Organ transplant professionals make tough decisions when it comes to deciding which organs are suitable for transplant and which organs should be discarded. Due to stringent guidelines, clinicians in the United States must discard about 2,000 donated kidneys each year.

There are currently more than 95,000 people on the kidney transplant waiting list, according to UNOS; reclaiming some of the discarded kidneys has the potential to save lives.

There is some debate among transplant leaders regarding these lost organs. Some are concerned about the viability of the discarded organs, while others say that using these organs are too risky.

The results of a new study show that many of the kidneys transplanted in France would have been discarded in the United States. This study is the first of its kind.

Comparing Kidney Utilization Patterns and Outcomes in the U.S. and France

Using information from the Paris Transplant Group’s prospective cohort data and the UNOS registry collected in the decade between 2004 and 2014, researchers compared the quality of donated kidneys and kidney transplant outcomes between France and the U.S. During that time, there were 125,936 kidneys procured for transplant in the U.S., and 4,287 kidneys in the Paris Transplant Group cohort.

The researchers found that a significantly higher proportion of kidneys transplanted in France were higher-risk organs according to their kidney donor profile index (KDPI) as compared to the United States (median 65 [39-90] vs. 42 [19-67] in the U.S., p<0.0001).

The KDPI of U.S. kidneys increased only slightly, rising from a mean KDPI of 42 to a KDPI of 44 in the decade between 2004 and 2014. The KDPI rose steadily in France throughout that period, from a mean KDPI of 54 to 67, reflecting a trend towards more aggressive organ use.

Next, the researchers used the Kaplan-Meier method to assess graft survival for these higher-KDPI kidney transplants in France. They found that the 3- and 5-year survival for KDPI 80 to 90 kidneys was 88 and 83 percent. The 3- and 5-year survival rates for KDPI 91 to 99 kidneys were 83 and 79 percent, and 81 and 78 percent for KDPI 10.

Using a logistic regression model to predict the scope of kidney discard in the U.S., the team of researchers estimated that many of the kidneys used in transplants in France would have been discarded in the United States. The scientists randomly selected 951 transplanted kidneys in France according to the organ’s probably of discard in the U.S., and calculated that the use of those organs in the United States would have translated to 3,000 allograft life-years saved.

The authors concluded their study by saying, "these results provide fresh evidence that some kidneys discarded in the U.S. are a lost opportunity that could have benefitted some wait-listed patients."

Olivier Aubert, M.D., Ph.D., from the Paris Translational Research Center for Organ Transplantation, and colleagues presented their findings at the American Society of Nephrology's Kidney Week, held Oct. 23-28 in San Diego.