy is a relatively safe procedure.

Changes in Bone Histomorphometry after Kidney Transplantation

BACKGROUND AND OBJECTIVES

Over the past decade, the management of CKD-mineral and bone disorder has changed substantially, altering the pattern of bone disease in CKD. We aimed to evaluate the natural history of kidney bone disease in contemporary kidney transplant recipients and patients on dialysis.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

Sixty one patients on dialysis who were referred to kidney transplantation participated in this prospective cohort study during November 2009 and December 2010. We performed baseline bone biopsies while the patients were on dialysis and repeated the procedure in 56 patients at 2 years after kidney transplantation or 2 years after baseline if transplantation was not performed. Measurements of mineral metabolism and bone turnover, as well as dual energy x-ray absorptiometry scans, were obtained concurrently.

RESULTS

A total of 37 out of 56 participants received a kidney transplant, of which 27 underwent successful repeat bone biopsy. The proportion of patients with high bone turnover declined from 63% at baseline to 19% at 2 years after kidney transplantation, whereas the proportion of those with low bone turnover increased from 26% to 52%. Of 19 participants remaining on dialysis after 2 years, 13 underwent successful repeat biopsy. The proportion of patients remaining on dialysis with high bone turnover decreased from 69% to 31%, and low bone turnover increased from 8% to 38%. Abnormal bone mineralization increased in transplant recipients from 33% to 44%, but decreased in patients remaining on dialysis from 46% to 15%. Trabecular bone volume showed little change after transplantation, but low bone volume increased in patients remaining on dialysis. Bone mineral density did not correlate with histomorphometric findings.

CONCLUSIONS

Bone turnover decreased over time both in patients remaining on dialysis and in kidney transplant recipients. Bone mineral density and bone biomarkers were not associated with bone metabolism changes detected in bone biopsy specimens.

International comparison of trends in patients commencing renal replacement therapy by primary renal disease

AIM

To examine international time trends in the incidence of renal replacement therapy (RRT) for end-stage renal disease (ESRD) by primary renal disease (PRD).

METHODS

Renal registries reporting on patients starting RRT per million population for ESRD by PRD from 2005 to 2014, were identified by internet search and literature review. The average annual percentage change (AAPC) with a 95% confidence interval (CI) of the time trends was computed using Joinpoint regression.

RESULTS

There was a significant decrease in the incidence of RRT for ESRD due to diabetes mellitus (DM) in Europe (AAPC = -0.9; 95%CI -1.3; -0.5) and to hypertension/renal vascular disease (HT/RVD) in Australia (AAPC = -1.8; 95%CI -3.3; -0.3), Canada (AAPC = -2.9; 95%CI -4.4; -1.5) and Europe (AAPC = -1.1; 95%CI -2.1; -0.0). A decrease or stabilization was observed for glomerulonephritis in all regions and for autosomal dominant polycystic kidney disease (ADPKD) in all regions except for Malaysia and the Republic of Korea. An increase of 5.2-16.3% was observed for DM, HT/RVD and ADPKD in Malaysia and the Republic of Korea.

CONCLUSION

Large international differences exist in the trends in incidence of RRT by primary renal disease. Mapping of these international trends is the first step in defining the causes and successful preventative measures of CKD.

Cumulative Risk of End-Stage Renal Disease Among Patients With Type 2 Diabetes: A Nationwide Inception Cohort Study

OBJECTIVE

To estimate long-term cumulative risk of end-stage renal disease (ESRD) after diagnosis of type 2 diabetes.

RESEARCH DESIGN AND METHODS

This nationwide population-based inception cohort study included 421,429 patients with type 2 diabetes diagnosed in 1990-2011; patients were followed until the end of 2013. Data linkage between several national health care registers in Finland, covering 100% of the population, enabled the inclusion of almost all inhabitants who started taking diabetes medication or were hospitalized for diabetes. Cumulative risk of ESRD and hazard ratios [HR] for ESRD and death were estimated according to age, sex, and time period of diabetes diagnosis.

RESULTS

Among 421,429 patients with type 2 diabetes, 1,516 developed ESRD and 150,524 died during 3,458,797 patient-years of follow-up. Cumulative risk of ESRD was 0.29% at 10 years and 0.74% at 20 years from diagnosis of diabetes. Risk was higher among men than among women (HR 1.93 [95% CI 1.72-2.16]), decreased with older age at diagnosis (HR 0.70 [95% CI 0.60-0.81] for age 60-69 vs. 40-49 years), and was lower for those diagnosed in 2000-2011 than in 1990-1994 (HR 0.72 [95% CI 0.63-0.81]). Patients diagnosed with diabetes in 2000-2011 had lower risk of death during follow-up than those diagnosed in 1990-1994 (HR 0.64 [95% CI 0.63-0.65]).

CONCLUSIONS

Cumulative risk of ESRD is minimal among patients with type 2 diabetes compared with their risk of death. Patients diagnosed with diabetes at an older age have a lower risk of ESRD due to higher competing mortality.

The European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report 2016: a summary

Background

This article summarizes the ERA-EDTA Registry’s 2016 Annual Report, by describing the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in 2016 within 36 countries.

Methods

In 2017 and 2018, the ERA-EDTA Registry received data on patients undergoing RRT for ESRD in 2016 from 52 national or regional renal registries. In all, 32 registries provided individual patient data and 20 provided aggregated data. The incidence and prevalence of RRT and the survival probabilities of these patients were determined.

Results

In 2016, the incidence of RRT for ESRD was 121 per million population (pmp), ranging from 29 pmp in Ukraine to 251 pmp in Greece. Almost two-thirds of patients were men, over half were aged ≥65 years and almost a quarter had diabetes mellitus as their primary renal diagnosis. Treatment modality at the start of RRT was haemodialysis for 84% of patients. On 31 December 2016, the prevalence of RRT was 823 pmp, ranging from 188 pmp in Ukraine to 1906 pmp in Portugal. In 2016, the transplant rate was 32 pmp, varying from 3 pmp in Ukraine to 94 pmp in the Spanish region of Catalonia. For patients commencing RRT during 2007–11, the 5-year unadjusted patient survival probability on all RRT modalities combined was 50.5%. For 2016, the incidence and prevalence of RRT were higher among men (187  and 1381 pmp) than women (101 and 827 pmp), and men had a higher rate of kidney transplantation (59 pmp) compared with women (33 pmp). For patients starting dialysis and for patients receiving a kidney transplant during 2007–11, the adjusted patient survival probabilities appeared to be higher for women than for men.

Implementation of a transition model to adult care may not be enough to improve results: National study of kidney transplant recipients

Adolescents with a kidney transplant (KT) require special attention during the transition of care. Few longitudinal studies have assessed the effect of transition models (TM) on patient outcomes. Between 1986 and 2013, 239 pediatric patients underwent KT in Finland, of whom 132 have been transferred to adult care. In 2005, a TM was developed following international recommendations. We compared patient (PS) and graft survival (GS) rates before and after the introduction of the TM. PS and GS at 10 years were similar before and after the implementation of the TM (PS 85% and 90% respectively, P = 0.626; GS 60% and 58%, respectively, P = 0.656). GS was lower in patients transplanted at age 10-18 than in patients transplanted at a younger age in the TM cohort (79% vs 95%, P < 0.001). During the first five years after transfer, 63% of patients had stable KT function, 13% had deteriorating function and 24% lost their KT. Altogether 32 out of 132 patients lost their kidney allograft within five years after transfer to adult care (13 before and 19 after TM implementation, P = 0.566). The implementation of this TM had no effect on PS or GS. Further measures to improve our TM are in progress.

Performance of an easy-to-use prediction model for renal patient survival: an external validation study using data from the ERA-EDTA Registry

Background

An easy-to-use prediction model for long-term renal patient survival based on only four predictors [age, primary renal disease, sex and therapy at 90 days after the start of renal replacement therapy (RRT)] has been developed in The Netherlands. To assess the usability of this model for use in Europe, we externally validated the model in 10 European countries.

Methods

Data from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry were used. Ten countries that reported individual patient data to the registry on patients starting RRT in the period 1995-2005 were included. Patients <16  years of age and/or with missing predictor variable data were excluded. The external validation of the prediction model was evaluated for the 10- (primary endpoint), 5- and 3-year survival predictions by assessing the calibration and discrimination outcomes.

Results

We used a data set of 136 304 patients from 10 countries. The calibration in the large and calibration plots for 10 deciles of predicted survival probabilities showed average differences of 1.5, 3.2 and 3.4% in observed versus predicted 10-, 5- and 3-year survival, with some small variation on the country level. The concordance index, indicating the discriminatory power of the model, was 0.71 in the complete ERA-EDTA Registry cohort and varied according to country level between 0.70 and 0.75.

Conclusions

A prediction model for long-term renal patient survival developed in a single country, based on only four easily available variables, has a comparably adequate performance in a wide range of other European countries.

Mortality due to bleeding, myocardial infarction and stroke in dialysis patients

Essentials Mortality due to bleeding vs. arterial thrombosis in dialysis patients is unknown. We compared death causes of 201 918 dialysis patients with the general population. Dialysis was associated with increased mortality risks of bleeding and arterial thrombosis. Clinicians should be aware of the increased bleeding and thrombosis risks.

SUMMARY

Background Dialysis has been associated with both bleeding and thrombotic events. However, there is limited information on bleeding as a cause of death versus arterial thrombosis as a cause of death. Objectives To investigate the occurrence of bleeding, myocardial infarction and stroke as causes of death in the dialysis population as compared with the general population. Methods We included 201 918 patients from 11 countries providing data to the ERA-EDTA Registry who started dialysis treatment between 1994 and 2011, and followed them for 3 years. Age-standardized and sex-standardized mortality rate ratios for bleeding, myocardial infarction and stroke as causes of death were calculated in dialysis patients as compared with the European general population. Associations between potential risk factors and these causes of death in dialysis patients were investigated by calculating hazard ratios (HRs) with 95% confidence intervals (CIs) by the use of Cox proportional-hazards regression. Results As compared with the general population, the age-standardized and sex-standardized mortality rate ratios in dialysis patients were 12.8 (95% CI 11.9-13.7) for bleeding as a cause of death (6.2 per 1000 person-years among dialysis patients versus 0.3 per 1000 person-years in the general population), 13.4 (95% CI 13.0-13.9) for myocardial infarction (22.5 versus 0.9 per 1000 person-years), and 12.4 (95% CI 11.9-12.9) for stroke (14.3 versus 0.7 per 1000 person-years). Conclusion Dialysis patients have highly increased risks of death caused by bleeding and arterial thrombosis as compared with the general population. Clinicians should be aware of the increased mortality risks caused by these conditions.

Type 2 diabetic patients on renal replacement therapy: Probability to receive renal transplantation and survival after transplantation

Background

Type 2 diabetic (T2DM) patients on renal replacement therapy (RRT) seldom receive a kidney transplant, which is partly due to age and comorbidities. Adjusting for case mix, we investigated whether T2DM patients have equal opportunity for renal transplantation compared to other patients on dialysis, and whether survival after transplantation is comparable.

Methods

Patients who entered RRT in Finland in 2000–2010 (n = 5419) were identified from the Finnish Registry for Kidney Diseases and followed until the end of 2012. Of these, 20% had T2DM, 14% type 1 diabetes (T1DM) and 66% other than diabetes as the cause of ESRD. Uni-/multivariate survival analysis techniques were employed to assess the probability of kidney transplantation after the start of dialysis and survival after transplantation.

Results

T2DM patients had a relative probability of renal transplantation of 0.18 (95% CI 0.15–0.22, P<0.001) compared to T1DM patients: this increased to 0.51 (95% CI 0.36–0.72, P<0.001) after adjustment for case mix (age, gender, laboratory values and comorbidities). When T2DM patients were compared to non-diabetic patients, the corresponding relative probabilities were 0.25 (95% CI 0.20–0.30, P<0.001) and 0.59 (95% CI 0.43–0.83, P = 0.002). After renal transplantation when adjusted for age and gender, relative risk of death was 1.25 (95% CI 0.64–2.44, P = 0.518) for T1DM patients and 0.72 (0.43–1.22, P = 0.227) for other patients compared to T2DM patients.

Conclusions

T2DM patients had a considerably lower probability of receiving a kidney transplant, which could not be fully explained by differences in the patient characteristics. Survival within 5 years after transplantation is comparably good in T2DM patients.

Characteristics and Outcomes of Patients With Systemic Sclerosis (Scleroderma) Requiring Renal Replacement Therapy in Europe: Results From the ERA-EDTA Registry

RATIONALE & OBJECTIVE

Data for outcomes of patients with end-stage renal disease (ESRD) secondary to systemic sclerosis (scleroderma) requiring renal replacement therapy (RRT) are limited. We examined the incidence and prevalence of ESRD due to scleroderma in Europe and the outcomes among these patients following initiation of RRT.

STUDY DESIGN

Registry study of incidence and prevalence and a matched cohort study of clinical outcomes.

SETTING & PARTICIPANTS

Patients represented in any of 19 renal registries that provided data to the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry between 2002 and 2013.

PREDICTOR

Scleroderma as the identified cause of ESRD.

OUTCOMES

Incidence and prevalence of ESRD from scleroderma. Recovery from RRT dependence, patient survival after ESRD, and graft survival after kidney transplantation.

ANALYTICAL APPROACH

Incidence and prevalence were calculated using population data from the European Union and standardized to population characteristics in 2005. Patient and graft survival were compared with 2 age- and sex-matched control groups without scleroderma: (1) diabetes mellitus as the cause of ESRD and (2) conditions other than diabetes mellitus as the cause of ESRD. Survival analyses were performed using Kaplan-Meier analysis and Cox regression.

RESULTS

342 patients with scleroderma (0.14% of all incident RRT patients) were included. Between 2002 and 2013, the range of adjusted annual incidence and prevalence rates of RRT for ESRD due to scleroderma were 0.11 to 0.26 and 0.73 to 0.95 per million population, respectively. Recovery of independent kidney function was greatest in the scleroderma group (7.6% vs 0.7% in diabetes mellitus and 2.0% in other primary kidney diseases control group patients, both P<0.001), though time required to achieve recovery was longer. The 5-year survival probability from day 91 of RRT among patients with scleroderma was 38.9% (95% CI, 32.0%-45.8%), whereas 5-year posttransplantation patient survival and 5-year allograft survival were 88.2% (95% CI, 75.3%-94.6%) and 72.4% (95% CI, 55.0%-84.0%), respectively. Adjusted mortality from day 91 on RRT was higher among patients with scleroderma than observed in both control groups (HRs of 1.25 [95% CI, 1.05-1.48] and 2.00 [95% CI, 1.69-2.39]). In contrast, patient and graft survival after kidney transplantation did not differ between patients with scleroderma and control groups.

LIMITATIONS

No data for extrarenal manifestations, treatment, or recurrence.

CONCLUSIONS

Survival of patients with scleroderma who receive dialysis for more than 90 days was worse than for those with other causes of ESRD. Patient survival after transplantation was similar to that observed among patients with ESRD due to other conditions. Patients with scleroderma had a higher rate of recovery from RRT dependence than controls.

Secular Trends in Infection-Related Mortality after Kidney Transplantation

BACKGROUND AND OBJECTIVES

Infections are the most common noncardiovascular causes of death after kidney transplantation. We analyzed the current infection-related mortality among kidney transplant recipients in a nationwide cohort in Finland.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Altogether, 3249 adult recipients of a first kidney transplant from 1990 to 2012 were included. Infectious causes of death were analyzed, and the mortality rates for infections were compared between two eras (1990-1999 and 2000-2012). Risk factors for infectious deaths were analyzed with Cox regression and competing risk analyses.

RESULTS

Altogether, 953 patients (29%) died during the follow-up, with 204 infection-related deaths. Mortality rate (per 1000 patient-years) due to infections was lower in the more recent cohort (4.6; 95% confidence interval, 3.5 to 6.1) compared with the older cohort (9.1; 95% confidence interval, 7.6 to 10.7); the incidence rate ratio of infectious mortality was 0.51 (95% confidence interval, 0.30 to 0.68). The main causes of infectious deaths were common bacterial infections: septicemia in 38% and pulmonary infections in 45%. Viral and fungal infections caused only 2% and 3% of infectious deaths, respectively (such as individual patients with Cytomegalovirus pneumonia, Herpes simplex virus meningoencephalitis, Varicella zoster virus encephalitis, and Pneumocystis jirovecii infection). Similarly, opportunistic bacterial infections rarely caused death; only one death was caused by Listeria monocytogenes, and two were caused by Mycobacterium tuberculosis. Only 23 (11%) of infection-related deaths occurred during the first post-transplant year. Older recipient age, higher plasma creatinine concentration at the end of the first post-transplant year, diabetes as a cause of ESKD, longer pretransplant dialysis duration, acute rejection, low albumin level, and earlier era of transplantation were associated with increased risk of infectious death in multivariable analysis.

CONCLUSIONS

The risk of death due to infectious causes after kidney transplantation in Finland dropped by one half since the 1990s. Common bacterial infections remained the most frequent cause of infection-related mortality, whereas opportunistic viral, fungal, or unconventional bacterial infections rarely caused deaths after kidney transplantation.

Incidence of End-Stage Renal Disease in Patients With Type 1 Diabetes

OBJECTIVE

To investigate how risk of end-stage renal disease (ESRD) among patients with type 1 diabetes has changed over time and further how the risk is affected by age, sex, and time period of diagnosis of diabetes.

RESEARCH DESIGN AND METHODS

A cohort including all patients <30 years old diagnosed with type 1 diabetes in Finland in 1965-2011 was followed until start of renal replacement therapy, death, or end of follow-up at the end of 2013. Altogether, 29,906 patients were included. The main outcome was cumulative risk of ESRD, accounting for death as a competing risk.

RESULTS

The patients were followed up for a median of 20 years. During 616,403 patient-years, 1,543 ESRD cases and 4,185 deaths were recorded. The cumulative risk of ESRD was 2.2% after 20 years and 7.0% after 30 years from the diabetes diagnosis. The relative risk of ESRD was 0.13 (95% CI 0.08-0.22) among patients diagnosed in 1995-2011 compared with those diagnosed in 1965-1979. Patients <5 years old at the time of diagnosis had the lowest risk of ESRD after diagnosis. With the cumulative risk of ESRD estimated from time of birth, the patients aged 5-9 years at diabetes diagnosis were at highest risk.

CONCLUSIONS

The cumulative risk of ESRD has decreased markedly during the past five decades. This highlights the importance of modern treatment of diabetes and diabetic nephropathy.

Early failure of kidney transplants in the current era-a national cohort study

Although short-term outcome after kidney transplantation has improved, a small proportion of grafts are lost during the first year. We characterize in detail all early graft losses in the current era in a nationwide cohort of kidney transplant recipients. Altogether 2447 kidney transplantations, performed between June 2004 and October 2016, were included. All graft losses (return to dialysis or patient death) occurring during the first post-transplant year were characterized. During the first post-tranplant year, altogether 109 grafts were lost, 67 grafts failed, and 42 patients died. Fifty-five per cent of the deaths were due to cardiovascular causes, and 29% due to infectious causes. Twenty-one per cent of the failed grafts were primary nonfunction of unknown reason, 34% were lost due to venous thrombosis and 9% due to arterial thrombosis, but only 10 (15%) patients lost a graft due to acute cellular or humoral rejection. Independent risk factors for death included diabetes, and longer duration of pretransplant dialysis treatment, whereas risk factors for graft failure included increased level of panel-reactive antibodies and increased cold ischaemia time. Kidney allografts are rarely lost due to immunological reasons during the first post-transplant year. The most common causes of early death after transplantation are cardiovascular and infectious causes.

Kidney transplant outcomes from older deceased donors: a paired kidney analysis by the European Renal Association-European Dialysis and Transplant Association Registry

As the median age of deceased kidney donors rises, updated knowledge of transplant outcomes from older deceased donors in differing donor-recipient age groups is required. Using ERA-EDTA Registry data we determined survival outcomes of kidney allografts donated from the same older deceased donor (55-70 years), and transplanted into one recipient younger and one recipient of similar age to the donor. The recipient pairs were divided into two groups: group 1; younger (median age: 52 years) and older (60 years) and group 2; younger (41 years) and older (60 years). A total of 1410 adults were transplanted during 2000-2007. Compared to the older recipients, the mean number of functioning graft years at 10 years was 6 months longer in the group 1 and group 2 younger recipients (P < 0.001). Ten-year graft survival was 54% and 40% for the group 1 younger and older recipients, and 60% and 49% for the group 2 younger and older recipients. Paired Cox regression analyses showed a lower risk of graft failure (group 1 younger; adjusted relative risk [RRa]:0.57, 95% CI:0.41-0.79, and group 2 younger; RRa:0.63, 95% CI:0.47-0.85) in younger recipients. Outcomes from older deceased donor allografts transplanted into differing donor-recipient age groups are better than previously reported. These allografts remain a valuable transplant resource, particularly for similar-aged recipients.