A Johns Hopkins transplant surgeon has found strong evidence that women over 45 are significantly less likely to be placed on a kidney transplant list than their equivalent male counterparts, even though women who receive a transplant stand an equal chance of survival.
"As woman age, that discrepancy widens to the point where woman over 75 are less than half as likely as men to be placed on a kidney transplant list," says lead researcher and Johns Hopkins transplant surgeon Dorry Segev, M.D. "If the women have multiple illnesses, the discrepancy is even worse."
In a new study, which appears online Jan. 7 in the Journal of the America Society of Nephrology , Segev and his team looked at data from the United States Renal Data System (USRDS) kidney transplant list of 563,197 patients who developed first-onset end-stage renal disease between 2000 and 2005. USRDS tracks all patients who start dialysis, get placed on the transplant waiting list or receive a transplanted organ. The likelihood of getting on a transplant list was calculated after adjusting for factors that determine the patient's relative rate of survival after transplantation compared to dialysis.
When the results were stratified for age, the likelihood that women age 18 to 45 years made it onto the transplant list was equivalent to that of men. However, as women's age increased, their likelihood of being placed on the transplant list fell incrementally. Women ages 46 to 55 were 3 percent less likely to be put on the list, women ages 56 to 65 years were 15 percent less likely, women ages 66 to 75 were 29 percent less likely, and women 75 or older were 59 percent less likely. These disparities existed whether the recipient was seeking a deceased donor kidney or a live donor kidney. The chance of a woman getting listed was worse if she had additional diseases such as diabetes or heart disease.
Segev says he believes the gap is the result of what he calls an unsubstantiated "perceived frailty" of woman that factors subconsciously into the listing process. Two main steps determine who is placed on the UNOS kidney transplant list: referral by a nephrologist and the patient's acting on that referral.
"It appears as though either the nephrologist believes women have a worse chance of survival or some women don't think they will have a good outcome," says Segev. "Once they are listed, however, woman and men have an equal chance of getting a kidney, regardless of age."
Segev says this "perceived frailty" has no basis in fact. For every age group analyzed in this study, women had similar or slightly higher survival rates after transplantation than men.
"This is different from most factors that create access to transplant disparities, such as obesity and race," says Segev. "Those disparities continue even once you've been listed - for example, blacks are less likely to get listed, and once they're listed, are also less likely to receive a transplant."
Other researchers from the Johns Hopkins University School of Medicine who contributed to this study include Robert Montgomery, M.D., Ph.D., and Lauren M. Kucirka of the Department of Surgery; and Pooja C. Oberai, M.D., Rulan S. Parekh, M.D., L. Ebony Boulware, M.D., M.P.H., and Neil R. Powe, M.D., M.P.H., M.B.A., of the Department of Medicine.