Sex Differences in Kidney Transplantation: Austria and the United States, 1978–2018

Background

Systematic analyses about sex differences in wait-listing and kidney transplantation after dialysis initiation are scarce. We aimed at identifying sex-specific disparities along the path of kidney disease treatment, comparing two countries with distinctive health care systems, the US and Austria, over time.

Methods

We analyzed subjects who initiated dialysis from 1979–2018, in observational cohort studies from the US and Austria. We used Cox regression to model male-to-female cause-specific hazard ratios (csHRs, 95% confidence intervals) for transitions along the consecutive states dialysis initiation, wait-listing, kidney transplantation and death, adjusted for age and stratified by country and decade of dialysis initiation.

Results

Among 3,053,206 US and 36,608 Austrian patients starting dialysis, men had higher chances to enter the wait-list, which however decreased over time [male-to-female csHRs for wait-listing, 1978–1987: US 1.94 (1.71, 2.20), AUT 1.61 (1.20, 2.17); 2008–2018: US 1.35 (1.32, 1.38), AUT 1.11 (0.94, 1.32)]. Once wait-listed, the advantage of the men became smaller, but persisted in the US [male-to-female csHR for transplantation after wait-listing, 2008–2018: 1.08 (1.05, 1.11)]. The greatest disparity between men and women occurred in older age groups in both countries [male-to-female csHR for wait-listing after dialysis, adjusted to 75% age quantile, 2008–2018: US 1.83 (1.74, 1.92), AUT 1.48 (1.02, 2.13)]. Male-to-female csHRs for death were close to one, but higher after transplantation than after dialysis.

Conclusions

We found evidence for sex disparities in both countries. Historically, men in the US and Austria had 90%, respectively, 60% higher chances of being wait-listed for kidney transplantation, although these gaps decreased over time. Efforts should be continued to render kidney transplantation equally accessible for both sexes, especially for older women.

Temporal Trends in the Quality of Deceased Donor Kidneys and Kidney Transplant Outcomes in Europe: an analysis by the ERA-EDTA Registry

Background

We investigated 10-year trends in deceased donor kidney quality expressed as the kidney donor risk index (KDRI) and subsequent effects on survival outcomes in a European transplant population.

Methods

Time trends in the crude and standardized KDRI between 2005 and 2015 by recipient age, sex, diabetic status and country were examined in 24 177 adult kidney transplant recipients in seven European countries. We determined 5-year patient and graft survival probabilities and the risk of death and graft loss by transplant cohort (Cohort 1: 2005–06, Cohort 2: 2007–08, Cohort 3: 2009–10) and KDRI quintile.

Results

The median crude KDRI increased by 1.3% annually, from 1.31 [interquartile range (IQR) 1.08–1.63] in 2005 to 1.47 (IQR 1.16–1.90) in 2015. This increase, i.e. lower kidney quality, was driven predominantly by increases in donor age, hypertension and donation after circulatory death. With time, the gap between the median standardized KDRI in the youngest (18–44 years) and oldest (>65 years) recipients widened. There was no difference in the median standardized KDRI by recipient sex. The median standardized KDRI was highest in Austria, the Netherlands and the Basque Country (Spain). Within each transplant cohort, the 5-year patient and graft survival probability were higher for the lowest KDRIs. There was no difference in the patient and graft survival outcomes across transplant cohorts, however, over time the survival probabilities for the highest KDRIs improved.

Conclusions

The overall quality of deceased donor kidneys transplanted between 2005 and 2015 has decreased and varies between age groups and countries. Overall patient and graft outcomes remain unchanged.

Impact of cardiovascular risk stratification strategies in kidney transplantation over time

BACKGROUND

Kidney transplant recipients exhibit a dramatically increased cardiovascular (CV) risk. In 2007, Austrian centres implemented a consensus of comprehensive CV screening programme prior to kidney transplantation (KT). The consensus placed a particular emphasis on screening for coronary artery disease (CAD) with cardiac computed tomography (CT) or coronary angiography (CAG) in patients with diabetes mellitus, known CAD or those having multiple conventional CV risk factors. Here, we investigate if this affected risk stratification and post-transplant CV outcomes.

METHODS

In a retrospective chart review, we evaluated 551 KTs performed from 2003 to 2015 in our centre. Patients were categorized into three groups: KT before (2003-07), directly after (2008-11) and 5 years after (2012-15) implementation of the consensus. We analysed clinical characteristics, the rate of cardiac CTs and CAGs prior to KT as well as major adverse cardiac events (MACEs) during a 2-year follow-up after KT.

RESULTS

The three study groups showed a homogeneous distribution of comorbidities and age. Significantly more cardiac CTs (13.6% versus 10.2% versus 44.8%; P = 0.002) and CAGs (39.6% versus 43.9% versus 56.2%; P = 0.003) were performed after the consensus. Coronary interventions were performed during 42 out of 260 CAGs (16.2%), the cumulative 2-year MACE incidence was 8.7%. Regarding MACE occurrence, no significant difference between the three groups was found.

CONCLUSION

CV risk stratification has become more rigorous and invasive after the implementation of the consensus; however, this was not associated with an improvement in CV outcome.

The ERA-EDTA Registry Annual Report 2017: a summary

Background

This article presents a summary of the 2017 Annual Report of the European Renal Association–European Dialysis and Transplant Association (ERA-EDTA) Registry and describes the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in 37 countries.

Methods

The ERA-EDTA Registry received individual patient data on patients undergoing RRT for ESRD in 2017 from 32 national or regional renal registries and aggregated data from 21 registries. The incidence and prevalence of RRT, kidney transplantation activity and survival probabilities of these patients were calculated.

Results

In 2017, the ERA-EDTA Registry covered a general population of 694 million people. The incidence of RRT for ESRD was 127 per million population (pmp), ranging from 37 pmp in Ukraine to 252 pmp in Greece. A total of 62% of patients were men, 52% were ≥65 years of age and 23% had diabetes mellitus as the primary renal disease. The treatment modality at the onset of RRT was haemodialysis for 85% of patients. On 31 December 2017, the prevalence of RRT was 854 pmp, ranging from 210 pmp in Ukraine to 1965 pmp in Portugal. The transplant rate in 2017 was 33 pmp, ranging from 3 pmp in Ukraine to 103 pmp in the Spanish region of Catalonia. For patients commencing RRT during 2008–12, the unadjusted 5-year patient survival probability for all RRT modalities combined was 50.8%.

Sex-specific analysis of haemodialysis prevalence, practices and mortality over time: the Austrian Dialysis Registry from 1965 to 2014

BACKGROUND

Despite a higher prevalence of chronic kidney disease among women, more men than women start renal replacement therapy (RRT). We hypothesized that gender differences in health care access exist and therefore aimed at determining whether characteristics and outcomes of haemodialysis patients over time differ by sex.

METHODS

We studied all 28 323 adults who began haemodialysis during 1965-2014 in the Austrian Dialysis Registry, analysing trends in patient characteristics by sex and decade with mortality (via Cox regression), which was compared with the mortality of the Austrian general population.

RESULTS

More men than women started haemodialysis (60.1% men versus 39.9% women overall), with minor differences among decades and age groups. The male:female mortality rate ratio in the general population ranged from 1.2 to 2.4 for age groups >18 years and in haemodialysis patients ranged from 0.80 to 1.3 (closer to 1 than in the general population, but consistently >1 in Decades 3-5). In recent decades, diabetes and hypertension replaced glomerulonephritis as the primary cause of end-stage renal disease in both men and women. Interaction analyses showed the mortality risk associated with haemodialysis access (only recorded in Decade 5) was significantly lower for men than for women.

CONCLUSIONS

The male:female mortality rate ratio and the proportion of women starting haemodialysis were remarkably stable, which does not support the hypothesis of gender differences in health care/haemodialysis access or could imply that such differences might have persisted over decades. Future research should expand to other countries and other forms of RRT.

Exclusion of pregnancy in dialysis patients: diagnostic performance of human chorionic gonadotropin

Background

A positive pregnancy test in acute or chronically ill patients has implications for the use of potentially mutagenic or teratogenic products in urgent medical therapies such as the use of chemotherapies or therapies with immunosuppressants, for anesthesia, and for time-sensitive indications like urgent surgery or organ Transplantation.

Despite a lack of evidence, it is currently believed that human chorionic gonadotropin serum concentrations are always elevated in female dialysis patients even without pregnancy. It is also believed that human chorionic gonadotropin cannot be used to confirm or exclude pregnancy.

Methods

Human chorionic gonadotropin was examined in female dialysis patients (18–50 years of age), and was classified as positive above 5 mlU/ml. In addition, fertility status was determined. For an enhanced index test, the cut-off of 5 mIU/ml was used for potentially fertile patients and 14 mIU/ml for infertile patients to calculate diagnostic test accuracy. The ideal cut-off for human chorionic gonadotropin was estimated using Liu’s method with bootstrapped 95% confidence intervals. Predictors of human chorionic gonadotropin increase were analyzed using multivariable linear regression.

Results

Among 71 women, two (2.8%) were pregnant, 46 (64.8%) potentially fertile, and 23 (32.4%) infertile. We observed human chorionic gonadotropin concentrations > 5 mIU/ml in 10 patients, which had a sensitivity of 100% (95% confidence interval: 100 to 100), a specificity of 86% (95% confidence interval: 77 to 94), a positive predictive value of 17% (95% confidence interval: 8 to 25) and a negative predictive value of 100% (95% confidence interval: 100 to 100) for the diagnosis of pregnancy. Using a cut-off > 14 mIU/ml for infertile patients or the exclusion of infertile patients increased specificity to 93% or 98%, respectively. The ideal cut-off was 25 mIU/ml (95% confidence interval: 17 to 33). Pregnancy and potential fertility, but not age, were independent predictors of human chorionic gonadotropin.

Conclusion

Human chorionic gonadotropin is elevated > 5mIU/ml in 14.5% of non-pregnant dialysis patients of child-bearing age. In potentially fertile women, this cut-off can be used to exclude pregnancy. In case of an unknown fertility status, the ideal human chorionic gonadotropin cut-off was 25 mIU/ml.

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.

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.

Prospective Comparison of a Metal-Free Ceramic Total Knee Arthroplasty with an Identical Metal System

Aims The aim of this open-label, prospective, short-term study was to carry out an initial comparison of a completely metal-free ceramic with a geometrically identical metallic arthroplasty over a 1-year follow-up period.

Methods This study investigates a completely metal-free system using a composite matrix material containing aluminum oxide (Al2O3, BPK-S Integration, Peter Brehm GmbH, Weisendorf, Germany) or zirconium oxide (ZrO2, BPK-S Integration Ceramic, Biolox Delta-CeramTec GmbH, Plochingen, Germany). Eighty patients (40 in each group) received either a completely metal-free ceramic system (matrix of aluminum and zirconium oxide) or an anatomically identical metallic knee system made of a cobalt-chromium alloy. Clinical assessment was performed preoperatively, and during follow-up at 3 and 12 months, using the Knee Society Score, Oxford Knee Score, and EQ-5D-VAS. For radiological evaluation, standard preoperative and postoperative standardized radiographs were taken at the given follow-up visits.

Results The postoperative clinical scores improved significantly at the 3- and 12-month follow-ups, but did not differ statistically between the two groups. The radiologically evaluated mean postoperative mechanical and anatomical axes showed proper alignment within both groups at all times. No revision surgery had to be performed, and no complications or loosening were recorded whatsoever.

Conclusions To our knowledge, this is the first study comparing a total ceramic metal-free knee system with a geometrically identical metallic TKA (total knee arthroplasty). Longer follow-ups will be required to demonstrate the overall efficiency of this TKR and perhaps to expand its medical indication.

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.

Lifetime risk of renal replacement therapy in Europe: a population-based study using data from the ERA-EDTA Registry

Background

Upcoming KDIGO guidelines for the evaluation of living kidney donors are expected to move towards a personal risk-based evaluation of potential donors. We present the age and sex-specific lifetime risk of renal replacement therapy (RRT) for end-stage renal disease in 10 European countries.

Methods

We defined lifetime risk of RRT as the cumulative incidence of RRT up to age 90 years. We obtained RRT incidence rates per million population by 5-year age groups and sex using data from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry, and used these to estimate the cumulative incidence of RRT, adjusting for competing mortality risk.

Results

Lifetime risk of RRT varied from 0.44% to 2.05% at age 20 years and from 0.17% to 1.59% at age 70 years across countries, and was twice as high in men as in women. Lifetime RRT risk decreased with age, ranging from an average of 0.77% to 0.44% in 20- to- 70-year-old women, and from 1.45% to 0.96% in 20- to- 70-year-old men. The lifetime risk of RRT increased slightly over the past decade, more so in men than in women. However, it appears to have stabilized or even decreased slightly in more recent years.

Conclusions

The lifetime risk of RRT decreased with age, was lower in women as compared with men of equal age and varied considerably throughout Europe. Given the substantial differences in lifetime risk of RRT between the USA and Europe, country-specific estimates should be used in the evaluation and communication of the risk of RRT for potential living kidney donors.

Mortality in dialysis patients with cinacalcet use: A large observational registry study

BACKGROUND

Secondary hyperparathyroidism (sHPT) is associated with higher mortality in dialysis patients. The calcimimetic cinacalcet reduces intact parathyroid hormone (iPTH) in dialysis patients. The randomized controlled EVOLVE trial failed to unequivocally prove survival advantage of cinacalcet in dialysis patients. However, recent post hoc analyses suggested a benefit in subgroups of dialysis patients. Large observational cohort studies may represent an option to better determine such subgroups.

METHODS

Data from the nationwide Austrian registry of dialysis patients between January 2004 and December 2009 were analyzed with follow-up until December 2010. All-cause and cardiovascular mortality analyses were performed using the Kaplan-Meier and Cox proportional hazards regression. To reduce confounding effects a propensity score (PS) based method (matching by stratification) was used for group comparison.

RESULTS

The cohort included 7983 dialysis patients, 1572 (19.7%) were prescribed cinacalcet. During a median follow-up of 2.7years, 3574 (44.8%) patients died, including 1342 (16.8%) deaths from cardiovascular causes. Survival analyses in the PS-matched study population (n=6109) showed lower all-cause mortality for cinacalcet-treated as compared to untreated patients only in subsets characterized by younger age, low prevalence of diabetes, iPTH levels between 300 and 599pg/mL, concomitant therapy with vitamin D and phosphate binders.

CONCLUSIONS

Our data suggest that a subgroup of dialysis patients, namely those with moderate sHPT, younger age and without diabetes benefit from cinacalcet with reduced overall and cardiovascular mortality. These findings may help to identify populations for further controlled trials and may allow a more individualized sHPT treatment using cinacalcet in specific patient subgroups.

The European Renal Association - European Dialysis and Transplant Association Registry Annual Report 2014: a summary

Background: This article summarizes the European Renal Association – European Dialysis and Transplant Association Registry’s 2014 annual report. It describes the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in 2014 within 35 countries.

Methods: In 2016, the ERA-EDTA Registry received data on patients who in 2014 where undergoing RRT for ESRD, from 51 national or regional renal registries. Thirty-two registries provided individual patient level data and 19 provided aggregated patient level data. The incidence, prevalence and survival probabilities of these patients were determined.

Results: In 2014, 70 953 individuals commenced RRT for ESRD, equating to an overall unadjusted incidence rate of 133 per million population (pmp). The incidence ranged by 10-fold; from 23 pmp in the Ukraine to 237 pmp in Portugal. Of the patients commencing RRT, almost two-thirds were men, over half were aged ≥65 years and a quarter had diabetes mellitus as their primary renal diagnosis. By day 91 of commencing RRT, 81% of patients were receiving haemodialysis. On 31 December 2014, 490 743 individuals were receiving RRT for ESRD, equating to an unadjusted prevalence of 924 pmp. This ranged throughout Europe by more than 10-fold, from 157 pmp in the Ukraine to 1794 pmp in Portugal. In 2014, 19 406 kidney transplantations were performed, equating to an overall unadjusted transplant rate of 36 pmp. Again this varied considerably throughout Europe. For patients commencing RRT during 2005–09, the 5-year-adjusted patient survival probabilities on all RRT modalities was 63.3% (95% confidence interval 63.0–63.6). The expected remaining lifetime of a 20- to 24-year-old patient with ESRD receiving dialysis or living with a kidney transplant was 21.9 and 44.0 years, respectively. This was substantially lower than the 61.8 years of expected remaining lifetime of a 20-year-old patient without ESRD.

Response to active hepatitis B vaccination and mortality in incident dialysis patients

All patients with advanced chronic kidney disease or on renal replacement therapy should receive active hepatitis B vaccination. The aim of this retrospective cohort study was to investigate the association between the immune response to hepatitis B vaccination and all-cause, cardiovascular or infection-related mortality in incident dialysis patients starting dialysis between 2001 and 2008 (n=426) in two Austrian dialysis centers. Vaccination response was defined as follows: absent anti-HBs antibody titer or a titer <10IU/L was classified as non-response, seroconversion (SC) was defined as a titer ⩾10IU/L, and seroprotection (SP) as a titer ⩾100IU/L. Kaplan-Meier survival curves and multivariable adjusted Cox Proportional Hazards Models were used to determine the association between vaccination response and all-cause, cardiovascular and infection-related mortality. Of all patients 207 (48.6%) were non-responders, SC was observed in 219 (51.4%), SP in 118 (27.7%) patients. During a median follow-up of 51.2 months 228 (53.5%) patients died. Patients with SP and SC showed a significantly lower all-cause (p<0.001 for both) and cardiovascular mortality (p=0.006 for SP, p=0.01 for SC). SP and SC were independently associated with a significant risk reduction for all-cause mortality (SP: HR 0.69, 95% CI 0.49-0.97, p=0.03; SC: HR 0.72, 95% CI 0.55-0.95, p=0.02). In conclusion, achieving seroconversion and seroprotection after active hepatitis B vaccination is associated with significantly reduced all-cause mortality in incident dialysis patients. This simple and readily available tool allows estimation of patient survival independently of other well-known key parameters such as age, gender, the presence of diabetes and markers of malnutrition and inflammation.

Anthropometric and Metabolic Risk Factors for ESRD Are Disease-Specific: Results from a Large Population-Based Cohort Study in Austria

BACKGROUND

Anthropometric and metabolic risk factors for all-cause end-stage renal disease (ESRD) may vary in their impact depending on the specific primary renal disease.

METHODS

In this Austrian population-based prospective cohort study (n = 185,341; 53.9% women) the following data were collected between 1985 and 2005: age, sex, body mass index (BMI), fasting blood glucose (FBG) from 1988, blood pressure, total cholesterol (TC), triglycerides (TG), gamma-glutamyl transferase (GGT) and smoking status. These data were merged with the Austrian Dialysis and Transplant Registry to identify ESRD patients. Cox proportional hazards models were applied to calculate hazard ratios (HR) for all-cause ESRD as well as for cause-specific ESRD due to the following primary renal diseases: autosomal dominant polycystic kidney disease (ADPKD), vascular nephropathy (VN), diabetic nephropathy (DN) and other diseases (OD).

RESULTS

During a mean follow-up of 17.5 years 403 participants developed ESRD (ADPKD 36, VN 97, DN 86, and OD 184). All parameters except TG and GGT were significantly associated with all-cause ESRD risk. Particular cause-specific ESRD risk factor patterns were found: for ADPKD increased risk from hypertension (HR 11.55); for VN from smoking (HR 1.81), hypertension (HR 2.37), TG (≥5.70 vs. <1.17 mmol/L: HR 9.27); for DN from smoking (HR 1.77), BMI (≥30 vs. 18.5-24.9 kg/m2: HR 7.55), FBG (≥6.94 vs. <5.55 mmol/L: HR 7.67), hypertension (HR 1.08), TG (≥5.70 vs. <1.17 mmol/L: HR 2.02), GGT (HR 2.14); and for OD from hypertension (HR 2.29), TG (≥5.70 vs. <1.17 mmol/L: HR 6.99) and TC (≥6.22 vs. <5.18 mmol/L: HR 1.56).

CONCLUSIONS

Particular anthropometric and metabolic ESRD risk factors differ in importance depending on the primary renal disease. This needs to be considered for future preventive and therapeutic strategies addressing cause-specific ESRD.

Renal replacement therapy in Europe: a summary of the 2013 ERA-EDTA Registry Annual Report with a focus on diabetes mellitus

Background

This article provides a summary of the 2013 European Renal Association–European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report (available at http://www.era-edta-reg.org), with a focus on patients with diabetes mellitus (DM) as the cause of end-stage renal disease (ESRD).

Methods

In 2015, the ERA-EDTA Registry received data on renal replacement therapy (RRT) for ESRD from 49 national or regional renal registries in 34 countries in Europe and bordering the Mediterranean Sea. Individual patient data were provided by 31 registries, while 18 registries provided aggregated data. The total population covered by the participating registries comprised 650 million people.

Results

In total, 72 933 patients started RRT for ESRD within the countries and regions reporting to the ERA-EDTA Registry, resulting in an overall incidence of 112 per million population (pmp). The overall prevalence on 31 December 2013 was 738 pmp (n = 478 990). Patients with DM as the cause of ESRD comprised 24% of the incident RRT patients (26 pmp) and 17% of the prevalent RRT patients (122 pmp). When compared with the USA, the incidence of patients starting RRT pmp secondary to DM in Europe was five times lower and the incidence of RRT due to other causes of ESRD was two times lower. Overall, 19 426 kidney transplants were performed (30 pmp). The 5-year adjusted survival for all RRT patients was 60.9% [95% confidence interval (CI) 60.5–61.3] and 50.6% (95% CI 49.9–51.2) for patients with DM as the cause of ESRD.

The changing trends and outcomes in renal replacement therapy: data from the ERA-EDTA Registry

BACKGROUND

This study examines the time trends in incidence, prevalence, patient and kidney allograft survival and causes of death (COD) in patients receiving renal replacement therapy (RRT) in Europe.

METHODS

Eighteen national or regional renal registries providing data to the European Renal Association-European Dialysis and Transplant Association Registry between 1998 and 2011 were included. Incidence and prevalence time trends between 2001 and 2011 were studied with Joinpoint and Poisson regression. Patient and kidney allograft survival and COD between 1998 and 2011 were analysed using Kaplan-Meier and competing risk methods and Cox regression.

RESULTS

From 2001 to 2008, the adjusted incidence of RRT rose by 1.1% (95% CI: 0.6, 1.7) annually to 131 per million population (pmp). During 2008-2011, the adjusted incidence fell by 2.2% (95% CI: -4.2, -0.2) annually to 125 pmp. This decline occurred predominantly in patients aged 45-64 years, 65-74 years and in the primary renal diseases diabetes mellitus type 1 and 2, renovascular disease and glomerulonephritis. Between 2001 and 2011, the overall adjusted prevalence increased from 724 to 1032 pmp (+3.3% annually, 95% CI: 2.8, 3.8). The adjusted 5-year patient survival on RRT improved between 1998-2002 and 2003-2007 [adjusted hazard ratio (HRa) 0.85, 95% CI: 0.84, 0.86]. Comparing these time periods, the risk of cardiovascular deaths fell by 25% (HRa 0.75, 95% CI: 0.74, 0.77). However the risk of malignant death rose by 9% (HRa 1.09, 95% CI: 1.03, 1.16) in patients ≥65 years.

CONCLUSION

This European study shows a declining RRT incidence, particularly in patients aged 45-64 years, 65-74 years and secondary to diabetic nephropathy. Encouragingly, the adjusted RRT patient survival continues to improve. The risk of cardiovascular death has decreased, though the risk of death from malignancy has increased in the older population.

Trends in dialysis modality choice and related patient survival in the ERA-EDTA Registry over a 20-year period

BACKGROUND

Although previous studies suggest similar patient survival for peritoneal dialysis (PD) and haemodialysis (HD), PD use has decreased worldwide. We aimed to study trends in the choice of first dialysis modality and relate these to variation in patient and technique survival and kidney transplant rates in Europe over the last 20 years.

METHODS

We used data from 196 076 patients within the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry who started renal replacement therapy (RRT) between 1993 and 2012. Trends in the incidence rate and prevalence on Day 91 after commencing RRT were quantified with Joinpoint regression. Crude and adjusted hazard ratios (HRs) for 5-year dialysis patient and technique survival were calculated using Cox regression. Analyses were repeated using propensity score matching to control for confounding by indication.

RESULTS

PD prevalence dropped since 2007 and HD prevalence stabilized since 2009. Incidence rates of PD and HD decreased from 2000 and 2009, respectively, while the incidence of kidney transplantation increased from 1993 onwards. Similar 5-year patient survival for PD versus HD patients was found in 1993-97 [adjusted HR: 1.02, 95% confidence interval (95% CI): 0.98-1.06], while survival was higher for PD patients in 2003-07 (HR: 0.91, 95% CI: 0.88-0.95). Both PD (HR: 0.95, 95% CI: 0.91-1.00) and HD technique survival (HR: 0.93, 95% CI: 0.87-0.99) improved in 2003-07 compared with 1993-97.

CONCLUSIONS

Although initiating RRT on PD was associated with favourable patient survival when compared with starting on HD treatment, PD was often not selected as initial dialysis modality. Over time, we observed a significant decline in PD use and a stabilization in HD use. These observations were explained by the lower incidence rate of PD and HD and the increase in pre-emptive transplantation.

Diabetes-related end-stage renal disease in Austria 1965-2013

BACKGROUND

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD) in Austria, accounting for a high burden of morbidity and mortality. In this nationwide study, we aimed to evaluate the incidence and fate of patients with DKD-ESRD over time.

METHODS

Data (collected annually) from the Austrian Dialysis- and Transplant Registry were analysed for the development of ESRD due to DKD from 1965 to 2013.

RESULTS

Over 48 years, 8322 and 22 975 patients with ESRD due to diabetes and non-diabetes, respectively, entered dialysis. While DKD-ESRD-patients were not dialysed until 1974, in 1975 seven type 1- and one type 2-diabetics started dialysis (1.06 per million population-PMP). In the mid-eighties, DKD-ESRD-patients increasingly were accepted for dialysis (1986: 14.53 PMP, 1996: 31.16 PMP). After a peak incidence of 415 diabetic ESRD-patients in 2006 (50.19 PMP), numbers decreased continuously thereafter (2013: 299 patients, 35.73 PMP). Mean age at start of dialysis increased over time and was lower in type 1- and higher in type 2- compared with non-diabetic patients. Five-year-survival-probability in two diabetic ESRD-cohorts, starting in 2007/08 and 10 years earlier was calculated. Five-year-survival was 28% in 1997/98 and 37.5% in 2007/08. Adjusted relative risk reduction was 33% (HR 0.67, CI 95% 0.57-0.78; P < 0.001).

CONCLUSION

Despite a growing prevalence of diabetes, the incidence of diabetic ESRD has decreased after 2006. Five-year-survival-probability has improved over 10 years. Multifactorial therapeutic interventions may have resulted in this improvement.

Renal replacement therapy in Europe: a summary of the 2012 ERA-EDTA Registry Annual Report

BACKGROUND

This article summarizes the 2012 European Renal Association-European Dialysis and Transplant Association Registry Annual Report (available at www.era-edta-reg.org) with a specific focus on older patients (defined as ≥65 years).

METHODS

Data provided by 45 national or regional renal registries in 30 countries in Europe and bordering the Mediterranean Sea were used. Individual patient level data were received from 31 renal registries, whereas 14 renal registries contributed data in an aggregated form. The incidence, prevalence and survival probabilities of patients with end-stage renal disease (ESRD) receiving renal replacement therapy (RRT) and renal transplantation rates for 2012 are presented.

RESULTS

In 2012, the overall unadjusted incidence rate of patients with ESRD receiving RRT was 109.6 per million population (pmp) (n = 69 035), ranging from 219.9 pmp in Portugal to 24.2 pmp in Montenegro. The proportion of incident patients ≥75 years varied from 15 to 44% between countries. The overall unadjusted prevalence on 31 December 2012 was 716.7 pmp (n = 451 270), ranging from 1670.2 pmp in Portugal to 146.7 pmp in the Ukraine. The proportion of prevalent patients ≥75 years varied from 11 to 32% between countries. The overall renal transplantation rate in 2012 was 28.3 pmp (n = 15 673), with the highest rate seen in the Spanish region of Catalonia. The proportion of patients ≥65 years receiving a transplant ranged from 0 to 35%. Five-year adjusted survival for all RRT patients was 59.7% (95% confidence interval, CI: 59.3-60.0) which fell to 39.3% (95% CI: 38.7-39.9) in patients 65-74 years and 21.3% (95% CI: 20.8-21.9) in patients ≥75 years.

Mortality and incidence of renal replacement therapy in people with type 1 diabetes mellitus--a three decade long prospective observational study in the Lainz T1DM cohort

CONTEXT AND OBJECTIVE

We investigated long term mortality, requirement for renal replacement therapy (RRT), and incidence of other late diabetic complications in an observational cohort study of 641 people with type 1 diabetes (T1DM).

DESIGN

Prospective observational cohort study.

SETTING

The study was conducted at a Tertiary Diabetes Centre in Vienna, Austria.

PATIENTS

A cohort with all people with T1DM (n = 641, 47% females, 30 ± 11 years) attending their annual diabetes review was created in 1983-1984. Biomedical data were collected.

MAIN OUTCOME MEASURES

In 2013 we investigated mortality rates and incidence rates of RRT by record linkage with national registries and incidence of other major diabetes complications by questionnaire.

RESULTS

156 (24%) patients died [mortality rate: 922 (95%CI: 778-1066) per 100 000 person years]. Fifty-five (8.6%) received RRT [incidence rate: 335 (95%CI: 246-423) per 100 000 person years]. The 380 questionnaires (78% return rate) recorded cardiac events, strokes, limb amputations, and/or blindness, affecting 21.8% of survivors. Mortality and incidence of RRT increased in each quartile of baseline HbA1c, with the lowest rates in the quartile with HbA1c ≤ 6.5% (48 mmol/mol) (P < .05).

CONCLUSIONS

In people with established type 1 diabetes who were observed for almost three decades, the overall mortality was 24% and the incidence of renal replacement therapy was 8.6%, with a 21.8% combined incidence rate of the other hard endpoints in the surviving people. A clear linear relationship between early glycemic control and the later development of end stage renal disease and mortality has been found.

Use of vascular access for haemodialysis in Europe: a report from the ERA-EDTA Registry

BACKGROUND

Although arteriovenous fistulas (AVFs) are actively promoted, their use at the start of haemodialysis (HD) seems to be decreasing worldwide. In this paper, we describe recent trends in incidence and prevalence of vascular access types in Europe from 2005 to 2009 and their relationship with patient characteristics and survival.

METHODS

Ten European renal registries participating in the ERA-EDTA Registry provided data on incidence (n = 13,044) and/or prevalence (n = 75,715) of vascular access types. We used logistic regression to assess which factors influence the likelihood to be treated with an AVF rather than another type.

RESULTS

The use of AVFs at the start of HD showed a significant decreasing trend from 42% in 2005 to 32% in 2009 (P < 0.0001), while the use of central venous catheters (CVCs) increased from 58 to 68% (P < 0.0001). A similar evolution pattern was observed for the prevalence; use of AVFs decreased from 66 to 62% and use of CVCs increased from 28 to 32%. There was a large international variation in the use of the different vascular access types. Female patients [adjusted odds ratio: 0.84, 95% confidence interval (CI): 0.78-0.90] and those ≥80 years (0.77, 95% CI: 0.67-0.90) were least likely to start HD with an AVF.

CONCLUSION

In Europe, there is a decreasing trend in the use of AVFs and an increasing trend in the use of CVCs at the start and after the start of HD. We cannot explain all between-country variations we found, and more research is needed to clarify how healthcare around vascular access is organized in Europe.

Renal replacement therapy in Europe: a summary of the 2011 ERA-EDTA Registry Annual Report

Background

This article provides a summary of the 2011 ERA–EDTA Registry Annual Report (available at www.era-edta-reg.org).

Methods

Data on renal replacement therapy (RRT) for end-stage renal disease (ESRD) from national and regional renal registries in 30 countries in Europe and bordering the Mediterranean Sea were used. From 27 registries, individual patient data were received, whereas 17 registries contributed data in aggregated form. We present the incidence and prevalence of RRT, and renal transplant rates in 2011. In addition, survival probabilities and expected remaining lifetimes were calculated for those registries providing individual patient data.

Results

The overall unadjusted incidence rate of RRT in 2011 among all registries reporting to the ERA–EDTA Registry was 117 per million population (pmp) (n = 71.631). Incidence rates varied from 24 pmp in Ukraine to 238 pmp in Turkey. The overall unadjusted prevalence of RRT for ESRD on 31 December 2011 was 692 pmp (n = 425 824). The highest prevalence was reported by Portugal (1662 pmp) and the lowest by Ukraine (131 pmp). Among all registries, a total of 22 814 renal transplantations were performed (37 pmp). The highest overall transplant rate was reported from Spain, Cantabria (81 pmp), whereas the highest rate of living donor transplants was reported from Turkey (39 pmp). For patients who started RRT between 2002 and 2006, the unadjusted 5-year patient survival on RRT was 46.8% [95% confidence interval (CI) 46.6–47.0], and on dialysis 39.3% (95% CI 39.2–39.4). The unadjusted 5-year patient survival after the first renal transplantation performed between 2002 and 2006 was 86.7% (95% CI 86.2–87.2) for kidneys from deceased donors and 94.3% (95% CI 93.6–95.0) for kidneys from living donors.

Left atrial diameter and survival among renal allograft recipients

BACKGROUND AND OBJECTIVES

Sequential echocardiography is routinely performed in patients with ESRD listed for transplantation. The benefit of this labor- and time-intensive measure, however, remains unclear. Thus, this study elucidated the various obtained routine echocardiography parameters that best predicted mortality and graft survival after renal transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study investigated 553 first renal transplant recipients listed in the Austrian Dialysis and Transplant Registry between 1992 and 2011 who had echocardiographic analysis at transplantation and survived at least 1 year. Cox proportional hazards models with the purposeful selection algorithms for covariables were used to identify predictors of mortality and graft loss. A Fine and Gray model was used to evaluate cause-specific death.

RESULTS

During a median follow-up of 7.14 years, 81 patients died, and 59 patients experienced graft loss after the first year. The Kaplan-Meier analysis showed that 85% of patients with a left atrial diameter below the median of 53 mm were alive 10 years after transplantation, whereas only 70% of those patients with a left atrial diameter equal to or above the median had survived (P<0.001). In the multivariable model, left atrial diameter (per millimeter) independently predicted overall mortality (hazard ratio, 1.06; 95% confidence interval, 1.03 to 1.08; P<0.001) and cause-specific cardiac death (hazard ratio, 1.04; 95% confidence interval, 1.00 to 1.08; P=0.04). Functional graft loss was predicted by the right atrial diameter (hazard ratio, 1.04; 95% confidence interval, 1.02 to 1.07; P=0.001).

CONCLUSION

The left atrial diameter determined at transplantation predicted overall and cardiac mortality. Patients with widely enlarged left atria exhibit a considerably reduced life expectancy. It remains to be determined, however, whether renal transplantation is futile in these patients.

Influence of body mass index on the association of weight changes with mortality in hemodialysis patients

BACKGROUND AND OBJECTIVES

A high body mass index (BMI) is associated with lower mortality in patients undergoing hemodialysis. Short-term weight gains and losses are also related to lower and higher mortality risk, respectively. The implications of weight gain or loss may, however, differ between obese individuals and their nonobese counterparts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Current Management of Secondary Hyperparathyroidism: A Multicenter Observational Study (COSMOS) is an observational study including 6797 European hemodialysis patients recruited between February 2005 and July 2007, with prospective data collection every 6 months for 3 years. Time-dependent Cox proportional hazard regressions assessed the effect of BMI and weight changes on mortality. Analyses were performed after patient stratification according to their starting BMI.

RESULTS

Among 6296 patients with complete data, 1643 died. At study entry, 42% of patients had a normal weight (BMI, 20-25 kg/m(2)), 11% were underweight, 31% were overweight, and 16% were obese (BMI ≥ 30 kg/m(2)). Weight loss or gain (<1% or >1% of body weight) was strongly associated with higher rates of mortality or survival, respectively. After stratification by BMI categories, this was true in nonobese categories and especially in underweight patients. In obese patients, however, the association between weight loss and mortality was attenuated (hazard ratio, 1.28 [95% confidence interval (CI), 0.74 to 2.14]), and no survival benefit of gaining weight was seen (hazard ratio, 0.98 [95% CI, 0.59 to 1.62]).

CONCLUSIONS

Assuming that these weight changes were unintentional, our study brings attention to rapid weight variations as a clinical sign of health monitoring in hemodialysis patients. In addition, a patient's BMI modifies the strength of the association between weight changes with mortality.

Use of phosphate-binding agents is associated with a lower risk of mortality

Hyperphosphatemia has been associated with higher mortality risk in CKD 5 patients receiving dialysis. Here, we determined the association between the use of single and combined phosphate-binding agents and survival in 6797 patients of the COSMOS study: a 3-year follow-up, multicenter, open-cohort, observational prospective study carried out in 227 dialysis centers from 20 European countries. Patient phosphate-binding agent prescriptions (time-varying) and the case-mix-adjusted facility percentage of phosphate-binding agent prescriptions (instrumental variable) were used as predictors of the relative all-cause and cardiovascular mortality using Cox proportional hazard regression models. Three different multivariate models that included up to 24 variables were used for adjustments. After multivariate analysis, patients prescribed phosphate-binding agents showed a 29 and 22% lower all-cause and cardiovascular mortality risk, respectively. The survival advantage of phosphate-binding agent prescription remained statistically significant after propensity score matching analysis. A decrease of 8% in the relative risk of mortality was found for every 10% increase in the case-mix-adjusted facility prescription of phosphate-binding agents. All single and combined therapies with phosphate-binding agents, except aluminum salts, showed a beneficial association with survival. The findings made in the present association study need to be confirmed by randomized controlled trials to prove the observed beneficial effect of phosphate-binding agents on mortality.

Renal replacement therapy in Europe-a summary of the 2010 ERA-EDTA Registry Annual Report

Background

This study provides a summary of the 2010 European Renal Association–European Dialysis and Transplant Association (ERA–EDTA) Registry Annual Report (available at www.era-edta-reg.org).

Methods

This report includes data on renal replacement therapy (RRT) using data from the national and regional renal registries in 29 countries in Europe and bordering the Mediterranean Sea. Individual patient data were received from 27 registries, whereas 18 registries contributed data in aggregated form. We present incidence and prevalence of RRT, transplant rates, survival probabilities and expected remaining lifetimes. The latter two are solely based on individual patient records.

Results

In 2010, the overall incidence rate of RRT for end-stage renal disease (ESRD) among all registries reporting to the ERA–EDTA Registry was 123 per million population (pmp) (n = 91 798). The highest incidence rate was reported by Turkey (252pmp) and the lowest reported by Montenegro (21 pmp). The overall prevalence of RRT for ESRD at 31 December 2010 among all registries reporting to the ERA–EDTA Registry was 741 pmp (n = 551 005). The prevalence varied from 124 pmp in Ukraine to 1580 pmp in Portugal. The overall number of renal transplantations performed in 2010 among all registries was 29.2 pmp (n = 21 740). The highest overall transplant rate was reported from Spain, Cantabria (73 pmp), whereas the highest transplant rate for living donor kidneys was reported from the Netherlands (28 pmp). For patients who started RRT between 2001 and 2005, the unadjusted 5-year patient survival on RRT was 46.2% [95% confidence interval (CI) 46.0–46.3], and on dialysis 38.6% (95% CI 38.5–38.8). The unadjusted 5-year patient survival after the first renal transplantation performed between 2001 and 2005 was 86.6% (95% CI 86.1–87.1) for deceased donor kidneys and 94.1% (95% CI 93.4–94.8) for living donor kidneys.

New primary renal diagnosis codes for the ERA-EDTA

The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry has produced a new set of primary renal diagnosis (PRD) codes that are intended for use by affiliated registries. It is designed specifically for use in renal centres and registries but is aligned with international coding standards supported by the WHO (International Classification of Diseases) and the International Health Terminology Standards Development Organization (SNOMED Clinical Terms). It is available as supplementary material to this paper and free on the internet for non-commercial, clinical, quality improvement and research use, and by agreement with the ERA-EDTA Registry for use by commercial organizations. Conversion between the old and the new PRD codes is possible. The new codes are very flexible and will be actively managed to keep them up-to-date and to ensure that renal medicine can remain at the forefront of the electronic revolution in medicine, epidemiology research and the use of decision support systems to improve the care of patients.

COSMOS: the dialysis scenario of CKD-MBD in Europe

BACKGROUND

Chronic kidney disease-mineral and bone disorders (CKD-MBD) are important complications of CKD5D patients that are associated with mortality.

METHODS

COSMOS is a multicentre, open cohort, prospective, observational 3-year study carried out in haemodialysis patients from 20 European countries during 2005-07. The present article describes the main characteristics of the European dialysis population, the current practice for the prevention, diagnosis and treatment of secondary hyperparathyroidism and the differences across different European regions.

RESULTS

The haemodialysis population in Europe is an aged population (mean age 64.8±14.2 years) with a high prevalence of diabetes (29.5%) and cardiovascular disease (76.0%), and 28.7% of patients have been on haemodialysis more than 5 years. Patients from the former Eastern countries are younger (59.3±14.3 versus 66.0±13.9), having a lower proportion of diabetics (24.1 versus 30.7%). There were relevant differences in the frequency of measurement of the main CKD-MBD biochemical parameters [Ca, P and parathyroid hormone (PTH)] and the Eastern countries showed a poorer control of these biochemical parameters (K/DOQI and K/DIGO targets). Overall, 48.0% of the haemodialysis patients received active vitamin D treatment. Calcitriol use doubled that of alfacalcidiol in the Mediterranean countries, whereas the opposite was found in the non-Mediterranean countries. The criteria followed to perform parathyroidectomy were different across Europe. In the Mediterranean countries, the level of serum PTH considered to perform parathyroidectomy was higher than in non-Mediterranean countries; as a result, in the latter, more parathyroidectomies were performed in the year previous to inclusion to COSMOS.

CONCLUSIONS

The COSMOS baseline results show important differences across Europe in the management of CKD-MBD.

Outcomes of male patients with Alport syndrome undergoing renal replacement therapy

BACKGROUND AND OBJECTIVES

Patients with the hereditary disease Alport syndrome commonly require renal replacement therapy (RRT) in the second or third decade of life. This study compared age at onset of RRT, renal allograft, and patient survival in men with Alport syndrome receiving various forms of RRT (peritoneal dialysis, hemodialysis, or transplantation) with those of men with other renal diseases.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with Alport syndrome receiving RRT identified from 14 registries in Europe were matched to patients with other renal diseases. A linear spline model was used to detect changes in the age at start of RRT over time. Kaplan-Meier method and Cox regression analysis were used to examine patient and graft survival.

RESULTS

Age at start of RRT among patients with Alport syndrome remained stable during the 1990s but increased by 6 years between 2000-2004 and 2005-2009. Survival of patients with Alport syndrome requiring dialysis or transplantation did not change between 1990 and 2009. However, patients with Alport syndrome had better renal graft and patient survival than matched controls. Numbers of living-donor transplantations were lower in patients with Alport syndrome than in matched controls.

CONCLUSIONS

These data suggest that kidney failure in patients with Alport syndrome is now being delayed compared with previous decades. These patients appear to have superior patient survival while undergoing dialysis and superior patient and graft survival after deceased-donor kidney transplantation compared with patients receiving RRT because of other causes of kidney failure.

Hemoglobin variability after renal transplantation is associated with mortality

Anemia is a common problem after renal transplantation. Therefore, the patients are treated with erythropoietin stimulating agents (ESAs). The varying response to treatment contributes to hemoglobin variability, which might be associated with mortality. We conducted a retrospective cohort study of first kidney allograft recipients between 1990 and 2008 represented in the Austrian Transplant Registry. We included 1441 patients of whom 683 received ESAs at any time after transplantation. Cox regression with cubic splines and linear estimates and the purposeful selection algorithm of covariables were used. The measure of variability was the moving standard deviation computed at three monthly intervals for the entire graft life. The hazard ratio (HR) of mortality and graft loss in the spline models increased with hemoglobin variability. The linear HR for mortality was 2.35 (95% confidence interval 1.75-3.17, P<0.001) and functional graft loss 2.45 (1.76-3.40, P<0.001). In an adjusted Cox model (ESA use, hemoglobin, age, diabetes, days on dialysis, eGFR, biopsy confirmed acute rejection and year of transplantation), hemoglobin variability was associated with mortality (HR: 2.11; 1.51-2.94; P<0.001). No association with functional graft loss could be detected (HR: 1.34; 0.93-1.93; P=0.121). These findings suggest that hemoglobin variability is associated with mortality of renal allograft recipients.

Epidemiology of uromodulin-associated kidney disease - results from a nation-wide survey

BACKGROUND/AIMS

Uromodulin-associated kidney disease (UAKD) is caused by uromodulin mutations and leads to end-stage renal disease. Our objective was to examine the epidemiology of UAKD.

METHODS

Data from all UAKD families in Austria were collected. Patients included in the Austrian Dialysis and Transplantation Registry (OEDTR) with unclear diagnoses or genetic diseases were asked whether they had (1) a family history of kidney disease or (2) had suffered from gout. Patients with gout and autosomal dominant renal disease underwent mutational analysis. Kaplan-Meier and Cox analysis was employed to estimate time to renal failure.

RESULTS

Of the 6,210 patients in the OEDTR, 541 were approached with a questionnaire; 353 patients answered the questionnaire. Nineteen of them gave two affirmative answers. In 7 patients, an autosomal dominant renal disease was found; in 1 patient a UMOD mutation was identified. One family was diagnosed through increased awareness as a consequence of the study. At present, 14 UAKD patients from 5 families are living in Austria (1.67 cases per million), and 6 of them require renal replacement therapy (0.73 per 1,000 patients). Progression to renal failure was significantly associated with UMOD genotype.

CONCLUSION

UAKD patients can be identified by a simple questionnaire. UMOD genotype may affect disease progression.

Time trend in access to the waiting list and renal transplantation: a comparison of four European countries

BACKGROUND

To examine the time trend and international differences in access to the waiting list and renal transplantation of patients with end-stage kidney disease.

METHODS

We included all patients (n = 30 961) from Austria, Norway, the Netherlands and Scotland who started renal replacement therapy (RRT) between 1995 and 2003 with their kidney transplant waiting list data (until 31 December 2005) and follow-up data on RRT and mortality (until 31 December 2007). The outcome measure was access to the waiting list within 2 years and to a first renal transplant within 4 years from the start of RRT, expressed as incidence per million age-related population (p.m.a.r.p.) per year. To estimate trends over time, mean percentage annual change (MPAC) and 95% confidence interval (CI) were calculated.

RESULTS

In each country, the number of patients starting RRT > 65 years increased significantly over time, whereas the number of renal transplants did not increase to the same extent. Only in Norway were almost all patients on the waiting list transplanted within 4 years of RRT start if they were < 65 years. In patients who started RRT > 65 years, the access to renal transplantation was high in Norway (49 p.m.a.r.p.) and low in Austria ( < 26 p.m.a.r.p.), the Netherlands and Scotland (both < 10 p.m.a.r.p.) but increased significantly in Austria (MPAC = 9.8%; 95% CI = 3.9-16.9) and the Netherlands (MPAC = 9.0%; 95% CI = 3.2-15.0).

CONCLUSION

Only in Norway, virtually all patients on the waiting list < 65 years received a transplant within 4 years after the start of RRT and, remarkably, also most of those > 65 years of age.

The effect of timing of the first kidney transplantation on survival in children initiating renal replacement therapy

BACKGROUND

Controversy exists concerning the timing of the first kidney transplantation for children who need to start renal replacement therapy (RRT). Our aim was to estimate the effect of timing of the first transplantation on patient survival in children, for the first time also taking into account the mortality on dialysis before transplantation.

METHODS

We included 2091 patients who started RRT between the age of 3 and 18 years in the period 1988-2007, from 13 European renal registries. A multistate model was used to simulate patient survival assuming (i) pre-emptive transplantation, (ii) transplantation after 1 or 2 years on dialysis and (iii) remaining on dialysis.

RESULTS

Over the 20-year period, the highest 8-year survival probabilities were achieved in children transplanted pre-emptively {living donor (LD): 95.9% [95% confidence interval (CI): 93.1-98.8], deceased donor (DD): 95.3% (95% CI: 90.9-99.9)} rather than after 2 years of dialysis [LD: 94.2% (95% CI: 91.6-96.8), DD: 93.4% (95% CI: 91.0-95.9)], although these differences were not statistically significant.

CONCLUSIONS

Even after taking mortality on dialysis into account, the potentially negative effect of postponing transplantation for 1 or 2 years was relatively small and not statistically significant. Therefore, if pre-emptive transplantation is not possible, starting RRT with a short period of dialysis and receiving a transplant thereafter seems an acceptable alternative from the perspective of patient survival.

Senescence rates in patients with end-stage renal disease: a critical appraisal of the Gompertz model

The most frequently used model to describe the exponential increase in mortality rate over age is the Gompertz equation. Logarithmically transformed, the equation conforms to a straight line, of which the slope has been interpreted as the rate of senescence. Earlier, we proposed the derivative function of the Gompertz equation as a superior descriptor of senescence rate. Here, we tested both measures of the rate of senescence in a population of patients with end-stage renal disease. It is clinical dogma that patients on dialysis experience accelerated senescence, whereas those with a functional kidney transplant have mortality rates comparable to the general population. Therefore, we calculated the age-specific mortality rates for European patients on dialysis (n=274 221; follow-up=594 767 person-years), for European patients with a functioning kidney transplant (n=61 286; follow-up=345 024 person-years), and for the general European population. We found higher mortality rates, but a smaller slope of logarithmic mortality curve for patients on dialysis compared with both patients with a functioning kidney transplant and the general population (P<0.001). A classical interpretation of the Gompertz model would imply that the rate of senescence in patients on dialysis is lower than in patients with a functioning transplant and lower than in the general population. In contrast, the derivative function of the Gompertz equation yielded the highest senescence rates for patients on dialysis, whereas the rate was similar in patients with a functioning transplant and the general population. We conclude that the rate of senescence is better described by the derivative function of the Gompertz equation.

Cost-effectiveness analysis of renal replacement therapy in Austria

BACKGROUND

Providing renal replacement therapy (RRT) for end-stage renal disease patients is resource intensive. Despite growing financial pressure in health care systems worldwide, cost-effectiveness studies of RRT modalities are scarce.

METHODS

We developed a Markov model of costs, quality of life and survival to compare three different assignment strategies to chronic RRT in Europe.

RESULTS

Mean annual treatment costs for haemodialysis were €43,600 during the first 12 months, €40,000 between 13 and 24 months and €40,600 beyond 25 months after initiation of treatment. Mean annual treatment costs for peritoneal dialysis were €25,900 during the first 12 months, €15,300 between 13 and 24 months and €20,500 beyond 25 months. Mean annual therapy costs for a kidney transplantation during the first 12 months were €50,900 from a living donor, €51,000 from a deceased donor, €17,200 between 13 and 24 months and €12,900 beyond 25 months after engraftment. Over the next 10 years in Austria with a population of 8 million people, increased assignment to peritoneal dialysis of 20% incident patients saved €26 million with a discount rate of 3% and gained 839 quality-adjusted life years (QALYs); additionally, increasing renal transplants to 10% from live donations saved €38 million discounted and gained 2242 QALYs.

CONCLUSIONS

Live donor renal transplantation is cost effective and associated with increase in QALYs. Therefore, preemptive live kidney transplantation should be promoted from a fiscal as well as medical point of view.

Association of ESA hypo-responsiveness and haemoglobin variability with mortality in haemodialysis patients

BACKGROUND

Anaemia is a common complication in dialysis patients. In most cases, it is treated with erythropoietin-stimulating agents (ESA). It is not entirely clear whether the variability of haemoglobin caused by changing ESA response is associated with increased mortality. Therefore, we conducted a retrospective cohort study to evaluate ESA responsiveness and haemoglobin variability in association with mortality.

METHODS

We used the Austrian dialysis and transplant registry, and identified 932 patients who were on maintenance haemodialysis in the years 2005-08 with recorded weekly ESA doses and haemoglobin concentrations. ESA response was defined as a positive regression slope over the observation period. Cox regression analysis with spline functions and purposeful variable selection algorithms were used.

RESULTS

Adjusted Cox regression analysis showed an increased mortality risk in subjects with wide ranges of haemoglobin variability (from <10 to >12 g/dL) (HR = 2.38, 95% CI 1.20-4.71, P = 0.013). Furthermore, patients that never reached haemoglobin levels >10 g/dL despite ESA therapy exhibited the highest risk of mortality (HR = 6.37, 95% CI 2.15-18.82, P < 0.001). ESA hypo-responsiveness was associated with increased risk of mortality in the low as well as high haemoglobin ranges [HR = 2.06, 95% CI 1.49-2.86 at haemoglobin of 9.5 g/dL and HR = 1.64, 95% CI 0.68-3.92 at 13.5 g/dL both vs. 11 g/dL (reference)]. ESA dose equivalents >16,000 units per week were associated with increased mortality in ESA responders (HR = 1.30, 95% CI 1.02-1.64). However, in hypo-responders, mortality is not associated with ESA dose (HR = 1.02, 95% CI 0.87-1.20) [both at weekly ESA dose of 20,000 units vs. 16,000 (reference)].

CONCLUSIONS

These findings suggest that the risk of mortality of haemodialysis patients requiring ESA therapy is lowest if the haemoglobin concentration is stably maintained in the range between 10 and 12 g/dL with weekly ESA dose equivalents <16,000 units.

Anderson-Fabry disease: a case-finding study among male kidney transplant recipients in Austria

The diagnosis of Anderson-Fabry disease is often delayed or even missed. As severe renal manifestations are a hallmark of alfa-galactosidase A (AGAL) deficiency, we tested the hypothesis that Anderson-Fabry disease is under-recognized among male kidney transplant recipients. This nation-wide study in Austria enrolled 1306 patients (ca 65% of all kidney transplanted males) from 30 kidney centers. AGAL activity was determined from filter paper dried blood spots by a fluorescence assay. A positive screening test was defined by an AGAL activity below 1.5 nmol/h/ml. In patients with a positive blood spot-screening test, AGAL activity was re-examined in peripheral blood leukocytes. Genetic testing for mutations in the GLA gene was performed by sequencing to confirm the diagnosis of Anderson-Fabry disease. Two previously not recognized cases with Anderson-Fabry disease were identified. Our study is the first showing that a diagnosis of Anderson-Fabry disease can be missed even in patients who undergo kidney transplantation. Case-finding strategies may be considered a useful tool for diagnosis of this rare disease that may be somewhat more prevalent among kidney transplant recipients compared with dialysis populations.

From registry data collection to international comparisons: examples of haemodialysis duration and frequency

BACKGROUND

The purpose of this study was to investigate haemodialysis (HD) dose practice patterns in different European countries in the light of the European Best Practice Guidelines (EBPG) and to study the associations of patient characteristics and country with weekly dialysis duration.

METHODS

Renal registries in Europe were asked to contribute to the study with individual patient data on weekly HD duration, number of HD sessions a week and last measured Kt/V. Additional items were age, sex, date of first renal replacement therapy (RRT), dry weight, height, HD modality, HD technique, diabetes status and vascular access type. Multivariate logistic regression was used to study the probability of receiving HD for <12 h per week.

RESULTS

Seven registries contributed data on 26 136 patients on HD on 31 December 2005. Eighty-three percent of the patients received HD for at least 12 h per week as recommended by the EBPG (range 49.0-97.3% across countries). Multivariate analysis showed significant differences across countries concerning the risk of receiving <12 h. Other risk factors included age (older), sex (female), BMI (low) and duration of RRT (shorter). Diabetes was associated with longer total HD duration.

CONCLUSION

This study shows a great international variability in weekly HD duration and some discrepancies between current practices and the EBPG. It also points out the difficulty of obtaining and comparing Kt/V values under current registry practices.