Clinical

Donor race does not predict liver graft failure

Last Updated: 2010-03-05 19:12:21 -0400 (Reuters Health)

By Frederik Joelving

NEW YORK (Reuters Health) - Donor race has been linked to liver graft failure, but the association can be largely explained by transplant center characteristics and hepatitis status, a new study finds.

"Our data largely refute suggestions that donor race be considered" as a risk factor for graft survival, the researchers note in their report, published February 19 in Gastroenterology.

For the study, they analyzed data from the United Network for Organ Sharing (UNOS) on all primary adult liver transplants performed from 2003 to 2005.

After excluding status 1 recipients and patients with hepatocellular carcinoma, nearly 11,000 transplants remained for analysis. Donors were Caucasian in 70% of cases, African American in 15%, Asian/ Pacific Islander in 2%, and "other" in 13% (mostly Hispanic). The mean donor age was 42 years.

During a median follow-up of three years, 2,687 grafts failed and 2,253 patients died. Crude graft survival rates were 74% with Caucasian livers, 72% for African-American livers, 70% for livers from "other" races, and 65% for Asian/Pacific Islander livers (p<0.01).

Compared to Caucasian donors, the hazard ratios for graft failure were 1.41 for Asian/Pacific-Islander organs, 1.16 for "other" organs, and 1.11 for African-American grafts.

But the differences became non-significant for Asian/Pacific-Islander and African-American livers after stratifying cases by transplant center and adjusting for age, height, and hepatitis B core antibody status of donors as well as serum creatinine and hepatitis C status of recipients.

For donors of "other" race, however, the hazard ratio remained significant (HR=1.19). The researchers speculate that unmeasured confounders -- including more advanced liver disease in recipients and a higher likelihood of receiving a partial or split organ -- could be involved.

Graft survival also depended on recipient race. For example, the risk of transplanting an African American liver was lower when the recipient race was "other" (HR=0.62).

"Even if there is a risk associated with race, it is not uniform for all pairs," lead author Dr. Sumeet Asrani told Reuters Health by e-mail. "Hence, assigning a singular risk is misleading."

Dr. Asrani, of the Mayo Clinic in Rochester, Minnesota, and colleagues also tested how donor race affected the so-called donor risk index, a number that reflects the risk of liver graft failure.

Donor race was included in the index as one of several factors after earlier research showed it had a significant impact on outcomes. However, in the new study, excluding race did not change the concordance statistics when donor factors such as age, height and cerebrovascular death were considered.

"In our opinion, this analysis provides sufficient grounds to recommend against using donor race in the organ allocation process," said Dr. Asrani.

But Dr. Sandy Feng, head of the team that derived the donor risk index, said it was not used for allocation purposes, and that surgeons did not consider race in their transplant decisions.

"The donor risk index was not derived with allocation in mind," she said.

A transplant surgeon at the University of California, San Francisco, Dr. Feng added that although race could very well be a surrogate factor, she would have liked more information about the underlying causes.

"If there is a center-based problem, then what is it?" she asked. "I would encourage them to dig deeper."

Gastroenterology 2010.