Part 2 of Disparities in Liver Transplant Allocation Shift but Still Exist

[Guest guest]

Part 2 of Disparities in Liver Transplant Allocation Shift but Still Exist

" Whether these differences result from true anatomic differences or represent a

problem not addressed by the use of the MELD score mandates further

investigation, " the researchers wrote.

Still, they said, waiting times and death rates have fallen for all patient

groups since MELD was introduced.

The objective MELD system replaced an earlier allocation procedure that

prioritized recipients primarily by length of time they had already waited and

by subjective disease severity assessments.

In the study, the researchers analyzed data on 21,895 liver transplant waiting

list registrants from 1996 through 2000, before MELD's adoption, and 23,793

registrants from 2002 through 2006, after its introduction.

Before MELD, 27% of black patients died or became too sick for transplant within

three years of registering compared with 21.7% of white patients (OR 1.51, 95%

CI 1.15 to 1.98), the researchers found.

After the MELD system was established, the black-white odds ratio shrank to 0.96

(95% CI 0.74 to 1.26).

Similarly, a racial disparity in the likelihood of receiving a transplant within

three years also disappeared with the introduction of MELD.

Under the old system, the odds ratio for blacks versus whites receiving a donor

liver within three years was 0.75 (95% CI 0.59 to 0.97).

In the MELD era, the odds ratio was 1.04 (95% CI 0.84 to 1.28).

The researchers said that black patients continue to show higher MELD scores

than whites, reflecting more severe liver disease.

" It remains to be determined why black patients get listed at a more advanced

stage of disease, " the researchers said, but they suggested that blacks may face

extra barriers in being referred for transplants.

The researchers also found that regional variations persisted after MELD was

instituted -- patients who live in (or have the money to travel to) regions with

a higher ratio of donors to transplant candidates (such as the southeastern

U.S.) can receive organ transplants far earlier and at a lower MELD score.

In addition, they found the gender gap in access to liver transplantation

applied only to recipients without a diagnosis of hepatocellular carcinoma.

Among the relatively small number of patients with liver cancer (2% of the

pre-MELD cohort, 8% post-MELD), there was no difference between men and women

during the MELD era in waiting times or deaths and loss of eligibility while

waiting.

In an accompanying commentary, A. Axelrod, M.D., M.B.A., of

Dartmouth-Hitchcock Medical Center in Hanover, N.H., and A. Pomfret,

M.D., Ph.D., of the Lahey Clinic in Burlington, Mass., suggested that the MELD

system may not adequately account for average size differences between women and

men.

They pointed out that " the sex disparity is likely a reflection of several

factors, including a limitation in the MELD calculation, body and organ size

considerations, and potentially differences in the etiology of the underlying

liver disease. "

As an example, they wrote, " because women have less body mass, the inclusion of

creatinine rather than weight-adjusted glomerular filtration rate in theMELD

score is likely to underestimate their degree of renal dysfunction. " So, they

said, MELD scores would be lower in women with the same degree of renal failure,

decreasing their access to organs.

" Women are also smaller, " they wrote, " limiting the pool of available organs.

Women may wait longer for a size-appropriate organ because livers from pediatric

donors are preferentially allocated to children awaiting transplantation. In

addition, a small organ can be used in a larger individual, but the converse is

not always possible. "

" It appears logical to adjust the MELD score based on sex to ensure that the

risk of death is comparable for men and women who have the same MELD score, "

they wrote.

" Consideration should also be given to expanding access to pediatric donors for

women who are less than a certain weight or size. "

Nevertheless, Drs. Axelrod and Pomfret wrote, " the current MELD system is

clearly a step toward achieving the goal of an equitable, efficient, and

transparent organ allocation system. "

The researchers noted that the study was limited by changes in data recording

over time by liver transplant registries and by modifications to the MELD

formula during the study period.

The study also included only patients who were formally registered to receive

liver transplants, not others who might have been eligible but were not referred

for transplant. Racial and other disparities in referrals are well-known, the

researchers noted.

The study was funded by the National Institutes of Health.

No potential conflicts of interest were reported by the study authors or

editorialists.

Primary source: Journal of the American Medical Association

Source reference:

Moylan C, et al., " Disparities in liver transplantation before and after

introduction of the MELD score " AMA 2008; 300: 2371-78.

Additional source: Journal of the American Medical Association

Source reference:

Axelrod D, et al., " Race and sex disparities in liver transplantation: progress

toward achieving equal access? " JAMA 2008; 300: 2425-26.

[Guest guest]

Part 2 of Disparities in Liver Transplant Allocation Shift but Still Exist

" Whether these differences result from true anatomic differences or represent a

problem not addressed by the use of the MELD score mandates further

investigation, " the researchers wrote.

Still, they said, waiting times and death rates have fallen for all patient

groups since MELD was introduced.

The objective MELD system replaced an earlier allocation procedure that

prioritized recipients primarily by length of time they had already waited and

by subjective disease severity assessments.

In the study, the researchers analyzed data on 21,895 liver transplant waiting

list registrants from 1996 through 2000, before MELD's adoption, and 23,793

registrants from 2002 through 2006, after its introduction.

Before MELD, 27% of black patients died or became too sick for transplant within

three years of registering compared with 21.7% of white patients (OR 1.51, 95%

CI 1.15 to 1.98), the researchers found.

After the MELD system was established, the black-white odds ratio shrank to 0.96

(95% CI 0.74 to 1.26).

Similarly, a racial disparity in the likelihood of receiving a transplant within

three years also disappeared with the introduction of MELD.

Under the old system, the odds ratio for blacks versus whites receiving a donor

liver within three years was 0.75 (95% CI 0.59 to 0.97).

In the MELD era, the odds ratio was 1.04 (95% CI 0.84 to 1.28).

The researchers said that black patients continue to show higher MELD scores

than whites, reflecting more severe liver disease.

" It remains to be determined why black patients get listed at a more advanced

stage of disease, " the researchers said, but they suggested that blacks may face

extra barriers in being referred for transplants.

The researchers also found that regional variations persisted after MELD was

instituted -- patients who live in (or have the money to travel to) regions with

a higher ratio of donors to transplant candidates (such as the southeastern

U.S.) can receive organ transplants far earlier and at a lower MELD score.

In addition, they found the gender gap in access to liver transplantation

applied only to recipients without a diagnosis of hepatocellular carcinoma.

Among the relatively small number of patients with liver cancer (2% of the

pre-MELD cohort, 8% post-MELD), there was no difference between men and women

during the MELD era in waiting times or deaths and loss of eligibility while

waiting.

In an accompanying commentary, A. Axelrod, M.D., M.B.A., of

Dartmouth-Hitchcock Medical Center in Hanover, N.H., and A. Pomfret,

M.D., Ph.D., of the Lahey Clinic in Burlington, Mass., suggested that the MELD

system may not adequately account for average size differences between women and

men.

They pointed out that " the sex disparity is likely a reflection of several

factors, including a limitation in the MELD calculation, body and organ size

considerations, and potentially differences in the etiology of the underlying

liver disease. "

As an example, they wrote, " because women have less body mass, the inclusion of

creatinine rather than weight-adjusted glomerular filtration rate in theMELD

score is likely to underestimate their degree of renal dysfunction. " So, they

said, MELD scores would be lower in women with the same degree of renal failure,

decreasing their access to organs.

" Women are also smaller, " they wrote, " limiting the pool of available organs.

Women may wait longer for a size-appropriate organ because livers from pediatric

donors are preferentially allocated to children awaiting transplantation. In

addition, a small organ can be used in a larger individual, but the converse is

not always possible. "

" It appears logical to adjust the MELD score based on sex to ensure that the

risk of death is comparable for men and women who have the same MELD score, "

they wrote.

" Consideration should also be given to expanding access to pediatric donors for

women who are less than a certain weight or size. "

Nevertheless, Drs. Axelrod and Pomfret wrote, " the current MELD system is

clearly a step toward achieving the goal of an equitable, efficient, and

transparent organ allocation system. "

The researchers noted that the study was limited by changes in data recording

over time by liver transplant registries and by modifications to the MELD

formula during the study period.

The study also included only patients who were formally registered to receive

liver transplants, not others who might have been eligible but were not referred

for transplant. Racial and other disparities in referrals are well-known, the

researchers noted.

The study was funded by the National Institutes of Health.

No potential conflicts of interest were reported by the study authors or

editorialists.

Primary source: Journal of the American Medical Association

Source reference:

Moylan C, et al., " Disparities in liver transplantation before and after

introduction of the MELD score " AMA 2008; 300: 2371-78.

Additional source: Journal of the American Medical Association

Source reference:

Axelrod D, et al., " Race and sex disparities in liver transplantation: progress

toward achieving equal access? " JAMA 2008; 300: 2425-26.