Kidney transplant centers might be discarding useful kidneys because of suboptimal biopsy results, according to a new study published in the the Journal of the American Society of Nephrology. The investigators found that biopsy results did not appear to impact long-term patient outcomes following transplantation of kidneys from living donors, and that most deceased donor kidneys with suboptimal biopsy results were still functioning five years after transplantation.

Discard rates for deceased donor kidneys in the United States are at an all-time high, and transplant centers frequently cite biopsy findings as the reason for not accepting kidneys obtained from donors for transplantation. The importance of biopsy results in determining how well a kidney will function post-transplant remains unclear, however.

Sumit Mohan, MD, MPH from Columbia University College of Physicians & Surgeons and New York Presbyterian Hospital, and his colleagues analyzed nearly 1,000 kidney biopsy samples that were processed under ideal circumstances and read by experienced renal pathologists.

The investigators found that biopsy results did not appear to impact long-term patient outcomes following transplantation of kidneys from living donors. Also, living donor kidneys with suboptimal biopsy results had better outcomes than deceased donor kidneys with optimal results.

Outcomes following kidney transplantation using deceased donor kidneys were influenced by biopsy findings; however, the team estimated that even transplantation with kidneys with the worst biopsy findings would result in several additional years of life for a patient compared with remaining on dialysis.

“Also, 73% of deceased donor kidneys with suboptimal biopsy results were still functioning at 5 years, suggesting that discards based on biopsy findings may be inappropriate and merits further study,” said Mohan. “Understanding the true impact of suboptimal biopsy findings is essential to reducing the inappropriate discard of valuable kidneys from deceased donors.”

Study co-authors include Eric Campenot, MD, Mariana Chiles, MPH, Dominick Santoriello, MD, Eric Bland, MA, R. John Crew, MD, Paul Rosenstiel, MD, Geoffrey Dube, MD, Ibrahim Batal, MD, Jai Radhakrishnan, MD, MS, P. Rodrigo Sandoval, MD, James Guarrera, MD, Michael Stokes, MD, Vivette D’Agati, MD, David Cohen, MD, Lloyd Ratner, MD, MPH, and Glen Markowitz, MD.