Underestimating Women's Renal Function Puts Them at Lower Priority on the Transp

[Clark]

http://www.prnewswire.com/news-releases/underestimating-womens-renal-function-puts-them-at-lower-priority-on-the-transplantation-list-300176665.html

Underestimating Women's Renal Function Puts Them at Lower Priority on the Transplantation List

The allocation of scarce liver organs for transplantation is an important and complex issue. The Model for End-Stage Liver Disease (MELD) score is a remarkably good tool to prioritize the livers to the sickest candidates. However, since the introduction of MELD score in liver allocation, women became less likely than men to undergo LT.

Glomerular filtration rate (GFR) is the rate of filtered fluid through the kidney. Serum creatinine is an indicator of renal health, and is used in equations of GFR estimation, as well as in MELD score. Because women have lower muscle mass, they routinely have a lower level of creatinine production. A more accurate assessment of a patient's renal function could be obtained by measuring glomerular filtration.

Researchers from the Mayo Clinic and Stanford University presented data at The Liver Meeting, the annual meeting of the American Association for the Study of Liver Diseases, that demonstrate that the use of creatinine as an indicator of kidney health in MELD scores results in a bias against women waiting for liver transplantation.

"Women are disadvantaged in the current allocation system," according to Alina M. Allen, MD, who is the principal investigator for the study. She continues, "They are 20 percent less likely than men to receive a liver organ. Our analysis of 97,371 waitlisted subjects in the UNOS database from 2002 to 2013 shows that most of the disparity is derived from their shorter stature, as it can be technically difficult to transplant a large liver into a much smaller body. Additionally, men are more likely to receive exception MELD points, largely due to the higher incidence of hepatocellular carcinoma. However, even after accounting for these biologically plausible differences between sexes, a liver transplant deficit (albeit lower, of 8%) in women remains.”

The authors of this abstract studied 611 patients listed for liver transplantation by The Mayo Clinic for which one actual glomerular filtration measurement was made. They determined that compared to men with the same degree of renal dysfunction (measured GFR), women receive 1-2 less MELD points due to lower serum creatinine levels. Addition of sodium to MELD (MELD-Na) further exacerbates the gender disparity in renal function estimation. In 2013, the Organ Procurement and Transplantation Network began the policy of Share 35, the goal of which is to increase regional access to liver transplants for the sickest patients. The process is for regions to share organs for the most urgent patients. These patients must have a score of 35 or higher to benefit from the policy. In women with MELD scores of 33-34, underestimation by 1-2 points could negatively impact their access to available livers through the Share 35 policy.

Dr. Allen has suggested changes and also addresses the need for continued study, "Our data strongly advocates that policy makers should consider options to overcome the inherent sex differences in factors that impact access to allocation of livers, such as renal function estimation, height, and receipt of MELD exception scores. Within this framework of analysis, adding 1 point to women's MELD can hypothetically overcome the deficit. The exact extent needs to be further assessed with simulation models before changes in policy are considered.”

Abstract title: Could Share 35 disadvantage women?