Introduction

OPTN/SRTR 2018 Annual Data Report: Introduction

Introduction for the OPTN/SRTR 2018 Annual Data Report

This introduction provides a brief overview of trends in waitlist and transplant activity for solid organs in the United States. Trends vary substantially by organ type, and more detailed descriptions can be found in the respective organ-specific Annual Data Report chapters. The observed changes are usually explained by several possible reasons, which are always difficult to ascertain from observational data. Rather, observed changes should be considered as signposts pointing the way to further inquiry. The 2018 Annual Data Report covers transplants through December 31, 2018.

Trends in Kidney Transplantation

In 2018, positive trends in supply and demand for kidney transplants continued, with increases in total, deceased donor, and living donor transplants, and relatively little change in the number of active candidates listed for deceased donor transplant (Figure INT 1). Between 2007 and 2012, the number of candidates on the waiting list grew by 15.1%, while from 2013 to 2018, the number of active candidates on the deceased donor waiting list declined by 0.6%. The number of new active candidates added to the waiting list increased by 5.6% between 2007 and 2012, and continued to grow by 6.4% between 2013 and 2018 (Figure INT 3). Hence, the number of transplants performed has been keeping pace with the growth in demand reflected by the number of candidates added to the waiting list. However, we do not know how many suitable transplant candidates were not added to the waiting list.

The number of kidney transplants in recipients of all ages, alone or with another organ, declined by 1.2% between 2007 and 2012 (Figure INT 5). This was due to a 7.0% decline in living donor transplants, along with a 1.9% increase in deceased donor transplants. However, between 2013 and 2018, the total number of kidney transplants increased by 24.6%, due to a 30.5% increase in deceased donor transplants and a 12.3% increase in living donor transplants. Last year alone saw increases of 5.0% and 10.9% in deceased and living donor transplants, respectively.

Despite improved trends in which the number of kidney transplants keeps pace with the number of new patients added to the deceased donor waiting list, many candidates who need a transplant are left waiting. Despite 22,003 kidney transplants performed in 2018, 60,075 active candidates remained on the waiting list at the end of that year. At the same time, the number of kidneys recovered for transplant but not transplanted increased in 2018 (Figure INT 7). Between 2007 and 2012, the proportion of kidneys recovered for transplant but not transplanted increased by 1.4%, but between 2013 and 2018, this proportion increased by 4.7%, from 18.2% to 19.0%.

Graft and patient survival continue to improve after kidney transplant. Among transplant recipients from 2009 to 2013, 1-year patient survival was 97.4% and 5-year patient survival 90.0% (Figure INT 8).

Trends in Pancreas Transplantation

The demand for pancreas transplant has declined since 2007, likely due to improvements in the medical treatment of diabetes. Since 2007, numbers of candidates on the waiting list for pancreas alone or pancreas after kidney transplant declined every year except 2012, and the number waiting for a combined kidney and pancreas transplant declined in every year except 2014 (Figure INT 2). The number of candidates on the waiting list for a pancreas transplant alone or a pancreas after kidney transplant declined by 13.2% in 2018, while the number on the waiting list for a combined kidney and pancreas transplant declined by 2.3%. Trends were similar in the number of new additions to the pancreas transplant waiting list (Figure INT 4). Since 2007, the total number of pancreas transplants performed in the US declined in every year except 2016 and 2018; in 2018, the total number of pancreas transplants increased by 2.5%, from 1002 to 1027 (Figure INT 6). Not surprisingly, patient survival after pancreas transplant is similar to survival after kidney transplant. In the cohort of recipients from 2009 to 2013, 1-year patient survival was 97.3% and 5-year patient survival 90.9% (Figure INT 8).

Trends in Liver Transplantation

Trends in liver transplant have been remarkable. The number of patients on the waiting list continues to decline (Figure INT 1). Between 2007 and 2012, the number on the waiting list grew by 4.0%, while between 2013 and 2018 it declined by 17.3%, including a decline of 3.7% in 2018. The number of additions to the waiting list increased by 5.1% between 2007 and 2012, but increased by 12.1% between 2013 and 2018 (Figure INT 3). The number of transplants declined by 3.7% from 2007 to 2012, but increased by 27.8% from 2013 to 2018 (Figure INT 5). This increase reflects a 26.5% increase in deceased donor transplants, from 6203 to 7849, and a 59.1% increase in living donor transplants, from 252 to 401. Both were record numbers in 2018. The proportion of livers recovered for transplant but not transplanted declined by 11.4%, from 9.5% in 2013 to 8.4% in 2018 (Figure INT 7). Patient survival of recipients between 2009 and 2013 was 89.8% at 1 year and 77.7% at 5 years (Figure INT 8).

Trends in Intestine Transplantation

The number of intestine transplants remains very small. In the past decade, the number of intestine transplants declined by 41.9%, from 179 in 2009 to 104 in 2018 (Figure INT 6). Among intestine recipients between 2009 and 2013, 1-year survival was 74.8% and 5-year survival 55.7% (Figure INT 8).

Trends in Heart Transplantation

The number of patients on the waiting list for heart transplant grew by 55.6%, from 2016 candidates in 2009 to 3137 in 2015. However, the waiting list declined by 3.5% to 2885 in 2018 from 2990 in 2017, because the number of transplants increased and kept pace with additions to the waiting list (Figure INT 2). The number of new active candidates added to the waiting list increased almost every year between 2011 and 2018 (Figure INT 4). The number of transplants performed increased by 53.5% between 2009 and 2018 (Figure INT 6). Among the cohort of recipients between 2009 and 2013, 1-year patient survival was 90.5% and 5-year survival 79.5% (Figure INT 8).

Trends in Lung Transplantation

The number of active candidates on the lung waiting list changed little between 2009 and 2018 (Figure INT 2). But 2018 saw a 7.7% increase in the number of new candidates added, and between 2009 and 2018, the number of candidates added increased by 40.7% (Figure INT 4). Hence, the number of transplants has kept pace with the number of new candidates. Indeed, between 2009 and 2018, the number of lung transplants increased by 51.6% (Figure INT 6). Patient survival after lung transplant continues to improve. Among recipients between 2009 and 2013, 1-year survival was 86.0% and 5-year survival 57.3% (Figure INT 8).

Summary

Since 2013, there has been rapid growth in overall numbers of solid organ transplants in the US. The most rapid increases have been in heart (34.7%), lung (31.7%), liver (27.8%), and kidney (24.6%) transplants. Pancreas transplants have increased almost not at all over this time period (0.9%). Intestine transplants increased 27.5% from 2013 to 2014, remained stable through 2016, then declined back to 2013 levels by 2017. Based on the numbers of organs recovered for transplant but not transplanted, there appears to be room for further improvement, especially with regard kidney transplants; 19% of kidneys recovered for transplant were never transplanted in 2018.

href = '#INT_8_all_km_death_5yr_1_b64'>Figure INT 8. Patient survival among all transplant recipients, 2009-2013, by organ

isolated kidney or liver
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A line plot for candidates active on the kidney or liver waiting list on december 31 of the year; the kidney category increases by 19.7% from 50.2 candidates (in thousands) at 2007 to 60.1 candidates (in thousands) at 2018; and the liver category decreases by 13.0% from 12.2 candidates (in thousands) at 2007 to 10.6 candidates (in thousands) at 2018. — **Figure INT 1. Candidates active on the kidney or liver waiting list on December 31 of the year**
Candidates concurrently listed at multiple centers are counted once. Those with concurrent listings and active at any program are considered active. Active status is assessed on December 31 of the year.

A line plot for candidates active on the waiting list for organs other than isolated kidney or liver on december 31 of the year; the kidney to pancreas category decreases by 37.9% from 1.3 candidates (in thousands) at 2007 to 0.8 candidates (in thousands) at 2018; the pancreas (pta+pak) category decreases by 60.4% from 0.5 candidates (in thousands) at 2007 to 0.2 candidates (in thousands) at 2018; the intestine category is 0.2 candidates (in thousands) at 2007 and remains relatively constant with a value of 0.2 candidates (in thousands) at 2018; the heart category increases by 101.5% from 1.4 candidates (in thousands) at 2007 to 2.9 candidates (in thousands) at 2018; and the lung category increases by 18.4% from 1 candidates (in thousands) at 2007 to 1.2 candidates (in thousands) at 2018. — **Figure INT 2. Candidates active on the waiting list for organs other than isolated kidney or liver on December 31 of the year**
Candidates concurrently listed at multiple centers are counted once. Those with concurrent listings and active at any program are considered active. PAK, pancreas after kidney; PTA, pancreas transplant alone. Active status is assessed on December 31 of the year.

A line plot for new candidates added to the kidney or liver waiting list during the year; the kidney category increases by 16.8% from 29.3 candidates (in thousands) at 2007 to 34.2 candidates (in thousands) at 2018; and the liver category increases by 21.8% from 10.3 candidates (in thousands) at 2007 to 12.6 candidates (in thousands) at 2018. — **Figure INT 3. New candidates added to the kidney or liver waiting list during the year**
A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Candidates concurrently listed at multiple centers are counted once. Active and inactive patients are included; active status for kidney candidates is determined on day 7 after first listing.

A line plot for new candidates added to the waiting list during the year for organs other than isolated kidney or liver; the kidney to pancreas category decreases by 17.9% from 1.5 candidates (in thousands) at 2007 to 1.2 candidates (in thousands) at 2018; the pancreas (pta+pak) category decreases by 55.2% from 0.7 candidates (in thousands) at 2007 to 0.3 candidates (in thousands) at 2018; the intestine category decreases by 50.5% from 0.3 candidates (in thousands) at 2007 to 0.1 candidates (in thousands) at 2018; the heart category increases by 48.1% from 3.1 candidates (in thousands) at 2007 to 4.6 candidates (in thousands) at 2018; and the lung category increases by 63.6% from 1.9 candidates (in thousands) at 2007 to 3.2 candidates (in thousands) at 2018. — **Figure INT 4. New candidates added to the waiting list during the year for organs other than isolated kidney or liver**
A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Candidates concurrently listed at multiple centers are counted once. Active and inactive patients are included. PAK, pancreas after kidney; PTA, pancreas transplant alone.

A line plot for total counts of kidney or liver transplants; the kidney category increases by 25.7% from 17.5 transplants (in thousands) at 2007 to 22 transplants (in thousands) at 2018; and the liver category increases by 27.0% from 6.5 transplants (in thousands) at 2007 to 8.2 transplants (in thousands) at 2018. — **Figure INT 5. Total counts of kidney or liver transplants**
Kidney: patients undergoing kidney or SPK transplant. Retransplants and multi-organ transplants are included. SPK, simultaneous pancreas-kidney.

A line plot for total counts of transplants for organs other than isolated kidney or liver; the pancreas category decreases by 22.9% from 1.3 transplants (in thousands) at 2007 to 1 transplants (in thousands) at 2018; the intestine category decreases by 47.5% from 0.2 transplants (in thousands) at 2007 to 0.1 transplants (in thousands) at 2018; the heart category increases by 53.6% from 2.2 transplants (in thousands) at 2007 to 3.4 transplants (in thousands) at 2018; and the lung category increases by 70.9% from 1.5 transplants (in thousands) at 2007 to 2.6 transplants (in thousands) at 2018. — **Figure INT 6. Total counts of transplants for organs other than isolated kidney or liver**
Pancreas: patients undergoing pancreas or SPK transplant. Heart: patients undergoing heart or heart-lung transplant. Lung: patients undergoing lung or heart-lung transplant. Retransplants and multi-organ transplants are included. SPK, simultaneous pancreas-kidney.

A line plot for rates of organs recovered for transplant and not transplanted; the kidney category is 18.4 percent at 2007 and remains relatively constant with a value of 19 percent at 2018; the pancreas category decreases by 29.0% from 30 percent at 2007 to 21.3 percent at 2018; the liver category decreases by 25.9% from 11.4 percent at 2007 to 8.4 percent at 2018; the intestine category decreases by 16.8% from 4.4 percent at 2007 to 3.6 percent at 2018; the heart category decreases by 41.7% from 1.1 percent at 2007 to 0.7 percent at 2018; and the lung category increases by 51.8% from 5 percent at 2007 to 7.7 percent at 2018. — **Figure INT 7. Rates of organs recovered for transplant and not transplanted**
Percentage of organs not transplanted out of all organs recovered for transplant. Kidneys recovered en-bloc are counted once, and kidneys recovered separately are counted twice.

A line plot for patient survival among all transplant recipients, 2009-2013, by organ; the kidney category is 100 percent at 0 Months post-transplant and remains relatively constant with a value of 90 percent at 60 Months post-transplant; the pancreas category is 100 percent at 0 Months post-transplant and remains relatively constant with a value of 90.9 percent at 60 Months post-transplant; the liver category decreases by 22.3% from 100 percent at 0 Months post-transplant to 77.7 percent at 60 Months post-transplant; the intestine category decreases by 44.3% from 100 percent at 0 Months post-transplant to 55.7 percent at 60 Months post-transplant; the heart category decreases by 20.5% from 100 percent at 0 Months post-transplant to 79.5 percent at 60 Months post-transplant; and the lung category decreases by 42.7% from 100 percent at 0 Months post-transplant to 57.3 percent at 60 Months post-transplant. — **Figure INT 8. Patient survival among all transplant recipients, 2009-2013, by organ**
Patient survival estimated using unadjusted Kaplan-Meier methods. For recipients of more than one transplant during the period, only the first is considered. Similar overall survival rates for kidney and pancreas recipient may obscure one organ's line on the graph.