OPTN/SRTR 2015 Annual Data Report: Introduction

This introduction provides a brief overview of trends in waitlist and transplant activity for solid organs in the United States. Explanations of trends vary substantially by organ type, and details can be found in the respective organ-specific Annual Data Report chapters.

Trends in Kidney Transplantation

Last year (2015) was the first full year that the new kidney allocation system (KAS) was in effect, generating much interest in how the OPTN allocation changes would affect the numbers of listings and transplants. At year-end 2015, the number of active patients on the deceased donor kidney transplant waiting list increased by 0.6% compared with year-end 2014. The active kidney waiting list has grown every year over the past decade, 27.4% in total (Figure INT 1). The number of new candidates (active and inactive) added to the kidney waiting list declined by 3.9% in 2015 compared with 2014, but whether this 1-year change is a transient aberration or a new trend remains to be seen (Figure INT 3). The new allocation policy allows waiting time to accrue with the start of maintenance dialysis, prompting speculation that transplant programs might delay listing patients until their evaluations were completed, knowing that this would not disadvantage them once they were listed. Concerns that this practice would be widespread seem to have been unwarranted. Nevertheless, the small decline in new listings in 2015 may be in part a result of this new policy.

In 2015 compared with 2014, the number of kidney transplants increased by 4.4%, the largest 1-year increase in 12 years (Figure INT 5). The increase was mostly due to a 5.6% increase in deceased donor transplants; a small (1.6%) increase in living donor transplants also occurred. It was reassuring that the new KAS did not appear to have an overall negative effect on the number of kidney transplants. Unfortunately, the number of kidneys removed for transplant but not transplanted increased by 2.7% in 2015 compared with 2014 (Figure INT 7). Over the past decade, this number has increased by 15.6%, from 16.5% to 19.1%. Reasons cited include a general decline in the potential for long-term function of many deceased donor kidneys, as well as a putative aversion to risk taking on the part of transplant programs concerned about their public outcomes and regulatory scrutiny.

Trends in Pancreas Transplantation

Demand for pancreas transplants has declined dramatically. In the past decade, the year-end number of active candidates on the waiting list for simultaneous pancreas and kidney transplant declined by 31.4%, and for pancreas alone or pancreas after kidney transplant by 50.8% (Figure INT 2). Numbers of new additions to these waiting lists declined similarly (Figure INT 4). Pancreas transplants have declined by 31.9% since 2006, likely reflecting reduced demand (Figure INT 6). In 2015, 25.1% of pancreata retrieved for transplant were not transplanted (Figure INT 7). The decline in pancreas transplants is probably due to a combination of factors, including improvements in non-invasive therapies for diabetes that obviate the need for pancreas transplant and the difficulty and potential complications of the transplant surgery.

Trends in Liver Transplantation

The second most common organ transplanted in the US is liver. Interestingly, the number of active liver transplant candidates on the waiting list has been slowly declining (Figure INT 1). From year-end 2014 to 2015, the number declined by 4.3%. The number of new additions (active and inactive) to the waiting list has increased by 10.5% over the past decade, and by 0.3% from 2014 to 2015 (Figure INT 3). The number of liver transplants has increased by 7.2% since 2006 (Figure INT 5). The 5.9% increase in liver transplants between 2014 and 2015 was the largest increase in 12 years (Figure INT 5). Most of it was due to an increase in deceased donor liver transplants (4.9%); however, the number of living donor liver transplants increased from 280 in 2014 to 359 in 2015 (28.2%). More liver transplants were performed in 2015 than in any year in the past 12 years. Since hepatitis C is the most common cause of end-stage liver disease requiring liver transplant, there is hope that new direct-acting antiviral agents will ultimately reduce the need for liver transplants. In the meantime, a shortage of livers for transplant remains. The rate of livers recovered for transplant but not transplanted has declined by 5.4% in the past decade and by 0.5% between 2014 and 2015 (Figure INT 7).

Trends in Intestine Transplantation

The number of intestine transplants has remained small. In 2015, 141 intestine transplants were performed. Between 2006 and 2015, the number of intestine transplants declined by 19.4%, from 175 to 141 (Figure INT 6). During this time, the number of candidates on the waiting list was virtually unchanged (Figure INT 2).

Trends in Heart Transplantation

The demand for heart transplants continues to grow steadily. In the past decade, the number of active candidates on the heart transplant waiting list at year-end increased by 130% (Figure INT 2). In this same time period, the number of new active and inactive candidates added to the list increased by 41.6% (Figure INT 4). Meanwhile, the number of heart transplants increased by 26.8% in the past decade, and by 5.2% between 2014 and 2015 (Figure INT 6). The number of hearts retrieved for transplant has not kept pace with the demand. The percentage of hearts recovered for transplant but not transplanted declined slightly (8.1%) from 2006 to 2015 (Figure INT 7). It is apparent that the growth in the waiting list has exceeded the growth in the number of transplants. This may in part reflect the proliferation of effective cardiac assist devices that allow patients to survive longer on the waiting list.

Trends in Lung Transplantation

Increases in numbers of lung transplants continue to exceed those for any other organ. Between 2006 and 2015, the number of lung transplants increased by 44.3% (Figure INT 6), and by 6.3% between 2014 and 2015. The number of active candidates on the lung transplant waiting list at year-end has grown by 14.7% over the past decade (Figure INT 2), while the number of active and inactive new additions to the waiting list has increased by 42.4% over the same time period (Figure INT 4). The number of lungs retrieved for transplant but not transplanted has increased, but remains relatively low, 6.7% in 2015 (Figure INT 7).

Summary

For the past 3 years in a row, the number of kidney transplants performed in the US has increased. Nevertheless, the waiting list continues to grow and despite this, almost 20% of deceased donor kidneys retrieved for transplant are not transplanted. Numbers of pancreas transplants continue to decline, likely due to improvements in diabetes management. The number of liver transplants is growing slowly, but has not met the demand from candidates added to the waiting list every year. This trend is likely to continue. In contrast, heart and lung transplants have shown the greatest growth in numbers over the past decade. Details behind these trends in solid organ transplantation can be found in this yearӳ Annual Data Report organ-specific chapters.

Figure List

Intro