The New Kidney Allocation System (KAS):

The First 18 Months

Darren Stewart, MS

John Beck, MSME

Anna Kucheryavaya, MS

UNOS Research Department

Slideset updated 08/12/2016

1. Background

2. Transplant volume

3. Regional distribution of transplants

4. Pediatric transplants

5. “Bolus” effects CPRA 99-100 recipients

Recipients with 10+ years on dialysis

6. Kidney utilization

7. Recipient outcomes

8. KDPI mapping table error (April 20 – May 19, 2016)

Topics

2

KAS implemented Dec 4, 2014

Key goals:

Make better use of available kidneys

Increase transplant opportunities for difficult-to-match patients (increased

equity)

Increase fairness by awarding waiting time points based on dialysis start date

Have minimal impact on most candidates

Background

3

Pre-KAS: Dec 4, 2013 – Dec 3, 2014 (12 months)

Post-KAS: Dec 4, 2014 – May 31, 2016 (~18 months)

Some slides include a longer post-KAS evaluation (e.g., 19 or 20 months, as indicated)

Analysis periods

4

936.0

867.9

1,079.0

895.0939.7

1,039.41,012.0

0.0

200.0

400.0

600.0

800.0

1,000.0

1,200.0

01

/31

/14

02

/28

/14

03

/31

/14

04

/30

/14

05

/31

/14

06

/30

/14

07

/31

/14

08

/31

/14

09

/30

/14

10

/31

/14

11

/30

/14

12

/31

/14

01

/31

/15

02

/28

/15

03

/31

/15

04

/30

/15

05

/31

/15

06

/30

/15

07

/31

/15

08

/31

/15

09

/30

/15

10

/31

/15

11

/30

/15

12

/31

/15

01

/31

/16

02

/29

/16

03

/31

/16

04

/30

/16

05

/31

/16

06

/30

/16

Solitary deceased donor kidney transplants under KASPre vs. post-KAS trends

Transplant volume increased 6.9%, from 896.0 to 955.7 per month.

KA

S im

ple

men

tati

on

Over time (per 30 days) Overall (per 30 days)

896.0955.7

0

500

1000

Pre-KAS (12/4/13 - 12/3/14) Post-KAS (12/4/14 - 5/31/16)

Nu

mb

er o

f tr

ansp

lan

ts

6.9%↑

1 year 18 months

June 2016

5

Regional distribution of kidney transplants

Most changes in % of transplants by Region were very small.

Largest relative changes: Region 9↑; Region 6↓. 6

3.7

13.1

14.3

9.8

20.8

2.7

8.5

4.2

8.3

6.3

8.5

3.9

12.613.3

9.4

17.2

4.5

7.0 7.06.2

7.6

11.3

3.6

12.913.9

9.6

18.0

3.8

6.7 6.46.9

7.4

10.8

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11

OPTN Region

WL: 11/30/2014 TXs: 12/04/2013-12/03/2014 TXs: 12/04/2014-05/31/2016

0.2% 0.2%

0.5%

0.9% 0.8% 0.6%

2.8%

4.3%

0.7% 0.8%

2.2%

3.8%

0.7% 0.8%

2.4%

4.0%

0.7% 0.8%

2.4%

3.8%

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

Age 0-5 Age 6-10 Age 11-17 Age 0-17

WL Snapshot 11/30/14 Pre-KAS (1 year) Post (mos 1-6) Post (mos 7-12) Post (mos 13-20)

Trends in pediatric transplants

Pediatrics represent 0.9% of the kidney WL and account for about 4% of transplants.

Small Post-KAS increase for age 6-10, decreases for age 0-5, 11-17, and overall.

Percent of DD Kidney Transplants to Pediatrics (results through July 31, 2016)

(Dec

20

15

–Ju

ly 2

01

6)

7

(Dec

3, 2

01

4 –

Ma

y 2

01

5)

(Ju

n 2

01

5 –

No

v 2

01

5)

(Dec

4, 2

01

3 –

Dec

3, 2

01

4)

1.8%

12.8% 12.2% 10.8%

26.3%

3.2%

10.6%

5.5% 6.8%

3.2%

6.9%

4.1%

7.5%

17.1%

13.2%

21.4%

2.1%

5.6% 7.1%

5.1%

7.5%

9.4%

4.0%

10.4%

16.3% 15.5% 15.2%

3.2%

6.6%

8.5%

5.0%

7.5% 7.8%

0%

5%

10%

15%

20%

25%

30%

35%

40%

1 2 3 4 5 6 7 8 9 10 11

WL Snapshot 11/30/14 Txs 12-Mos PRE-KAS Txs 20-Mos POST-KAS

Geographic distribution of pediatric kidney transplants

Most regions had higher or similar percent of pediatric transplants post-KAS.

However, the % of pediatric transplants occurring in region 5 dropped from 21.4% to

15.2%. 26.3% of pediatric candidates are registered in Region 5.

Percent of Pediatric DD Kidney Transplants by Region (through July 31, 2016)

(Dec 3, 2014 – July 31, 2016)

8

CPRA 99-100% recipient “bolus effect”

Transplants to CPRA 99-100% patients rose sharply after KAS but have tapered to around 10%.

1.8%1.6%

3.2%

2.3%2.0%

2.9%

1.8%

3.5%2.9%2.5%2.8%

2.4%

17.7%

15.7%15.4%

13.4%

14.6%

12.6%13.4%

11.7%

11.2%

12.2%11.8%12.4%

11.9%

10.2%

10.6%10.1%

9.7%

9.5%

9.9%

0%

10%

20%

% o

f tr

ansp

lan

ts t

o C

PR

A 9

9-1

00

% r

ecip

ien

ts

Transplant date

KA

S im

ple

men

tati

on

(June 2016)

9

High dialysis time recipient “bolus effect”

After KAS, the % of transplants to recipients with 10+ years of dialysis rose sharply to nearly 19% but has tapered to about 7%.

4.0%

5.5%

3.8%4.2%

4.8% 5.0%

3.4%

4.3%

18.6%

16.6%

12.1%

11.1%

12.7%

8.7%

8.1%

8.6%

7.2%

7.5% 7.1%6.9%

5.2%

6.6%6.4%7.0%

5.9%6.9%

0%

10%

20%

% o

f tr

ansp

lan

ts t

o C

PR

A 9

9-1

00

% r

ecip

ien

ts

Transplant date

KA

S im

ple

men

tati

on

(May 2016)

Based on CMS Crownweb dialysis dataset as of 3/31/2016

10

“Discard rate” = percentage of kidneys recovered for transplant but

not transplanted. Rate increased, fell, then rose again post-KAS.

Kidney Utilization by KDPI

2.3%6.4%

17.0%

54.8%

18.5%

2.0%

7.5%

18.2%

59.9%

20.3%

2.5%5.8%

17.8%

56.6%

18.5%

2.2%5.4%

20.0%

59.3%

20.7%

0%

25%

50%

75%

0-20 21-34 35-85 86-100 Overall

KDPI

Pre-KAS Post (mos 1-6) Post (mos 7-12) Post (mos 12-18)(mos. 13-18)

11

Kid

ney

dis

card

rat

e

Overall, the discard rate rose from 18.5% to 19.8% (p=0.001). The

increase was most evident for KDPI 86-100% kidneys.

2.3%6.4%

17.0%

54.8%

18.5%

2.2%6.2%

18.7%

58.7%

19.8%

0%

25%

50%

75%

0-20 21-34 35-85 86-100 Overall

KDPI

Pre-KAS Post-KAS (18 mos)

Kidney Utilization by KDPI

12

Kid

ney

dis

card

rat

e

Delayed graft function (DGF) rates (1 year pre vs. 18-months post KAS)

DGF = dialysis within first week

The percentage of recipients requiring dialysis within the first week after

transplant increased from 24.3% pre-KAS to 29.5% after KAS.

Increase driven by more high dialysis time recipients and other factors.

24.3

29.5

0

10

20

30

40

Pre-KAS Post-KAS

% d

elay

ed g

raft

fu

nct

ion

13

23.3%23.5%

25.2%24.8%

25.9%26.1%

24.0%

26.2%

23.2%

24.9%

22.9%22.0%

31.3%32.6%

28.0%

30.7%

31.6%31.7%

27.5%

29.5%

27.5%28.4%

27.6% 28.0%

28.9%

32.0%

28.9%30.0%

25.9%

30.4%

0%

5%

10%

15%

20%

25%

30%

35%

14-Aug-13 22-Nov-13 2-Mar-14 10-Jun-14 18-Sep-14 27-Dec-14 6-Apr-15 15-Jul-15 23-Oct-15 31-Jan-16 10-May-16 18-Aug-16

DGF Trend (transplants through May, 2016)

Slight decline in DGF rate post-KAS (p=0.03), likely due to diminishing

bolus effects (e.g., fewer high dialysis time recipients).

Estimated post-KAS trend

Log(odds) = -0.8093 – 0.00023*day

(p = 0.03)

KA

S im

ple

men

tati

on

Transplant date

14

95.7495.31

90

100

12/04/2013-12/03/2014 12/04/2014-10/31/2015

Six Month Survival

(60% of accepts)

(28%)(40%)

Log-rank p-value=0.12

Six month graft survival rate over 95%. Patient survival over 97% but slightly lower than pre-KAS (p<0.05).

% G

raft

su

rviv

al a

t 6

mo

nth

s

98.0597.63

90

100

12/04/2013-12/03/2014 12/04/2014-10/31/2015

% P

atie

nt

surv

ival

at

6 m

on

ths

Transplant date Transplant date

Log-rank p-value=0.04

15

Many very highly sensitized and high dialysis time patients have

been transplanted under KAS

Transplants to these groups have tapered over 18 months

Deceased donor transplant volume has increased 7%

However, utilization of recovered kidneys has not improved

Largest impact on pediatric transplants was observed in Region 5.

DGF has increased but is slowly trending downward

Post-KAS, 6-month graft (95.3%) and recipient (97.6%) survival are

excellent, though slightly lower than pre-KAS.

Highlights: First 18 months of KAS

16

Additional information

For more detailed analyses of KAS’s impact after 1 year, other resources are available:

https://www.transplantpro.org/wp-content/uploads/sites/3/KAS_12month_analysis.pdf

Stewart, D. E., Kucheryavaya, A. Y., Klassen, D. K., Turgeon, N. A., Formica, R. N., & Aeder, M. I. (2016). Changes in Deceased Donor Kidney Transplantation One Year After KAS Implementation. American Journal of Transplantation, 16(6), 1834-1847.)

17

Incorrect KDPI Mapping Table

18

KDRI was incorrectly mapped to KDPI between April 20, 2016 –May 19, 2016 Start of problem: 2016-04-20 07:34:13.020

Problem fixed: 2016-05-19 11:31:34.640

Source of problem: incorrect “mapping table” uploaded for converting KDRI to KDPI

Impact: All KDPI values* displayed in DonorNet and used for allocation were higher

than they should have been.

On average, the displayed KDPI was 17 points higher than the correct value. The maximum deviation was 21 points.

Background

* Except KDPI values of 100%, since KDPI cannot be higher than 100%.

Shift in KDPI values due to incorrect mapping for 930 affected transplants

KDPI

Actual KDPI’s

Incorrectly

mapped

KDPI’s

0-20 21-34 35-85 86-100

Distribution of KDPI used for allocation shifted to higher values.

Mean=46.4

Mean=63.7

KAS sequences dependent upon KDPI

A: KDPI 0-20% B: KDPI 21-34% C: KDPI 35-85% D: KDPI 86-100%CPRA 98-100% CPRA 98-100% CPRA 98-100% CPRA 98-100%0 ABDR mismatch (EPTS 0-20%) 0 ABDR mismatch 0 ABDR mismatch 0 ABDR mismatch Local prior living donors Local prior living donors Local prior living donors Local + regional A2/A2B-->BLocal pediatrics Local pediatrics Local A2/A2B-->B Local + regional candidatesLocal A2/A2B-->B (EPTS 0-20%) Local A2/A2B-->B Local candidates National A2/A2B-->BLocal EPTS 0-20% Local candidates Regional A2/A2B-->B National candidates0 ABDR mismatch (EPTS 21-100%) Regional pediatrics Regional candidatesLocal A2/A2B-->B (EPTS 21-100%) Regional A2/A2B-->B National A2/A2B-->BLocal EPTS 21-100% Regional candidates National candidatesRegional pediatrics National pediatricsRegional A2/A2B-->B (EPTS 0-20%) National A2/A2B-->BRegional EPTS 0-20% National candidatesRegional A2/A2B-->B (EPTS 21-100%)Regional EPTS 21-100%National pediatrics

National A2/A2B-->B (EPTS Top 20%)National EPTS 0-20%

21

Differences in allocation sequence due to incorrect KDPI

149 fewer transplants were allocated per sequence A (KDPI 0-20).

121 more transplants were allocated per sequence D (KDPI 86-100).

A B C D

22

23.6%

26.8%

24.7%

27.4%

22.3%22.3%

25.8%25.5%25.0%

27.2%

28.9%

24.8%

26.7%26.2%

24.7%24.6%

26.8%

16.3%

27.6%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

09/18/14 12/27/14 04/06/15 07/15/15 10/23/15 01/31/16 05/10/16 08/18/16

% of Solitary Adult DD kidney transplants to EPTS 0-20% recipients

Apr 20-May 19

Impact of incorrect KDPI mappingEPTS 0-20% recipients

Transplants to EPTS 0-20% adults dropped and rebounded after the system

was fixed.

Post-KAS mean = 25.5%

Monthly min = 22.3%

Monthly max = 28.9%

(Post-KAS min, mean, and max are pre Apr 20)

May 20-Jun 19 (post-fix)

23

76.1%

72.9%75.1%

72.5%

77.6%77.7%

74.2%74.5%75.0%72.8%

71.1%

75.1%73.3%73.8%

75.3%75.4%73.2%

83.7%

72.3%

50.0%

75.0%

100.0%

09/18/14 12/27/14 04/06/15 07/15/15 10/23/15 01/31/16 05/10/16 08/18/16

% of Solitary Adult DD kidney transplants to EPTS 21-100% recipients

Apr 20-May 19

Apr 1-Apr 19

Impact of incorrect KDPI mappingEPTS 21-100% recipients

Transplants to EPTS 21-100% adults increased then returned to previous levels

after the fix.

Post-KAS mean = 74.5%

Monthly min = 71.1%

Monthly max = 77.7%

(Post-KAS min, mean, and max are pre Apr 20)

May 20-Jun 19(post-fix)

24

The correct table was uploaded on May 19th, 2016

Tested by IT department and validated by Research department

Working as expected since May 19th, 2016

New processes put in place to prevent future problems of this nature

All programs that performed a transplant during this period were

informed of the correct (lower) KDPI value for each recipient.

Fixing the problem

25

Recipient characteristic

Pre-KAS (12/4/13-12/3/14)

Post-KAS (12/4/14 –4/19/16)

KDPI mapped incorrectly 4/20/16 –5/19/16

After correction 5/20/16 –6/19/16

EPTS 0-20% (n/a) 25.5% 16.3% 27.6%

EPTS 21-100% (n/a) 74.5% 83.7% 72.3%

Age 18-34 8.7% 12.7% 9.5% 12.0%

Age 65+ 23.0% 18.3% 25.0% 17.8%

Pediatric recipients 4.2% 3.8% 2.4% 5.1%

Impact on distribution of deceased donor kidney transplants% of transplants received by groups of recipients

The distribution of transplants shifted toward older recipients during this one month period but subsequently returned to previous levels.

26

Deceased donor kidney transplant volume remained on par with post-KAS

average and was 9% above the pre-KAS average.

The kidney discard rate was slightly higher (22.9%, vs. 19.7% post-KAS average) but

not outside normal, observed monthly variation

For this one month period, the distribution of transplants resembled pre-KAS

with respect to longevity matching and recipient ages.

Pediatric transplants declined slightly but rebounded sharply post-fix.

Transplants to highly sensitized and African American patients were unaffected.

Impact of KDPI mapping error: summary of findings

27

UNOS Research DepartmentData Quality TeamCatherine Monstello, RRT, CPHQJohn Beck, MSMESherri WilliamsBrooke Chenault, CCRAJessie Maker, MSTammy SneadTenisha AtobrahPenny BrockSharon GravesClay McDonaldJo Smith

Data ScientistsHarris McGehee

Data Analytics TeamSarah TarantoTim BakerJude Maghirang, MSYulin ChengEric BeesonAlex GarzaHeather NeilDenise TrippAnn Harper, MPHJaime WilliamsonWes RossonAlice Toll

Scientists and AnalystsLeah Edwards, PhDErick Edwards, PhDWida Cherikh, PhDBob Carrico, PhDJohn Rosendale, MSDarren Stewart, MSJennifer Wainright, PhDMarissa Clark-Quimby, MSAmber Wilk, PhDAnna Kucheryavaya, MSMike Curry, MSRead Urban, MPHVictoria Garcia, MPHAmanda Robinson, MSLeadership

Ryan Ehrensberger, PhD, FACHEDavid Klassen, MDCherri Taylor