Waitlist Time, Age, and Social Vulnerability: Impact on the Survival Benefit of Deceased Donor Kidney Transplantation Versus Long-term Dialysis Among Patients With End-stage Renal Disease

BACKGROUND

We sought to define the survival benefit of kidney transplantation versus long-term dialysis relative to waitlist time on dialysis, social vulnerability, and age among end-stage renal transplant candidates.

METHODS

End-stage renal disease patients who were candidates for their first deceased donor kidney transplantation between 2008 and 2020 were identified using the US Renal Data System. Survival probabilities for patient survival were compared using the restricted mean survival times (RMSTs) across different age and social vulnerability index (SVI) ranges.

RESULTS

Among 149 923 patients, 68 795 (45.9%) patients underwent a kidney transplant and 81 128 (54.1%) remained on dialysis. After propensity-score matching (n = 58 035 in each cohort), the 5-y RMST difference between kidney transplant and dialysis demonstrated an increasing trend in mean life-years gained within 5 y of follow-up relative to advancing age (<30 y: 0.40 y, 95% confidence interval, 0.36-0.44 y versus >70 y: 0.75 y, 95% confidence interval, 0.70-0.80 y). Conversely, disparities in 5-y RMSTs remained consistent relative to social vulnerability (median 5-y RMST difference: 0.62 y comparing low versus high SVI). When considering waitlist duration, stratified analyses demonstrated increasing trends across different age groups with the largest RMST differences observed among older patients aged ≥70 y. Notably, longer waitlist durations (>3 y) yielded more pronounced RMST differences compared with shorter durations (<1 y).

CONCLUSIONS

These data underscore the survival benefit associated with kidney transplantation over long-term dialysis across various age and SVI ranges. Transplantation demonstrated a greater advantage among older patients who had a longer waitlist duration.

Influence of diabetes and other risk factors on in-hospital mortality following kidney transplantation: an analysis of the Spanish National Hospital Discharge Database from 2016 to 2020

INTRODUCTION

To assess time trends in incidence, clinical characteristics, complications, and hospital outcomes among patients with type 1 diabetes (T1D), with type 2 diabetes (T2D), and patients without diabetes who underwent kidney transplant (KT); to identify variables associated with in-hospital mortality (IHM); and to determine the impact of the COVID-19 pandemic.

RESEARCH DESIGN AND METHODS

We used a nationwide discharge database to select KT recipients admitted to Spanish hospitals from 2016 to 2020. We stratified patients according to diabetes status. We used multivariable logistic regression to identify the variables associated with IHM.

RESULTS

A total of 14 594 KTs were performed in Spain (T2D, 22.28%; T1D, 3.72%). The number of KTs rose between 2016 and 2019 and and decreased from 2019 to 2020 in all groups. In patients with T2D, the frequency of KT complications increased from 21.08% in 2016 to 34.17% in 2020 (p<0.001). Patients with T2D had significantly more comorbidity than patients with T1D and patients without diabetes (p<0.001). Patients with T1D experienced KT rejection significantly more frequently (8.09%) than patients with T2D (5.57%).COVID-19 was recorded in 26 out of the 2444 KTs performed in 2020, being found in 6 of the 39 patients deceased that year (15.38%) and in 0.83% of the survivors.The variables associated with IHM were comorbidity and complications of KT. The presence of T1D was associated with IHM (OR 2.6; 95% CI 1.36 to 5.16) when patients without diabetes were the reference category. However, T2D was not associated with a higher IHM (OR 0.86; 95% CI 0.61 to 1.2).

CONCLUSIONS

The COVID-19 pandemic led to a decrease in the number of transplants. Patients with T1D have more rejection of the transplanted organ than patients with T2D. Fewer women with T2D undergo KT. The presence of T1D is a risk factor for IHM.

Healthcare costs after kidney transplantation compared to dialysis based on propensity score methods and real world longitudinal register data from Sweden

This study aimed to estimate the healthcare costs of kidney transplantation compared with dialysis using a propensity score approach to handle potential treatment selection bias. We included 693 adult wait-listed patients who started renal replacement therapy between 1998 and 2012 in Region Skåne and Stockholm County Council in Sweden. Healthcare costs were measured as annual and monthly healthcare expenditures. In order to match the data structure of the kidney transplantation group, a hypothetical kidney transplant date of persons with dialysis were generated for each dialysis patient using the one-to-one nearest-neighbour propensity score matching method. Applying propensity score matching and inverse probability-weighted regression adjustment models, the potential outcome means and average treatment effect were estimated. The estimated healthcare costs in the first year after kidney transplantation were €57,278 (95% confidence interval (CI) €54,467-60,088) and €47,775 (95% CI €44,313-51,238) for kidney transplantation and dialysis, respectively. Thus, kidney transplantation leads to higher healthcare costs in the first year by €9,502 (p = 0.066) compared to dialysis. In the following two years, kidney transplantation is cost saving [€36,342 (p < 0.001) and €44,882 (p < 0.001)]. For patients with end-stage renal disease, kidney transplantation reduces healthcare costs compared with dialysis over three years after kidney transplantation, even though the healthcare costs are somewhat higher in the first year. Relating the results of existing estimates of costs and health benefits of kidney transplantation shows that kidney transplantation is clearly cost-effective compared to dialysis in Sweden.

Renal Transplantation in the Elderly: Are They All the Same? A Multicenter, Comorbidity-Based Study

INTRODUCTION

The age for kidney transplantation (KT) is no longer a limitation and several studies have shown benefits in the survival of elderly patients. The aim of this study was to examine the relationship of the baseline Charlson comorbidity index (CCI) score to morbidity and mortality after transplantation.

METHODS

In this multicentric observational retrospective cohort study, we included patients older than 60 years admitted on the waiting list (WL) for deceased donor KT from January 01, 2006, to December 31, 2016. The CCI score was calculated for each patient at inclusion on the WL.

RESULTS

Data for analysis were available of 387 patients. The patients were divided in tertiles of CCI: group 1 (CCI: 1-2) n = 117, group 2 (CCI: 3-4) n = 158, and group 3 (CCI: ≥5) n = 112. Patient survival was significantly different between CCI groups at 1, 3, and 5 years, respectively: 90%, 88%, and 84% for group 1, 88%, 80%, and 72% for group 2, and 87%, 75%, and 63% for group 3 (p < 0.0001). Variables associated with mortality were CCI score (p < 0.0001), HLA mismatch (p = 0.014), length of hospital stay (p < 0.0001), surgical complications (p = 0.048).

CONCLUSION

Individualized strategies to modify these variables may improve patient's morbidity and mortality after KT.

Prognosis Factors of Patients Undergoing Renal Replacement Therapy

BACKGROUND

Survival in patients with end-stage kidney disease (ESKD) on renal replacement therapy (RRT) is less than that of the general population of the same age, and depends on patient factors, the medical care received, and the type of RRT used. The objective of this study is to analyze the factors associated with survival in patients undergoing RRT.

METHODS

We conducted a retrospective observational study of adult patients with an incident of ESKD on RRT in Andalusia from 1 January 2008 to 31 December 2018. Patient characteristics, nephrological care received, and survival from the beginning of RRT were evaluated. A survival model for the patient was developed according to the variables studied.

RESULTS

A total of 11,551 patients were included. Median survival was 6.8 years (95% CI (6.6; 7.0)). After starting RRT, survival at one year and five years was 88.7% (95% CI (88.1; 89.3)) and 59.4% (95% CI (58.4; 60.4)), respectively. Age, initial comorbidity, diabetic nephropathy, and a venous catheter were independent risk factors. However, non-urgent initiation of RRT and follow-up in consultations for more than six months had a protective effect. It was identified that renal transplantation (RT) was the most influential independent factor in patient survival, with a risk ratio of 0.13 (95% CI (0.11; 0.14)).

CONCLUSIONS

The receiving of a kidney transplant was the most beneficial modifiable factor in the survival of incident patients on RRT. We consider that the mortality of the renal replacement treatment should be adjusted, taking into account both modifiable and nonmodifiable factors to achieve a more precise and comparable interpretation.

Years of Potential Life Lost on Renal Replacement Therapy: Retrospective Study Cohort

BACKGROUND

Chronic kidney disease is the non-communicable disease with the highest growth in morbidity and mortality. Renal transplantation (RT) is the first option of renal replacement in end-stage kidney disease (ESKD) and dialysis is an alternative. However, there is no objective quantification of the impact of both options on a patient's overall survival. The purpose of our study is to assess the potential years of life lost by patients on renal replacement therapy.

METHODS

Retrospective study cohort conducted from 2008 to 2018 based on autonomic data registry.

RESULTS

11,551 patients included who received renal replacement therapy (RRT) in a range of age from 15 to 94 years. The mean age at the time of onset was 62.7 years, 95% confidence interval (95% CI) (62.4; 63.0). The mortality rate of RRT patients was 42.2%, 95% CI (41.5; 43.3) and the mean age at death was 72.7 years, 95% CI (72.4; 73.1). The number of patients with ESKD treated with RT was 3776, 32.7% of the total, 95% CI (31.8; 33.5). The total amount of years of potential life lost (YPLL) in the entire cohort was 77,831.3 years, 48,010.1 years in men, and 29,821.2 years in women. The mean number of YPLL per patient with RRT was 6.74 years in both sexes, 6.95 years in women, and 6.61 years in men. The mean number of potential years of life lost in dialysis patients was 9.0 years in both sexes, 8.8 years in men, and 9.2 years in women, while among kidney transplant recipients this figure decreased to 2.2 years in both men and women.

CONCLUSIONS

End-stage chronic kidney disease in renal replacement therapy by dialysis causes an average of 9.0 years of life potentially lost for each patient on dialysis treatment, while having received a kidney transplant reduces this figure by 75.6%.

Textbook Outcome as a Quality Metric in Living and Deceased Donor Kidney Transplantation

BACKGROUND

Quality in kidney transplantation is measured using 1-year patient and graft survival. Because 1-year patient and graft survival exceed 95%, this metric fails to measure a spectrum of quality. Textbook outcomes (TO) are a composite quality metric offering greater depth and resolution. We studied TO after living donor (LD) and deceased donor (DD) kidney transplantation.

STUDY DESIGN

United Network for Organ Sharing data for 69,165 transplant recipients between 2013 and 2017 were analyzed. TO was defined as patient and graft survival of 1 year or greater, 1-year glomerular filtration rate of greater than 40 mL/min, absence of delayed graft function, length of stay of 5 days or less, no readmissions during the first 6 months, and no episodes of rejection during the first year after transplantation. Bivariate analysis identified characteristics associated with TO, and covariates were incorporated into multivariable models. Five-year conditional survival was measured, and center TO rates were corrected for case complexity to allow center-level comparisons.

RESULTS

The national average TO rates were 54.1% and 31.7% for LD and DD transplant recipients. The hazard ratio for death at 5 years for recipients who did not experience TO was 1.92 (95% CI 1.68 to 2.18, p ≤ 0.0001) for LD transplant recipients and 2.08 (95% CI 1.93 to 2.24, p ≤ 0.0001) for DD transplant recipients. Center-level comparisons identify 18% and 24% of centers under-performing in LD and DD transplantation. High rates of TO do not correlate with transplantation center volume.

CONCLUSION

Kidney transplant recipients who experience TO have superior long-term survival. Textbook outcomes add value to the current standards of 1-year patient and graft survival.

Equity of access to renal transplantation: a European perspective

PURPOSE OF REVIEW

Renal transplantation offers the chance for patients with end-stage renal disease (ESRD) to have a significantly longer, healthier and better quality life compared with remaining on dialysis. Inequities have been demonstrated at multiple points in the transplantation pathway. In this review, the factors contributing to inequity in access to renal transplantation will be explored from a European perspective.

RECENT FINDINGS

Despite improvements in patient assessment and revision of organ-offering schemes, there remain persistent inequities in access to the waiting list, allocation of a deceased donor transplant, receiving a living donor transplant and achieving preemptive transplantation. Older age, lower socioeconomic status and health literacy are key factors that continue to impact equity of access to transplantation.

SUMMARY

A number of modifiable factors have been identified affecting access to transplantation, Increased patient education together with a better access to and promotion of living donation may help address some of these inequities.

Factors Affecting Access to the Kidney Transplant Waiting List in Eastern Hungary

Kidney transplantation is the best available treatment choice for patients suffering from end-stage renal disease; however, not all patients with end-stage renal disease have equal access to it. The aim of the study was to measure the factors that may influence access to the kidney transplant waiting list in eastern Hungary. A total of 254 patients with renal failure between 18 and 75 years old from 8 dialysis centers participated in the study. The factors associated with access to the waiting list were identified by univariate descriptive analysis and multivariate logistic regression analysis where the outcome variable was placement on the kidney transplant waiting list. Our findings demonstrates that patients registered on the waiting list were younger (odds ratio [OR] = 0.96; 95% confidence interval [CI], 0.94-0.98), were male (OR = 0.54; 95% CI, 0.30-0.98), were economically active (OR = 0.53; 95% CI, 0.29-0.98), and had greater knowledge in the field (OR = 1.17; 95% CI, 1.03-1.33). Disparity in access to the kidney transplant waiting list in Hungary does exist.

Recent advances in medical image processing for the evaluation of chronic kidney disease

Assessment of renal function and structure accurately remains essential in the diagnosis and prognosis of Chronic Kidney Disease (CKD). Advanced imaging, including Magnetic Resonance Imaging (MRI), Ultrasound Elastography (UE), Computed Tomography (CT) and scintigraphy (PET, SPECT) offers the opportunity to non-invasively retrieve structural, functional and molecular information that could detect changes in renal tissue properties and functionality. Currently, the ability of artificial intelligence to turn conventional medical imaging into a full-automated diagnostic tool is widely investigated. In addition to the qualitative analysis performed on renal medical imaging, texture analysis was integrated with machine learning techniques as a quantification of renal tissue heterogeneity, providing a promising complementary tool in renal function decline prediction. Interestingly, deep learning holds the ability to be a novel approach of renal function diagnosis. This paper proposes a survey that covers both qualitative and quantitative analysis applied to novel medical imaging techniques to monitor the decline of renal function. First, we summarize the use of different medical imaging modalities to monitor CKD and then, we show the ability of Artificial Intelligence (AI) to guide renal function evaluation from segmentation to disease prediction, discussing how texture analysis and machine learning techniques have emerged in recent clinical researches in order to improve renal dysfunction monitoring and prediction. The paper gives a summary about the role of AI in renal segmentation.

Quantifying the Treatment Effect of Kidney Transplantation Relative to Dialysis on Survival Time: New Results Based on Propensity Score Weighting and Longitudinal Observational Data from Sweden

Using observational data to assess the treatment effects on outcomes of kidney transplantation relative to dialysis for patients on renal replacement therapy is challenging due to the non-random selection into treatment. This study applied the propensity score weighting approach in order to address the treatment selection bias of kidney transplantation on survival time compared with dialysis for patients on the waitlist. We included 2676 adult waitlisted patients who started renal replacement therapy in Sweden between 1 January 1995, and 31 December 2012. Weibull and logistic regression models were used for the outcome and treatment models, respectively. The potential outcome mean and the average treatment effect were estimated using an inverse-probability-weighted regression adjustment approach. The estimated survival times from start of renal replacement therapy were 23.1 years (95% confidence interval (CI): 21.2-25.0) and 9.3 years (95% CI: 7.8-10.8) for kidney transplantation and dialysis, respectively. The survival advantage of kidney transplantation compared with dialysis was estimated to 13.8 years (95% CI: 11.4-16.2). There was no significant difference in the survival advantage of transplantation between men and women. Controlling for possible immortality bias reduced the survival advantage to 9.1-9.9 years. Our results suggest that kidney transplantation substantially increases survival time compared with dialysis in Sweden and that this consequence of treatment is equally distributed over sex.

Renal Transplantation in Patients Older Than 60 Years With High Comorbidity. Is There a Survival Benefit? A Multicenter Study in Argentina

BACKGROUND

The impact of renal transplantation (RT) in the elderly with many comorbid conditions is a matter of concern. The aim of our study was to assess the impact of RT on the survival of patients older than 60 years compared with those remaining on the waiting list (WL) according to their comorbidities.

METHODS

In this multicentric observational retrospective cohort study, we included all patients older than 60 years old admitted on the WL from 01 January 2006 to 31 December 2016. The Charlson comorbidity index (CCI) score was calculated for each patient at inclusion on the WL. Kidney donor risk index was used to assess donor characteristics.

RESULTS

One thousand and thirty-six patients were included on the WL of which 371 (36%) received an RT during a median follow-up period of 2.5 (1.4-4.1) years. Patient survival was higher after RT compared to patients remaining on the WL, 87%, 80%, and 72% versus 87%, 55%, and 30% at 1, 3, and 5 years, respectively. After RT survival at 5 years was 37% higher for patients with CCI ≥ 3, and 46% higher in those with CCI < 3, compared with patients remaining on the WL. On univariate and multivariate analysis, patient survival was independently associated with a CCI of ≥3 (hazard ratio 1.62; confidence interval 1.09-2.41; P < 0.02) and the use of calcineurin-based therapy maintenance therapy (hazard ratio 0.53; confidence interval 0.34-0.82; P < 0.004).

CONCLUSIONS

Our study showed that RT improved survival in patients older than 60 years even those with high comorbidities. The survival after transplantation was also affected by comorbidities.

Usefulness of morphometric image analysis with Sirius Red to assess interstitial fibrosis after renal transplantation from uncontrolled circulatory death donors

Early interstitial fibrosis (IF) correlates with long-term renal graft dysfunction, highlighting the need for accurate quantification of IF. However, the currently used Banff classification exhibits some limitations. The aim of our study was to precisely describe the progression of IF after renal transplantation using a new morphometric image analysis method relying of Sirius Red staining. The morphometric analysis we developed showed high inter-observer and intra-observer reproducibility, with ICC [95% IC] of respectively 0.75 [0.67–0.81] (n = 151) and 0.88 [0.72–0.95] (n = 21). We used this method to assess IF (mIF) during the first year after the kidney transplantation from 66 uncontrolled donors after circulatory death (uDCD). Both mIF and interstitial fibrosis (ci) according to the Banff classification significantly increased the first three months after transplantation. From M3 to M12, mIF significantly increased whereas Banff classification failed to highlight increase of ci. Moreover, mIF at M12 (p = 0.005) correlated with mean time to graft function recovery and was significantly associated with increase of creatininemia at M12 and at last follow-up. To conclude, the new morphometric image analysis method we developed, using a routine and cheap staining, may provide valuable tool to assess IF and thus to evaluate new sources of grafts.

Waiting List and Kidney Transplant Vascular Risk: An Ongoing Unmet Concern

BACKGROUND

Chronic kidney disease (CKD) is an important independent risk factor for adverse cardiovascular events in patients waitlisted for kidney transplantation (KT). Although KT reduces cardiovascular risk, these patients still have a higher all-cause and cardiovascular mortality than the general population. This concerning situation is due to a high burden of traditional and nontraditional risk factors as well as uremia-related factors and transplant-specific factors, leading to 2 differentiated processes under the framework of CKD, atherosclerosis and arteriosclerosis. These can be initiated by insults to the vascular endothelial endothelium, leading to vascular calcification (VC) of the tunica media or the tunica intima, which may coexist. Several pathogenic mechanisms such as inflammation-related endothelial dysfunction, mineral metabolism disorders, activation of the renin-angiotensin system, reduction of nitric oxide, lipid disorders, and the fibroblast growth factor 23-klotho axis are involved in the pathogenesis of atherosclerosis and arteriosclerosis, including VC.

SUMMARY

This review focuses on the current understanding of atherosclerosis and arteriosclerosis, both in patients on the waiting list as well as in kidney transplant recipients, emphasizing the cardiovascular risk factors in both populations and the inflammation-related pathogenic mechanisms. Key Message: The importance of cardiovascular risk factors and the pathogenic mechanisms related to inflammation in patients waitlisted for KT and kidney transplant recipients.

[Identifying the specific causes of kidney allograft loss: A population-based study]

INTRODUCTION

Results of kidney transplantation have been improving but long-term allograft survival remains disappointing. The objective of the present study was to identify the specific causes of renal allograft loss, to assess their incidence and long-term outcomes.

METHODS

A total of 4783 patients from four French centres, transplanted between January 2004 and January 2014 were prospectively included. A total of 9959 kidney biopsies (protocol and for cause) performed between January 2004 and March 2015 were included. Donor and recipient clinical and biological parameters as well as anti-HLA antibody directed against the donor were included. The main outcome was the long-term kidney allograft survival, including the study of the associated causes of graft loss, the delay of graft loss according to their causes and the determinants of graft loss.

RESULTS

There were 732 graft losses during the follow-up period (median time: 4.51 years) with an identified cause in 95.08 %. Kidney allograft survival at 9 years post-transplant was 78 %. The causes of allograft loss were: antibody-mediated rejection (31.69 %), thrombosis (25.55 %), medical intercurrent disease (14.62 %), recurrence of primary renal disease (7.1 %), BK- or CMV-associated nephropathy (n=35, 4.78 %), T cell-mediated rejection (4.78 %), urological disease (2.46 %) and calcineurin inhibitor nephrotoxicity (1.09 %).

CONCLUSION

The main causes of allograft loss were antibody-mediated rejection and thrombosis. These results encourage efforts to prevent and detect these complications earlier in order to improve allograft survival.

Mortality in Elderly Waiting-List Patients Versus Age-Matched Kidney Transplant Recipients: Where is the Risk?

The number of elderly patients on the waiting list (WL) for kidney transplantation (KT) has risen significantly in recent years. Because KT offers a better survival than dialysis therapy, even in the elderly, candidates for KT should be selected carefully, particularly in older waitlisted patients. Identification of risk factors for death in WL patients and prediction of both perioperative risk and long-term post-transplant mortality are crucial for the proper allocation of organs and the clinical management of these patients in order to decrease mortality, both while on the WL and after KT. In this review, we examine the clinical results in studies concerning: a) risk factors for mortality in WL patients and KT recipients; 2) the benefits and risks of performing KT in the elderly, comparing survival between patients on the WL and KT recipients; and 3) clinical tools that should be used to assess the perioperative risk of mortality and predict long-term post-transplant survival. The acknowledgment of these concerns could contribute to better management of high-risk patients and prophylactic interventions to prolong survival in this particular population, provided a higher mortality is assumed.

Patient and Graft Survival Among Sexagenarian and Septuagenarian Renal Transplant Recipients and Donors: The Context for Older Recipients

Due to the increasing number of patients with end-stage renal disease, there is a growing demand for transplants for recipients and donors aged 60 years and older. Using data from the Scientific Registry of Transplant Recipients, we performed survival analyses and multivariate logistic regression to help guide transplant professional decisions regarding the selection of graft type (living vs deceased) and donor age (60-69 vs 70+ years) for recipients aged 60 years and older.

Stem cell-derived kidney cells and organoids: Recent breakthroughs and emerging applications

The global rise in the numbers of kidney patients and the shortage in transplantable organs have led to an increasing interest in kidney-specific regenerative therapies, renal disease modelling and bioartificial kidneys. Sources for large quantities of high-quality renal cells and tissues would be required, also for applications in in vitro platforms for compound safety and efficacy screening. Stem cell-based approaches for the generation of renal-like cells and tissues would be most attractive, but such methods were not available until recently. This situation has drastically changed since 2013, and various protocols for the generation of renal-like cells and precursors from pluripotent stem cells (PSC) have been established. The most recent breakthroughs were related to the establishment of various protocols for the generation of PSC-derived kidney organoids. In combination with recent advances in genome editing, bioprinting and the establishment of predictive renal screening platforms this results in exciting new possibilities. This review will give a comprehensive overview over current PSC-based protocols for the generation of renal-like cells, precursors and organoids, and their current and potential applications in regenerative medicine, compound screening, disease modelling and bioartificial organs.

[Access to kidney transplantation's waiting list: Setting up a clinical pathway]

Early information about the kidney transplant is recommended to begin quickly the process of registration on the kidney transplantation waiting list, even for the patients not dialyzed at stage V of the renal insufficiency. It is a strategic choice for the patient care. From the arrival of all the patients in our center of dialysis, a systematic evaluation of the access to the kidney transplant waiting list is organized thanks to a clinical pathway. The impact of this new organization was estimated at 18 months with regard to the information about the kidney transplant transmitted to the patient, of the time required for the assessment of pre-kidney transplant evaluation, and of putting in contraindication. On 78 incident patients, 64 received the information concerning the kidney transplant. After 18 months, 50 clinical pathways are finalized at the time of the analysis among which 25 with a period lower than 6 days and 25 with a median of 169 days. A significant difference of age exists between both groups. The main causes of definitive medical contraindications were estimated. Twenty-two percent of the clinical pathway finalized is awaiting lifting of temporary contraindication. The management of the patient is improved, due to motivation of all the medical teams and a considerable work of coordination between the secretarial department and the department of transplantation in teaching hospital.

Clinical outcomes in Asian elderly kidney transplant recipients: a multicenter cohort study

BACKGROUND

The kidney transplantation rate in elderly patients is increasing rapidly. However, the clinical outcomes of kidney transplantation in elderly patients have not yet been thoroughly evaluated.

METHODS

This multicenter cohort study included adult kidney transplant recipients (KTRs) admitted to five major tertiary hospitals in Korea between 1997 and 2012. A total of 3,565 adult participants were enrolled. Patient survival, allograft survival, and biopsy-proven acute rejection (BPAR) of 242 elderly recipients (≥ 60 years) were assessed and compared with those of a younger population.

RESULTS

Patients were divided into five groups according to age at time of transplantation. The proportion of elderly patients was 6.7 % (mean age, 63.1 ± 2.7 years; n = 242). The numbers of male patients (69.4%), those with diabetes mellitus history (36.3%), and those with pretransplantation ischemic heart disease history (17.7%) were significantly higher in the elderly group than in the younger age groups. Elderly patients were more likely to receive a cadaveric kidney, and overall mortality rates were significantly higher in the elderly patients (1-year survival 93.3%, 5-year survival 91.3%). However, death-censored allograft survival rate and BPAR were not affected by patient age (P = .104 and .501, respectively). Among the elderly, BPAR and female donors were independent risk factors for allograft loss.

CONCLUSION

The overall survival rate of the elderly KTRs was significantly lower than that of younger KTRs. However, the death-censored allograft survival rate did not differ between groups. Kidney transplantation should not be stagnated especially in elderly patients with end-stage renal disease.

Association between kidney transplant center performance and the survival benefit of transplantation versus dialysis

BACKGROUND AND OBJECTIVES

Despite the benefits of kidney transplantation, the total number of transplants performed in the United States has stagnated since 2006. Transplant center quality metrics have been associated with a decline in transplant volume among low-performing centers. There are concerns that regulatory oversight may lead to risk aversion and lack of transplantation growth.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study of adults (age≥18 years) wait-listed for kidney transplantation in the United States from 2003 to 2010 using the Scientific Registry of Transplant Recipients was conducted. The primary aim was to investigate whether measured center performance modifies the survival benefit of transplantation versus dialysis. Center performance was on the basis of the most recent Scientific Registry of Transplant Recipients evaluation at the time that patients were placed on the waiting list. The primary outcome was the time-dependent adjusted hazard ratio of death compared with remaining on the transplant waiting list.

RESULTS

Among 223,808 waitlisted patients, 59,199 and 32,764 patients received a deceased or living donor transplant, respectively. Median follow-up from listing was 43 months (25th percentile=25 months, 75th percentile=67 months), and there were 43,951 total patient deaths. Deceased donor transplantation was independently associated with lower mortality at each center performance level compared with remaining on the waiting list; adjusted hazard ratio was 0.24 (95% confidence interval, 0.21 to 0.27) among 11,972 patients listed at high-performing centers, adjusted hazard ratio was 0.32 (95% confidence interval, 0.31 to 0.33) among 203,797 patients listed at centers performing as expected, and adjusted hazard ratio was 0.40 (95% confidence interval, 0.35 to 0.45) among 8039 patients listed at low-performing centers. The survival benefit was significantly different by center performance (P value for interaction <0.001).

CONCLUSIONS

Findings indicate that measured center performance modifies the survival benefit of kidney transplantation, but the benefit of transplantation remains highly significant even at centers with low measured quality. Policies that concurrently emphasize improved center performance with access to transplantation should be prioritized to improve ESRD population outcomes.

Survival and hospitalization for intensive home hemodialysis compared with kidney transplantation

Canadian patients receiving intensive home hemodialysis (IHHD; ≥16 hours per week) have survival comparable to that of deceased donor kidney transplant recipients in the United States, but a comparison with Canadian kidney transplant recipients has not been conducted. We conducted a retrospective cohort study of consecutive, adult IHHD patients and kidney transplant recipients between 2000 and 2011 at a large Canadian tertiary care center. The primary outcome was time-to-treatment failure or death for IHHD patients compared with expanded criteria, standard criteria, and living donor recipients, and secondary outcomes included hospitalization rate. Treatment failure was defined as a permanent switch to an alternative dialysis modality for IHHD patients, and graft failure for transplant recipients. The cohort comprised 173 IHHD patients and 202 expanded criteria, 642 standard criteria, and 673 living donor recipients. There were 285 events in the primary analysis. Transplant recipients had a reduced risk of treatment failure/death compared with IHHD patients, with relative hazards of 0.45 (95% confidence interval [95% CI], 0.31 to 0.67) for living donor recipients, 0.39 (95% CI, 0.26 to 0.59) for standard criteria donor recipients, and 0.42 (95% CI, 0.26 to 0.67) for expanded criteria donor recipients. IHHD patients had a lower hospitalization rate in the first year of treatment compared with standard criteria donor recipients and in the first 3 months of treatment compared with living donor and expanded criteria donor recipients. In this cohort, kidney transplantation was associated with superior treatment and patient survival, but higher early rates of hospitalization, compared with IHHD.

Survival of renal transplantation patients older than 60 years: a single-center experience

BACKGROUND

Elderly patients are the fastest growing population requiring renal replacement therapy. It has been stated that renal transplantation may be the best treatment option for these patients. However, it has been observed that older patients have a higher mortality rate than those who are younger. Yet the factors that determine post-transplantation outcomes in this population remain poorly defined. The aims of this study were to evaluate the graft and patient survival in kidney transplant recipients who are older than 60 years of age to identify relevant predictive factors.

METHODS

In this population-based retrospective cohort study of 201 kidney transplantations performed in elderly patients from January 2002 throughout June 2009, we estimated the 1-,3-,and 5-year patients and graft survival rates. We also evaluated the complications and the predictors of poor outcomes. Survival times were analyzed using the Kaplan-Meier method and survival differences assessed with Mantel-Cox log rank-test. We performed a Cox proportional hazards regression models to evaluate the impact of baseline and treatment characteristics on patient and graft survival.

RESULTS

Graft and patient survival rates at 1, 3, and 5 years were 76.4%, 71.3%, and 54.3%, and 78.2%, 73.8%, and 56.4%, respectively. Graft survival rates censored for patient death with a functioning graft were 93.1, 92.1, and 89%. Patient survival rates differed between diabetic and nondiabetic subjects at 1, 3 and 5 years (69.5% versus 83.6%; 59.8% versus 72.3%; 43.6% versus 65.7%; P = .008). On multivariate analysis, the factors associated with patients survival were diabetes mellitus (hazard ratio [HR] 2.058, 95% confidence interval [CI] 1.173-3.611, P = .012) and the 1-month serum creatinine value was > 1.6 mg/dL (HR 2.108 for each point increase, 95% CI 1.521-2.921, P = .000). Furthermore, there was an insignificant trend forward an association between active or past smoker and lower patient survival (HR 1.689, 95% CI 0.937-3.043, P = .08). The main causes of graft loss were patient death (79.5%). acute rejection (6.8%), and chronic allograft nephropathy (5.5%).

CONCLUSION

Renal transplantation can be performed safely and with acceptable outcomes in elderly patients after appropriate clinical evaluation. The grafts show excellent survival albeit that deaths with a functional graft continue to be an important issue.

Overestimation of the probability of death on peritoneal dialysis by the Kaplan-Meier method: advantages of a competing risks approach

Background

In survival analysis, patients on peritoneal dialysis are confronted with three different outcomes: transfer to hemodialysis, renal transplantation, or death. The Kaplan-Meier method takes into account one event only, so whether it adequately considers these different risks is questionable. The more recent competing risks method has been shown to be more appropriate in analyzing such situations.

Methods

We compared the estimations obtained by the Kaplan-Meier method and the competing risks method (namely the Kalbfleisch and Prentice approach), in 383 consecutive incident peritoneal dialysis patients. By means of simulations, we then compared the Kaplan-Meier estimations obtained in two virtual centers where patients had exactly the same probability of death. The only difference between these two virtual centers was whether renal transplantation was available or not.

Results

At five years, 107 (27.9%) patients had died, 109 (28.4%) had been transferred to hemodialysis, 91 (23.8%) had been transplanted, and 37 (9.7%) were still alive on peritoneal dialysis; before five years, 39 (10.2%) patients were censored alive on peritoneal dialysis. The five-year probabilities estimated by the Kaplan-Meier and the competing risks methods were respectively: death: 50% versus 30%; transfer to hemodialysis: 59% versus 32%; renal transplantation: 39% versus 26%; event-free survival: 12% versus 12%. The sum of the Kaplan-Meier estimations exceeded 100%, implying that patients could experience more than one event, death and transplantation for example, which is impossible. In the simulations, the probability of death estimated by the Kaplan-Meier method increased as the probability of renal transplantation increased, although the probability of death actually remained constant.

Conclusion

The competing risks method appears more appropriate than the Kaplan-Meier method for estimating the probability of events in peritoneal dialysis in the context of univariable survival analysis.

Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes

Individual studies indicate that kidney transplantation is associated with lower mortality and improved quality of life compared with chronic dialysis treatment. We did a systematic review to summarize the benefits of transplantation, aiming to identify characteristics associated with especially large or small relative benefit. Results were not pooled because of expected diversity inherent to observational studies. Risk of bias was assessed using the Downs and Black checklist and items related to time-to-event analysis techniques. MEDLINE and EMBASE were searched up to February 2010. Cohort studies comparing adult chronic dialysis patients with kidney transplantation recipients for clinical outcomes were selected. We identified 110 eligible studies with a total of 1 922 300 participants. Most studies found significantly lower mortality associated with transplantation, and the relative magnitude of the benefit seemed to increase over time (p < 0.001). Most studies also found that the risk of cardiovascular events was significantly reduced among transplant recipients. Quality of life was significantly and substantially better among transplant recipients. Despite increases in the age and comorbidity of contemporary transplant recipients, the relative benefits of transplantation seem to be increasing over time. These findings validate current attempts to increase the number of people worldwide that benefit from kidney transplantation.

Tuberculosis following kidney transplantation: clinical features and outcome. A French multicentre experience in the last 20 years

BACKGROUND

Kidney transplant recipients are at high risk of opportunistic infection. The aims of this study were to describe the epidemiology, clinical features and prognosis of Tuberculosis (TB) in kidney transplant recipients.

METHODS

Retrospective observational study conducted in 14 French transplant centres involving all cases of TB that occurred in kidney transplant recipients between 1986 and 2006.

RESULTS

Among the 16146 kidney transplantations performed during the study period, 74 (0.45%) developed TB. The country of birth was a highly endemic area for TB in 20 (40.8%) patients. Time from kidney transplantation to TB was 10 months (4-27). Extrapulmonary and disseminated TB accounted for 33 (67.4%) cases. The most common symptoms were fever (71.7%), weight loss (41.3%) and asthenia (39.1%). Coexisting infections were diagnosed in 11 (22.4%) patients. Microbial sensitivity tests revealed no case of multidrug-resistant TB. Haemophagocytic syndrome associated with TB was diagnosed in 5 (10.2%) cases with 60% of mortality (P = 0.0005). Median length of antituberculous therapy was 12 (9.5-12) months. Immunosuppressive therapy was reduced in 22 (44.9%) patients without adverse consequence on the graft. Overall, hospital mortality was 6.1% and 1-year graft survival was 97%.

CONCLUSIONS

Kidney transplantation increases the risk of TB, with a high rate of extrapulmonary disease. Symptoms of infection are often attenuated, leading to delayed diagnosis. Overall prognosis is good but haemophagocytic syndrome is associated with high mortality. Country of birth might be taken into account in the decision of post-transplantation treatment of latent TB.

Acute respiratory failure in kidney transplant recipients: a multicenter study

INTRODUCTION

Data on pulmonary complications in renal transplant recipients are scarce. The aim of this study was to evaluate acute respiratory failure (ARF) in renal transplant recipients.

METHODS

We conducted a retrospective observational study in nine transplant centers of consecutive kidney transplant recipients admitted to the intensive care unit (ICU) for ARF from 2000 to 2008.

RESULTS

Of 6,819 kidney transplant recipients, 452 (6.6%) required ICU admission, including 200 admitted for ARF. Fifteen (7.5%) of these patients had combined kidney-pancreas transplantations. The most common causes of ARF were bacterial pneumonia (35.5%), cardiogenic pulmonary edema (24.5%) and extrapulmonary acute respiratory distress syndrome (ARDS) (15.5%). Pneumocystis pneumonia occurred in 11.5% of patients. Mechanical ventilation was used in 93 patients (46.5%), vasopressors were used in 82 patients (41%) and dialysis was administered in 104 patients (52%). Both the in-hospital and 90-day mortality rates were 22.5%. Among the 155 day 90 survivors, 115 patients (74.2%) were dialysis-free, including 75 patients (65.2%) who recovered prior renal function. Factors independently associated with in-hospital mortality were shock at admission (odds ratio (OR) 8.70, 95% confidence interval (95% CI) 3.25 to 23.29), opportunistic fungal infection (OR 7.08, 95% CI 2.32 to 21.60) and bacterial infection (OR 2.53, 95% CI 1.07 to 5.96). Five factors were independently associated with day 90 dialysis-free survival: renal Sequential Organ Failure Assessment (SOFA) score on day 1 (OR 0.68/SOFA point, 95% CI 0.52 to 0.88), bacterial infection (OR 0.43, 95% CI 0.21 to 0.90), three or four quadrants involved on chest X-ray (OR 0.44, 95% CI 0.21 to 0.91), time from hospital to ICU admission (OR 0.98/day, 95% CI 0.95 to 0.99) and oxygen flow at admission (OR 0.93/liter, 95% CI 0.86 to 0.99).

CONCLUSIONS

In kidney transplant recipients, ARF is associated with high mortality and graft loss rates. Increased Pneumocystis and bacterial prophylaxis might improve these outcomes. Early ICU admission might prevent graft loss.

Achievements and challenges in bioartificial kidney development

Bioartificial kidneys (BAKs) combine a conventional hemofilter in series with a bioreactor unit containing renal epithelial cells. The epithelial cells derived from the renal tubule should provide transport, metabolic, endocrinologic and immunomodulatory functions. Currently, primary human renal proximal tubule cells are most relevant for clinical applications. However, the use of human primary cells is associated with many obstacles, and the development of alternatives and an unlimited cell source is one of the most urgent challenges. BAKs have been applied in Phase I/II and Phase II clinical trials for the treatment of critically ill patients with acute renal failure. Significant effects on cytokine concentrations and long-term survival were observed. A subsequent Phase IIb clinical trial was discontinued after an interim analysis, and these results showed that further intense research on BAK-based therapies for acute renal failure was required. Development of BAK-based therapies for the treatment of patients suffering from end-stage renal disease is even more challenging, and related problems and research approaches are discussed herein, along with the development of mobile, portable, wearable and implantable devices.

Benefit of kidney transplantation beyond 70 years of age

Background. Kidney transplantation generally improves long-term survival in patients with end-stage renal disease. However, in patients older than 70 years of age, only limited data are available that directly compare the potential survival benefit of transplantation versus dialysis.

Methods. All patients aged above 70 years who started dialysis between 1990 and 2005 and were waitlisted for kidney transplantation were included in the study. They were categorized according to time periods of inclusion (1990–99 vs 2000–05). Survival rates of altogether 286 dialysis patients were analyzed with a Kaplan–Meier model, as well as with a time-dependent Cox model. Comparisons were made between those who received a transplant and those who did not, and further between the two time periods.

Results. Median age at inclusion was 73.6 years (interquartile range 72.3–75.6). Two hundred and thirty-three patients (81%) received a kidney transplant during follow-up. Transplant recipients experienced an increased mortality in the first year after transplantation when compared to waitlisted patients. Patients starting dialysis between 1990 and 1999 had no significant long-term benefit of transplantation; HR for death 1.01 (0.58–1.75). In contrast, there was a substantial long-term benefit of transplantation among those starting dialysis after 2000; HR for death 0.40 (0.19–0.83), P = 0.014.

Conclusions. Survival after kidney transplantation in patients over 70 years has improved during the last decade and offers a survival advantage over dialysis treatment. Our experience supports the use of kidney transplantation in this age group if an increased early post-operative risk is accepted. This transplant policy may be challenged for priority reasons.