Kidneys infected with Hepatitis C virus work just as well as uninfected kidneys after transplant indicating they are safe to use
Kidneys from donors who were infected with the Hepatitis C virus are now routinely used in transplants, and research shows that they function just as well as uninfected kidneys, even a year after transplantation.
There are over two million adults in the US with Hepatitis C virus (HCV) infection, and due to the opioid epidemic, there has been a substantial increase in the number of young organ donors who have become infected, say experts.
Accordingly, results from the new analysis are reassuring that the use of these organs is safe and effective in the near-term, say researchers from the University of Pennsylvania School of Medicine.
"Our study shows that transplants with HCV- infected kidneys are now routinely performed at many centers, and they are functioning well at one year after transplant," says Dr. Peter P. Reese from the University of Pennsylvania. The findings have been published in the Journal of the American Society of Nephrology.
According to the research team, the findings provide strong evidence that HCV-infected kidneys are a valuable resource for transplantation, and that disincentives for accepting these organs should be addressed.
They add that in the future, it may also get harder for patients with pre-existing HCV infection to get access to these HCV-infected organs for transplantation. "These findings represent a small, but important victory in the effort to make every organ donation count," says Dr. Vishnu S. Potluri from the University of Pennsylvania.
Why the study?
For decades, most HCV-infected organs in the US were discarded partly because of concerns that the organs were associated with significantly lower survival rates. Since 2015, physicians have successfully transplanted these kidneys and treated the infection with antiviral medications after transplantation.
As a result, there has been a significant increase in the number of transplants using HCV-infected kidneys across the US.
However, since HCV can damage the kidneys, it was not clear whether the HCV-infected kidneys would function comparably to similar uninfected kidneys, particularly in patients who did not have the virus, until now.
"Despite the increased use of HCV-infected organs and promising outcomes, the Kidney Donor Profile Index (KDPI) calculator — which combines a variety of donor factors to summarize the likelihood of organ failure after deceased donor transplant — still assigns much worse risk scores to organs from HCV-positive donors," says the team.
What the findings say
To find out if HCV-infected kidneys have a comparable function to similar uninfected kidneys, the research team from the University of Pennsylvania analyzed the national transplant registry data (2015-2019) on the use of HCV-infected kidneys. They compared outcomes for HCV-infected kidneys to similar quality HCV-uninfected kidneys.
"We deployed a widely-used mathematical formula, called the Chronic Kidney Disease Epidemiology Collaboration equation, to estimate each recipient's glomerular filtration rate (eGFR). The eGFR is a measure that determines how well the blood is filtered by the kidneys," say researchers.
"The lower the GFR number, the worse the kidney function. For example, having a GFR below 60 is abnormal. Recipients who received HCV-infected kidneys had an eGFR of 66.3 at the one-year mark. Patients who received uninfected kidneys had an eGFR of 67.1," says the team.
Researchers found that there has been a change in the use of HCV-infected kidneys. The findings show that before September 2018, the majority of HCV-infected organs were transplanted into patients who already had HCV infection.
Since then, nearly 75% of the patients who were transplanted with HCV-infected kidneys did not already have the virus. "Since September 2018, the majority of HCV-infected kidneys were transplanted into patients without the infection," the findings state.
In addition to finding that HCV-infected kidneys functioned similarly to uninfected kidneys throughout the first year after transplantation, the team found that transplant centers and patients were increasingly willing to accept the organs.
The analysis reveals a threefold increase in the number of transplant centers using HCV-infected kidneys. For example, the number of transplant centers using HCV-infected kidneys jumped from 11 in 2015 to 39 centers through the first three months of 2019.
Despite the increased acceptance and use of these kidneys, researchers found that nearly 40% of the HCV-infected kidneys donated between January 2018 and March 2019 were discarded.
"While the discard rate of these organs has declined in recent years, our findings suggest there is still substantial opportunity to expand the use of HCV-infected organs. Our results suggest we should make it a priority to maximize the use of good-quality HCV-infected organs," says Potluri.
According to Dr. Reese, the results also provide additional evidence that the KDPI does not accurately assess the quality of kidneys from HCV-positive donors.
"Rescaling the index to reflect these positive outcomes might lead clinicians to offer these kidneys to younger patients with longer life expectancy, when clinically appropriate, and could help expand access for the nearly 100,000 Americans awaiting a kidney transplant," he says.