New research from Johns Hopkins specialists suggests
that obese kidney disease
patients face not only the usual long odds of a tissue
match and organ rejection but also
are significantly less likely than normal-weight people to
receive a kidney transplant at
all.
The study results, published online Dec. 19 in the
Journal of the American Society
of Nephrology, reveal that morbidly obese patients
(those who on average weigh 100
pounds more than their ideal weight) are on the transplant
waiting list for a median of
five years, two more than for a patient of normal
weight.
Because patients tend to get sicker the longer they
wait on dialysis, obese patients
are 44 percent less likely than normal-weight patients to
ever receive a kidney
transplant, the researchers report. Each year, 8 percent of
the patients on the list die
waiting for a kidney.
Transplant surgeon Dorry Segev, who led the study,
suggests that obese patients
might be turned down, sometimes multiple times, because of
the added costs and poorer
outcomes associated with transplants in overweight
patients.
"Being overweight should not be a disqualifying and
discriminating factor against
these patients," Segev said.
At Johns Hopkins, he added, the rate at which
overweight, severely obese and
morbidly obese patients are listed and receive transplants
is much higher than the
national average. As a result, the waiting times for obese
patients are not significantly
different.
"Patients understandably believe that being placed on
the transplant waiting list is
an implicit promise of fair, unbiased treatment under a
transparent allocation scheme,"
Segev said. "Unfortunately, the system that has been
established nationally may not be
living up to that promise."
The study's findings may be explained, he said, by
economic pressures as well as
medical ones. He noted that Medicare, the principal insurer
for kidney transplants, pays a
set amount for the operation regardless of a patient's
overall health, difficulty of the
operation, length of stay, postoperative care and
complications, all of which may increase
substantially with obese patients. Transplant centers,
therefore, may be under pressure
to avoid operating on these individuals. In addition, Segev
said, centers with lower
surgical survival rates overall risk losing Medicare
funding.
The researchers analyzed data from 132,353 men and
women with kidney disease
who were on the United Network for Organ Sharing
deceased-donor kidney
transplantation list from 1995 to 2006 in the United
States.
Patients' weights were rated using the body mass index
scale, which is weight in
kilograms divided by height in meters squared. A normal BMI
is 18.5. Overweight is 25
(25 to 30), obese is 30 to 35, severely obese is 35 to 40,
and morbidly obese is 40 to 60.
Of the group analyzed, 48,349 were of normal weight;
45,411, overweight; 25,509,
obese; 9,479, severely obese; and 3,605, morbidly obese.
After adjusting for additional health factors that
might affect a person's
eligibility for transplantation (such as blood type, age,
type of kidney disease, diabetes
and heart disease), the researchers found that the
likelihood of receiving a transplant,
when compared to patients with a normal weight, decreases
by 4 percent for overweight
patients, 7 percent for obese patients, 28 percent for
severely obese patients and 44
percent for morbidly obese patients.
Segev said that the number of overweight patients
joining the United Network for
Organ Sharing waiting list has gone up markedly in the last
decade as the rate of obesity
has grown in the U.S. population. From 1995 to 2005, the
number of severely obese
patients added to the list increased by 310 percent, and
the number of morbidly obese
patients added to the list increased by 247 percent. In
contrast, the number of people of
normal weight added to the list increased by only 33
percent.
"The transplant community needs to develop appropriate
guidelines stipulating
which patients are appropriate for transplantation, and to
do our best to treat them
equally," Segev said. "Similarly, both outcomes evaluation
and reimbursement need to
reflect the varying difficulty of care for these patients
in order to remove the
disincentives of taking on challenging cases."
A study by Johns Hopkins surgeon Anne Lidor is
currently examining whether
overweight transplant patients should be recommended for
gastric bypass surgery at the
time they're first listed.
"This would improve survival while the patient is
waiting for a kidney and also
improve survival after receiving the kidney, which should
eliminate any potential bias for
receiving a kidney in a timely fashion," Segev said.
Additional Johns Hopkins researchers who contributed
to this paper are Robert A.
Montgomery, Christopher E. Simpkins, Jayme E. Locke and
Daniel S. Warren, all of the
School of Medicine's Department
of Surgery; and Richard E. Thompson, of the Bloomberg
School of Public Health.
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