An alternative approach to estimate age-related mortality of kidney transplant recipients compared to the general population: results in favor of old-to-old transplantations

Age at Time of Kidney Transplantation as a Predictor for Mortality, Graft Loss and Self-Rated Health Status: Results From the Swiss Transplant Cohort Study

Introduction: The effect of age on health outcomes in kidney transplantation remains inconclusive. This study aimed to analyze the relationship between age at time of kidney transplantation with mortality, graft loss and self-rated health status in adult kidney transplant recipients.

Methods: This study used data from the Swiss Transplant Cohort Study and included prospective data of kidney transplant recipients between 2008 and 2017. Time-to-event analysis was performed using Cox’ regression analysis, and -in the case of graft loss- competing risk analysis. A random-intercept regression model was applied to analyse self-rated health status.

Results: We included 2,366 kidney transplant recipients. Age at transplantation linearly predicted mortality. It was also predictive for graft loss, though nonlinearly, showing that recipients aged between 35 and 55 years presented with the lowest risk of experiencing graft loss. No relationship of age with self-rated health status was detected.

Conclusion: Higher mortality in older recipients complies with data from the general population. The non-linear relationship between age and graft loss and the higher scored self-rated health status at all follow-up time-points compared to the pre-transplant status -regardless of age- highlight that age alone might not be an accurate measure for risk prediction and clinical decision making in kidney transplantation.

Long-term mortality among kidney transplant recipients with and without diabetes: a nationwide cohort study in the USA

INTRODUCTION

Little is known about the role diabetes (type 1 (T1D) and type 2 (T2D)) plays in modifying prognosis among kidney transplant recipients. Here, we compare mortality among transplant recipients with T1D, T2D and non-diabetes-related end-stage kidney disease (ESKD).

RESEARCH DESIGN AND METHODS

We included 254 188 first-time single kidney transplant recipients aged ≥18 years from the US Renal Data System (2000-2018). Diabetes status, as primary cause of ESKD, was defined using International Classification of Disease 9th and 10th Clinical Modification codes. Multivariable-adjusted Cox regression models (right-censored) computed risk of death associated with T1D and T2D relative to non-diabetes. Trends in standardized mortality ratios (SMRs) (2000-2017), relative to the general US population, were assessed using Joinpoint regression.

RESULTS

A total of 72 175 (28.4%) deaths occurred over a median survival time of 14.6 years. 5-year survival probabilities were 88%, 85% and 77% for non-diabetes, T1D and T2D, respectively. In adjusted models, mortality was highest for T1D (HR=1.95, (95% CI: 1.88 to 2.03)) and then T2D (1.65 (1.62 to 1.69)), as compared with non-diabetes. SMRs declined for non-diabetes, T1D, and T2D. However, in 2017, SMRs were 2.38 (2.31 to 2.45), 6.55 (6.07 to 7.06), and 3.82 (3.68 to 3.98), for non-diabetes, T1D and T2D, respectively.

CONCLUSIONS

In the USA, diabetes type is an important modifier in mortality risk among kidney transplant recipients with highest rates among people with T1D-related ESKD. Development of effective interventions that reduce excess mortality in transplant recipients with diabetes is needed, especially for T1D.

Impact of acute kidney injury in deceased donors with high Kidney Donor Profile Index on posttransplant clinical outcomes: a multicenter cohort study

BACKGROUND

This study evaluated the impact of acute kidney injury (AKI) on posttransplant clinical outcomes for deceased donor (DD) kidney transplantation (KT) using the Kidney Donor Profile Index (KDPI) system.

METHODS

Overall, 657 kidney transplant recipients (KTRs) receiving kidneys from 526 DDs from four transplant centers were included. We divided them into the high and low KDPI donor groups by 65%, the KDPI score, and both groups were subdivided into the AKI-DDKT and non-AKI-DDKT subgroups according to AKI in DDs.

RESULTS

There was no significant difference in the incidence of delayed graft function (DGF) between the high and low KDPI-KTR groups; however, the AKI-DDKT subgroup showed significantly higher incidence of DGF than the non-AKI-DDKT subgroup in both groups (p = 0.001, p < 0.001, respectively). The death-censored graft survival rate was significantly lower in the high KDPI-KTR group than in the low KDPI-KTR group (p = 0.005). Only in the high KDPI-KTR group, the death-censored graft survival rate was significantly lower in the KT from DDs with AKI stage 3 than KT from DDs with non-AKI or AKI stage 1 or 2 (p = 0.040). The interaction between AKI stage 3 in DDs and high KDPI on the allograft outcome was significant (p = 0.002).

CONCLUSION

KTs from DDs with AKI stage 3 showed an adverse impact on the allograft outcome in the high KDPI-KTR group. Therefore, DDs with a high KDPI score should be managed carefully so that severe AKI does not occur prior to KT.

Impact of Kidney Donor Profile Index Scores on Post-Transplant Clinical Outcomes Between Elderly and Young Recipients, A Multicenter Cohort Study

We investigated if clinical outcomes after kidney transplantation (KT) from deceased donors (DDs) with high Kidney Donor Profile Index (KDPI) can be different according to the age of KT recipients (KTRs). Six-hundred fifty-seven KTRs from 526 DDs were included from four transplant centers. We divided KTRs into elderly-KTR and young-KTR groups based on age 60 and each group was subdivided into high- or low-KDPI subgroup based on KDPI score of 65%. We compared short-term and long-term clinical outcomes among those four subgroups (low KDPI-young KTR, low KDPI-elderly-KTR, high KDPI-young-KTR, high KDPI-elderly-KTR). In short-term outcomes including acute rejection, BK virus and CMV infection, there was no significant difference among the four subgroups. In the long-term outcomes, the development of cardiovascular disease was higher in the high KDPI-elderly-KTR group than the other groups. In comparison of allograft survival rate, the high KDPI-young KTR subgroup showed highest risk for allograft failure and there was significant interaction between high-KDPI donors and young-KTR on allograft survival rate (P = 0.002). However, there was no significant difference in comparison of the patient survival rate. In conclusion, clinical impact of high-KDPI in DDs on post-transplant allograft survival may be less significant in elderly-KTR than in young-KTR.

Impact of acute kidney injury in elderly versus young deceased donors on post-transplant outcomes: A multicenter cohort study

We investigated the impact of acute kidney injury (AKI) in elderly deceased-donors (DDs) vs. AKI in young DDs on post-transplant clinical outcomes. A total of 709 kidney transplant recipients (KTRs) from 602 DDs at four transplant centers were enrolled. KTRs were divided into young-DDKT and elderly-DDKT groups according to the age of DD of 60 years. Both groups were subdivided into non-AKI-KT and AKI-KT subgroups according to AKI in DDs. We investigated short-term and long-term clinical outcomes of non-AKI-DDKT and AKI-DDKT subgroups within young-DDKT and elderly-DDKT groups. The incidence of DGF in the AKI-DDKT subgroup was higher and the allograft function within 12 months after KT in the AKI-DDKT subgroup was lower than those in the non-AKI-DDKT subgroup in both young-DDKT and elderly-DDKT groups. Death-censored allograft survival rate was significantly lower in the AKI-elderly-DDKT subgroup than that in the non-AKI-elderly-DDKT subgroup, but it did not differ between AKI-young-DDKT and non-AKI-young-DDKT subgroup. In multivariable analysis, AKI-elderly-DDKT was an independent risk factor for allograft failure (hazard ratio: 2.648, 95% CI: 1.170-5.994, p = 0.019) and a significant interaction between AKI and old age in DDs on allograft failure was observed (p = 0.001). AKI in elderly DDs, but not in young DDs, can significantly affect long-term allograft outcomes of KTRs.

Prediction of Three-Year Mortality After Deceased Donor Kidney Transplantation in Adults with Pre-Transplant Donor and Recipient Variables

Background

Prognostic models for 3-year mortality after kidney transplantation based on pre-transplant donor and recipient variables may avoid futility and thus improve donor organ allocation.

Material/Methods

There were 1546 consecutive deceased-donor kidney transplants in adults (January 1, 2000 to December 31, 2012) used to identify pre-transplant donor and recipient variables with significant independent influence on long-term survival (Cox regression modelling). Detected factors were used to develop a prognostic model for 3-year mortality in 1289 patients with follow-up of >3 years (multivariable logistic regression). The sensitivity and specificity of this model’s prognostic ability was assessed with the area under the receiver operating characteristic curve (AUROC).

Results

Highly immunized recipients [hazard ratio (HR: 2.579, 95% CI: 1.272–4.631], high urgency recipients (HR: 3.062, 95% CI: 1.294–6.082), recipients with diabetic nephropathy (HR: 3.471, 95% CI: 2.476–4.751), as well as 0, 1, or 2 HLA DR mismatches (HR: 1.349, 95% CI: 1.160–1.569) were independent and significant risk factors for patient survival. Younger recipient age ≤42.1 years (HR: 0.137, 95% CI: 0.090–0.203), recipient age 42.2–52.8 years (HR: 0.374, 95% CI: 0.278–0.498), recipient age 52.9–62.8 years (HR: 0.553, 95% CI: 0.421–0.723), short cold ischemic times ≤11.8 hours (HR: 0.602, 95% CI: 0.438–0.814) and cold ischemic times 11.9–15.3 hours (HR: 0.736, 95% CI: 0.557–0.962) reduced this risk independently and significantly. The AUROC of the derived model for 3-year post-transplant mortality with these variables was 0.748 (95% CI: 0.689–0.788).

Conclusions

Older, highly immunized or high urgency transplant candidates with anticipated longer cold ischemic times, who were transplanted with the indication of diabetic nephropathy should receive donor organs with no HLA DR mismatches to improve their mortality risk.

Impact of acute kidney injury in expanded criteria deceased donors on post-transplant clinical outcomes: multicenter cohort study

Background

The problem of organ shortage is an important issue in kidney transplantation, but the effect of kidney donation on AKI is unclear. The aim of this study was to investigate the impact of acute kidney injury (AKI) on post-transplant clinical outcomes for deceased donor kidney transplantation (DDKT) using standard criteria donors (SCDs) versus expanded criteria donors (ECDs).

Methods

Five-hundred nine KT recipients receiving kidneys from 386 deceased donors (DDs) were included from three transplant centers. Recipients were classified into the SCD-KT or ECD-KT group according to corresponding DDs and both groups were divided into the AKI-KT or non-AKI-KT subgroups according to AKI in donor. We compared the clinical outcomes among those four groups and investigated the interaction between AKI in donors and ECD on allograft outcome.

Results

The incidence of delayed allograft function was higher when the donors had AKI within SCD-KT and ECD-KT groups. In allograft biopsies within 3 months, chronic change was more significant in the AKI-ECD-KT subgroup than in the non-AKI-ECD-KT subgroup, but it did not differ between AKI-SCD-KT and non-AKI-SCD-KT group. AKI-ECD-KT showed higher risk for death-censored allograft failure than the other three groups and a significant interaction was observed between AKI in donors and ECD on the allograft outcome.

Conclusions

The presence of AKI in ECDs significantly impacted the long-term allograft outcomes of kidney transplant recipients, but it did not in SCDs.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1225-1) contains supplementary material, which is available to authorized users.

Long-term Mortality After Kidney Transplantation in a Nationwide Cohort of Patients With Type 1 Diabetes in Finland

OBJECTIVE

To examine time trends in mortality rates and causes of death in patients with type 1 diabetes and end-stage renal disease on dialysis and after kidney transplantation.

RESEARCH DESIGN AND METHODS

In a nationwide retrospective cohort analysis, all patients with type 1 diabetes in Finland who received a kidney transplant alone were compared with patients who remained on dialysis. The main outcome was patient survival after starting dialysis. The cohort was divided into dialysis, functioning kidney transplant, and dialysis after transplant loss. Causes of death were retrieved and standardized mortality ratios calculated.

RESULTS

We studied 2,383 patients. Patients survived a median of 15.9 years after a successful transplant, 11.2 years if transplant function was lost, and 2.9 years if they remained on chronic dialysis. Standardized mortality ratio decreased in all subgroups during the past four decades: from 2005 onwards, it was 3.9 in patients receiving a kidney transplant, 11.5 in patients with graft loss, and 32.5 in patients on dialysis. The most common cause of death in all patients was ischemic heart disease (45%) followed by infection (18%), which was more common in patients on dialysis.

CONCLUSIONS

Kidney transplantation is the treatment of choice for patients with type 1 diabetes and end-stage renal disease because it substantially reduces the excess death risk when compared with dialysis. Even when kidney graft function is lost, the excess death risk is still considerably lower. Although overall mortality has decreased over the years, premature death due to ischemic heart disease remains high.

Low-risk Prostate Cancer Prior to or After Kidney Transplantation

CONTEXT

Organ transplantation requires immunosuppression, which was regarded as a risk factor for tumor induction and tumor progression in all types of malignancy. Until recently, any form of active neoplasia was, therefore, regarded as contraindicative to organ transplantation. However, there is growing evidence that the increased tumor risk by immunosuppression is restricted to particular subgroups of malignancy, whereas others such as prostate cancer (PCa) are not negatively influenced.

OBJECTIVE

To compare life expectancy (LE) under various low-risk situations of PCa (untreated low-risk primary tumor, slowly progressing asymptomatic biochemical recurrence after curative treatment) with LE under renal replacement therapy. To discuss the question whether or not low-risk untreated or incurable situations of PCa must be regarded contraindicative to kidney transplantation (KT) or to transplantation of other organs.

EVIDENCE ACQUISITION

A systematic literature search was conducted using PubMed to identify original and review articles regarding PCa risk after KT as well as the natural history of untreated and treated situations of PCa. Articles published between 1991 and 2018 were reviewed and selected with the consensus of all the authors.

EVIDENCE SYNTHESIS

No evidence could be found that KT and immunosuppression are associated with an increased PCa-related risk, neither in incidence nor in aggressiveness.

CONCLUSIONS

Screening for and treatment of PCa in applicants for KT or in patients after KT should be performed in an individualized manner on the basis of lifetime risk calculations. In particular, untreated or incurable low-risk manifestations (presumed LE >10 yr) of PCa cannot be regarded as strictly contraindicative against KT.

PATIENT SUMMARY

For prostate cancer, even when left untreated, a number of low-risk situations can be defined which are associated with a life expectancy (LE) of 15 yr and more. The LE of elderly patients suffering from end-stage renal failure often does not significantly exceed 15 yr even after kidney transplantation (KT). When remaining on dialysis, however, their further LE is significantly reduced and often far below 15 yr. To the best of the presently available knowledge, KT does not worsen or accelerate the course of untreated low-risk prostate cancer. Even in the presence of untreated low-risk prostate cancer, patients with end-stage renal failure must, therefore, be expected to significantly benefit from KT.

A High Comorbidity Score Should Not be a Contraindication for Kidney Transplantation

BACKGROUND

Currently, potential kidney transplant patients more often suffer from comorbidities. The Charlson Comorbidity Index (CCI) was developed in 1987 and is the most used comorbidity score. We questioned to what extent number and severity of comorbidities interfere with graft and patient survival. Besides, we wondered whether the CCI was best to study the influence of comorbidity in kidney transplant patients.

METHODS

In our center, 1728 transplants were performed between 2000 and 2013. There were 0.8% cases with missing values. Nine pretransplant comorbidity covariates were defined: cardiovascular disease, cerebrovascular accident, peripheral vascular disease, diabetes mellitus, liver disease, lung disease, malignancy, other organ transplantation, and human immunodeficiency virus positivity. The CCI used was unadjusted for recipient age. The Rotterdam Comorbidity in Kidney Transplantation score was developed, and its influence was compared to the CCI. Kaplan-Meier analysis and multivariable Cox proportional hazards analysis, corrected for variables with a known significant influence, were performed.

RESULTS

We noted 325 graft failures and 215 deaths. The only comorbidity covariate that significantly influenced graft failure censored for death was peripheral vascular disease. Patient death was significantly influenced by cardiovascular disease, other organ transplantation, and the total comorbidity scores. Model fit was best with the Rotterdam Comorbidity in Kidney Transplantation score compared to separate comorbidity covariates and the CCI. In the population with the highest comorbidity score, 50% survived more than 10 years.

CONCLUSIONS

Despite the negative influence of comorbidity, patient survival after transplantation is remarkably good. This means that even patients with extensive comorbidity should be considered for transplantation.

Mortality Prediction after the First Year of Kidney Transplantation: An Observational Study on Two European Cohorts

After the first year post transplantation, prognostic mortality scores in kidney transplant recipients can be useful for personalizing medical management. We developed a new prognostic score based on 5 parameters and computable at 1-year post transplantation. The outcome was the time between the first anniversary of the transplantation and the patient’s death with a functioning graft. Afterwards, we appraised the prognostic capacities of this score by estimating time-dependent Receiver Operating Characteristic (ROC) curves from two prospective and multicentric European cohorts: the DIVAT (Données Informatisées et VAlidées en Transplantation) cohort composed of patients transplanted between 2000 and 2012 in 6 French centers; and the STCS (Swiss Transplant Cohort Study) cohort composed of patients transplanted between 2008 and 2012 in 6 Swiss centers. We also compared the results with those of two existing scoring systems: one from Spain (Hernandez et al.) and one from the United States (the Recipient Risk Score, RRS, Baskin-Bey et al.). From the DIVAT validation cohort and for a prognostic time at 10 years, the new prognostic score (AUC = 0.78, 95%CI = [0.69, 0.85]) seemed to present significantly higher prognostic capacities than the scoring system proposed by Hernandez et al. (p = 0.04) and tended to perform better than the initial RRS (p = 0.10). By using the Swiss cohort, the RRS and the the new prognostic score had comparable prognostic capacities at 4 years (AUC = 0.77 and 0.76 respectively, p = 0.31). In addition to the current available scores related to the risk to return in dialysis, we recommend to further study the use of the score we propose or the RRS for a more efficient personalized follow-up of kidney transplant recipients.

Poor organ quality and donor-recipient age mismatch rather than poor donation rates account for the decrease in deceased kidney transplantation rates in a Germany Transplant Center

Kidney transplantation is limited not by technical or immunological challenges but by lack of donor organs. Whereas the number of patients on waiting list increased, the transplantation rate decreased. We analyzed the development of decline rates and reasons as well as the fate of declined organs. In total, 1403 organs offered to 1950 patients between 2001 and 2010 were included. Of 440 organs offered between 2009 and 2011 that were declined, we investigated whether these organs were transplanted elsewhere and requested delayed graft function, creatinine, graft and patient survival. Data were compared to results of transplantations at the same time at our center. Decline rate increased from 47% to 87%. Main reasons were poor organ quality and donor-recipient age or size mismatch. Of the rejected organs, 55% were transplanted at other centers with function, graft and patient survival equivalent to patients transplanted at our center during that period. The number of decline has increased over time mainly due to a growing number of marginal donors accounting for poor organ quality or a mismatch of donor and recipient. If proper donor-recipient selection is performed, many organs that would otherwise be discarded can be transplanted successfully.