Development and external validation study combining existing models and recent data into an up-to-date prediction model for evaluating kidneys from older deceased donors for transplantation.

With a rising demand for kidney transplantation, reliable pre-transplant assessment of organ quality becomes top priority. In clinical practice, physicians are regularly in doubt whether suboptimal kidney offers from older donors should be accepted. Here, we externally validate existing prediction models in a European population of older deceased donors, and subsequently developed and externally validated an adverse outcome prediction tool. Recipients of kidney grafts from deceased donors 50 years of age and older were included from the Netherlands Organ Transplant Registry (NOTR) and United States organ transplant registry from 2006-2018. The predicted adverse outcome was a composite of graft failure, death or chronic kidney disease stage 4 plus within one year after transplantation, modelled using logistic regression. Discrimination and calibration were assessed in internal, temporal and external validation. Seven existing models were validated with the same cohorts. The NOTR development cohort contained 2510 patients and 823 events. The temporal validation within NOTR had 837 patients and the external validation used 31987 patients in the United States organ transplant registry. Discrimination of our full adverse outcome model was moderate in external validation (C-statistic 0.63), though somewhat better than discrimination of the seven existing prediction models (average C-statistic 0.57). The model's calibration was highly accurate. Thus, since existing adverse outcome kidney graft survival models performed poorly in a population of older deceased donors, novel models were developed and externally validated, with maximum achievable performance in a population of older deceased kidney donors. These models could assist transplant clinicians in deciding whether to accept a kidney from an older donor.

Allocation to highly sensitized patients based on acceptable mismatches results in low rejection rates comparable to nonsensitized patients.

Whereas regular allocation avoids unacceptable mismatches on the donor organ, allocation to highly sensitized patients within the Eurotransplant Acceptable Mismatch (AM) program is based on the patient's HLA phenotype plus acceptable antigens. These are HLA antigens to which the patient never made antibodies, as determined by extensive laboratory testing. AM patients have superior long-term graft survival compared with highly sensitized patients in regular allocation. Here, we questioned whether the AM program also results in lower rejection rates. From the PROCARE cohort, consisting of all Dutch kidney transplants in 1995-2005, we selected deceased donor single transplants with a minimum of 1 HLA mismatch and determined the cumulative 6-month rejection incidence for patients in AM or regular allocation. Additionally, we determined the effect of minimal matching criteria of 1 HLA-B plus 1 HLA-DR, or 2 HLA-DR antigens on rejection incidence. AM patients showed significantly lower rejection rates than highly immunized patients in regular allocation, comparable to nonsensitized patients, independent of other risk factors for rejection. In contrast to highly sensitized patients in regular allocation, minimal matching criteria did not affect rejection rates in AM patients. Allocation based on acceptable antigens leads to relatively low-risk transplants for highly sensitized patients with rejection rates similar to those of nonimmunized individuals.

Antibodies against ARHGDIB are associated with long-term kidney graft loss.

The clinical significance of non-HLA antibodies on renal allograft survival is a matter of debate, due to differences in reported results and lack of large-scale studies incorporating analysis of multiple non-HLA antibodies simultaneously. We developed a multiplex non-HLA antibody assay against 14 proteins highly expressed in the kidney. In this study, the presence of pretransplant non-HLA antibodies was correlated to renal allograft survival in a nationwide cohort of 4770 recipients transplanted between 1995 and 2006. Autoantibodies against Rho GDP-dissociation inhibitor 2 (ARHGDIB) were significantly associated with graft loss in recipients transplanted with a deceased-donor kidney (N = 3276) but not in recipients of a living-donor kidney (N = 1496). At 10 years after deceased-donor transplantation, recipients with anti-ARHGDIB antibodies (94/3276 = 2.9%) had a 13% lower death-censored covariate-adjusted graft survival compared to the anti-ARHGDIB-negative (3182/3276 = 97.1%) population (hazard ratio 1.82; 95% confidence interval, 1.32-2.53; P = .0003). These antibodies occur independently from donor-specific anti-HLA antibodies (DSA) or other non-HLA antibodies investigated. No significant relations with graft loss were found for the other 13 non-HLA antibodies. We suggest that pretransplant risk assessment can be improved by measuring anti-ARHGDIB antibodies in all patients awaiting deceased-donor transplantation.

Psychosocial consequences of living kidney donation: a prospective multicentre study on health-related quality of life, donor-recipient relationships and regret.

BACKGROUND: Previous studies have indicated decreased health-related quality of life (HRQoL) shortly after kidney donation, returning to baseline in the longer term. However, a subgroup of donors experiences persistent HRQoL problems. To identify which HRQoL aspects are impacted most by the donation and to identify at-risk donors, more specific insight into psychosocial donation consequences is needed. METHODS: The current study examined the HRQoL course, donor-perceived consequences of donation for donors, recipients and donor-recipient relationships, and regret up to 12 months post-donation in donors from seven Dutch transplantation centres. Kidney donor candidates (n = 588) completed self-report questionnaires early in the screening procedure, of which 361 (61%) donated their kidney. RESULTS: Data for 230 donors (64%) with complete assessments before donation and 6 and 12 months post-donation were analysed. Results indicated that donor physical HRQoL was comparable at all time points, except for an increase in fatigue that lasted up to 12 months post-donation. Mental HRQoL decreased at 6 months post-donation, but returned to baseline at 12 months. Donors reported large improvements in recipient's functioning and a smaller influence of the recipient's kidney disease or transplantation on the donor's life over time. A subgroup experienced negative donation consequences with 14% experiencing regret 12 months post-donation. Predictors of regret were more negative health perceptions and worse social functioning 6 months post-donation. The strongest baseline predictors of higher fatigue levels after donation were more pre-donation fatigue, worse general physical functioning and a younger age. CONCLUSIONS: Future research should examine predictors of HRQoL after donation to improve screening and to provide potential interventions in at-risk donors.

A paired kidney analysis on the impact of pre-transplant anti-HLA antibodies on graft survival.

BACKGROUND: Pre-transplant donor-specific anti-human leucocyte antigen (HLA) antibodies (DSAs) are associated with impaired kidney graft survival while the clinical relevance of non-donor-specific anti-HLA antibodies (nDSAs) is more controversial. The aim of the present paired kidney graft study was to compare the clinical relevance of DSAs and nDSAs. METHODS: To eliminate donor and era-dependent factors, a post hoc paired kidney graft analysis was performed as part of a Dutch multicentre study evaluating all transplantations between 1995 and 2005 with available pre-transplant serum samples. Anti-HLA antibodies were detected with a Luminex single-antigen bead assay. RESULTS: Among 3237 deceased donor transplantations, we identified 115 recipient pairs receiving a kidney from the same donor with one recipient being DSA positive and the other without anti-HLA antibodies. Patients with pre-transplant DSAs had a significantly lower 10-year death-censored graft survival (55% versus 82%, P=0.0001). We identified 192 pairs with one recipient as nDSA positive (against Class I and/or II) and the other without anti-HLA antibodies. For the patients with nDSAs against either Class I or II, graft survival did not significantly differ compared with patients without anti-HLA antibodies (74% versus 77%, P = 0.79). Only in patients with both nDSAs Class I and II was there a trend towards a lower graft survival (58%, P = 0.06). Lastly, in a small group of 42 recipient pairs, 10-year graft survival in recipients with DSAs was 49% compared with 68% in recipients with nDSAs (P=0.11). CONCLUSION: This paired kidney analysis confirms that the presence of pre-transplant DSAs in deceased donor transplantations is a risk marker for graft loss, whereas nDSAs in general are not associated with a lower graft survival. Subgroup analysis indicated that only in broadly sensitized patients with nDSAs against Class I and II, nDSAs may be a risk marker for graft loss in the long term.

Effect of initial immunosuppression on long-term kidney transplant outcome in immunological low-risk patients.

BACKGROUND: Few studies have evaluated the effect of different immunosuppressive strategies on long-term kidney transplant outcomes. Moreover, as they were usually based on historical data, it was not possible to account for the presence of pretransplant donor-specific human-leukocyte antigen antibodies (DSA), a currently recognized risk marker for impaired graft survival. The aim of this study was to evaluate to what extent frequently used initial immunosuppressive therapies increase graft survival in immunological low-risk patients. METHODS: We performed an analysis on the PROCARE cohort, a Dutch multicentre study including all transplantations performed in the Netherlands between 1995 and 2005 with available pretransplant serum (n = 4724). All sera were assessed for the presence of DSA by a luminex single-antigen bead assay. Patients with a previous kidney transplantation, pretransplant DSA or receiving induction therapy were excluded from the analysis. RESULTS: Three regimes were used in over 200 patients: cyclosporine (CsA)/prednisolone (Pred) (n = 542), CsA/mycophenolate mofetil (MMF)/Pred (n = 857) and tacrolimus (TAC)/MMF/Pred (n = 811). Covariate-adjusted analysis revealed no significant differences in 10-year death-censored graft survival between patients on TAC/MMF/Pred therapy (79%) compared with patients on CsA/MMF/Pred (82%, P = 0.88) or CsA/Pred (79%, P = 0.21). However, 1-year rejection-free survival censored for death and failure unrelated to rejection was significantly higher for TAC/MMF/Pred (81%) when compared with CsA/MMF/Pred (67%, P < 0.0001) and CsA/Pred (64%, P < 0.0001). CONCLUSION: These results suggest that in immunological low-risk patients excellent long-term kidney graft survival can be achieved irrespective of the type of initial immunosuppressive therapy (CsA or TAC; with or without MMF), despite differences in 1-year rejection-free survival.

Pretransplant C3d-Fixing Donor-Specific Anti-HLA Antibodies Are Not Associated with Increased Risk for Kidney Graft Failure.

Background Complement-fixing antibodies against donor HLA are considered a contraindication for kidney transplant. A modification of the IgG single-antigen bead (SAB) assay allows detection of anti-HLA antibodies that bind C3d. Because early humoral graft rejection is considered to be complement mediated, this SAB-based technique may provide a valuable tool in the pretransplant risk stratification of kidney transplant recipients.Methods Previously, we established that pretransplant donor-specific anti-HLA antibodies (DSAs) are associated with increased risk for long-term graft failure in complement-dependent cytotoxicity crossmatch-negative transplants. In this study, we further characterized the DSA-positive serum samples using the C3d SAB assay.Results Among 567 pretransplant DSA-positive serum samples, 97 (17%) contained at least one C3d-fixing DSA, whereas 470 (83%) had non-C3d-fixing DSA. At 10 years after transplant, patients with C3d-fixing antibodies had a death-censored, covariate-adjusted graft survival of 60%, whereas patients with non-C3d-fixing DSA had a graft survival of 64% (hazard ratio, 1.02; 95% confidence interval, 0.70 to 1.48 for C3d-fixing DSA compared with non-C3d-fixing DSA; P=0.93). Patients without DSA had a 10-year graft survival of 78%.Conclusions The C3d-fixing ability of pretransplant DSA is not associated with increased risk for graft failure.

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.

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.

Pre-donation cognitions of potential living organ donors: the development of the Donation Cognition Instrument in potential kidney donors.

Background: Cognitions surrounding living organ donation, including the motivation to donate, expectations of donation and worries about donation, are relevant themes during living donor evaluation. However, there is no reliable psychometric instrument assessing all these different cognitions. This study developed and validated a questionnaire to assess pre-donation motivations, expectations and worries regarding donation, entitled the Donation Cognition Instrument (DCI). Methods: Psychometric properties of the DCI were examined using exploratory factor analysis for scale structure and associations with validated questionnaires for construct validity assessment. Results: From seven Dutch transplantation centres, 719 potential living kidney donors were included. The DCI distinguishes cognitions about donor benefits, recipient benefits, idealistic incentives, gratitude and worries about donation (Cronbach's alpha 0.76-0.81). Scores on pre-donation cognitions differed with regard to gender, age, marital status, religion and donation type. With regard to construct validity, the DCI was moderately correlated with expectations regarding donor's personal well-being and slightly to moderately to health-related quality of life. Conclusions: The DCI is found to be a reliable instrument assessing cognitions surrounding living organ donation, which might add to pre-donation quality of life measures in facilitating psychosocial donor evaluation by healthcare professionals.

Increased risk of graft failure and mortality in Dutch recipients receiving an expanded criteria donor kidney transplant.

Survival of expanded criteria donor (ECD) kidneys and their recipients has not been thoroughly evaluated in Europe. Therefore, we compared the outcome of ECD and non-ECD kidney transplantations in a Dutch cohort, stratifying by age and diabetes. In all first Dutch kidney transplants in recipients ≥18 years between 1995 and 2005, both relative risks (hazard ratios, HR) and adjusted absolute risk differences (RD) for ECD kidney transplantation were analysed. In 3062 transplantations [recipient age 49.0 (12.8) years; 20% ECD], ECD kidney transplantation was associated with graft failure including death [HR 1.62 (1.44-1.82)]. The adjusted HR was lower in recipients ≥60 years of age [1.32 (1.07-1.63)] than in recipients 40-59 years [1.71 (1.44-2.02) P = 0.12 for comparison with ≥60 years] and recipients 18-39 years [1.92 (1.42-2.62) P = 0.03 for comparison with ≥60 years]. RDs showed a similar pattern. In diabetics, the risks for graft failure and death were higher than in the nondiabetics. ECD kidney grafts have a poorer prognosis than non-ECD grafts, especially in younger recipients (<60 years), and diabetic recipients. Further studies and ethical discussions should reveal whether ECD kidneys should preferentially be allocated to specific subgroups, such as elderly and nondiabetic individuals.

Epidemiology and management of hypertension in paediatric and young adult kidney transplant recipients in The Netherlands.

INTRODUCTION: Hypertension in kidney transplant recipients (KTRs) is a risk factor for cardiovascular mortality and graft loss. Data on the prevalence of hypertension and uncontrolled hypertension (uHT) in paediatric and young adult KTRs are scarce. Also, it is unknown whether 'transition' (the transfer from paediatric to adult care) influences control of hypertension. We assessed the prevalence of hypertension and uHT among Dutch paediatric and young adult KTRs and analysed the effects of transition. Additionally, we made an inventory of variations in treatment policies in Dutch transplant centres. METHODS: Cross-sectional and longitudinal national data from living KTRs ≤30 years of age (≥1-year post-transplant, eGFR >20 mL/min) were extracted from the 'RICH Q' database, which comprises information about all Dutch KTRs <19 years of age, and the Netherlands Organ Transplant Registry database for adult KTRs (≥18-30 years of age). We used both upper-limit blood pressure (BP) thresholds for treatment according to Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. uHT was defined as a BP above the threshold. A questionnaire on treatment policies was sent to paediatric and adult nephrologists at eight Dutch transplant centres. RESULTS: Hypertension and uHT were more prevalent in young adult KTRs (86.4 and 75.8%) than in paediatric KTRs (62.7 and 38.3%) according to the KDIGO definition. Time after transplantation was comparable between these groups. Longitudinal analysis showed no evidence of effect of transition on systolic BP or prevalence of uHT. Policies vary considerably between and within centres on the definition of hypertension, BP measurement and antihypertensive treatment. CONCLUSION: Average BP in KTRs increases continuously with age between 6 and 30 years. Young adult KTRs have significantly more uHT than paediatric KTRs according to KDIGO guidelines. Transition does not influence the prevalence of uHT.

The DESCARTES-Nantes survey of kidney transplant recipients displaying clinical operational tolerance identifies 35 new tolerant patients and 34 almost tolerant patients.

BACKGROUND: Kidney recipients maintaining a prolonged allograft survival in the absence of immunosuppressive drugs and without evidence of rejection are supposed to be exceptional. The ERA-EDTA-DESCARTES working group together with Nantes University launched a European-wide survey to identify new patients, describe them and estimate their frequency for the first time. METHODS: Seventeen coordinators distributed a questionnaire in 256 transplant centres and 28 countries in order to report as many 'operationally tolerant' patients (TOL; defined as having a serum creatinine <1.7 mg/dL and proteinuria <1 g/day or g/g creatinine despite at least 1 year without any immunosuppressive drug) and 'almost tolerant' patients (minimally immunosuppressed patients (MIS) receiving low-dose steroids) as possible. We reported their number and the total number of kidney transplants performed at each centre to calculate their frequency. RESULTS: One hundred and forty-seven questionnaires were returned and we identified 66 TOL (61 with complete data) and 34 MIS patients. Of the 61 TOL patients, 26 were previously described by the Nantes group and 35 new patients are presented here. Most of them were noncompliant patients. At data collection, 31/35 patients were alive and 22/31 still operationally tolerant. For the remaining 9/31, 2 were restarted on immunosuppressive drugs and 7 had rising creatinine of whom 3 resumed dialysis. Considering all patients, 10-year death-censored graft survival post-immunosuppression weaning reached 85% in TOL patients and 100% in MIS patients. With 218 913 kidney recipients surveyed, cumulative incidences of operational tolerance and almost tolerance were estimated at 3 and 1.5 per 10 000 kidney recipients, respectively. CONCLUSIONS: In kidney transplantation, operational tolerance and almost tolerance are infrequent findings associated with excellent long-term death-censored graft survival.

Nighttime kidney transplantation is associated with less pure technical graft failure.

PURPOSE: To minimize cold ischemia time, transplantations with kidneys from deceased donors are frequently performed during the night. However, sleep deprivation of those who perform the transplantation may have adverse effects on cognitive and psychomotor performance and may cause reduced cognitive flexibility. We hypothesize that renal transplantations performed during the night are associated with an increased incidence of pure technical graft failure. METHODS: A retrospective analysis of data of the Dutch Organ Transplant Registry concerning all transplants from deceased donors between 2000 and 2013 was performed. Nighttime surgery was defined as the start of the procedure between 8 p.m. and 8 a.m. The primary outcome measure was technical graft failure, defined as graft loss within 10 days after surgery without signs of (hyper)acute rejection. RESULTS: Of 4.519 renal transplantations in adult recipients, 1.480 were performed during the night. The incidence of pure technical graft failure was 1.0 % for procedures started during the night versus 2.6 % for daytime surgery (p = .001). In a multivariable model, correcting for relevant donor, recipient and graft factors, daytime surgery was an independent predictor of pure technical graft failure (p < .001). CONCLUSIONS: Limitation of this study is mainly to its retrospective design, and the influence of some relevant variables, such as the experience level of the surgeon, could not be assessed. We conclude that nighttime surgery is associated with less pure technical graft failures. Further research is required to explore factors that may positively influence the performance of the surgical team during the night.

Is the Reluctance for the Implantation of Right Donor Kidneys Justified?

BACKGROUND: The lengths of right renal veins are shorter when compared to their left counterparts. Since the implantation of kidneys with short renal veins is considered more challenging, many surgeons prefer left kidneys for transplantation. Therefore, our hypothesis is that the implantation of right kidneys from living and deceased donors is associated with more technical graft failures as compared to left kidneys. METHODS: Two consecutive cohorts of adult renal allograft recipients of living (n = 4.372) and deceased (n = 5.346) donor kidneys between January 1, 2000 and January 1, 2013 were analyzed. Data were obtained from the prospectively maintained electronic database of the Dutch Organ Transplant Registry. Technical graft failure was defined as failure of the renal allograft within 10 days after renal transplantation without signs of acute rejection. RESULTS: In the living donor kidney transplantation cohort, the implantation of right donor kidneys was associated with a higher incidence of technical graft failure (multivariate analysis p = 0.03). For recipients of deceased donor kidneys, the implantation of right kidneys was not significantly associated with technique-related graft failure (multivariate analysis p = 0.16). CONCLUSIONS: Our data show that the implantation of right kidneys from living donors is associated with a higher incidence of technique-related graft failure as compared to left kidneys.

Request for organ donation without donor registration: a qualitative study of the perspectives of bereaved relatives.

BACKGROUND: In the Netherlands, consent from relatives is obligatory for post mortal donation. This study explored the perspectives of relatives regarding the request for consent for donation in cases without donor registration. METHODS: A content analysis of narratives of 24 bereaved relatives (14 in-depth interviews and one letter) of unregistered, eligible, brain-dead donors was performed. RESULTS: Relatives of unregistered, brain-dead patients usually refuse consent for donation, even if they harbour pro-donation attitudes themselves, or knew that the deceased favoured organ donation. Half of those who refused consent for donation mentioned afterwards that it could have been an option. The decision not to consent to donation is attributed to contextual factors, such as feeling overwhelmed by the notification of death immediately followed by the request; not being accustomed to speaking about death; inadequate support from other relatives or healthcare professionals, and lengthy procedures. CONCLUSION: Healthcare professionals could provide better support to relatives prior to donation requests, address their informational needs and adapt their message to individual circumstances. It is anticipated that the number of consenting families could be enlarged by examining the experience of decoupling and offering the possibility of consent for donation after circulatory death if families refuse consent for donation after brain-death.

Characteristics and Outcomes of Granulomatosis With Polyangiitis (Wegener) and Microscopic Polyangiitis Requiring Renal Replacement Therapy: Results From the European Renal Association-European Dialysis and Transplant Association Registry.

BACKGROUND: This study describes the incidence and outcomes of European patients requiring renal replacement therapy (RRT) for kidney failure due to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: 12 renal registries providing individual RRT patient data to the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry in 1993-2012 participated. PREDICTOR: Cause of primary kidney disease: AAV (ie, granulomatosis with polyangiitis [Wegener] and microscopic polyangiitis) versus 3 separate matched control groups without AAV: (1) primary glomerulonephritis, (2) diabetes mellitus, and (3) disease other than diabetes mellitus as the cause of primary kidney disease, including glomerulonephritis (termed "nondiabetes"). OUTCOMES: Incidence, causes of death, and survival. MEASUREMENTS: ERA-EDTA primary renal disease codes. RESULTS: 2,511 patients with AAV (1,755, granulomatosis with polyangiitis; 756, microscopic polyangiitis) were identified, representing an incidence of 1.05 per million population (pmp) for granulomatosis with polyangiitis (predominating in Northern Europe) and 0.45 pmp for microscopic polyangiitis (prevailing in Southern Europe). Kidney transplantation was performed in 558 (22.2%) patients with vasculitis. The 10-year probability for survival on RRT after day 91 was 32.5% (95% CI, 29.9%-35.1%) in patients with vasculitis. Survival on RRT after day 91 did not differ between AAV and matched nondiabetes patients. Patient and transplant survival after kidney transplantation, adjusted for time period and country, was better in AAV than in matched nondiabetes patients (HRs of 0.81 [95% CI, 0.67-0.99] and 0.82 [95% CI, 0.69-0.96], respectively). LIMITATIONS: No data for extrarenal manifestations, treatment, and relapses. CONCLUSIONS: Geographical differences in the incidence of RRT for kidney failure due to granulomatosis with polyangiitis and microscopic polyangiitis copied their distribution in the general population. Overall survival on RRT after day 91 for patients with AAV was similar to that for patients with nondiabetes diagnoses. Our results suggest that patients with AAV are suitable candidates for kidney transplantation with favorable survival outcomes.

Improved Mortality Prediction in Dialysis Patients Using Specific Clinical and Laboratory Data.

BACKGROUND: Risk prediction models can be used to inform patients undergoing renal replacement therapy about their survival chances. Easily available predictors such as registry data are most convenient, but their predictive value may be limited. We aimed to improve a simple prediction model based on registry data by incrementally adding sets of clinical and laboratory variables. METHODS: Our data set includes 1,835 Dutch patients from the Netherlands Cooperative Study on the Adequacy of Dialysis. The potential survival predictors were categorized on availability. The first category includes easily available clinical data. The second set includes laboratory values like albumin. The most laborious category contains glomerular filtration rate (GFR) and Kt/V. Missing values were substituted using multiple imputation. Within 1,225 patients, we recalibrated the registry model and subsequently added parameter sets using multivariate Cox regression analyses with backward selection. On the other 610 patients, calibration and discrimination (C-index, integrated discrimination improvement (IDI) index and net reclassification improvement (NRI) index) were assessed for all models. RESULTS: The recalibrated registry model showed adequate calibration and discrimination (C-index=0.724). Adding easily available parameters resulted in a model with 10 predictors, with similar calibration and improved discrimination (C-index=0.784). The IDI and NRI indices confirmed this, especially for short-term survival. Adding laboratory values resulted in an alternative model with similar discrimination (C-index=0.788), and only the NRI index showed minor improvement. Adding GFR and Kt/V as candidate predictors did not result in a different model. CONCLUSION: A simple model based on registry data was enhanced by adding easily available clinical parameters.

Mortality from infections and malignancies in patients treated with renal replacement therapy: data from the ERA-EDTA registry.

BACKGROUND: Infections and malignancies are the most common non-cardiovascular causes of death in patients on chronic renal replacement therapy (RRT). Here, we aimed to quantify the mortality risk attributed to infections and malignancies in dialysis patients and kidney transplant recipients when compared with the general population by age group and sex. METHODS: We followed 168 156 patients included in the ERA-EDTA registry who started RRT in 1993-2007 until 1 January 2012. Age- and cause-specific mortality rates per 1000 person-years (py) and mortality rate ratios (MRRs) compared with the European general population (WHO) were calculated. To identify risk factors, we used Cox regression. RESULTS: Infection-related mortality was increased 82-fold in dialysis patients and 32-fold in transplant recipients compared with the general population. Female sex, diabetes, cancer and multisystem disease were associated with an increased risk of infection-related mortality. The sex difference was most pronounced for dialysis patients aged 0-39 years, with women having a 32% (adjusted HR 1.32 95% CI 1.09-1.60) higher risk of infection-related mortality than men. Mortality from malignancies was 2.9 times higher in dialysis patients and 1.7 times higher in transplant recipients than in the general population. Cancer and multisystem disease as primary causes of end-stage renal disease were associated with higher mortality from malignancies. CONCLUSION: Infection-related mortality is highly increased in dialysis and kidney transplant patients, while the risk of malignancy-related death is moderately increased. Young women on dialysis may deserve special attention because of their high excess risk of infection-related mortality. Further research into the mechanisms, prevention and optimal treatment of infections in this vulnerable population is required.

Urinary biomarkers after donor nephrectomy.

As the beginning of living-donor kidney transplantation, physicians have expressed concern about the possibility that unilateral nephrectomy can be harmful to a healthy individual. To investigate whether the elevated intra-abdominal pressure (IAP) during laparoscopic donor nephrectomy causes early damage to the remaining kidney, we evaluated urine biomarkers after laparoscopic donor nephrectomy. We measured albumin and alpha-1-microglobulin (α-1-MGB) in urine samples collected during and after open and laparoscopic donor nephrectomy and laparoscopic cholecystectomy and colectomy. Additionally, kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were measured in urine samples collected during and after laparoscopic donor nephrectomy and colectomy. The same biomarkers were studied in patients randomly assigned to standard or low IAP during laparoscopic donor nephrectomy. We observed a peak in urinary albumin excretion during all procedures. Urine α-1-MGB rose in the postoperative period with a peak on the third postoperative day after donor nephrectomy. Urine α-1-MGB did not increase after laparoscopic cholecystectomy and colectomy. After laparoscopic nephrectomy, we observed slight increases in urine KIM-1 during surgery and in urine NGAL at day 2-3 after the procedure. After laparoscopic colectomy, both KIM-1 and NGAL were increased in the postoperative period. There were no differences between the high- and low-pressure procedure. Elevated urinary α-1-MGB suggests kidney damage after donor nephrectomy, occurring irrespective of IAP during the laparoscopic procedure.