New Solutions to Reduce Discard of Kidneys Donated for Transplantation

A Five-Tier System for Improving the Categorization of Transplant Program Performance

OBJECTIVE

To better inform health care consumers by better identifying differences in transplant program performance.

DATA SOURCE

Adult kidney transplants performed in the United States, January 1, 2012-June 30, 2014.

STUDY DESIGN

In December 2016, the Scientific Registry of Transplant Recipients instituted a five-tier system for reporting transplant program performance. We compare the differentiation of program performance and the simulated misclassification rate of the five-tier system with the previous three-tier system based on the 95 percent credible interval.

DATA COLLECTION

Scientific Registry of Transplant Recipients database.

PRINCIPAL FINDINGS

The five-tier system improved differentiation and maintained a low misclassification rate of less than 22 percent for programs differing by two tiers.

CONCLUSION

The five-tier system will better inform health care consumers of transplant program performance.

Survival Benefit of Transplantation with a Deceased Diabetic Donor Kidney Compared with Remaining on the Waitlist

BACKGROUND AND OBJECTIVES

Use of diabetic donor kidneys has been a necessary response to the donor organ shortage. Recipients of diabetic donor kidneys have higher mortality risk compared with recipients of nondiabetic donor kidneys. However, the survival benefit of transplantation with diabetic donor kidneys over remaining on the waitlist has not been previously evaluated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed an observational cohort study of 437,619 kidney transplant candidates from the Organ Procurement and Transplantation Network database, including 8101 recipients of diabetic donor kidneys and 126,560 recipients of nondiabetic donor kidneys. We used time-varying Cox proportional hazards modeling to assess the mortality risk of accepting a diabetic donor kidney compared with remaining on the waitlist or receiving a nondiabetic donor kidney.

RESULTS

Among transplant recipients, median follow-up was 8.9 years and mortality rate was 35 deaths per 1000 person-years. Recipients of diabetic donor kidneys had 9% lower mortality compared with remaining on the waitlist or transplantation with a nondiabetic donor kidney (adjusted hazard ratio, 0.91; 95% confidence interval, 0.84 to 0.98). Although recipients of nondiabetic donor kidneys with a Kidney Donor Profile Index score >85% had lower mortality risk (adjusted hazard ratio, 0.86; 95% confidence interval, 0.81 to 0.91), recipients of diabetic donor kidneys with an index score >85% did not show any difference (adjusted hazard ratio, 1.09; 95% confidence interval, 0.97 to 1.22). Patients aged <40 years attained no survival benefit from transplantation with diabetic donor kidneys; diabetic patients at centers with long waitlist times attained the greatest survival benefit.

CONCLUSIONS

Diabetic donor kidneys appear associated with higher mortality risk compared with nondiabetic donor kidneys, but offer greater survival benefit compared with remaining on the waitlist for many candidates. Patients with high risk of mortality on the waitlist at centers with long wait times appear to benefit most from transplantation with diabetic donor kidneys.

[New scores in renal transplantation: How can we use them?]

In renal transplant medicine, several scores have been recently developed in order to help decision-making in clinical practice. The aim of this update is to focus on these new scores that allow to better estimate the quality of the renal transplant, to refine the allocation policy, to help registration of old recipients on the waiting list, or to evaluate the risk to develop end-stage renal failure after living donation.

Abdominal Aortic Calcification in Living Kidney Donors

OBJECTIVE

This study assesses the association between abdominal aortic calcification (AAC) and renal function of living kidney donors and evaluate AAC as a surrogate marker for nephrosclerosis.

METHODS

Between January 2010 and March 2013, 287 donors who underwent living donor nephrectomy were enrolled. We analyzed computed tomography angiographies and quantified AAC scores by calculating the Agatston score for the abdominal aorta. The donors were stratified into the non-AAC group (AAC score = 0; n = 238) and the AAC group (AAC score >0; n = 49). The relationship between AAC and perioperative estimated glomerular filtration rate was analyzed. For the 180 donors consenting to implantation biopsy, the nephrosclerosis score was defined as the sum of abnormalities, including glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriosclerosis.

RESULTS

The mean AAC score was 185.5 ± 263.3 in the AAC group. The AAC group was older than the non-AAC group (51.1 ± 6.1 vs 37.9 ± 11 years; P < .001). Perioperative renal function was not different between the 2 groups. However, among the AAC group, donors with an AAC score of >100 were associated with delayed renal function recovery (P = .035). Donors with AAC were more likely to have glomerulosclerosis (50.0% vs 29.1%; P = .022), tubular atrophy (62.5% vs 33.1%; P = .002), and a higher nephrosclerosis score (P = .002).

CONCLUSIONS

Living donors with an AAC score of >100 require close observation because they have a higher probability of delayed renal function recovery after donation. AAC is associated with nephrosclerosis in healthy adults.

Current Status of Kidney Transplant Outcomes: Dying to Survive

Kidney transplantation is associated with improved survival compared with maintenance dialysis. In the United States, post-transplant outcomes have steadily improved over the last several decades, with current 1-year allograft and patient survival rates well over 90%. Although short-term outcomes are similar to those in the international community, long-term outcomes appear to be inferior to those reported by other countries. Differences in recipient case mix, allocation polices, and health care coverage contribute to the long-term outcome disparity. This review presents the current status of kidney transplant outcomes in the United States and compares them with the most recent outcomes from Australia and New Zealand, Europe, and Canada. In addition, early trends after implementation of the new kidney allocation system in the United States and its potential impact on post-transplant outcomes are discussed.