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Similar lung transplant waitlist mortality for children and adults

NEW YORK (Reuters Health) – Rates of death on the waiting list for a lung transplant in the U.S. are similar for adults and children, except for the youngests patients (those under age five), according to a new analysis of transplant registry data.

Still, some experts believe that in the modern era, there should be broader sharing between adults and kids on the lung transplant list.

Earlier this year, a Federal Court ordered the U.S. Secretary of Health and Human Services to allow a 10-year-old girl to be considered alongside older candidates for lung offers from adolescent and adult donors. In response, the Scientific Registry of Transplant Recipients (SRTR) undertook an independent review of deceased donor lung allocation and how it affects children.

A temporary policy adopted by the Organ Procurement and Transplantation Network (OPTN) in 2013 allows US lung transplant programs to submit requests to the Lung Review Board for candidates aged younger than 12 years to be also listed as adolescent candidates, thereby giving candidates aged 0 to 11 years greater access to donors of all ages.

Usually, lungs from adolescent donors (12-17 years old) are preferentially offered to adolescent candidates and then to local candidates aged 0 to 11 years if there are no local adolescent candidates. Lungs from donors aged 0 to 11 years are preferentially offered to candidates aged 0 to 11 years.

Dr. Bertram L. Kasiske from the Minneapolis Medical Research Foundation and Hennepin County Medical Center, Minneapolis, Minnesota and colleagues used SRTR data to examine trends in waitlist mortality and transplant rates between 1999 and 2011.

Candidates aged 0 to 5 years had higher death rates on the waiting list than other groups, whereas mortality rates for candidates aged 6 to 11 years were similar to rates for candidates aged 12 years or older, according to a report online December 12th in the American Journal of Transplantation.

There was no systematic pattern of elevated mortality either before or after the 2005 implementation of the lung allocation score (LAS)-based lung allocation system for candidates aged 12 years or older.

Although transplant rates for pediatric candidates under 12 years old were lower than rates for adult candidates (12 years and older) after the LAS was implemented in 2005, more recently the rates have been similar, the authors say. Results were similar when candidates aged 6-11 years, 12-17 years, and 18-34 years were evaluated.

“Candidates aged younger than 12 years are incentivized to register on the waiting list early to accumulate waiting time, but this incentive is absent for candidates aged 12 years or older, who receive lung offers determined by the LAS-based allocation system,” the researchers explain. “Therefore, time on the waiting list is not comparable with respect to disease severity for candidates aged older and younger than 12 years.”

“We limited our comparisons to candidates who are active on the waiting list,” they add, “but even this approach assumes that disease severity is comparable for all active time on the waiting list for children and adults.”

“The OPTN Executive Committee action of June 10, 2013 expires on July 1, 2014,” the authors say. “In the meantime, OPTN will consider whether permanent changes in the lung allocation policy should be made.”

Dr. Kasiske declined to comment on the paper.

Dr. Stuart C. Sweet from Washington University in St. Louis, Missouri, who co-authored an editorial published with the study, told Reuters Health by email, “The most important thing to recognize here is that the small numbers of patients needing lung transplants in the under 12 age group will create a significant risk of a type II statistical error (i.e., failing to find a statistically significant difference in spite of there really being one present). Therefore, anyone evaluating this data needs to keep that in mind when recommending a course of action.”

“Because the laws governing transplantation specifically direct the OPTN to consider the unique needs of children and other minority populations, I believe that it is incumbent on the OPTN to give children the benefit of the doubt when evaluating the performance of the allocation system and recommending change,” Dr. Sweet said.

“With the current technology and preservation solutions, it no longer makes sense to prioritize adolescent lungs for adults in the local allocation zone who have lower urgency and lower anticipated transplant benefit ahead of children and adolescents within the next allocation zone (i.e., zone A) who are be sicker and have greater potential benefit,” Dr. Sweet added. “That is why I have recommended to the Thoracic Committee that they consider broader sharing of adolescent lungs to potential pediatric recipients ahead of adults.”

Dr. Sweet also commented on the apparent trend toward fewer pediatric lung transplants in recent years. “I think that it is difficult to interpret the 2013 overall lung transplant data available from the OPTN website as transplant data is probably two to three months behind the calendar date (if you look at the numbers from other solid organs the year to date numbers are similarly low),” he said. “With regard to pediatrics, I think that improvements in the care of patients with cystic fibrosis and pulmonary hypertension has led to delay in the need for transplant for pediatric patients with these disease processes and relatively stable US pediatric lung transplant numbers over the past few years.”

Dr. David J. Lederer, Associate Medical Director of the Lung Transplant Program at New York Presbyterian Hospital/Columbia University Medical Center in New York, told Reuters Health, “This is an important study, and these findings are reassuring in that kids seem to undergo lung transplantation at about the same rate as adults. While one could conclude that the study provides evidence to support the current age-stratified allocation system, the ethical justification for prioritizing adults over kids on the waiting list when a donor is over 17 years of age remains elusive. Why shouldn’t a 16 year old kid on the waiting list have the same shot as a 70 year old adult when the donor is 20 years old? Size matching can be handled separately from age.”

“This entire issue could be resolved if each of us agreed to donate to our organs to those in need,” Dr. Lederer said. “There are 30,000 people with cystic fibrosis, up to 100,000 with pulmonary fibrosis, and perhaps 18 million with chronic obstructive pulmonary disease, yet fewer than 2,000 undergo lung transplantation each year. I’ve seen too many patients — young and old — die because of our organ shortage. It is time for this tragedy to end.”


Am J Transplant 2013.