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Burden of excess mortality after implementation of the new kidney allocation system may be borne disproportionately by middle-aged recipients.

ABSTRACT: Under the new kidney allocation system (KAS), implemented in 2014, the distribution of the best quality donor kidney grafts shifted between age groups, but it is unclear whether this change translates to meaningful differences in post-transplant outcomes. We conducted a retrospective cohort study of 20,345 deceased donor kidney transplant recipients before and 4,605 recipients after implementation of the KAS using data from the United Network of Organ Sharing. Overall, two-year mortality was greater among recipients in the post-KAS era compared with the pre-KAS era (6.31% vs 5.91% respectively, [p = 0.01]), and two-year graft loss was not significantly different between eras (9.95% and 9.65%, respectively [p = 0.13]). In analysis stratified by age group (18-45, 46-55, 56-65, and ?66 years), relative risk of mortality was 1.48 (95% confidence interval [CI] 1.09-1.98) among recipients 46-55 years old and 1.47 (95% CI 1.18-1.81) among recipients 56-65 years old. Relative risk of all-cause graft loss was 1.43 (95% CI 1.20-1.70) among recipients 56-65 years old. There were no significant differences in relative risk of mortality or graft loss associated with the KAS era among other age groups. After adjustment for recipient characteristics and characteristics of the changing donor pool, relative risk of two-year mortality and graft loss associated with the post-KAS era was attenuated for recipients aged 46-55 and 56-65 years, but remained statistically significant. In this early analysis after implementation of the KAS, there is suggestion that increased risk of mortality and graft loss may be disproportionately borne by middle-aged recipients, which is only partially accounted for by changes in recipient and donor characteristics. These findings signal a need to continue to monitor the effects of the KAS to ensure that allocation practices both maximize utility of the kidney graft pool and respect fairness between age groups.

SUBMITTER: Butler CR

PROVIDER: S-EPMC6345464 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Burden of excess mortality after implementation of the new kidney allocation system may be borne disproportionately by middle-aged recipients.

Butler Catherine R CR Perkins James D JD Johnson Christopher K CK Blosser Christopher D CD Bakthavatsalam Ramasamy R Leca Nicolae N Sibulesky Lena L

PloS one 20190124 1

Under the new kidney allocation system (KAS), implemented in 2014, the distribution of the best quality donor kidney grafts shifted between age groups, but it is unclear whether this change translates to meaningful differences in post-transplant outcomes. We conducted a retrospective cohort study of 20,345 deceased donor kidney transplant recipients before and 4,605 recipients after implementation of the KAS using data from the United Network of Organ Sharing. Overall, two-year mortality was gre ...[more]

PMID: 30677058

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Project description:Rationale & objectiveThe national kidney allocation system (KAS) implemented in December 2014 in the United States redefined the start of waiting time from the time of waitlisting to the time of kidney failure. Waitlisting has declined post-KAS, but it is unknown if this is due to transplant center practices or changes in dialysis facility referral and evaluation. The purpose of this study was to assess the impact of the 2014 KAS policy change on referral and evaluation for transplantation among a population of incident and prevalent patients with kidney failure.Study designCohort study.Setting & participants37,676 incident (2012-2016) patients in Georgia, North Carolina, and South Carolina identified within the US Renal Data System at 9 transplant centers and followed through December 2017. A prevalent population of 6,079 patients from the same centers receiving maintenance dialysis in 2012 but not referred for transplantation in 2012.ExposureKAS era (pre-KAS vs post-KAS).OutcomeReferral for transplantation, start of transplant evaluation, and waitlisting.Analytical approachMultivariable time-dependent Cox models for the incident and prevalent population.ResultsAmong incident patients, KAS was associated with increased referrals (adjusted HR, 1.16 [95% CI, 1.12-1.20]) and evaluation starts among those referred (adjusted HR, 1.16 [95% CI, 1.10-1.21]), decreased overall waitlisting (adjusted HR, 0.70 [95% CI, 0.65-0.76]), and lower rates of active waitlisting among those evaluated compared to the pre-KAS era (adjusted HR, 0.81 [95% CI, 0.74-0.90]). Among the prevalent population, KAS was associated with increases in overall waitlisting (adjusted HR, 1.74 [95% CI, 1.15-2.63]) and active waitlisting among those evaluated (adjusted HR, 2.01 [95% CI, 1.16-3.49]), but had no significant impact on referral or evaluation starts among those referred.LimitationsLimited to 3 states, residual confounding.ConclusionsIn the southeastern United States, the impact of KAS on steps to transplantation was different among incident and prevalent patients with kidney failure. Dialysis facilities referred more incident patients and transplant centers evaluated more incident patients after implementation of KAS, but fewer evaluated patients were placed onto the waitlist. Changes in dialysis facility and transplant center behaviors after KAS implementation may have influenced the observed changes in access to transplantation.

Project description:ImportanceInactive patients on the kidney transplant wait-list have a higher mortality. The implications of this status change on transplant outcomes between racial/ethnic groups are unknown.ObjectivesTo determine if activity status changes differ among races/ethnicities and levels of sensitization, and if these differences are associated with transplant probability after implementation of the Kidney Allocation System.Design, setting, and participantsA multistate model was constructed from the Organ Procurement and Transplantation Network kidney transplant database (December 4, 2014, to September 8, 2016). The time interval followed Kidney Allocation System implementation and provided at least 1-year follow-up for all patients. The model calculated probabilities between active and inactive status and the following competing risk outcomes: living donor transplant, deceased donor transplant, and death/other. This retrospective cohort study included 42 558 patients on the Organ Procurement and Transplantation Network kidney transplant wait-list following Kidney Allocation System implementation. To rule out time-varying confounding from relisting, analysis was limited to first-time registrants. Owing to variations in listing practices, primary center listing data were used for dually listed patients. Individuals listed for another organ or pancreatic islets were excluded. Analysis began July 2017.Main outcome and measuresProbabilities were determined for transitions between active and inactive status and the following outcome states: active to living donor transplant, active to deceased donor transplant, active to death/other, inactive to living donor transplant, inactive to deceased donor transplant, and inactive to death/other.ResultsThe median (interquartile range) age at listing was 55.0 (18.0-89.0) years, and 26 535 of 42 558 (62.4%) were men. White individuals were 43.3% (n = 18 417) of wait-listed patients, while black and Hispanic individuals made up 27.8% (n = 11 837) and 19.5% (n = 8296), respectively. Patients in the calculated plasma reactive antibody categories of 0% or 1% to 79% showed no statistically significant difference in transplant probability among races/ethnicities. White individuals had an advantage in transplant probability over black individuals in calculated plasma reactive antibody categories of 80% to 89% (hazard ratio [HR], 1.8 [95% CI, 1.4-2.2]) and 90% or higher (HR, 2.4 [95% CI, 2.1-2.6]), while Hispanic individuals had an advantage over black individuals in the calculated plasma reactive antibody group of 90% or higher (HR, 2.5 [95% CI, 2.1-2.8]). Once on the inactive list, white individuals were more likely than Hispanic individuals (HR, 1.2 [95% CI, 1.17-1.3]) or black individuals (HR, 1.4 [95% CI, 1.3-1.4]) to resolve issues for inactivity resulting in activation.Conclusions and relevanceFor patients who are highly sensitized, there continues to be less access to kidney transplant in the black population after the implementation of the Kidney Allocation System. Health disparities continue after listing where individuals from minority groups have greater difficulty in resolving issues of inactivity.

Project description:ImportanceThe Organ Procurement and Transplantation Network (OPTN) approved changes to the US kidney allocation system in 2019. The potential effects of this policy change using transplant rates normalized to end-stage kidney disease (ESKD) incidence have not been investigated.ObjectiveTo estimate how the OPTN kidney allocation policy will affect areas of the US currently demonstrating low rates of kidney transplant, when accounting for the regional burden of ESKD.Design, setting, and participantsThis cross-sectional population-based economic evaluation analyzed access of patients with ESKD to kidney transplant in the US. Participants included patients with incident ESKD, those on the kidney transplant wait list, and those who received a kidney transplant. Data were collected from January 1 to December 31, 2017, and were analyzed in 2019.Main outcomes and measuresThe probability of a patient with ESKD being placed on the transplant wait list or receiving a deceased donor kidney transplant. States and donor service areas (DSAs) were compared for gains and losses in rates of transplanted kidneys under the new allocation system. Transplant rates were normalized for ESKD burden.ResultsA total of 122 659 patients had incident ESKD in the US in 2017 (58.2% men; mean [SD] age, 62.8 [15.1] years). The probability of a patient with ESKD receiving a deceased donor kidney transplant varied 3-fold across the US (from 6.36% in West Virginia to 18.68% in the District of Columbia). Modeling of the OPTN demonstrates that DSAs from New York (124%), Georgia (65%), and Illinois (56%) are estimated to experience the largest increases in deceased donor kidney allocation. Other than Georgia, these states have kidney transplant rates per incident ESKD cases above the mean (of 50 states plus the District of Columbia, New York is 16th and Illinois is 24th). In contrast, DSAs from Nevada (-74%), Ohio (-67%), and North Carolina (-61%)-each of which has a transplant rate per incident ESKD cases significantly below the mean-are estimated to experience the largest decreases in deceased donor allocation (of 50 states plus the District of Columbia, North Carolina is 34th, Ohio is 38th, and Nevada is 47th).Conclusions and relevanceThe new OPTN-approved kidney allocation policy may result in worsening geographic disparities in access to transplants when measured against the burden of ESKD within a particular region of the US.

Project description:BackgroundPrevious clinical studies have shown that various measures of glucose metabolism are associated with a risk of chronic kidney disease in different populations, but results were not consistent. In this study we assessed measures of glucose metabolism and their association with kidney function in a population-based study.MethodsThe Netherlands Epidemiology of Obesity study is a population-based cohort study of middle-aged men and women. We categorized the study population according to glycaemic levels into normoglycaemia (reference group), pre-diabetes mellitus (pre-DM), known DM and newly diagnosed DM. Outcome variables were serum creatinine, estimated glomerular filtration rate (eGFR), glomerular hyperfiltration (defined as an eGFR >90th percentile; >102 mL/min/1.73 m2) and micro-albuminuria. We examined the association between measures of glucose metabolism [fasting glucose, haemoglobin A1c (HbA1c), fasting insulin, glucose area under the curve (AUC), insulin AUC, Homoeostatic Model Assessment of Insulin Resistance (HOMA-IR), HOMA of β-cell function (HOMA-B) and disposition index] and measures of kidney function.ResultsOf the total population (N = 6338), 55% of participants were classified as normoglycaemic (reference), 35% as pre-DM, 7% as DM and 4% as newly diagnosed DM. Compared with the reference group, diagnosed and newly diagnosed DMs were associated with a slightly higher trend in eGFR {+2.1 mL/min/1.73 m2 [95% confidence interval (CI) -0.2-4.4] and +2.7 mL/min/1.73 m2 [95% CI -0.3-5.7], respectively}. A 1% higher HbA1c was associated with increased odds of hyperfiltration [odds ratio (OR) 1.41 (95% CI 1.06-1.88)]. Higher levels of fasting plasma glucose, AUC glucose and HOMA-B were associated with hyperfiltration. Fasting insulin, AUC insulin and HOMA-IR were not associated with hyperfiltration. The OR of microalbuminuria was 1.21 (95% CI 1.04-1.42) per mmol/L higher fasting glucose concentrations.ConclusionsBoth fasting and post-prandial glucose and HOMA-B, but not measures of insulin resistance, were associated with glomerular hyperfiltration, while fasting glucose was also associated with microalbuminuria.

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Burden of excess mortality after implementation of the new kidney allocation system may be borne disproportionately by middle-aged recipients.

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Burden of excess mortality after implementation of the new kidney allocation system may be borne disproportionately by middle-aged recipients.

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