In a multi-country study, investigators find that the US could reduce the number of deaths for patients waiting for kidney transplants if they accept older kidneys.
Olivier Aubert, MD, PhD
With an estimated 3500 donated kidneys thrown out each year in the US, a greater acceptance of kidneys from older donors with more comorbidities could yield more survival benefits for wait-listed patients.
In a cohort study, investigators led by Olivier Aubert, MD, PhD, Paris Translational Research Center for Organ Transplantation, analyzed the use of 156,089 deceased donor kidneys in the US and 29,984 in France, and found that the discard rate in the US is nearly twice of that of France.
The team examined validated registries from the 2 countries comprising comprehensive cohorts of deceased donors with organs offered to kidney transplant centers between 2004-2014 and used logistic regression to model organ acceptance and discard rates.
The investigators also used a computer simulation and found the US would have an increase of about 132,445 allograft life-years if the country had a decreased discard rate similar France, while providing major survival benefits to the population on the wait-list for kidneys.
Of the 156,089 kidneys recovered in the US during the 10-year study period, 128,102 were transplanted, while 27,987 were discarded. On the other hand, France recovered 29,984 kidneys during that time, transplanting 27,252 of them and discarding 2732 kidneys.
The mean age of kidneys transplanted in the US was 36.5 years, while the mean age was 50.9 years in France (P  < .001).
Kidney quality did not change much in the US over time (mean [SD] kidney donor risk index [KDRI], 1.30 [.48] in 2004 vs 1.32 [.46] in 2014), while it rose steadily in France, reflecting a temporal trend of more aggressive organ use (mean [SD] KDRI, 1.37 [.47] in 2004 vs 1.74 [.72] in 2014; P  < .001).
“We applied the French-based allocation model to the population of US deceased donor kidneys and found that 17,435 (62%) of kidneys discarded in the United States would have instead been transplanted under the French system,” the authors wrote. “We further determined that a redesigned system with more aggressive organ acceptance practices would generate an additional 132,445 allograft life-years in the United States over the 10-year observation period.”
Approximately 5000 patients in the US and 3000 in Europe die annually waiting for a kidney transplant. In recent years, new treatment approaches have emerged, allowing doctors to manage the complications of kidney transplantation, even with the lowest-quality kidneys.
The leading reason for the discarded kidneys is the intense regulatory scrutiny of US transplant programs, which could lose their credentials if the 1-year death and graft failure outcomes exceed the predicted outcomes.
Another reason for the low acceptance rate of kidneys could be financial because managing complications such as delayed graft function prolongs hospitalization.
The role of kidney biopsies is also a flawed method for assessing allograft quality, promoting needlessly discarding kidneys if the pathologic analysis is completed by individuals who lack sufficient time and skill.
“Our results strongly suggest that patients wait-listed for kidney transplantation would benefit if US transplant programs were more willing to accept lower-quality kidneys, particularly from older deceased donors,” the authors wrote. “Notably, the higher KDRI scores of kidneys transplanted in France vs the United States was primarily owing to older donor age and not to the wider use of kidneys from donors with other specific characteristics that may negatively impact allograft quality, such as hepatitis C seropositivity or cardiac death.”
The study, “Disparities in Acceptance of Deceased Donor Kidneys Between the United States and France and Estimated Effects of Increased US Acceptance,” was published online in JAMA Internal Medicine.