Preemptive renal transplant candidate survival, access to care, and renal function at listing

Comparing the Net Benefits of Adult Deceased Donor Kidney Transplantation for a Patient on the Preemptive Waiting List vs a Patient Receiving Dialysis

IMPORTANCE

Preemptive kidney transplantation is the preferred treatment for end-stage kidney disease. However, deceased donor (DD) kidneys are limited, and the net benefit of allocating kidneys to a preemptively waitlisted patient rather than to a patient receiving dialysis is unclear.

OBJECTIVE

To estimate the net benefit and costs of allocating kidneys to preemptively waitlisted patients vs those receiving dialysis.

DESIGN, SETTING, AND PARTICIPANTS

This medical decision analytical model used data from the 2020 US Renal Data System to calculate patient survival among waitlisted patients who received a DD kidney transplant. Four patients were simulated, with similar characteristics: (1) a patient on the preemptive waiting list receiving a DD transplant, (2) a patient on the preemptive waiting list never receiving a transplant, (3) a waitlisted patient already receiving dialysis (dialysis vintage <1 year) receiving a transplant, and (4) a waitlisted patient already receiving dialysis (dialysis vintage <1 year) never receiving a transplant. Annual probability of initiating dialysis (for patients 1 and 2) and duration of dialysis (for patients 3 and 4) were varied in sensitivity analyses.

EXPOSURES

Allocating a DD kidney to a patient on the preemptive waiting list vs the same kidney to a patient receiving dialysis for less than 1 year, with similar recipient characteristics.

MAIN OUTCOMES AND MEASURES

Differences in projected quality-adjusted life-years (QALYs) and total costs.

RESULTS

In a simulated patient with a mean start age of 50 years (range, 30-64 years), the patient receiving a preemptive DD transplantation experienced 10.58 (95% CI, 10.36-10.80) QALYs, and the patient on the preemptive waiting list never transplanted experienced 6.83 (95% CI, 6.67-6.99) QALYs. The patient receiving DD transplantation after less than 1 year of dialysis experienced 10.33 (95% CI, 10.21-10.55) QALYs, and the patient receiving dialysis who remained on the waiting list experienced 6.20 (95% CI, 6.04-6.36) QALYs; allocating a DD kidney to the preemptive patient added 3.75 (95% CI, 3.57-3.93) QALYs, whereas allocating the kidney to the patient already receiving dialysis added 4.13 (95% CI, 3.92-4.31) QALYs. While the estimated posttransplant survival was longest for the preemptive transplant recipient, preferentially allocating the kidney to the preemptive patient results in 0.39 (95% CI, 0.49-0.29) fewer QALYs. The net cost of preemptive transplantation was $54 100 (95% CI, $44 100-$64 100) more than transplantation to a waitlisted patient. If the rate of transitioning to dialysis was 20 (rather than 33) events per 100 patient waiting list-years, the net QALYs were -0.67 (95% CI, -0.78 to -0.56). If the patient was receiving dialysis for 3 to 4 years (vs <1 year) the net benefit was not significantly different; however, net costs were considerably higher for the preemptive option.

CONCLUSIONS AND RELEVANCE

In this decision analytic model study, although allocating DD kidneys to patients preemptively was the best option from a patient perspective, allocating DD kidneys to patients receiving dialysis was a better use of a scare resource from a societal perspective.

Global Estimates of Capacity for Kidney Transplantation in World Countries and Regions

BACKGROUND

Kidney transplantation (KT) is the optimal treatment for kidney failure and is associated with better quality of life and survival relative to dialysis. However, knowledge of the current capacity of countries to deliver KT is limited. This study reports on findings from the 2018 International Society of Nephrology Global Kidney Health Atlas survey, specifically addressing the availability, accessibility, and quality of KT across countries and regions.

METHODS

Data were collected from published online sources, and a survey was administered online to key stakeholders. All country-level data were analyzed by International Society of Nephrology region and World Bank income classification.

RESULTS

Data were collected via a survey in 182 countries, of which 155 answered questions pertaining to KT. Of these, 74% stated that KT was available, with a median incidence of 14 per million population (range: 0.04-70) and median prevalence of 255 per million population (range: 3-693). Accessibility of KT varied widely; even within high-income countries, it was disproportionately lower for ethnic minorities. Universal health coverage of all KT treatment costs was available in 31%, and 57% had a KT registry.

CONCLUSIONS

There are substantial variations in KT incidence, prevalence, availability, accessibility, and quality worldwide, with the lowest rates evident in low- and lower-middle income countries. Understanding these disparities will inform efforts to increase awareness and the adoption of practices that will ensure high-quality KT care is provided around the world.

Early Referral, Living Donation, and Preemptive Kidney Transplant

BACKGROUND

Preemptive kidney transplant (PKT) is recognized as the most beneficial and cost-effective form of renal replacement therapy among patients with end-stage renal disease. Despite optimal outcomes and improved quality of life associated with PKT, its use as a first renal replacement therapy remains low among patients with end-stage renal disease. The goal of this retrospective cohort study was to compare, among adult kidney transplant recipients, characteristics across PKT status.

METHODS

We compared the characteristics of patients who did and did not have a PKT over 5 years, from 2010 to 2014, using the electronic health records of Kaiser Permanente Mid-Atlantic States.

RESULTS

A total of 233 patients received a kidney-alone transplant, and, of these, 44 patients (19%) were PKT and 189 patients (81%) were non-PKT. Of the patients in the PKT group, 43% received a kidney from a deceased donor. PKT recipients were more often White, had polycystic kidney disease or glomerulonephritis, received a living donor organ, and were transplanted at certain transplant centers. Estimated glomerular filtration rate on listing for those who received a deceased donor transplant was higher in PKT than non-PKT patients listed pre-dialysis.

CONCLUSIONS

PKT was associated with having a living kidney donor and with having a higher estimated glomerular filtration rate at listing for deceased donor recipients.

Age disparities in transplantation

PURPOSE OF REVIEW

The aim of this review is to outline disparities in liver and kidney transplantation across age spectrum. Disparities do not involve only recipients whose age may severely affect the possibility to access to a potentially life-saving procedure, but donors as well. The attitude of transplant centers to use older donors reflects on waiting list mortality and drop-out. This review examines which age categories are currently harmed and how different allocation systems may minimize disparities.

RECENT FINDINGS

Specific age categories suffer disparities in the access to transplantation. A better understanding of how properly evaluate graft quality, a continuous re-evaluation of the most favorable donor-to-recipient match and most equitable allocation system are the three key points to promote 'justice and equality' among transplant recipients.

SUMMARY

The duty to protect younger patients waiting for transplantation and the request of older patients to have access to potentially life-saving treatment urge the transplant community to use older organs thus increasing the number of available grafts, to evaluate new allocation systems with the aim to maximize 'utility' while respecting 'equity' and to avoid 'futility' thus minimizing waiting list mortality and drop-out, and improving the survival benefits for all patients requiring a transplant.

VIDEO ABSTRACT

http://links.lww.com/COOT/A9.

Redesigning Kidney Disease Care to Improve Value Delivery

This article describes the articulation, development, and deployment of a machine learning (ML) model-driven value solution for chronic kidney disease (CKD) in a health system. The ML model activated an electronic medical record (EMR) trigger that alerted CKD patients to seek primary care. Simultaneously, primary care physicians (PCPs) received an alert that a CKD patient needed an appointment. Using structured checklists, PCPs addressed and controlled comorbid conditions, reconciled drug dosing and choice to CKD stage, and ordered prespecified laboratory and imaging tests pertinent to CKD. After completion of checklist prescribed tasks, PCPs referred patients to nephrology. CKD patients had multiple comorbidities and ML recognition of CKD provided a facile insight into comorbid burden. Operational results of this program have exceeded expectations and the program is being expanded to the entire health system. This paradigm of ML-driven, checklist-enabled care can be used agnostic of EMR platform to deliver value in CKD through structured engagement of complexity in health systems.

Trends in Disparities in Preemptive Kidney Transplantation in the United States

BACKGROUND AND OBJECTIVES

Long wait times for deceased donor kidneys and low rates of preemptive wait-listing have limited preemptive transplantation in the United States. We aimed to assess trends in preemptive deceased donor transplantation with the introduction of the new Kidney Allocation System (KAS) in 2014 and identify whether key disparities in preemptive transplantation have changed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified adult deceased donor kidney transplant recipients in the United States from 2000 to 2018 using the Scientific Registry of Transplant Recipients. Preemptive transplantation was defined as no dialysis before transplant. Associations between recipient, donor, transplant, and policy era characteristics and preemptive transplantation were calculated using logistic regression. To test for modification by KAS policy era, an interaction term between policy era and each characteristic of interest was introduced in bivariate and adjusted models.

RESULTS

The proportion of preemptive transplants increased after implementation of KAS from 9.0% to 9.8%, with 1.10 (95% confidence interval [95% CI], 1.06 to 1.14) times higher odds of preemptive transplantation post-KAS compared with pre-KAS. Preemptive recipients were more likely to be white, older, female, more educated, hold private insurance, and have ESKD cause other than diabetes or hypertension. Policy era significantly modified the association between preemptive transplantation and race, age, insurance status, and Human Leukocyte Antigen zero-mismatch (interaction P<0.05). Medicare patients had a significantly lower odds of preemptive transplantation relative to private insurance holders (pre-KAS adjusted OR, [aOR] 0.26; [95% CI, 0.25 to 0.27], to 0.20 [95% CI, 0.18 to 0.22] post-KAS). Black and Hispanic patients experienced a similar phenomenon (aOR 0.48 [95% CI, 0.45 to 0.51] to 0.41 [95% CI, 0.37 to 0.45] and 0.43 [95% CI, 0.40 to 0.47] to 0.40 [95% CI, 0.36 to 0.46] respectively) compared with white patients.

CONCLUSIONS

Although the proportion of deceased donor kidney transplants performed preemptively increased slightly after KAS, disparities in preemptive kidney transplantation persisted after the 2014 KAS policy changes and were exacerbated for racial minorities and Medicare patients.

Transplant waitlisting attenuates the association between hemodialysis access type and mortality

Prior studies have shown that beginning hemodialysis (HD) with a hemodialysis catheter (HC) is associated with worse mortality than with an arteriovenous fistula (AVF) or arteriovenous graft (AVG). We hypothesized that transplant waitlisting would modify the effect of HD access on mortality, given waitlist candidates' more robust health status. Using the US Renal Data System, we studied patients with incident ESRD who initiated HD between 2010 and 2015 with an AVF, AVG, or HC. We used Cox regression including an interaction term for HD access and waitlist status. There were 587,607 patients that initiated HD, of whom 82,379 (14.0%) were waitlisted for transplantation. Only 26,264 (4.5%) were transplanted. Among patients not listed, those with an AVF had a 34% lower mortality compared to HC [adjusted hazard ratio (aHR) 0.66, 95% confidence interval (CI) 0.65-0.67] while those with an AVG had a 21% lower mortality compared to HC (aHR 0.79, 95% CI 0.77-0.81). Transplant waitlisting attenuated the association between hemodialysis access type and mortality (interaction p < 0.001 for both AVF and AVG vs. HC). Among patients on the waitlist, those with an AVF had a 12% lower mortality compared to HC (aHR 0.88, 95% CI 0.84-0.93), while those with an AVG had no difference in mortality (aHR 0.95, 95% CI 0.84-1.08). While all patients benefit from AVF or AVG over HC, the benefit was attenuated in waitlisted patients. Efforts to improve health status and access to healthcare for non-waitlisted ESRD patients might decrease HD-associated mortality and improve rates of AVF and AVG placement.

Comparison of Clinical Outcomes Between Preemptive Transplant and Transplant After a Short Period of Dialysis in Living-Donor Kidney Transplantation: A Propensity-Score-Based Analysis

BACKGROUND The permissible extent of pretransplant dialysis for patient and allograft survival is unclear. We assumed that a short period of dialysis before living donor kidney transplantation (LDKT) will show the similar results as preemptive kidney transplantation (PKT). MATERIAL AND METHODS We retrospectively evaluated the outcomes of LDKT according to pretransplant dialysis duration in both unmatched cohorts (n=1984) and propensity-score-matched cohorts (n=986) cohorts. The primary study endpoint was post-transplantation patient survival and death-censored graft survival (DCGS) according to the duration of pretransplant dialysis by 19 months which was the best cutoff value to differentiate clinical outcomes with the use of the time-dependent area under the curve. RESULTS Of 1984 patients with LDKT at our center between January 2005 and September 2016, PKT was performed in 429 patients. The durations of pretransplant dialysis were <19 months in 962 recipients and ≥19 months in 593 recipients. There was no significant difference in mortality and DCGS between PKT and non-PKT recipients with pretransplant dialysis of <19 months. Patient survival (P=0.024) and DCGS (P=0.001) were worse in non-PKT recipients with pretransplant dialysis of ≥19 months. In the matched cohort, DCGS was significantly lower in non-PKT recipients with pretransplant dialysis of ≥19 months (P=0.037). It is likely that the incidence of biopsy-proven acute rejection was higher in this group (P=0.083). CONCLUSIONS Patient survival and DCGS were worse when the pretransplant dialysis duration was ³19 months in a propensity-score-matched LDKT cohort.

Refining the Policy for Timing of Kidney Transplant Waitlist Qualification

BACKGROUND

Earlier qualification for the kidney transplant waitlist expedites transplant and is therefore associated with improved outcomes. U.S. Organ Procurement and Transplantation Network policies state that "measured or calculated creatinine clearance or glomerular filtration rate less than or equal to 20 mL/min" triggers waitlist time accrual. The choice of qualification method is somewhat arbitrary, and the policy implies that decline in renal function is monotonic.

METHODS

(1) We used survival analysis to quantify temporal differences in waitlist qualification by applying 3 kidney-function-estimating equations (Cockcroft-Gault, Modification of Diet in Renal Disease study, Chronic Kidney Disease Epidemiology Collaboration) to serial creatinine measurements from 3 patient cohorts: 1 of waitlisted patients at a major U.S. academic center and 2 national, multicenter cohorts of chronic kidney disease patients (African American Study of Kidney Disease and Hypertension, Modification of Diet in Renal Disease). (2) Survival analysis assessed whether requiring patients to demonstrate persistently reduced renal function on 2 occasions at least 90 days apart would meaningfully change qualification order.

RESULTS

On average, time to waitlist qualification would be delayed on the order of 1 to 2 years by using calculated creatinine clearance (per the Cockcroft-Gault equation). Compared with current policy, requiring demonstration of persistently reduced renal function delayed qualification by 0.6 to 2.1 years and caused 40% to 50% of patients to switch the order in which they qualify by 6 months or more.

CONCLUSIONS

The kidney transplantation policies should be revised, such that timing of waitlist qualification is more standardized. We suggest that mention of using calculated creatinine clearance be dropped from the Organ Procurement and Transplantation Network policy wording and the units to quantify kidney function be changed to mL/min per 1.73 m2. Some consideration should be given to whether requiring persistently reduced renal function would better identify patients most likely to benefit from earlier waitlist qualification.

Association of Candidate Removals From the Kidney Transplant Waiting List and Center Performance Oversight

Approximately 59 000 kidney transplant candidates have been removed from the waiting list since 2000 for reasons other than transplantation, death, or transfers. Prior studies indicate that low-performance (LP) center evaluations by the Scientific Registry of Transplant Recipients (SRTR) are associated with reductions in transplant volume. There is limited information to determine whether performance oversight impacts waitlist management. We used national SRTR data to evaluate outcomes of 315 796 candidates on the kidney transplant waiting list (2007-2014). Compared to centers without LP, rates of waitlist removal (WLR) were higher at centers with LP evaluations (44.6/1000 follow-up years, 95% confidence interval [CI] 44.0, 45.1 versus 68.0/1000 follow-up years, 95% CI 66.6, 69.4), respectively, which was consistent after risk adjustment (adjusted hazard ratio [AHR] = 1.59, 95% CI 1.55, 1.63). Candidate mortality following waitlist removal was lower at LP centers (AHR = 0.90, 95% CI 0.87, 0.94). Analyses limited to LP centers indicated a significant increase in WLR (+28.6 removals/1000 follow-up years, p < 0.001), a decrease in transplant rates (-11.9/1000 follow-up years, p < 0.001) and a decrease in mortality after removal (-67.5 deaths/1000 follow-up years, p < 0.001) following LP evaluation. There is a significant association between LP evaluations and transplant center processes of care for waitlisted candidates. Further understanding is needed to determine the impact of performance oversight on transplant center quality of care and patient outcomes.

Prominent impact of community risk factors on kidney transplant candidate processes and outcomes

Numerous factors impact patients' health beyond traditional clinical characteristics. We evaluated the association of risk factors in kidney transplant patients' communities with outcomes prior to transplantation. The primary exposure variable was a community risk score (range 0-40) derived from multiple databases and defined by factors including prevalence of comorbidities, access and quality of healthcare, self-reported physical and mental health and socioeconomic status for each U.S. county. We merged data with the Scientific Registry of Transplant Recipients (SRTR) and utilized risk-adjusted models to evaluate effects of community risk for adult candidates listed 2004-2010 (n = 209 198). Patients in highest risk communities were associated with increased mortality (adjusted hazard ratio [AHR] = 1.22, 1.16-1.28), decreased likelihood of living donor transplantation (adjusted odds ratio [AOR] = 0.90, 0.85-0.94), increased waitlist removal for health deterioration (AHR = 1.36, 1.22-1.51), decreased likelihood of preemptive listing (AOR = 0.85, 0.81-0.88), increased likelihood of inactive listing (AOR = 1.49, 1.43-1.55) and increased likelihood of listing for expanded criteria donor kidneys (AHR = 1.19, 1.15-1.24). Associations persisted with adjustment for rural-urban location; furthermore the independent effects of rural-urban location were largely eliminated with adjustment for community risk. Average community risk varied widely by region and transplant center (median = 21, range 5-37). Community risks are powerful factors associated with processes of care and outcomes for transplant candidates and may be important considerations for developing effective interventions and measuring quality of care of transplant centers.

The kidney-first initiative: what is the current status of preemptive transplantation?

Preemptive kidney transplant (PKT)-defined as transplant before dialysis-has numerous advantages as a treatment approach for patients with advanced renal disease. In the past 15 years, PKT has become more common and has been performed at higher levels of estimated glomerular filtration rate, particularly among recipients of live-donor transplants, among whom timing of transplantation is easier to control. However, recent studies have raised important new concerns about unintended consequences of early versus late PKT. In this article, we review the convincing evidence that PKT offers diverse advantages for patients, discuss potential problems that might emerge from PKT at higher levels of renal function, examine the feasibility of a "just-in-time" PKT strategy for transplant centers, and discuss whether a new kidney allocation system could affect rates of PKT.