Jordi Comas

A paired survival analysis comparing hemodialysis and kidney transplantation from deceased elderly donors older than 65 years.

Background Kidney transplantation from deceased donors aged 65 years or older is associated with suboptimal patient and graft survival. In large registries, survival is longer after kidney transplantation than when remaining on dialysis. However, whether recipients of these old grafts survive longer than their dialysis counterparts is unknown. Methods We retrospectively assessed the outcomes of 5,230 recipients of first deceased donor grafts transplanted during the period of 1990 to 2010 in Catalonia, 915 of whom received grafts from donors 65 years or older. In a match-pair analysis, we aimed to pair each of 915 eligible cases with one control (1:1 ratio). Each pair had the same characteristics at the time of entering dialysis program: age, sex, primary renal disease, period of dialysis onset, and cardiovascular comorbidities. We found 823 pairs. Results Patient survival of 823 recipients of elderly donors was significantly higher than that of their 823 matched dialysis waitlisted nontransplanted partners (91.6%, 74.5%, and 55.5% vs. 88.8%, 44.2%, and 18.1%, respectively at 1, 5, and 10 years; P<0.001). The probability of death after the first year was similar (8.1% transplant vs 10.3% dialysis; P=0.137); however, analyzing the whole period, the adjusted proportional risk of death was 2.66 (95% confidence interval, 2.21–3.20) times higher for patients remaining on dialysis than for transplanted patients (P<0.001). Conclusion Our study demonstrates that despite the fact that kidney transplantation from elderly deceased donors is associated with reduced graft and patient survival, their paired counterpart patients remaining on dialysis have a risk of death 2.66 times higher.

Long-term outcome of antineutrophil cytoplasmic antibody-associated small vessel vasculitis after renal transplantation

The survival after renal transplantation of patients with antineutrophil cytoplasmic antibody (ANCA)‐associated to systemic vasculitis is as good as in other diseases, although most of the reports are based on small numbers of patients. Furthermore, it is not known whether comorbidities (cardiovascular [CV] disease and cancer) are more frequent than in general population. We report our experience and the analysis of the published data on this topic. The outcome after transplantation in 49 patients with ANCA‐associated small vessel vasculitis was compared with a control group. The relapse rate of vasculitis was 0.01 per patient per year. Comparison with the control patients revealed no difference in long‐term outcome, CV mortality or incidence of malignancies. In the published literature, patients with ANCA at transplantation and with Wegeners granulomatosis are at greater risk of relapse. Taking our own results together with the review of the literature, we conclude that patient and graft survival rates compare favorably with those in control group that the recurrence rate is very low and that there is no increase in the incidence of cancer or in CV mortality. Patients with ANCA at transplantation and with Wegeners granulomatosis have a higher relapse rate.

Renal replacement therapy in ADPKD patients: a 25-year survey based on the Catalan registry

BackgroundSome 7-10% of patients on replacement renal therapy (RRT) are receiving it because of autosomal dominant polycystic kidney disease (ADPKD). The age at initiation of RRT is expected to increase over time.MethodsClinical data of 1,586 patients (7.9%) with ADPKD and 18,447 (92.1%) patients with other nephropathies were analysed from 1984 through 2009 (1984–1991, 1992–1999 and 2000–2009).ResultsThe age at initiation of RRT remained stable over the three periods in the ADPKD group (56.7 ± 10.9 (mean ± SD) vs 57.5 ± 12.1 vs 57.8 ± 13.3 years), whereas it increased significantly in the non-ADPKD group (from 54.8 ± 16.8 to 63.9 ± 16.3 years, p < 0.001). The ratio of males to females was higher for non-ADPKD than for ADPKD patients (1.6–1.8 vs 1.1–1.2). The prevalence of diabetes was significantly lower in the ADPKD group (6.76% vs 11.89%, p < 0.001), as were most of the co-morbidities studied, with the exception of hypertension. The survival rate of the ADPKD patients on RRT was higher than that of the non-ADPKD patients (p < 0.001).ConclusionsOver time neither changes in age nor alterations in male to female ratio have occurred among ADPKD patients who have started RRT, probably because of the impact of unmodifiable genetic factors in the absence of a specific treatment.

Starting hemodialysis with catheter and mortality risk: persistent association in a competing risk analysis.

Purpose The vascular access (VA) used at hemodialysis (HD) inception is involved in the mortality risk. We analyzed the survival of incident patients over time according to the initial VA and the VA profile of patients who died during the first year of follow-up. Methods Data of VA were obtained from 9956 incident HD patients from the Catalan Registry. Results Over 12 years, 47.9% of patients initiated HD with a fístula, 1.2% with a graft, 15.9% with a tunneled catheter and 35% with an untunneled catheter. Regarding fistula use, the hazard ratio of death for all-causes over time when applying a multivariate competing risk model was 1.55 [95% confidence interval (CI): 1.42-1.69] and 1.43 (95% CI: 1.33-1.54) for patients with tunneled and untunneled catheter, respectively. During the first year of follow-up, the crude all-cause mortality rate (deaths/100 patient-years) was higher during the early (first 120 days) compared to the late (121-365 days) period: 18.3 (95% CI: 16.8-19.8) versus 15.4 (95% CI: 14.5-16.5). Regarding fistula use, for patients using untunneled and tunneled catheter, the odds ratio of death in the early period for all-causes was 3.66 (95% CI: 2.80-4.81) and 2.97 (95% CI: 2.17-4.06), for cardiovascular causes it was 2.76 (95% CI: 1.90-4.01) and 1.84 (95% CI: 1.17-2.89) and for infection-related causes it was 6.62 (95% CI: 3.11-14.05) and 4.58 (95% CI: 2.00-10.52), respectively. Conclusions Half of all incident patients in Catalonia are exposed to excessive mortality risk related to catheter and this scenario can be improved by early fistula placement.

Evolution of the incidence of chronic kidney disease Stage 5 requiring renal replacement therapy in the diabetic population of Catalonia

BACKGROUND Chronic kidney disease due to diabetes (DCKD) is the main known cause of renal replacement therapy (RRT) initiation. A Centers for Disease Control and Prevention study showed that the rate of DCKD cases initiating RRT among the overall DM population has dropped in the USA. Our main objective was to analyse this rate in Catalonia in 1994, 2002, 2006 and 2010. Cardiovascular risk factors (CVRF) in the diabetic population and characteristics and survival of DCKD patients on RRT were also evaluated. METHODS Data from the Catalan Renal Registry was used to learn the number of DCKD cases on RRT together with their characteristics and survival rates. Data from the Catalonia Health Survey established the diabetic population and also the prevalence of CVRF in this population. RESULTS The adjusted rate (95% CI) of patients initiating RRT with DCKD was 509.1 (484.6-533.7) pmp in 1994, 645.3 (621.6-669.0) in 2002, 602.6 (581.4-623.9) in 2006 and 600.0 (578.4-621.6) in 2010. Survival of DCKD patients in the 4th year of RRT had increased progressively from 35.9% for DCKD cases versus 64.9% for CKD cases due to other causes in 1994, to 39.9% versus 58.3% in 2002 and to 59.9% versus 65.9% in 2006. CONCLUSIONS Since 2002, the rates of patients with DCKD initiating RRT among the overall DM population decreased slightly in Catalonia. Survival in these cases has increased progressively and in 2006 is similar to the CKD patients due to other causes. This figure suggests a better overall management, especially of CVRF.

Vascular access for incident hemodialysis patients in Catalonia: analysis of data from the Catalan Renal Registry (2000-2011).

Purpose Arteriovenous fístula is the best vascular access (VA) for hemodialysis. We analyzed the VA used at first session and the factors associated with the likelihood to start hemodialysis by fistula in 2000-2011. Methods Data of VA type were obtained in 9,956 incident hemodialysis patients from the Catalan Registry. Results Overall, 47.9% of patients initiated hemodialysis with a fistula, 1.2% with a graft, 15.9% with a tunneled catheter and 35% with an untunneled catheter. The percentage of incident patients with fistula and catheter has remained stable at around 50% over the years. The likelihood to start hemodialysis with fistula was significantly lower in females [adjusted odds ratio: 0.69, 95% confidence interval (CI): 0.61-0.75], patients aged 18-44 years (0.78, 95% CI: 0.64-0.94), patients with comorbidity (0.67, 95% CI: 0.60-0.75) and tended to be lower in patients aged over 74 years (0.89, 95% CI: 0.78-1.01). The probability to use fistula was significantly higher in patients with polycystic kidney disease (2.08, 95% CI: 1.63-2.67), predialysis nephrology care longer than 2 years (4.14, 95% CI: 3.63-4.73) and steady chronic kidney disease (CKD) progression (10.97, 95% CI: 8.41-14.32). During 1 year of follow-up, 67.2% and 59.6% of patients using untunneled and tunneled catheter changed to fistula, respectively. Conclusions Starting hemodialysis by fistula was related with nonmodifiable patient characteristics and modifiable CKD practice processes, such as predialysis care duration. Half of the incident patients were exposed annually in Catalonia to potential catheter complications. This scenario can be improved by optimizing the processes of CKD care.

Does the obesity survival paradox of dialysis patients differ with age

Background: The obesity paradox of hemodialysis patients (the association between obesity and survival) could be modified by age. We hypothesize that whereas obesity associates with survival in elderly patients, it behaves as a mortality risk marker in younger individuals. Methods: Retrospective study of 2002-2010 adult incident hemodialysis to analyze the relationship between body mass index (BMI) and annual body weight changes with mortality in different age strata. Results: Included in the study were 6,290 individuals. A progressive decrease in mortality was associated with increasing BMI ranges. Both annual body weight gains and losses were associated with mortality. Similar results were observed in elderly individuals, but in the BMI values of young patients, there were no significant differences in mortality. Conclusion: There is a survival benefit with increasing BMI in patients overall. However, while these results persist in patients >65 years, in young people there are no changes in mortality. Patients with the highest inter-annual variability in weight have an increased risk.

Age may explain the association of an early dialysis initiation with poor survival

BACKGROUND Some studies postulate that early dialysis initiation may increase mortality. AIM The aim of the present study was to assess to what extent this was due to confounding by age. DESIGN Observational retrospective cohort study. METHODS We studied all patients starting dialysis therapy between 1 January 1995 and 31 December 2009 in our center. The following variables at dialysis initiation in end-stage renal disease (ESRD) patients were analysed: estimated glomerular filtration rate (eGFR), age, gender, diabetes mellitus, serum albumin, hemoglobin, period of dialysis initiation, history of ischemic heart disease and stroke. Multivariate Cox model was used to calculate adjusted patient survival. RESULTS Over the last 15 years, 428 patients initiated dialysis therapy in our reference area. Median eGFR at dialysis initiation was 8.16 ml/min. In the univariate analysis, increased eGFR, age, dialysis initiation 1995-1999/2000-2004, diabetes and history of ischemic heart disease were associated (P < 0.05) with increased mortality in ESRD. Patients that started dialysis program with eGFR > 8.16 were older than those who did it with eGFR < 8.16 (66 vs. 61 years, P < 0.001). The association between mortality and eGFR in the crude multivarite Cox model was lost when the model was adjusted by age. In the multivariate Cox model, dialysis initiation period, serum albumin and history of ischemic heart disease were associated with mortality. CONCLUSION History of ischemic heart disease, serum albumin and dialysis start before 2005 were risk factors for mortality in ESRD patients. Older age is usually associated with early dialysis initiation, so age adjustment is needed to perform studies aimed to calculate the effect of eGFR at dialysis initiation on survival.

Evaluation of a Deceased Donor Kidney Allocation Score. The Catalan Experience

Introduction Several countries have implemented their own kidney allocation policies to ensure the equity, transparency and patient benefit in the waiting list. In Catalonia, a new allocation model has been implemented during 2017, which uses a score developed to prioritize the recipients. Four analyses were designed to evaluate that score: 1. Concordance retrospective analysis: would that score have chosen the same recipient as the clinician did in the past? 2. Impact retrospective analysis: how would the recipient profile have changed if the new allocation model were applied in the past? 3. Prospective analysis: Has the concordance changed after providing the score only for information? Which are the causes for not choosing the recipients with higher scores? 4. Evaluation analysis: Has the concordance and patient profile changed after the new allocation model?. Methods Data from the registries of the Catalan Transplant Organization were used. The effective kidney offers from January 2014 to June 2016 and the daily recipients active on the deceased donor renal waiting list were considered for retrospective concordance (n=955) and impact analysis (n=1.046). The effective kidney offers from December 2016 to March 2017 were used for the prospective analysis (n=98). The recipients from the beginning of the new model (12th June 2017) to 31st October 2017 were used to evaluate it (n=208)*. Results RIn the concordance analysis, 282 (29.5%) kidney transplants (KT) were performed to a patient within the top 25th percentile values of the score (concordance). In the impact analysis, comparing the 1.046 KT performed with the 1.046 theoretical KT that would be performed using the new allocation model, we observe an increase of mean time on dialysis (from 36.3 to 57.2 months) and cpra I+II mean (from 51.6% to 64.9%), a decrease of the mean age from 59.2 to 57.9 years and a reduction of first KT from 89.2% to 76.2%. In the 98 KT studied in the prospective analysis, concordance increased up to 65.3%. The main causes for not choosing the recipients with higher values were the disagreement with the candidate (50.3%), immunologic causes (13.2%) and mistakes with the status of the recipient (21.9%). After the implementation of the new model the concordance remained at 65.8%. The mean time on dialysis was 53.5 months, the mean cpra I+II% was 33.8 and the mean age was 57,4 years. Conclusion Although the concordance between the clinician and the developed score was initially low, it increased significantly after providing the waiting list sorted by that score. Changes in the recipient profile observed in the impact analysis were the expected and desired ones. Finally, after the implementation we observe the expected increase of time on dialysis and younger recipients meanwhile the mean of cpra I+II % was lower than expected. * The results will be updated using recipients up to March 2018 in the presentation at 27th International Congress of The Transplantation Society.

Effect of Body Weight Variation in Kidney Transplantation: A Retrospective Cohorts Study.

Introduction Obese kidney allograft recipients have an increased risk of surgical complications, delayed graft function(DGF), prolonged hospital stay and late graft failure. However, there is lack of information regarding the effect of body mass index(BMI) variation after kidney transplantation(KT). Methods and Materials In this longitudinal study, we used data from Catalan Renal Registry including first KT recipients within 1990 and 2011. The annual change on post-transplantation BMI was calculated all patient follow-up (until December 2015). Main outcome variables were DGF, eGFR(CKD-EPI), patient and graft survival. Statistical analysis was adjusted for variables impacting on outcome. Results A total of 5,983 kidney trasnplant recipients were included. Obesity was observed in 609 patients(10.9%) at the time of transplantation. Obese patients were transplanted more recently, were younger and received kidneys from younger donors. Incidence of DGF was significantly higher in obese (40.38% vs 29.5%, P<0.001). Multivariate logistic regression model confirmed that baseline obesity was a risk factor for DGF (class I obesity: OR 1.6; 95%CI 1.3-2.1, P<0.001 and class II OR 2.2; 95%CI 1.5-3.2, P<0.001) whereas under-weight was protective (OR 0.5; 95%CI 0.3-0.8, P=0.005). Moreover, baseline obesity was a detrimental factor concerning long-term graft survival (SHR 1.25; 95%CI 1.03-1.51, P<0.05) without any effect on patient survival (SHR 0.93 95%CI 0.74-1.17, P= 0.53). In obese patients with functioning graft, BMI loss of >7% was associated with better patient survival, and a BMI loss of >7% was associated with worse graft survival. Conclusion Our conclusion is that BMI reduction after KT was not associated with eGFR improvement and only in those with a reduction of >7% patient survival was better with worse long-term graft survival.