Exponentially increased risk of infectious death in older renal transplant recipients

Development of a Risk Prediction Model for Infection After Kidney Transplantation Transmitted from Bacterial Contaminated Preservation Solution

Background

The risk of transplant recipient infection is unknown when the preservation solution culture is positive.

Methods

We developed a prediction model to evaluate the infection in kidney transplant recipients within microbial contaminated preservation solution. Univariate logistic regression was utilized to identify risk factors for infection. Both stepwise selection with Akaike information criterion (AIC) was used to identify variables for multivariate logistic regression. Selected variables were incorporated in the nomograms to predict the probability of infection for kidney transplant recipients with microbial contaminated preservation solution.

Results

Age, preoperative creatinine, ESKAPE, PCT, hemofiltration, and sirolimus had a strongest association with infection risk, and a nomogram was established with an AUC value of 0.72 (95% confidence interval, 0.64-0.80) and Brier index 0.20 (95% confidence interval, 0.18-0.23). Finally, we found that when the infection probability was between 20% and 80%, the model oriented antibiotic strategy should have higher net benefits than the default strategy using decision curve analysis.

Conclusion

Our study developed and validated a risk prediction model for evaluating the infection of microbial contaminated preservation solutions in kidney transplant recipients and demonstrated good net benefits when the total infection probability was between 20% and 80%.

Impact of Immunosenescence in Older Kidney Transplant Recipients: Associated Clinical Outcomes and Possible Risk Stratification for Immunosuppression Reduction

The number of older individuals receiving a kidney transplant as replacement therapy has significantly increased in the past decades and this increase is expected to continue. Older patients have a lower rate of acute rejection but an increased incidence of death with a functioning graft. Several factors, including an increased incidence of infections, post-transplant malignancy and cardiovascular comorbidity and mortality, contribute to this increased risk. Notwithstanding, kidney transplantation is still the best form of kidney replacement therapy in all patients with chronic kidney disease, including in older individuals. The best form of immunosuppression and the optimal dose of these medications in older recipients remains a topic of discussion. Pharmacological studies have usually excluded older patients and when included, patients were highly selected and their numbers insignificant to draw a reasonable conclusion. The reduced incidence of acute rejection in older recipients has largely been attributed to immunosenescence. Immunosenescence refers to the aging of the innate and adaptive immunity, accumulating in phenotypic and functional changes. These changes influences the response of the immune system to new challenges. In older individuals, immunosenescence is associated with increased susceptibility to infectious pathogens, a decreased response after vaccinations, increased risk of malignancies and cardiovascular morbidity and mortality. Chronic kidney disease is associated with premature immunosenescent changes, and these are independent of aging. The immunosenescent state is associated with low-grade sterile inflammation termed inflammaging. This chronic low-grade inflammation triggers a compensatory immunosuppressive state to avoid further tissue damage, leaving older individuals with chronic kidney disease in an immune-impaired state before kidney transplantation. Immunosuppression after transplantation may further enhance progression of this immunosenescent state. This review covers the role of immunosenescence in older kidney transplant recipients and it details present knowledge of the changes in chronic kidney disease and after transplantation. The impact of immunosuppression on the progression and complications of an immunosenescent state are discussed, and the future direction of a possible clinical implementation of immunosenescence to individualize/reduce immunosuppression in older recipients is laid out.

Impact of Obesity on Kidney Transplant Outcomes in Older Adults

BACKGROUND

The prevalence of obesity in older patients undergoing kidney transplantation is increasing. Older age and obesity are associated with higher risks of complications and mortality post-transplantation. The optimal management of this group of patients remains undefined.

METHODS

We retrospectively analyzed the United Network for Organ Sharing database of adults ≥70 years of age undergoing primary kidney transplant from January 1, 2014, to December 31, 2022. We examined patient and graft survival stratified by body mass index (BMI) in 3 categories, <30 kg/m2, 30 to 35 kg/m2, and >35 kg/m2. We also analyzed other risk factors that impacted survival.

RESULTS

A total of 14,786 patients ≥70 years underwent kidney transplantation. Of those, 9,731 patients had a BMI <30 kg/m2, 3,726 patients with a BMI of 30 to 35 kg/m2, and 1,036 patients with a BMI >35 kg/m2. During the study period, there was a significant increase in kidney transplants in patients ≥70 years old across all BMI groups. Overall, patient survival, death-censored graft survival, and all-cause graft survival were lower in obese patients compared with nonobese patients. Multivariable analysis showed worse patient survival and graft survival in patients with a BMI of 30 to 35 kg/m2, a BMI >35 kg/m2, a longer duration of dialysis, diabetes mellitus, and poor functional status.

CONCLUSION

Adults ≥70 years should be considered for kidney transplantation. Obesity with a BMI of 30 to 35 kg/m2 or >35 kg/m2, longer duration of dialysis, diabetes, and functional status are associated with worse outcomes. Optimization of these risk factors is essential when considering these patients for transplantation.

A Clinical Model to Predict the Occurrence of Select High-risk Infections in the First Year Following Heart Transplantation

Background

Invasive infection remains a dangerous complication of heart transplantation (HT). No objectively defined set of clinical risk factors has been established to reliably predict infection in HT. The aim of this study was to develop a clinical prediction model for use at 1 mo post-HT to predict serious infection by 1 y.

Methods

A retrospective cohort study of HT recipients (2000-2018) was performed. The composite endpoint included cytomegalovirus (CMV), herpes simplex or varicella zoster virus infection, blood stream infection, invasive fungal, or nocardial infection occurring 1 mo to 1 y post-HT. A least absolute shrinkage and selection operator regression model was constructed using 10 candidate variables. A concordance statistic, calibration curve, and mean calibration error were calculated. A scoring system was derived for ease of clinical application.

Results

Three hundred seventy-five patients were analyzed; 93 patients experienced an outcome event. All variables remained in the final model: aged 55 y or above, history of diabetes, need for renal replacement therapy in first month, CMV risk derived from donor and recipient serology, use of induction and/or early lymphodepleting therapy in the first month, use of trimethoprim-sulfamethoxazole prophylaxis at 1 mo, lymphocyte count under 0.75 × 103cells/µL at 1 mo, and inpatient status at 1 mo. Good discrimination (C-index 0.80) and calibration (mean absolute calibration error 3.6%) were demonstrated.

Conclusion

This model synthesizes multiple highly relevant clinical parameters, available at 1 mo post-HT, into a unified, objective, and clinically useful prediction tool for occurrence of serious infection by 1 y post-HT.

Survival after kidney transplantation compared with ongoing dialysis for people over 70 years of age: A matched-pair analysis

Kidney transplantation offers improved survival and quality of life compared to dialysis for most recipients; however, benefits for elderly patients (>70 years) remain uncertain. Using the Australia and New Zealand Dialysis and Transplant Registry (2009-2019), elderly transplant recipients were matched to a waitlisted dialysis patient by age, cause of end-stage kidney disease, and dialysis duration (paired controls). We censored dialysis patients at the time of transplant. Survival was compared using stratified Cox regression. Elderly transplant recipients (KTRs) (n = 465) were matched to waitlisted pairs. Transplant group mortality initially exceeded dialysis due to excess infection-related deaths (1.9 transplant versus 0.3 dialysis/100 patient-years, P = .03). Beyond month 9, a progressive survival benefit in favor of transplantation was apparent. Over a median follow-up of 1.7 years, mortality was 38% lower for KTRs (95% confidence interval 0.41-0.94, P = .02), and 5-year survival was 80% KTRs vs 53% dialysis (P < .001). Recipients of living and standard criteria donor kidneys acquired immediate survival advantage compared with dialysis, while recipients of expanded criteria donor's kidneys experienced elevated risk of death for the first 17 months. Compared with remaining on dialysis, elderly KTRs incur an increased risk of early posttransplant mortality but thereafter may anticipate progressively superior survival rates.

A paired-kidney allocation study found superior survival with HLA-DR compatible kidney transplants in the Eurotransplant Senior Program

The Eurotransplant Senior Program (ESP) has expedited the chance for elderly patients with kidney failure to receive a timely transplant. This current study evaluated survival parameters of kidneys donated after brain death with or without matching for HLA-DR antigens. This cohort study evaluated the period within ESP with paired allocation of 675 kidneys from donors 65 years and older to transplant candidates 65 years and older, the first kidney to 341 patients within the Eurotransplant Senior DR-compatible Program and 334 contralateral kidneys without (ESP) HLA-DR antigen matching. We used Kaplan-Meier estimates and competing risk analysis to assess all cause mortality and kidney graft failure, respectively. The log-rank test and Cox proportional hazards regression were used for comparisons. Within ESP, matching for HLA-DR antigens was associated with a significantly lower five-year risk of mortality (hazard ratio 0.71; 95% confidence interval 0.53-0.95) and significantly lower cause-specific hazards for kidney graft failure and return to dialysis at one year (0.55; 0.35-0.87) and five years (0.73; 0.53-0.99) post-transplant. Allocation based on HLA-DR matching resulted in longer cold ischemia (mean difference 1.00 hours; 95% confidence interval: 0.32-1.68) and kidney offers with a significantly shorter median dialysis vintage of 2.4 versus 4.1 yrs. in ESP without matching. Thus, our allocation based on HLA-DR matching improved five-year patient and kidney allograft survival. Hence, our paired allocation study suggests a superior outcome of HLA-DR matching in the context of old-for-old kidney transplantation.

Lowering maintenance immune suppression in elderly kidney transplant recipients; connecting the immunological and clinical dots

The management of long-term immune suppressive medication in kidney transplant recipients is a poorly explored field in the area of transplant medicine. In particular, older recipients are at an increased risk for side effects and have an exponentially increased risk of infection-related death. In contrast, an aged immune system decreases the risk of acute T-cell-mediated rejection in older recipients. Recent advances in alloimmunity research have shown a rapid and substantial decline in polyfunctional, high-risk CD4⁺ T cells post-transplantation. This lowers the direct alloreactivity responsible for T-cell-mediated rejection, also known as donor-specific hyporesponsiveness. Chronic antibody-mediated rejection (c-aABMR) is the most frequent cause of kidney graft loss in the long term. However, in older adults, c-aABMR as a cause of graft loss is outnumbered by death with a functioning graft. In addition, DSA development and a diagnosis of c-aABMR plateau ~10 years after transplantation, resulting in a very low risk for rejection thereafter. The intensity of immune suppression regimes could likely be reduced accordingly, but trials in this area are scarce. Tacrolimus monotherapy for 1 year after transplantation seems feasible in older kidney transplant recipients with standard immunological risk, showing the expected benefits of fewer infections and better vaccination responses.

The association of center volume with transplant outcomes in selected high-risk groups in kidney transplantation

BACKGROUND

In context of increasing complexity and risk of deceased kidney donors and transplant recipients, the impact of center volume (CV) on the outcomes of high-risk kidney transplants(KT) has not been well determined.

METHODS

We examined the association of CV and outcomes among 285 U.S. transplant centers from 2000-2016. High-risk KT were defined as recipient age ≥ 70 years, body mass index (BMI) ≥ 35 kg/m², receiving kidneys from donors with kidney donor profile index(KDPI) ≥ 85%, acute kidney injury(AKI), hepatitisC + . Average annual CV for the specific-high-risk KT categorized in tertiles. Death-Censored-Graft-Loss(DCGL) and death at 3 months, 1, 5, and 10 years were compared between CV tertiles using Cox-regression models.

RESULTS

Two hundred fifty thousand five hundred seventy-four KT were analyzed. Compared to high CV, recipients with BMI ≥ 35 kg/m² had higher risk of DCGL in low CV(aHR = 1.11,95%CI = 1.03-1.19) at 10 years; recipients with age ≥ 70 years had higher risk of death in low CV(aHR = 1.07,95%CI = 1.01-14) at 10 years. There was no difference of DCGL or death in low CV for donors with KDPI ≥ 85%, hepatitisC + , or AKI.

CONCLUSIONS

Recipients of high-risk KT with BMI ≥ 35 kg/m² have higher risk of DCGL and recipients age ≥ 70 years have higher risk of death in low CV, compared to high CV. Future studies should identify care practices associated with CV that support optimal outcomes after KT.

The aging of the immune system and its implications for transplantation

By the last third of life, most mammals, including humans, exhibit a decline in immune cell numbers, immune organ structure, and immune defense of the organism, commonly known as immunosenescence. This decline leads to clinical manifestations of increased susceptibility to infections, particularly those caused by emerging and reemerging microorganisms, which can reach staggering levels-infection with SARS-CoV-2 has been 270-fold more lethal to older adults over 80 years of age, compared to their 18-39-year-old counterparts. However, while this would be expected to be beneficial to situations where hyporeactivity of the immune system may be desirable, this is not always the case. Here, we discuss the cellular and molecular underpinnings of immunosenescence as they pertain to outcomes of solid organ and hematopoietic transplantation.

Biological drugs for systemic lupus erythematosus or active lupus nephritis and rates of infectious complications. Evidence from large clinical trials

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease that frequently affects the kidneys, known as lupus nephritis (LN). Such patients are treated with antimalarials, corticosteroids or immunosuppressive drugs, and more recently, target-specific biological drugs. Although efficacy of these therapies improved SLE-related outcomes, SLE remains associated with higher rates of infections. Here, we performed a comprehensive systemic review of infectious complications in clinical trials covering drug interventions for SLE or specifically for active LN. Our search in 15 online registries yielded a total of 1477 studies of which 14 matched our prespecified criteria. These covered the biological drugs anifrolumab, belimumab, and rituximab that were tested in patients with non-renal SLE and active LN.The available safety data from the SLE trials indicated that infectious complications such as herpes zoster, upper respiratory tract infection, nasopharyngitis, bronchitis, and urinary tract infection in patients receiving placebo were quite prevalent especially in the EXPLORER (rituximab) trial. Infections occurred mostly during the first year of LN therapy. Serious adverse events and infectious complications occurred more frequently in placebo-treated patients with active LN, especially in the BLISS-LN (belimumab) and LUNAR (rituximab) trials. Anifrolumab and rituximab increased the number of clinically relevant episodes of herpes zoster compared to belimumab in patients with active LN. Anifrolumab displayed a similar trend for influenza infections, which is consistent with the specific mechanisms-of-action of anifrolumab; highlighting drug-specific effects on infectious complications. In addition, standard-of-care therapy, e.g., MMF and immunosuppressants, as well as a longer SLE duration may also affect the incidence of serious adverse events and certain infectious complications in SLE patients with active LN.Infectious complications are common in SLE but even more common in patients with active LN, especially herpes zoster is strongly associated with active LN and anifrolumab therapy (OR 2.8, 95% CI 1.18 to 6.66, p = 0.018). Immunotherapy seems to impose unspecific and specific risks for infections. The latter may imply specific precautions such as preemptive vaccination and individual risk-benefit assessments.

Kidney transplantation or dialysis in older adults-an interview study on the decision-making process

BACKGROUND

In older patients with end-stage kidney disease (ESKD), the choice between kidney transplantation (KT) and dialysis may be more complex than in younger patients because of a higher prevalence of comorbidities and frailty. This study aims to provide greater insight into the current decision-making process by exploring the expectations, experiences and health outcome priorities of all stakeholders.

METHODS

We performed semi-structured interviews with patients ≥65 years with ESKD (eGFR <15 ml/min/1.73m2, KT recipient or treated with dialysis), patients' relatives and healthcare professionals (nephrologists, nurses and medical social workers). Interviews were conducted until data saturation and thematically analysed.

RESULTS

We performed 36 interviews (patients n = 18, relatives n = 5, healthcare professionals n = 13). Thematic analysis revealed five themes. Older patients' health outcome priorities were mostly related to quality of life (QOL). Individual older patients showed marked differences in the preferred level of engagement during the decision-making process (varying from 'wants to be in the lead' to 'follows the nephrologist') and in informational needs (varying from evidence-based to experience-based). On the contrary, healthcare professionals were quite unanimous on all aspects. They focused on determining eligibility for KT as start of the decision-making process, on clear and extensive information provision and on classical, medical outcomes.

CONCLUSIONS

The decision-making process could benefit from early identification of older patients' values, needs and health outcome priorities, in parallel with assessment of KT eligibility and before discussing the treatment options, and the explicit use of this information in further steps of the decision-making process.

Dialysis or kidney transplantation in older adults? A systematic review summarizing functional, psychological, and quality of life-related outcomes after start of kidney replacement therapy

Background

In older patients, the choice between kidney transplantation (KT) and dialysis may be complicated because of a high prevalence of comorbidities and geriatric syndromes. Ideally, this decision-making process focusses on older patients’ outcome priorities, which frequently include functional, psychological, and quality of life (QOL)-related outcomes.

Purpose

This systematic review aims to summarize functional, psychological (including cognition), and QOL-related outcomes after start of kidney replacement therapy (KRT) in older adults.

Methods

We searched PubMed and Embase for research that investigated change in these variables after start of KRT in patients aged ≥ 60 years. Data were extracted using the summary measures reported in the individual studies. Risk of bias was assessed with the ROBINS-I tool.

Results

Sixteen observational studies (prospective n = 9, retrospective n = 7; KT-recipients n = 3, dialysis patients n = 13) were included. The results show that QOL improves in the majority of the older KT recipients. After start of dialysis, QOL improved or remained stable for most patients, but this seems less prevalent than after KT. Functional status decreases in a substantial part of the older dialysis patients. Furthermore, the incidence of serious fall injuries increases after start of dialysis. Nutritional status seems to improve after start of dialysis.

Conclusion

The interpretability and comparability of the included studies are limited by the heterogeneity in study designs and significant risk of bias in most studies. Despite this, our overview of functional, psychological (including cognition), and QOL-related outcomes is useful for older adults and their clinicians facing the decision between KT and dialysis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-022-03208-2.

Influence of Calcineurin Inhibitor Choice on Outcomes in Kidney Transplant Recipients Aged ≥60 Y: A Collaborative Transplant Study Report

BACKGROUND

Patients aged ≥60 y represent the fastest growing population among kidney transplant recipients and waitlist patients. They show an elevated infection risk and are frequently transplanted with multiple human leukocyte antigen mismatches. Whether the choice of calcineurin inhibitor influences graft survival, mortality, or key secondary outcomes such as infections in this vulnerable recipient population is unknown.

METHODS

A total of 31 177 kidney transplants from deceased donors performed between 2000 and 2019 at European centers and reported to the Collaborative Transplant Study were analyzed using multivariable Cox and logistic regression analyses. All recipients were ≥60 y old and received tacrolimus (Tac) or cyclosporine A on an intention-to-treat basis, combined with mycophenolic acid or azathioprine plus/minus steroids.

RESULTS

The risk of 3-y death-censored graft loss and patient mortality did not differ significantly between Tac- and cyclosporine A-treated patients (hazard ratio 0.98 and 0.95, P = 0.74 and 0.20, respectively). No difference was found in the overall risk of hospitalization for infection (hazard ratio = 0.95, P = 0.19); however, a lower incidence of rejection treatment (hazard ratio = 0.81, P < 0.001) was observed in Tac-treated patients. Assessment of pathogen-specific hospitalizations revealed no difference in the risk of hospitalization due to bacterial infection (odds ratio = 1.00, P = 0.96), but a significantly higher risk of hospitalization due to human polyomavirus infection was found among Tac-treated patients (odds ratio = 2.45, P = 0.002). The incidence of de novo diabetes was higher for Tac-based immunosuppression (odds ratio = 1.79, P < 0.001).

CONCLUSIONS

Calcineurin inhibitor selection has no significant influence on death-censored graft survival, mortality, and overall infection risk in ≥60-y-old kidney transplant recipients.

Secondary Immunodeficiency Related to Kidney Disease (SIDKD)-Definition, Unmet Need, and Mechanisms

Kidney disease is a known risk factor for poor outcomes of COVID-19 and many other serious infections. Conversely, infection is the second most common cause of death in patients with kidney disease. However, little is known about the underlying secondary immunodeficiency related to kidney disease (SIDKD). In contrast to cardiovascular disease related to kidney disease, which has triggered countless epidemiologic, clinical, and experimental research activities or interventional trials, investments in tracing, understanding, and therapeutically targeting SIDKD have been sparse. As a call for more awareness of SIDKD as an imminent unmet medical need that requires rigorous research activities at all levels, we review the epidemiology of SIDKD and the numerous aspects of the abnormal immunophenotype of patients with kidney disease. We propose a definition of SIDKD and discuss the pathogenic mechanisms of SIDKD known thus far, including more recent insights into the unexpected immunoregulatory roles of elevated levels of FGF23 and hyperuricemia and shifts in the secretome of the intestinal microbiota in kidney disease. As an ultimate goal, we should aim to develop therapeutics that can reduce mortality due to infections in patients with kidney disease by normalizing host defense to pathogens and immune responses to vaccines.

Outcomes of Kidney Transplantation in the Elderly Recipients

Introduction:

In a developing country with a predominantly young population, the valid assumption is directed toward medical care toward the young. However, as medical technology has advanced, quality care has ensured better survival for the elderly population also. The aim of this study was to determine the clinical outcomes in elderly patients undergoing kidney transplantation.

Materials and Methods:

A retrospective analysis of 1150 patients who had undergone live related renal transplantation was done from January 2006 to December 2014. These patients were divided into two groups; Group 1: age >60 years (N = 150), Group 2: age 18–60 years (N = 1000). The clinical outcomes were compared.

Results:

The mean age in Group 1 was 69 ± 7.5 years (SD ± 7.5), and group 2 was 41 ± 8 years. In groups 1 and 2, males were 80% and 82%; death censored graft survival at 5 years was 82% and 87%; patient survival at 5 years was 86% and 94%, respectively. The incidence of biopsy-proven acute rejection was similar in both groups (11.3 vs. 10.2%, P = 0.12). Urinary tract infection was the most common infectious complication. Sepsis was the primary cause of death in both groups.

Conclusion:

In the elderly patients who underwent kidney transplantation, satisfactory graft function, and patient survival were maintained over a period of 60 months. Urinary tract infections were common, and sepsis was the most common cause of death with a surviving allograft. The acute rejection and mortality rates were comparable to the literature published from India so far.

The Risk of Postkidney Transplant Outcomes by Induction Choice Differs by Recipient Age

Supplemental Digital Content is available in the text.

Background.

Among adult kidney transplant (KT) recipients, the risk of post-KT adverse outcomes differs by type of induction immunosuppression. Immune response to induction differs as recipients age; yet, choice of induction is barely tailored by age likely due to a lack of evidence of the risks and benefits.

Methods.

Using Scientific Registry of Transplant Recipients data, we identified 39336 first-time KT recipients (2010–2016). We estimated the length of stay (LOS), acute rejection (AR), graft failure, and death by induction type using logistic and Cox regression weighted by propensity score to adjust for confounders. We tested whether these estimates differed by age (65+ versus 18–64 y) using a Wald test.

Results.

Overall, rabbit antithymocyte globulin (rATG) was associated with a decreased risk of AR (odds ratio = 0.79, 95% confidence interval [CI], 0.72-0.85) compared with basiliximab. The effect of induction on LOS and death (interaction P = 0.03 and 0.003) differed by recipient age. Discharge was on average 11% shorter in rATG among younger recipients (relative time = 0.89; 95% confidence interval [CI], 0.81-0.99) but not among older recipients (relative time = 1.01; 95% CI, 0.95-1.08). rATG was not associated with mortality among older (hazard ratio = 1.05; 95% CI, 0.96-1.15), but among younger recipients (hazard ratio = 0.87; 95% CI, 0.80-0.95), it was associated with reduced mortality risk.

Conclusions.

rATG should be considered to prevent AR, especially among recipients with high-immunologic risk regardless of age; however, choice of induction should be tailored to reduce LOS and risk of mortality, particularly among younger recipients.

Immunosuppression Regimen Use and Outcomes in Older and Younger Adult Kidney Transplant Recipients: A National Registry Analysis

BACKGROUND

Although the population of older transplant recipients has increased dramatically, there are limited data describing the impact of immunosuppression regimen choice on outcomes in this recipient group.

METHODS

National data for US Medicare-insured adult kidney recipients (N = 67 362; 2005-2016) were examined to determine early immunosuppression regimen and associations with acute rejection, death-censored graft failure, and mortality using multivariable regression analysis in younger (18-64 y) and older (>65 y) adults.

RESULTS

The use of antithymocyte globulin (TMG) or alemtuzumab (ALEM) induction with triple maintenance immunosuppression (reference) was less common in older compared with younger (36.9% versus 47.0%) recipients, as was TMG/ALEM + steroid avoidance (19.2% versus 20.1%) and mammalian target of rapamycin inhibitor (mTORi)-based (6.7% versus 7.7%) treatments. Conversely, older patients were more likely to receive interleukin (IL)-2-receptor antibody (IL2rAb) + triple maintenance (21.1% versus 14.7%), IL2rAb + steroid avoidance (4.1% versus 1.8%), and cyclosporine-based (8.3% versus 6.6%) immunosuppression. Compared with older recipients treated with TMG/ALEM + triple maintenance (reference regimen), those managed with TMG/ALEM + steroid avoidance (adjusted odds ratio [aOR], 0.440.520.61) and IL2rAb + steroid avoidance (aOR, 0.390.550.79) had lower risk of acute rejection. Older patients experienced more death-censored graft failure when managed with Tac + antimetabolite avoidance (adjusted hazard [aHR], 1.411.782.25), mTORi-based (aHR, 1.702.142.71), and cyclosporine-based (aHR, 1.411.782.25) regimens, versus the reference regimen. mTORi-based and cyclosporine-based regimens were associated with increased mortality in both older and younger patients.

CONCLUSIONS

Lower-intensity immunosuppression regimens (eg, steroid-sparing) appear beneficial for older kidney transplant recipients, while mTORi and cyclosporine-based maintenance immunosuppression are associated with higher risk of adverse outcomes.

Kidney Transplant Outcomes in elderly Recipients: An Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry Study

BACKGROUND

There is an increase in elderly patients receiving kidney transplant internationally. This study describes elderly kidney transplant recipient outcomes in Australia and New Zealand.

METHODS

The study included all adult first kidney transplant recipients in Australia and New Zealand from 2000 to 2015. Survival and graft outcomes were compared between elderly (≥70 years) and younger (18-69 years) recipients using Cox proportional hazards regression.

RESULTS

Overall, 10651 kidney transplant recipients were included, of which 279 (2.6%) were elderly adults. The proportion of elderly recipients increased from 0.6 to 4.4% from 2000 to 2015. Compared with younger recipients, elderly recipients were more likely to receive kidneys from deceased donors, elderly donors, and expanded criteria donors. Elderly recipients experienced poorer patient survival with 1- and 5-year survival ranging from 96% to 97% and 79% to 81%, respectively, compared with 97% to 99% and 90% 95% in younger recipients, respectively. Elderly recipients experienced comparable rates of delayed graft function and, in living donor kidney recipients, lower rates of acute rejection.

CONCLUSIONS

Kidney transplantation in the elderly population is increasing. Although elderly recipients had inferior survival and graft outcomes, elderly recipients generally received poorer quality kidneys. The outcomes achieved in this cohort of elderly adults are encouraging, and improving elderly recipient outcomes should be an important focus for research.

Rationale and design of the OPTIMIZE trial: OPen label multicenter randomized trial comparing standard IMmunosuppression with tacrolimus and mycophenolate mofetil with a low exposure tacrolimus regimen In combination with everolimus in de novo renal transplantation in Elderly patients

BACKGROUND

In 2019, more than 30 % of all newly transplanted kidney transplant recipients in The Netherlands were above 65 years of age. Elderly patients are less prone to rejection, and death censored graft loss is less frequent compared to younger recipients. Elderly recipients do have increased rates of malignancy and infection-related mortality. Poor kidney transplant function in elderly recipients may be related to both pre-existing (i.e. donor-derived) kidney damage and increased susceptibility to nephrotoxicity of calcineurin inhibitors (CNIs) in kidneys from older donors. Hence, it is pivotal to shift the focus from prevention of rejection to preservation of graft function and prevention of over-immunosuppression in the elderly. The OPTIMIZE study will test the hypothesis that reduced CNI exposure in combination with everolimus will lead to better kidney transplant function, a reduced incidence of complications and improved health-related quality of life for kidney transplant recipients aged 65 years and older, compared to standard immunosuppression.

METHODS

This open label, randomized, multicenter clinical trial will include 374 elderly kidney transplant recipients (≥ 65 years) and consists of two strata. Stratum A includes elderly recipients of a kidney from an elderly deceased donor and stratum B includes elderly recipients of a kidney from a living donor or from a deceased donor < 65 years. In each stratum, subjects will be randomized to a standard, tacrolimus-based immunosuppressive regimen with mycophenolate mofetil and glucocorticoids or an adapted immunosuppressive regimen with reduced CNI exposure in combination with everolimus and glucocorticoids. The primary endpoint is 'successful transplantation', defined as survival with a functioning graft and an eGFR ≥ 30 ml/min per 1.73 m2 in stratum A and ≥ 45 ml/min per 1.73 m2 in stratum B, after 2 years, respectively.

CONCLUSIONS

The OPTIMIZE study will help to determine the optimal immunosuppressive regimen after kidney transplantation for elderly patients and the cost-effectiveness of this regimen. It will also provide deeper insight into immunosenescence and both subjective and objective outcomes after kidney transplantation in elderly recipients.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03797196 , registered January 9th, 2019. EudraCT: 2018-003194-10, registered March 19th, 2019.

Leukocyte transcriptome indicators of development of infection in kidney transplant recipients

After kidney transplantation, infection and death are important clinical complications, especially for the growing numbers of older patients with limited resilience to withstand adverse events. Evaluation of changes in gene expression in immune cells can reveal the underlying mechanisms behind vulnerability to infection. A cohort of 60 kidney transplant recipients was evaluated. Gene expression in peripheral blood mononuclear cells 3 months after kidney transplantation was analyzed to compare differences between patients with infection and those who were infection-free in the first-year post-transplant. Pro-inflammatory genes such as IL1B, CCL4, and TNF were found to be downregulated in post-transplant PBMC from patients who developed infection. In contrast, genes involved in metabolism, HLA genes, and transcripts involved in type I interferon innate antiviral responses were found to be upregulated. Promoter-based bioinformatic analyses implicated increased activity of interferon regulatory factors, erythroid nuclear factor (E2), and CCAAT-enhancer-binding protein (C/EBP) in patients who developed infections. Differential patterns of gene expression were observed in patients who developed infection after kidney transplantation, with patterns distinct from changes associated with patient age, suggesting possible mechanisms behind vulnerability to infection. Assessment of gene expression in blood may offer an approach for patient risk stratification and monitoring after transplantation.

Clinical Outcomes of Older Kidney Transplant Recipients

BACKGROUND

Older kidney transplant recipients (OKTR) are vulnerable to infections and AKI, often prompting hospitalization. This study elucidates etiology of hospitalizations, AKI, and outcomes in OKTR.

METHODS

Retrospective study of 500 patients age ≥ 60, who underwent kidney transplantation from 2005-2015. Demographic, transplant, and outcomes data were collected.

RESULTS

OKTR had mean age 66 years; 59% males and 50% African Americans. 62% had at least one hospitalization post-transplant. Predictors of hospitalization were DGF, DM, panel reactive antibodies (PRA), dialysis duration. Hospitalization was mostly due to infection and surgical complications. Average length of stay was 6.4 days. OKTR with at least one hospitalization had 84% higher risk for graft loss (p=0.001). 56% of older kidney transplant recipients had at least one AKI episode post-transplant. Predictors of AKI included DGF, older, African American donor, and tacrolimus variability. The most common etiologies for AKI were infection, dehydration, and GI complications. OKTR with at least one AKI episode had 2.6-fold higher risk for graft loss (p<0.001).

CONCLUSIONS

Post-transplant hospitalization and AKI in OKTR significantly impact graft survival. Addressing comorbidities and risks in the pre-transplant and outpatient setting may help alleviate burden of hospitalization and risk of AKI in OKTR and improve graft outcomes.

Passive Microwave Biosensor for Real-Time Monitoring of Subsurface Bacterial Growth

A real-time and label-free microstrip sensor capable of detecting and monitoring subsurface growth of Escherichia coli (E. coli) on solid growth media such as Luria-Bertani (LB) agar is presented. The microwave ring resonator was designed to operate at 1.76 GHz to detect variations in the dielectric properties such as permittivity and loss tangent to monitor bacterial growth. The sensor demonstrated high efficiency in monitoring subsurface dynamics of E. coli growth between two layers of LB agar. The resonant amplitude variations (Δ Amplitude (dB)) were recorded for different volumes of E. coli (3 μL and 9 μL) and compared to control without E. coli for 36 hours. The control showed a maximum amplitude variation of 0.037 dB, which was selected as a threshold to distinguish between the presence and absence of E. coli growth. The measured results by sensors were further supported by microscopic images. It is worth noticing that the amplitude variations fit well with the Gompertz growth model. The rate of amplitude change correlating bacteria growth rate was calculated as 0.08 and 0.13 dB/hr. for 3 μL and 9 μL of E. coli, respectively. This work is a proof of concept to demonstrate the capability of microwave sensors to detect and monitor subsurface bacterial growth.

A Sequential Two-Step Cell-Based Assay Predicts Immunosuppression-Related Adverse Events

Immunosuppressants are associated with serious and often life-threatening adverse effects. To optimize immunotherapy, a tool that measures the immune reserve is necessary. We validated that a cell-based assay that measures TNF-α production by CD14⁺16⁺ intermediate monocytes following stimulation with EBV peptides has high sensitivity for the detection of over-immunosuppression (OIS) events. To develop a sequential, two-step assay with high specificity, we used PBMCs from kidney recipients (n = 87). Patients were classified as cases or controls, according to the occurrence of opportunistic infection, recurring bacterial infections, or de novo neoplasia. Patients who tested positive in the first step were randomly allocated to a training or a testing set for the development of the second step. In the discovery phase, an assay based on the examination of early mature B (eBm5) cells was able to discriminate OIS patients from controls with a specificity of 88%. The testing set also revealed a specificity of 88%. The interassay coefficient of variability between the experiments was 6.1%. Stratified analyses showed good diagnostic accuracy across tertiles of age and time posttransplant. In the adjusted model, the risk of OIS was more than 12 times higher in patients classified as positive than in those who tested negative (adjusted hazard ratio, 12.2; 95% confidence interval: 4.3-34.6). This sequential cell-based assay, which examines the monocyte and eBm5 cell response to EBV peptides, may be useful for identifying OIS in immunosuppressed patients.

Factors Influencing Long-Term Patient and Allograft Outcomes in Elderly Kidney Transplant Recipients

Introduction

Individuals aged ≥65 years are increasingly prevalent on the waitlist for kidney transplantation, yet evidence on recipient and donor factors that define optimal outcomes in elderly patients after kidney transplantation is scarce.

Methods

We used multivariable Cox regression modeling to determine the factors associated with all-cause death, death with a functioning graft, and overall and death-censored graft survival, using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry.

Results

A total of 802 kidney transplant recipients aged ≥65 years underwent their first transplantation between June 2006 and December 2016. Median age at transplantation was 68 years (interquartile range = 66−69 years). The 1-year and 5-year overall patient and graft survivals (95% confidence interval [CI]) were 95.1 (93.5−96.7) and 79.0 (75.1−82.9), and 92.9 (91.1−94.7) and 75.4 (71.3−79.5), respectively. Factors associated with higher risks of all-cause death included prevalent coronary artery disease (adjusted hazard ratio [95% confidence interval] = 1.47 [1.03–2.11]), cerebrovascular disease (1.99 [1.26–3.16]), increasing graft ischemic time (1.06 per hour [1.03–1.09]), donor age (1.02 per year [1.01–1.03]), delayed graft function (1.64 [1.13−2.39]), and peritoneal dialysis pretransplantation (1.71 [1.17–2.51]).

Conclusion

Prevalent vascular disease and peritoneal dialysis as a pretransplantation dialysis modality are risk factors associated with poorer outcomes in transplant recipients aged ≥65 years. Careful selection and evaluation of potential candidates may improve graft and patient outcomes in older patients.

Epidemiology, risk factors, and clinical impact of early post-transplant infection in older kidney transplant recipients: the Korean organ transplantation registry study

Background

As in younger recipients, post-transplant infection is a frequent and devastating complication after kidney transplantation (KT) in older recipients. However, few studies have analyzed characteristics of post-transplant infection in older kidney recipients. In this study of a nation-wide cohort of older kidney recipients, we investigated the current epidemiology, risk factors, and clinical impacts of early post-transplant infection, which was defined as infectious complications requiring hospitalization within the first 6 months after KT.

Methods

Three thousand seven hundred thirty-eight kidney recipients registered in the Korean Organ Transplantation Registry between 2014 and 2017 were enrolled. Recipients were divided into two groups, younger (n = 3081) and older (n = 657), with a cutoff age of 60 years. We observed characteristics of early post-transplant infection, and investigated risk factors for the development of infection. We also analyzed the association of early post-transplant infection with clinical outcomes including cardiac events, rejection, graft loss, and all-cause mortality.

Results

The incidence of early post-transplant infection was more frequent in older recipients (16.9% in younger group and 22.7% in older group). Bacteria were the most common causative pathogens of early post-transplant infection, and the most frequent site of infection was the urinary tract in both older and younger recipients. Older recipients experienced more mycobacterial infections, co-infections, and multiple site infections compared with younger recipients. In older recipients, female sex (HR 1.398, 95% CI 1.199–1.631), older donor age (HR 1.010, 95% CI 1.004–1.016), longer hospitalization after KT (HR 1.010, 95% CI 1.006–1.014), and experience of acute rejection (HR 2.907, 95% CI 2.471–3.419) were independent risk factors for the development of early post-transplant infection. Experiencing infection significantly increases the incidence of rejection, graft loss, and all-cause mortality.

Conclusion

Our results illustrate current trends, risk factors, and clinical impacts of early post-transplant infection after KT in older recipients. Considering the poor outcomes associated with early post-transplant infection, careful screening of recipients at high risk for infection and monitoring of recipients who experience infection are advised. In addition, since older recipients exhibit different clinical characteristics than younger recipients, further studies are needed to establish effective strategies for treating older recipients.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12877-020-01859-3.

The impact of age on patient tolerance of mycophenolate following kidney transplantation

BACKGROUND

In Scotland, standard maintenance immunosuppression following kidney transplantation consists of mycophenolate (MPA), tacrolimus and prednisolone irrespective of recipient age. We analyzed the tolerability of this immunosuppression regimen and the association with transplant outcomes.

METHODS

A national, multicentre retrospective analysis of patients transplanted in 2015 and 2016, comparing graft function, acute rejection, significant infection rates and immunosuppression dosing between patients aged 18 and 59 years (Group 1) and ≥60 years (Group 2).

RESULTS

Of the 490 patients, 26% were aged ≥60 years. Acute rejection (AR) rates at 1 year were 15% and 11% in Groups 1 and 2, respectively. Full-dose MPA was poorly tolerated with 53% in Group 1 and 77% in Group 2 requiring dose reduction or cessation. Female gender and age ≥60 years were independent predictors for MPA dose changes. One year following MPA dose reduction, AR risk was low (5%) in Group 2, however, those remaining on full dose MPA had a 79% increased rate of serious infections.

CONCLUSION

The majority of renal transplant recipients aged ≥60 fail to tolerate full-dose MPA. In this group, MPA dose reduction is associated with low rejection rates, but full-dose MPA is associated with high infection rates. We suggest that a tailored approach to immunosuppression in elderly recipients incorporating lower doses of MPA may be appropriate.

Transplanting the Elderly: Mandatory Age- and Minimal Histocompatibility Matching

Worldwide over 40% of patients receiving renal replacement therapy (RRT) are aged 65 years or older, a number that is still increasing. Renal transplantation is the preferred RRT, providing substantial survival benefit over those remaining on dialysis, including the elderly. Only 3% of patients aged 65 years or older accepted on the waiting list actually received a kidney transplant offer within the Eurotransplant allocation region. To increase the chance for elderly to receive a timely kidney transplant, the Eurotransplant Senior Program was introduced. The ESP supports local allocation of older kidneys to older donors in order to decrease cold ischemia time, while disregarding former exchange principles based on matching for HLA antigens. As a consequence, more elderly received a kidney transplant and a relative higher incidence of acute rejection resulted in additional courses of high steroids and/or depleting antibody therapy. Since death with a functioning graft due to infections is the dominant reason of graft loss in elderly, more intense clinical immunosuppression to prevent or treat acute rejection is not a very attractive option. Therefore in elderly kidney transplant candidates, we advocate reintroduction of minimal histocompatibility criteria (i.e., HLA-DR matching) followed by age-matching with mandatory local/regional allocation to also facilitate short cold ischemia.

Pneumococcal vaccination in lung transplant patients

Introduction: This review analyzes the efficacy of pneumococcal vaccinations in lung transplant patients before and after transplantation.Areas covered: This review addresses the risk for respiratory infections, in particular pneumococcal infections, in lung transplantation patients in the context of immunodeficiency and immunosuppressive medication. Vaccination is recommended to counteract the increased risk of pneumococcal infection, and the relevant guidelines are discussed in this review. The design of specific vaccination schedules is required because of the impaired antibody response in specific patient categories.Expert opinion: Lung transplantation candidates should be vaccinated with pneumococcal vaccines prior to transplantation. Currently, the 23-valent pneumococcal polysaccharide vaccine offers the broadest coverage, but the antibody response should be monitored. New generation pneumococcal conjugate vaccines with equally broad serotype coverage could be used in the future. During the post-transplantation period, the immune status of the patients should be monitored regularly, and vaccination should be repeated when indicated.

Assessment of infectious complications in elderly kidney transplant recipients receiving induction with anti-thymocyte globulin vs basiliximab

BACKGROUND

Elderly transplant recipients experience lower rates of acute rejection with higher rates of infectious complications compared to their younger counterparts. While less intensive immunosuppression may be preferable, there are no recommendations for depleting versus non-depleting induction strategies. We sought to compare infectious complications between anti-thymocyte globulin (ATG) and basiliximab (IL2RA) induction in elderly kidney transplant recipients (KTRs).

METHODS

We reviewed 146 KTRs ≥65 years receiving ATG or IL2RA induction. Per institution protocol, ATG was administered to patients with the following characteristics, irrespective of age: African American (AA), PRA ≥20%, and/or re-transplantation. Infectious complications (bacterial, viral, and invasive fungal) at 1 year were compared.

RESULTS

There were significantly more AA, deceased donors, and sensitized KTRs in the ATG group, reflecting criteria for induction agent. ATG KTRs experienced higher rates of overall infectious complications (77% vs 56%, P = .01), driven by increased bacterial (54% vs 39%, P = .08) and viral infections (51% vs 35%, P = .05). Urinary tract infections (UTIs) and CMV in particular occurred at high rates among ATG patients (46% and 32%, respectively). In multivariate analysis, the only independent risk factor associated with increased risk for infection was induction with ATG (adjusted HR 1.71 [95% CI 1.04-2.83], P = .04). Overall rates of immunologic outcomes were low.

CONCLUSION

Elderly KTRs receiving ATG are at an increased risk for infectious complications, largely attributed to high rates of UTIs and CMV. Additional strategies aimed at mitigating these complications in elderly patients requiring ATG may be beneficial.

Age matters: older age as a risk factor for CMV reactivation in the CMV serostatus-positive kidney transplant recipient

Evaluate risk factors for cytomegalovirus (CMV) reactivation during the first year after kidney transplantation in the CMV-seropositive older recipient. Retrospective single-center study. Between 2011 and 2015, 91 patients ≥ 65 years received a kidney transplant; these were matched with 91 controls, aged 40-60. Risk of CMV reactivation in the CMV-seropositive recipients was analyzed. Sixty-three older and 54 younger recipients were included; 50% had received CMV-directed prophylaxis. CMV reactivation was significantly more frequent in the older group (71.4% vs 44.4%, p = 0.003) and occurred earlier (p = 0.003). A multivariate model showed that only age was associated with CMV reactivation (OR 2.48, p = 0.03). After excluding patients that received thymoglobulin, older age group remained the only risk factor of CMV reactivation (OR 3.81, p = 0.014). Recurrent event analysis showed that the older cohort had an HR of 1.94 (p = 0.01) of CMV viremia; there was significant episode-cohort interaction (p < 0.01). While the older group had a higher risk of infection (HR = 2.43), after the initial episode the relative hazards were approximately equal (HR = 1.08, at period 2). This suggests that it is key to specifically avoid the first episode of reactivation. Universal prophylaxis or a hybrid prophylaxis model should be considered in the CMV-seropositive kidney transplant recipient aged ≥ 65 years.

Characterizing the pharmacokinetics and pharmacodynamics of immunosuppressant medicines and patient outcomes in elderly renal transplant patients

This review examines what is currently known about the pharmacokinetics and pharmacodynamics of commonly prescribed immunosuppressant medicines, tacrolimus, cyclosporine, mycophenolate and prednisolone, in elderly renal transplant recipients, and reported patient outcomes in this cohort. Renal transplantation is increasing rapidly in the elderly, however, currently, long-term patient outcomes are relatively poor compared to younger adults. Some studies have suggested that elderly recipients may have higher dose-adjusted exposure and/or lower clearance of the calcineurin inhibitors tacrolimus and cyclosporine; with one study reporting up to 50% reduction in tacrolimus exposure in the elderly. Elderly transplant recipients do not appear to have higher dosage-adjusted exposure to mycophenolic acid (MPA). The effects of ageing on the pharmacokinetics of prednisolone are unknown. Only one study has examined how aging effects drug target enzymes, reporting no difference in baseline inosine 5'-monophosphate dehydrogenase (IMPDH) activity and MPA-induced IMPDH activity in elderly compared to younger adult renal transplant recipients. In elderly transplant recipients, immunosenescence likely lowers the risk of acute rejection, but increases the risk of drug-related adverse effects. Currently, the three main causes of death in elderly renal transplant recipients are cardiovascular disease, infection and malignancy. One study has showed that renal transplant recipients aged over 65 years are seven times more likely to die with a functioning graft compared with young adults (aged 18-29 years). This suggests that an optimal balance between immunosuppressant medicine efficacy and toxicity is not achieved in elderly recipients, and further studies are needed to foster long-term graft and patient survival. Lower maintenance immunosuppressant targets in elderly recipients may decrease patient susceptibility to drug side effects, however, further studies are required and appropriate targets need to be established.

Epidemiology, Risk Factors, and Outcomes of Opportunistic Infections after Kidney Allograft Transplantation in the Era of Modern Immunosuppression: A Monocentric Cohort Study

Epidemiology of opportunistic infections (OI) after kidney allograft transplantation in the modern era of immunosuppression and the use of OI prevention strategies are poorly described. We retrospectively analyzed a single-center cohort on kidney allograft adult recipients transplanted between January 2008 and December 2013. The control group included all kidney recipients transplanted in the same period, but with no OI. We analyzed 538 kidney transplantations (538 patients). The proportion of OI was 15% (80 and 72 patients). OI occurred 12.8 (6.0–31.2) months after transplantation. Viruses were the leading cause (n = 54, (10%)), followed by fungal (n = 15 (3%)), parasitic (n = 6 (1%)), and bacterial (n = 5 (0.9%)) infections. Independent risk factors for OI were extended criteria donor (2.53 (1.48–4.31), p = 0.0007) and BK viremia (6.38 (3.62–11.23), p < 0.0001). High blood lymphocyte count at the time of transplantation was an independent protective factor (0.60 (0.38–0.94), p = 0.026). OI was an independent risk factor for allograft loss (2.53 (1.29–4.95), p = 0.007) but not for patient survival. Post-kidney transplantation OIs were mostly viral and occurred beyond one year after transplantation. Pre-transplantation lymphopenia and extended criteria donor are independent risk factors for OI, unlike induction therapy, hence the need to adjust immunosuppressive regimens to such transplant candidates.

Differences in Gene Expression in Older Compared With Younger Kidney Transplant Recipients

BACKGROUND

For the growing numbers of older transplant patients, increased incidence of infection and death compared with younger patients may limit the many benefits provided by transplantation. However, little is known about age-associated immune dysfunction in the older transplant recipient.

METHODS

A cohort of 60 kidney transplant recipients, 23 older (≥ 60y) and 37 younger (30-59y), matched on antithymocyte induction and donor type (living vs deceased) was evaluated. Gene expression in peripheral blood mononuclear cells 3 months after kidney transplantation was analyzed to compare differences between older and younger patients.

RESULTS

Proinflammatory genes were upregulated in older kidney transplant patients, including cytokines IL1-β and IL-6. Downregulated genes were associated with B-cell and T-cell function, including CCR7 and CD27. Analysis of predicted transcription factor binding suggested an increase in proinflammatory transcription factor CCAAT/enhancer binding protein β-binding sites in older patients, whereas interferon regulatory factor 2 transcription factor binding sites were less prevalent.

CONCLUSIONS

Older kidney transplant recipients exhibited multiple differences in gene expression compared with younger patients, with upregulation of proinflammatory genes and downregulation of adaptive immune response genes. These findings may explain the mechanism of increased vulnerability to infection and malignancy observed in older transplant patients.

Infections after kidney transplantation. Does age matter?

Infections threaten successful outcomes after kidney transplantation. Our aim was to determine if the number, types of infections and the risk factors for common infections differed between older compared to younger kidney transplant (KT) recipients in the first year after surgery. We performed a single-center retrospective cohort study. Between 2011 and 2015, 91 KTs were performed in patients ≥65 years of age; these were matched 1:1 (by year of transplantation, sex and race) to controls aged 40-60 years. Over 90% of both groups had an infectious complication. Urinary tract infections (UTIs) and cytomegalovirus (CMV) viremia were significantly more frequent in older recipients. Older adults had more late onset UTIs, including after stent removal. CMV viremia was more frequent in older adults in the 1-6 months post-transplant period. Due to our center-specific protocol utilizing pre-emptive monitoring in the CMV recipient-seropositive population, the higher CMV incidence in the aged recipient was driven by this subpopulation of older adults. No difference in pneumonias or bloodstream infections were found, nor in surgical complications, rejection or graft loss. Mortality was higher at 1-year post-transplant in the older recipients (9.9% vs 1.1%; P = 0.018). Prophylactic and immunosuppressive strategies may need to be altered for older KT recipients.

Frailty and Long-Term Post-Kidney Transplant Outcomes

PURPOSE OF REVIEW

To highlight recent research about frailty and its role as a predictor of adverse, long-term post-kidney transplant (KT) outcomes.

RECENT FINDINGS

Frailty is easily measured using the physical frailty phenotype (PFP) developed by gerontologist Dr. Linda Fried and colleagues. In recent studies, >50% of KT recipients were frail (20%) or intermediately frail (32%) at KT admission. Frail recipients were at 1.3-times higher risk of immunosuppression intolerance and 2.2-times higher risk of mortality, even after accounting for recipient, donor, and transplant factors; these findings were consistent with those on short-term post-KT outcomes. Pilot data suggests that prehabilitation may be an intervention that increases physiologic reserve in frail KT recipients.

SUMMARY

The PFP is a effective tool to measure frailty in ESRD that improves risk stratification for short-term and long-term post-KT outcomes. Interventions to improve physiologic reserve and prevent adverse KT outcomes, particularly among frail KT recipients, are needed.

Solid organ transplantation in older adults. Infectious and other age-related considerations

In the U.S., older adults aged 65 or above comprise nearly one quarter of the solid organ transplant (SOT) waitlists, and the number of transplants performed in this age group continues to increase. There are no specific guidelines for the assessment and follow up of the older SOT candidate or recipient. Older adults are at increased risk of infectious complications after SOT. Despite these complications and even with the use of suboptimal donors, overall outcomes are favorable. We provide an overview to specific consideration as they relate to the older SOT candidate and recipient.

Aging and End Stage Renal Disease Cause A Decrease in Absolute Circulating Lymphocyte Counts with A Shift to A Memory Profile and Diverge in Treg Population

There is a growing number of elderly kidney transplant (Ktx) recipients. Elderly recipients present lower acute rejection rates but higher incidence of infection and malignancies. Aging per se seems to result in a shift to memory profile and chronic kidney disease (CKD) in premature immunological aging. Understanding aging and CKD effects on the immune system can improve elderly Ktx immunosuppression. We analyzed the effects of aging and CKD in the immune system, comparing healthy adults (HAd) (n=14, 26±2y), healthy elderly (HEld) (n=15, 79±7y), end stage renal disease (ESRD) adults (EnAd) (n=18, 36±7y) and ESRD elderly (EnEld) (n=31, 65±3y) prior to Ktx regarding their naïve, memory and regulatory T and B peripheral lymphocytes. Aging and ESRD presented additive effect decreasing absolute numbers of B and T-lymphocytes, affecting memory, naive and regulatory subsets without synergic effect. Both resulted in higher percentages of T memory subsets and opposing effects on regulatory T (TREG) subsets, higher percentage in aging and lower in ESRD. Combined effect of aging and ESRD also resulted in higher regulatory B cell percentages. In addition to global lymphopenia and TCD4⁺ memory shift in both aging and ESRD, aging shifts to an immunoregulatory profile, inducing a increase in TREG percentages, contrasting with ESRD that decreases TREGs. Differential immunosuppression regimens for elderly Ktx may be required. (ClinicalTrials.gov number: NTC01631058).

Risk Factors for Early Graft Failure and Death After Kidney Transplantation in Recipients Older Than 70 Years

Introduction

Although kidney transplantation carries a survival benefit compared with dialysis, mortality, especially the first year after transplantation, is high in recipients older than 70. The aim of this study was to evaluate early death and graft failure, and to determine the risk factors associated with these events in this specific population.

Methods

All patients older than 70 years who received a kidney transplant between January 2000 and December 2014 in the North-West of France were included (n = 171). Baseline characteristics and outcomes after transplantation were studied. Kaplan-Meier analysis was performed to assess patient and graft survival, and Cox regression analysis to evaluate risk factors for graft failure and patient death.

Results

The mean recipient age was 73.3 ± 2.5 years. Death-censored graft survival at 1, 3, and 5 years were 82.6%, 78.7%, and 75.4%, respectively. Patient survival at 1, 3, and 5 years was 90.1%, 82.5%, and 68.1%, respectively. One year after transplantation, 17 patients (9.9%) were dead, mainly from infectious (58.5%) or cardiovascular disease (29.4%). According to the Cox multivariate analysis, the independent risk factors for death or graft failure during the first year were arrhythmia (odds ratio [OR] 2.26; 95% confidence interval [CI] 1.08–4.8), left-ventricular ejection fraction (LVEF) under 56% (OR 2.38; 95% CI 1.18–4.83), human leucocyte antigen (HLA) antibodies (OR 2.1; 95% CI 1.04–4.2), deceased donor from cardiovascular cause (OR 5.18; 95% CI 1.22–6.3), and acute rejection (OR 2.77; 95% CI 1.2–6.3).

Conclusion

In kidney transplant recipients older than 70 years, cardiac evaluation and immunosuppression optimization seem to be crucial to improve short-term patient and graft survival.

Predictors of Early and Late Mortality in Older Kidney Transplant Recipients

BACKGROUND

Older kidney patients with chronic kidney disease benefit significantly from kidney transplantation. However, these older transplant recipients have greater mortality after transplantation than younger transplant recipients. Understanding the impact of comorbidities on post-transplant mortality can improve risk stratification and patient selection.

METHODS

A single-center analysis of 3105 kidney transplant recipients was performed over a 12-year period. Comorbidities associated with death were evaluated in older and younger transplant recipients.

RESULTS

The 2 most important factors associated with increased mortality in the first 100 days after transplant were recipient age ≥60 and receipt of deceased donor organs (adjusted odds ratios, 3.29 and 5.80, respectively), with no statistically significant impact of recipient comorbidities. In the later post-transplant period (after the first 100 days), recipient age ≥60 and receipt of deceased donor organs (adjusted hazard ratios [HR] of 2.14 and 2.29, respectively) remained predictors of mortality. We also found that donor age ≥60 and the recipient having cardiovascular disease and diabetes were independent predictors of increased mortality. There was a statistically significant interaction between diabetes and heart disease and recipient age ≥60, with a lesser impact on late mortality in older patients compared to younger patients.

CONCLUSIONS

This analysis suggests that comorbidities have a larger impact later after transplantation, with less effect on older recipients. These observations suggest that certain comorbid conditions should be evaluated differently in older patients compared to younger ones.

Association of Kidney Donor Risk Index with the Outcome after Kidney Transplantation in the Eurotransplant Senior Program

Background

We evaluated the Kidney Donor Risk Index (KDRI) scoring system for kidney transplantation in the Eurotransplant Senior Program (ESP) that allocates kidneys from older donors to older recipients (≥65 years).

Material/Methods

We retrospectively analyzed data of 37 kidney transplant recipients and 36 kidney donors who participated in kidney transplantation program according to the ESP at our center from January 2004 until December 2013.

Results

Mean recipient and donor age was 67.9±2.6 and 70.5±4.0 years respectively. The mean KDRI score was 1.7±0.27. Uncensored graft survival after 1 year and 5 years was 64.2% and 53.7% respectively. Subgroup analysis showed that in kidney transplantation with KDRI >1.83, graft survival was significantly reduced compared to lower KDRI subgroups. KDRI was significantly correlated with serum creatinine level at discharge (r=0.4).

Conclusions

ESP kidneys represent a group of high-risk grafts with high KDRI scores. Higher KDRI scores in ESP kidneys was associated with reduced postoperative short-term and long-term graft outcomes. KDRI might be useful in decision-making for selecting donors for ESP kidney transplantation.

Single-center analysis of infectious complications in older adults during the first year after kidney transplantation

Infections are among the top three causes of death of older adults in the first year after kidney transplantation (KT). Our aim was to describe infectious complications among KT recipients aged ≥ 65 during the first 12 months post-transplant. Single-center retrospective cohort study. Ninety-one KTs had been performed in patients ≥ 65 years of age between 2011 and 2015. 92.3% of the patients developed at least one infection. Infectious episodes increased the risk of future infection by 10% (p = 0.0018) with each infection portending a greater risk. At a patient level, viral (71.4%) and bacterial (70.2%) infections predominated. Urinary tract infections were the most frequent complication (30.3%), followed by cytomegalovirus infections (22.7%). Infections were the main reason for readmission. 7.7% of the patients developed rejection; and overall 3.3% lost their graft. Mortality at 1 year was 9.9%. Older KT recipients have a high incidence of infectious complications the first year after KT. Infections were the number one reason for readmission, and an infection episode predicted future infections for the individual patient. Despite these complications, the majority of older KT recipients were alive with a functioning graft at 1 year.

Increased T cell immunosenescence and accelerated maturation phenotypes in older kidney transplant recipients

Older kidney transplant recipients experience increased rates of infection and death, and less rejection, compared with younger patients. However, little is known about immune dysfunction in older compared with younger kidney transplant recipients and whether it is associated with infection. We evaluated T cell phenotypes including maturation, immune senescence, and exhaustion in a novel investigation into differences in older compared with younger patients receiving identical immune suppression regimens. We evaluated PBMC from 60 kidney transplant recipients (23 older and 37 matched younger patients) by multiparameter immune phenotyping. Older kidney transplant recipients demonstrated decreased frequency of naïve CD4+ and CD8+ T cells, and increased frequency of terminally differentiated, immune senescent, and NK T cells expressing KLRG1. There was a trend towards increased frequency of T cell immune senescence in patients experiencing infection in the first year after transplantation, which reached statistical significance in a multivariate analysis. This pilot study reveals immune dysfunction in older compared with younger transplant recipients, and suggests a likely mechanism for increased vulnerability to infection. The ability to assess T cell maturation and immune senescence in transplant recipients offers the potential for risk stratification and customization of immune suppression to prevent infection and rejection after transplantation.

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.

Differences in Proinflammatory Cytokines and Monocyte Subtypes in Older as Compared With Younger Kidney Transplant Recipients

Supplemental digital content is available in the text.

Background

The number of elderly patients with end-stage kidney disease requiring kidney transplantation continues to grow. Evaluation of healthy older adults has revealed proinflammatory changes in the immune system, which are posited to contribute to age-associated illnesses via “inflamm-aging.” Immunologic dysfunction is also associated with impaired control of infections. Whether these immunologic changes are found in older kidney transplant recipients is not currently known, but may have important implications for risk for adverse clinical outcomes.

Methods

Three months after transplant, innate immune phenotype was evaluated by flow cytometry from 60 kidney transplant recipients (22 older [≥60 years] and 38 younger [<60 years old]). Multiplex cytokine testing was used to evaluate plasma cytokine levels. Younger patients were matched to older patients based on transplant type and induction immune suppression.

Results

Older kidney transplant recipients demonstrated decreased frequency of intermediate monocytes (CD14++CD16+) compared with younger patients (1.2% vs 3.3%, P = 0.007), and a trend toward increased frequency of proinflammatory classical monocytes (CD14++CD16−) (94.5% vs 92.1%) (P = 0.065). Increased levels of interferon-gamma (IFN-γ) were seen in older patients.

Conclusions

In this pilot study of kidney transplant recipients, we identified differences in the innate immune system in older as compared with younger patients, including increased levels of IFN-γ. This suggests that age-associated nonspecific inflammation persists despite immune suppression. The ability to apply noninvasive testing to transplant recipients will provide tools for patient risk stratification and individualization of immune suppression regimens to improve outcomes after transplantation.

Kidney Transplantation in Korean Patients With End-Stage Renal Disease Aged 65 and Older: A Single-Center Experience

BACKGROUND

The mean age of patients starting dialysis in Korea has increased to older than 60 years and the proportion of patients aged 65 and older exceeded 40% in 2014. Although the number of elderly dialysis patients is increasing rapidly, percentages of elderly patients undergoing kidney transplantation (KT) are very low.

METHODS

We retrospectively reviewed the medical records of patients who underwent KT at Keimyung University Dongsan Medical Center between 1982 and 2016. Elderly patients (≥65 years old) were compared with the control group of patients in their early sixties (60-64 years old).

RESULTS

Among a total of 1209 KT patients, those in their early sixties totaled 34 (2.8%) and the elderly totaled only 18 (1.5%). Patient and allograft survival rate showed no significant differences between the elderly and those in their early sixties. Death with a functioning graft accounted for 50% in both groups. However, occurrences of bacterial infection and tuberculosis were higher in the elderly (P = .011 and .047, respectively). In a multivariate analysis, longer duration of renal replacement therapy before KT and the occurrence of malignancy were independent risk factors for patient death (hazard ratio [HR], 1.027; P = .014; HR, 31.934; P = .016, respectively). Also, albuminuria at 6 months after KT was an independent risk factor for allograft loss (HR, 51.155; P = .016).

CONCLUSION

The overall survival rate of the elderly was not significantly lower than those in their early sixties. Even in the elderly, KT should not be delayed. In addition, careful surveillance for malignancy and measures to decrease the risk of infection are necessary.