Change in mortality risk over time in young kidney transplant recipients

Across all solid organs, adolescent age recipients have worse transplant organ survival than younger age children: A US national registry analysis

Univariate analyses suggest that adolescents have worse long-term allograft survival versus younger children across different SOT. This study's objective was to determine whether multivariate analyses of a large national database recording all deceased SOT (KI; LI; HR; LU) also show worse adolescent allograft survival in the different organs. Using data from the national Scientific Registry for Transplant Recipients in the USA for pediatric primary SOT from 1989 to 2010, we calculated median half-lives and constructed K-M graft survival curves. Recipient age at transplant (<12 or adolescent 12-17 yr) was fitted with other identical covariates into multivariate Cox proportional hazards models. In all SOT recipients, unadjusted graft survival curves demonstrated better graft survival for adolescents initially, followed by crossing of the lines, such that adolescent SOT recipients had worse survival after one yr (KI), 4.6 yr (LI), 4.4 yr (HR), and 1.6 yr (LU). Multivariate models of the post-cross period showed a significantly higher AHR for worse graft survival in adolescent age across all four SOTs: AHR 1.400 (KI), 1.958 (LI), 1.414 (HR), and 1.576 (LU). Improving adolescent long-term outcomes across all four organs will be a defining issue in the future.

Assessment and management of hypertension in transplant patients

Hypertension in renal transplant recipients is common and ranges from 50% to 80% in adult recipients and from 47% to 82% in pediatric recipients. Cardiovascular morbidity and mortality and shortened allograft survival are important consequences of inadequate control of hypertension. In this review, we examine the epidemiology, pathophysiology, and management considerations of post-transplant hypertension. Donor and recipient factors, acute and chronic allograft injury, and immunosuppressive medications may each explain some of the pathophysiology of post-transplant hypertension. As observed in other patient cohorts, renal artery stenosis and adrenal causes of hypertension may be important contributing factors. Notably, BP treatment goals for renal transplant recipients remain an enigma because there are no adequate randomized controlled trials to support a benefit from targeting lower BP levels on graft and patient survival. The potential for drug-drug interactions and altered pharmacokinetics and pharmacodynamics of the different antihypertensive medications need to be carefully considered. To date, no specific antihypertensive medications have been shown to be more effective than others at improving either patient or graft survival. Identifying the underlying pathophysiology and subsequent individualization of treatment goals are important for improving long-term patient and graft outcomes in these patients.

Adherence in Adolescent and Young Adult Kidney Transplant Recipients

Poor adherence to immunosuppressive medications may be the most important barrier to long term graft survival. An understanding of medication adherence and its determinants is critical to addressing this important problem. In this paper, we will review the different ways in which adherence may be compromised, summarize the evidence that young people constitute a particularly high risk group, and consider the consequences and impact of poor adherence. We will also review the determinants of adherence, including characteristics of the patient and family, the treatment regimen, the healthcare team and its organization, and the healthcare system. We will highlight the most common barriers to adherence identified by young people, and consider different methods of measuring adherence, along with the advantages and limitations of each. Finally, we will consider possible intervention strategies to improve adherence in young people.

The mortality risk with graft function has decreased among children receiving a first kidney transplant in the United States

Mortality has decreased in children with end stage kidney disease. Decreases in mortality during dialysis and improved graft survival contributed to this improvement. However, it is unknown if rates of death with graft function have also improved. We measured this in first transplant recipients under 21 years old registered in the USRDS. Cox models were used with a time-dependent renal replacement therapy modality variable to estimate the hazard ratios for death with graft function associated with a 1-year increment in the calendar year of transplant. There were 157,201 person-years of observation among 17,468 recipients with 82.2% of study time during graft function and 17.8% during dialysis after graft failure. There were 2003 deaths (12.7 deaths/1000 person-years) overall of which 985 occurred with graft function (7.6 deaths/1000 person-years) and 1018 occurred during dialysis after graft failure (36.1 deaths/1000 person-years). Each 1-year increment in calendar year of first transplant was associated with a significantly lower risk of death, both over all observation (HR 0.97 [0.96, 0.98]) and focusing on time with graft function (HR 0.98 [0.97, 0.99]). Living donation was significantly associated with better survival while dialysis after graft failure was associated with a much higher mortality risk (HR 4.85 [4.40, 5.35]) compared with graft function. Thus, the risk of death with graft function has decreased in children receiving a first kidney transplant. Increasing living donation and minimizing dialysis may further improve outcomes.

An observational cohort study of the effect of hypertension on the loss of renal function in pediatric kidney recipients

BACKGROUND

Post-transplant hypertension impacts negatively on renal graft survival. Our primary objective was to analyze the effect of hypertension on the glomerular filtration rate (GFR) slope.

METHODS

All clinical charts of children who underwent renal transplantation since the introduction of the routine use of ambulatory blood pressure monitoring (ABPM) were reviewed. Eligibility criteria for inclusion were measurement of GFR at 3 months, at 1 year post-transplant, and thereafter at yearly intervals; ABPM performed annually after transplantation; and functioning graft for a minimum of 2 years.

RESULTS

Sixty-eight (39 males) of 79 patients, aged 9.1±5.3 years, met the inclusion criteria. The mean follow-up was 6.2±2.8 years. Twenty-four patients had normotension or controlled hypertension throughout their follow-up (normotensive group). Forty-four patients had hypertension or noncontrolled hypertension at some point(s) during the follow-up period (hypertensive group). GFR slope was -1.6ml/min/1.73 m(2) per year (95% confidence interval (CI = -3.7 to 0.4) in the normotensive group and -2ml/min/1.73 m(2) per year (95% CI = -3 to -1.1) in the hypertensive group (P = 0.42). There was no difference between groups with regard to the change in GFR values from 3 months to 1 year and to last control (P = 0.87). At most recent control, the overall prevalence of controlled hypertension was 78.2% (95% CI = 63.6-89.1).

CONCLUSIONS

Although the results of our study are encouraging, they need to be confirmed in a larger prospective study using the same post-transplant follow-up protocol.

Impact of HLA mismatch at first kidney transplant on lifetime with graft function in young recipients

As HLA matching has been progressively de-emphasized in the American deceased donor (DD) kidney allocation algorithm, concerns have been raised that poor matching at first transplant may lead to greater sensitization and more difficulty finding an acceptable donor for a second transplant should the first transplant fail. We compared proportion of total observed lifetime with graft function after first transplant, and waiting times for a second transplant between individuals with different levels of HLA mismatch (MM) at first transplant. We studied patients recorded in the United States Renal Data System (1988-2009) who received a first DD transplant at age ≤21 years (n = 8433), and the subgroup who were listed for a second DD transplant following first graft failure (n = 2498). Compared with recipients of 2-3 MM first grafts, 4-6 MM graft recipients spent 12% less of their time and 0-1 MM recipients 15% more time with a functioning graft after the first transplant (both p < 0.0001); 4-6 MM recipients were significantly less likely (hazard ratio [HR] 0.87 [95% confidence interval 0.76, 0.98]; p = 0.03), and 0-1 MM recipients more likely (HR 1.26 [0.99, 1.60]; p = 0.06) to receive a second transplant after listing. The benefits of better HLA matching at first transplant on lifetime with graft function are significant, but relatively small.

Mortality after pediatric kidney transplantation in England--a population-based cohort study

The aim of this study was to explore mortality after pediatric kidney transplantation in England over the last decade. We used data from HES to select all kidney transplant procedures performed in England between April 2001 and March 2012. Data linkage analysis was performed with the ONS to identify all deaths occurring among this study cohort. Data for 1189 pediatric recipients were compared to 17 914 adult recipients (number of deaths, 33 vs. 2052, respectively, p < 0.001), with median follow-up 4.4 yr (interquartile range 2.2-7.3 yr). There was no difference in mortality within the pediatric cohort; age 0-1 (n = 25, patient survival 100.0%), age 2-5 (n = 198, patient survival 96.0%), age 6-12 (n = 359, patient survival 97.5%), and age 13-18 (n = 607, patient survival 97.4%), respectively (p = 0.567). The most common causes of death were renal (n = 8, 24.2%), infection (n = 6, 18.2%), and malignancy (n = 5, 15.2%). All deaths from malignancy were secondary to PTLD. In a fully adjusted Cox regression model, only white ethnicity was significantly associated with risk of pediatric mortality post-kidney transplantation (hazard ratio 2.7, 95% confidence interval [1.0-7.3], p = 0.047). To conclude, this population-based cohort study confirms low mortality after pediatric kidney transplantation with short follow-up.

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

End-stage kidney disease after pediatric nonrenal solid organ transplantation

OBJECTIVES

Adult solid organ transplant (SOT) recipients commonly develop advanced kidney disease; however, the burden of end-stage kidney disease (ESKD) in children after SOT is not well-described. The objectives of this study were to determine the incidence of ESKD after pediatric SOT and the relative risk by SOT type.

METHODS

Retrospective multicenter cohort study of children, ages ≤ 18 years, who received SOTs from 1990 through 2010 using Scientific Registry of Transplant Recipients data linked to the US Renal Data System. We performed a competing risks analysis to determine cumulative incidence of ESKD (chronic dialysis or kidney transplant), treating death as a competing risk, and fit a multivariable Cox regression model to assess hazard of ESKD by organ type.

RESULTS

The cohort included 16,604 pediatric SOT recipients (54% liver, 34% heart, 6% lung, 6% intestine, and 1% heart-lung). During a median follow-up of 6.2 years (interquartile range 2.2-12.1), 426 (3%) children developed ESKD. Compared with liver transplant recipients, in whom the incidence of ESKD was 2.1 cases per 1000 person-years, in adjusted analyses the highest risk of ESKD was among intestinal (hazard ratio [HR] 7.37, P < .001), followed by lung (HR 5.79, P < .001) and heart transplant recipients (HR 1.79, P < .001).

CONCLUSIONS

In a 20-year national cohort of pediatric SOT recipients, the risk of ESKD was highest among intestinal and lung transplant recipients. The burden of earlier stages of chronic kidney disease is probably much higher; modifiable risk factors should be targeted to prevent progressive kidney damage in this high-risk population.

Mortality risk among children initially treated with dialysis for end-stage kidney disease, 1990-2010

IMPORTANCE

Most children with end-stage kidney disease (ESKD) are treated with dialysis prior to transplant. It is not known whether their outcomes have changed in recent years.

OBJECTIVE

To determine if all-cause, cardiovascular, and infection-related mortality rates for children and adolescents beginning dialysis improved between 1990 and 2010.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of patients younger than 21 years initially treated with dialysis for ESKD, recorded in the United States Renal Data System between 1990 and 2010. Children with a prior kidney transplant were excluded. We used Cox proportional hazard models to estimate the hazard ratios (HRs) for mortality associated with a 5-year increment in year of ESKD treatment initiation. Primary analyses censored observation at kidney transplant.

MAIN OUTCOMES AND MEASURES

All-cause, cardiovascular, and infection-related mortality.

RESULTS

A total of 3450 children younger than 5 years and 19,951 children 5 years or older started dialysis from 1990-2010. Of those younger than 5 years, 705 died during dialysis treatment (98.8/1000 person-years); mortality rates were 112.2 and 83.4 per 1000 person-years in those initiating dialysis in 1990-1994 and 2005-2010, respectively. Of those 5 years and older at treatment initiation, 2270 died during dialysis treatment (38.6/1000 person-years). Their mortality rates were 44.6 and 25.9 per 1000 person-years in those initiating dialysis in 1990-1994 and 2005-2010, respectively. Each 5-year increment in calendar year of dialysis initiation was associated with an adjusted HR of 0.80 (95% CI, 0.75-0.85) among children younger than 5 years at initiation and an HR of 0.88 (95% CI, 0.85-0.92) among those 5 years and older.

RESULTS

A total of 23,401 children and adolescents who initiated ESKD treatment with dialysis at younger than 21 years between 1990 and 2010 were identified. Crude mortality rates during dialysis treatment were higher among children younger than 5 years at the start of dialysis compared with those who were 5 years and older. Mortality rates for both children and adolescents being treated for ESKD with dialysis decreased significantly between 1990 and 2010.

CONCLUSIONS AND RELEVANCE

In the United States, there was a substantial decrease in mortality rates over time among children and adolescents initiating ESKD treatment with dialysis between 1990 and 2010. Further research is needed to determine the specific factors responsible for this decrease.

De novo cancer-related death in Australian liver and cardiothoracic transplant recipients

Evidence is sparse on the relative mortality risk posed by de novo cancers in liver and cardiothoracic transplant recipients. A retrospective cohort study was conducted in Australia using population-based liver (n = 1926) and cardiothoracic (n = 2718) registries (1984-2006). Standardized mortality ratios (SMRs) were computed by cancer type, transplanted organ, recipient age and sex. During a median 5-year follow-up, de novo cancer-related mortality risk in liver and cardiothoracic recipients was significantly elevated compared to the matched general population (n = 171; SMR = 2.83; 95% confidence interval [95%CI], 2.43-3.27). Excess risk was observed regardless of transplanted organ, recipient age group or sex. Non-Hodgkin lymphoma was the most common cancer-related death (n = 38; SMR = 16.6; 95%CI, 11.87-22.8). The highest relative risk was for nonmelanocytic skin cancer (n = 23; SMR = 49.6, 95%CI, 31.5-74.5), predominantly in males and in recipients of heart and lung transplants. Risk of death from de novo cancer was high in pediatric recipients (n = 5; SMR = 41.3; 95%CI, 13.4-96.5), four of the five deaths were non-Hodgkin lymphoma. De novo cancer was a leading cause of late death, particularly in heart and liver transplantation. These findings support tailored cancer prevention strategies, surveillance to promote early detection, and guidelines for managing immunosuppression once cancer occurs.

Long-term critical issues in pediatric renal transplant recipients: a single-center experience

Data on long-term outcomes after pediatric renal transplantation (Tx) are still limited. We report on a 20-year single-center experience. Medical charts of all consecutive pediatric Tx performed between 1987 and 2007 were reviewed. Data of patients who had been transferred to adult units were extracted from the French databases of renal replacement therapies. Outcomes were assessed using Kaplan-Meier and Cox models. Two hundred forty Tx were performed in 219 children (24.1% pre-emptive and 17.5% living related donor Tx). Median age at Tx was 11.1 years and median follow-up was 10.4 years. Patient survival was 94%, 92%, and 91% at 5, 10, and 15 years post-Tx, respectively. Overall, transplant survival was 92%, 82%, 72%, and 59% at 1, 5, 10, and 15 years post-Tx, respectively. The expected death-censored graft half-life was 20 years. Sixteen patients developed malignancies during follow-up. Median height at 18 years of age was 166 cm in boys and 152 cm in girls with 68% of patients being in the normal range. The proportion of socially disadvantaged young people was higher than in general population. Excellent long-term outcomes can be achieved in pediatric renal Tx, but specific problems such as malignancies, growth, and social outcome remain challenging.

New concepts and best practices for management of pre- and post-transplantation cancer

Solid-organ transplant recipients are at increased risk of developing cancer compared with the general population. Tumours can arise de novo, as a recurrence of a preexisting malignancy, or from the donated organ. The ATOS (Aula sobre Trasplantes de Órganos Sólidos; the Solid-Organ Transplantation Working Group) group, integrated by Spanish transplant experts, meets annually to discuss current advances in the field. In 2011, the 11th edition covered a range of new topics on cancer and transplantation. In this review we have highlighted the new concepts and best practices for managing cancer in the pre-transplant and post-transplant settings that were presented at the ATOS meeting. Immunosuppression plays a major role in oncogenesis in the transplant recipient, both through impaired immunosurveillance and through direct oncogenic activity. It is possible to transplant organs obtained from donors with a history of cancer as long as an effective minimization of malignancy transmission strategy is followed. Tumour-specific wait-periods have been proposed for the increased number of transplantation candidates with a history of malignancy; however, the patient's individual risk of death from organ failure must be taken into consideration. It is important to actively prevent tumour recurrence, especially the recurrence of hepatocellular carcinoma in liver transplant recipients. To effectively manage post-transplant malignancies, it is essential to proactively monitor patients, with long-term intensive screening programs showing a reduced incidence of cancer post-transplantation. Proposed management strategies for post-transplantation malignancies include viral monitoring and prophylaxis to decrease infection-related cancer, immunosuppression modulation with lower doses of calcineurin inhibitors, and addition of or conversion to inhibitors of the mammalian target of rapamycin.

Treatments and outcomes for end-stage renal disease following Wilms tumor

BACKGROUND

Little is known about treatment outcomes for children who have end-stage renal disease (ESRD) after treatment for Wilms tumor (WT).

METHODS

Time-to-transplant, graft failure, and survival outcomes were examined for 173 children enrolled on the National Wilms Tumor Study who developed ESRD.

RESULTS

Fifty-five patients whose ESRD resulted from progressive bilateral WT (PBWT) experienced high early mortality from WT that limited their opportunity for transplant (47% at 5 years) and survival (44% at 10 years) in comparison to population controls. The 118 patients whose ESRD was due to other causes (termed "chronic kidney disease"), many of whom had WT-associated congenital anomalies, had transplant (77% at 5 years) and survival (73% at 10 years) outcomes no worse than those for population controls. Graft failure following transplant was comparable for the two groups. Minority children had twice the median time to transplant as non-Hispanic whites and twice the mortality rates, also reflecting population trends.

CONCLUSIONS

In view of the continuing high mortality in patients with ESRD, and the dramatic improvement in outlook following kidney transplantation, re-evaluation of current guidelines for a 2-year delay in transplant following WT treatment may be warranted.

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.