Greater acceptance of lower-quality deceased-donor kidneys in the United States could help increase the number of patients who benefit from a kidney transplant, according to investigators.

The finding is from a study comparing kidney transplant practices in the United States and France from January 1, 2004 to December 31, 2014. During this period, 17.9% of deceased-donor kidneys in the United States were discarded compared with 9.1% in France, Olivier Aubert, MD, PhD, of the Paris Translational Research Center for Organ Transplantation in Paris, and colleagues reported in JAMA Internal Medicine.

Using computer simulation algorithms, the investigators calculated that 17,435 (62%) of the 27,987 deceased-donor kidneys discarded in the United States during the 10-year study period would have been transplanted under the French system. This pool of discarded kidneys in the United States would have provided an additional 132,445 allograft life-years over the 10-year period, according to the investigators.

“This finding indicates that the US kidney transplantation system, which has driven innovations in donor utilization in the domains of kidneys obtained after cardiac death and from hepatitis C virus-infected donors, still has substantial potential for growth by accepting more organs from donors who are older and have comorbidities including diabetes and hypertension,” the authors wrote.

During the study, the age and kidney donor risk index (KDRI) of deceased-donor kidneys increased in France while remaining stable in the United States. The mean age of transplanted deceased-donor kidneys was 36.5 years in the United States compared with 50.9 years in France. The higher KDRI in France was driven mainly by an increase in the mean donor age in France compared with the United States (56 vs 39 years in 2014).

In prediction models for kidney discard decisions, the authors found that a KDRI of 1, 2, 3, and 4 results in actual kidney discard rates of 5%, 45%, 80%, and 92%, respectively, in the United States compared with 3%, 13%, 27%, and 42% in France.

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In an accompanying editorial, Ryoichi Maenosono, MD, of Osaka Medical College in Osaka, Japan, and Stefan G. Tullius, MD, PhD, of Brigham and Women’s Hospital in Boston, pointed out that some differences exist in the study populations between the United States and France. For example, the US donor population has a different racial mix, with more African Americans, more donors after circulatory death, and more hepatitis C-positive donors, they wrote.

As for why more kidneys are discarded in the United States, Drs Maenosono and Tullius observed: “Specifics of regulatory, financial, or medical assessments appear to be the driving force. It is recognized that the overly stringent and restrictive process of monitoring transplant programs in the United States has resulted in many transplant programs taking a risk-averse approach.”

References

Aubert O, Reese PP, Audry B, et al. Disparities in acceptance of deceased donor kidneys between the United States and France and estimated effects of increased US acceptance [published online August 26, 2019]. JAMA Intern Med. doi: 10.1001/jamainternmed.2019.2322

Maenosono R, Tullius SG. Saving lives by saving kidneys for transplant [published online August 26, 2019]. JAMA Intern Med. doi:10.1001/jamainternmed.2019.2609