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American Journal of Transplantation 2011; 11: 450–462Wiley Periodicals Inc.
C© 2010 The AuthorsJournal compilation C© 2010 The American Society of
Transplantation and the American Society of Transplant Surgeons
doi: 10.1111/j.1600-6143.2010.03283.x
Long-Term Renal Allograft Survival in the UnitedStates: A Critical Reappraisal
K. E. Lamb, S. Lodhi and H.-U. Meier-Kriesche∗
Division of Nephrology, Hypertension and Transplantation,University of Florida, Gainesville, FL*Corresponding author: Herwig-Ulf Meier-Kriesche,[email protected]
Renal allograft survival has increased tremendouslyover past decades; this has been mostly attributedto improvements in first-year survival. This report de-scribes the evolution of renal allograft survival in theUnited States where a total of 252 910 patients re-ceived a single-organ kidney transplant between 1989and 2009. Half-lives were obtained from the Kaplan–Meier and Cox models. Graft half-life for deceased-donor transplants was 6.6 years in 1989, increased to8 years in 1995, then after the year 2000 further in-creased to 8.8 years by 2005. More significant improve-ments were made in higher risk transplants like ECDrecipients where the half-lives increased from 3 yearsin 1989 to 6.4 years in 2005. In low-risk populationslike living-donor-recipients half-life did not change with11.4 years in 1989 and 11.9 years in 2005. First-year at-trition rates show dramatic improvements across allsubgroups; however, attrition rates beyond the firstyear show only small improvements and are some-what more evident in black recipients. The significantprogress that has occurred over the last two decadesin renal transplantation is mostly driven by improve-ments in short-term graft survival but long-term at-trition is slowly improving and could lead to biggeradvances in the future.
Key words: Graft half-life, graft survival, kidney trans-plantation
Abbreviations: SRTR, Scientific Renal Transplant Reg-istry; SCD, Standard criteria deceased donor; ECD,Expanded criteria deceased donor; Tx, Transplant;Rec/Don LE 45, Recipient and donor age less than orequal to 45; KM, Kaplan-Meier.
Received 21 June 2010, revised 13 July 2010 andaccepted for publication 04 August 2010
Introduction
The specialty of kidney transplantation has made dramaticstrides over the decades evolving from an experimentalprocedure to the standard of care in the treatment of pa-tients with end-stage renal disease (1). Not only are the
outcomes after kidney transplantation good enough to im-prove the quality of life (2) of our patients, but it has alsobeen established as a life-saving procedure (3,4); yet thelife-saving benefit of a kidney transplant lasts only as longas the transplanted kidney (4). Technical and pharmaceu-tical progress have helped to improve outcomes progres-sively even over the last decade when excellent outcomeswere already considered standard of care. Now with graftsurvival rates in excess of 90% the question arises if anyfurther improvements are possible or even necessary. In2004 it became clear that the overall improvements ingraft survival after kidney transplantation were really drivenby improvements in first-year survival, whereas long-termgraft attrition remained largely unchanged over decades(5,6). This highlighted a whole other area where improve-ments might be possible and necessary. Especially nowwhen first-year survival rates are almost close to perfectit becomes clear that further improvements in long-termsurvival have to come through improvements in long graftmaintenance.
It is notoriously difficult to measure long-term survival, aslengthy follow-up is necessary to document it, yet periodicupdates on the long-term trends can potentially yield im-portant information especially when counseling patients inthe pretransplant phase regarding expectations of futureoutcomes.
The purpose of our present study was to reevaluate theevolution of short- and long-term renal allograft survival inthe United States with the most recent data provided bythe Scientific Renal Transplant Registry (SRTR).
Materials and Methods
Subjects
We examined data from the national SRTR database for renal transplantrecipients from 1989 to November 1, 2009. Analyses were conductedon adult transplant recipients 18 years or older. Multiorgan transplantswere excluded from the analysis. Data were analyzed separately for liv-ing and deceased-donor transplants, black recipients, nonblack recipients,first transplants and repeat transplants, for standard criteria donor (SCD)kidneys and expanded criteria donor (ECD) kidneys and for recipients withdonor and recipient ages below 45 years.
Outcome measures
We analyzed graft, patient and death-censored graft survival by estimatingsurvival half-lives and we analyzed attrition rates all stratified by year oftransplant.
450
Long-Term Renal Allograft Survival
Half-lives; Univariate half-lives were calculated as median half-lives, i.e.the intersection point of the Kaplan–Meier curve with the 50% survivalthreshold. We differentiated between actual half-lives for those instanceswhere all patients had reached the 50% mark, actuarial half-lives for thoseinstances when only a proportion of patients had reached the 50% markand projected half-lives when none of the patients reached the 50% mark.In the tables and figures actual and actuarial half-life were grouped togetherbut projected half-lives are shown separately. Projections were obtained byforecasting the Kaplan–Meier curves from a point of stable attrition, whichwas fairly consistently located between 3 and 8 years of survival yield-ing a period of 5 years from which the forecasts were based. Forecastedprojections were carried out using ordinary least squares point estimates.
Multivariate half-lives were obtained in the same fashion from the Coxproportional hazard models.
Attrition rates; Attrition rates were calculated by first acquiring actual 1-year,3-year, 5-year and 10-year survival rates. The total number of patients failedduring the time period was subtracted from the number of patients originallyentering the cohort and divided then by the original number entering thecohort to obtain an absolute failure percentage. The percentage of absolutefailures was then divided by the total number of years in the follow-upinterval to obtain a yearly failure rate.
Independent variables
Covariates used to calculate the adjusted half-lives from the Cox modelincluded recipient’s transplant age (reference group 18–34), pretransplantdiagnosis of diabetes (reference group diabetic), candidate race (referencegroup Caucasian) and candidate gender (reference group males) summa-rized for transplant year 1999 to yield the most up-to-date case mix forcomplete 10-years follow-up (7).
Statistical models
Outcomes were measured by the Kaplan–Meier models and the Cox mul-tivariate proportional hazard models. Half-lives were calculated based onactual and projected follow-up where applicable. Half-lives based on actualversus projected follow-up are displayed distinctly in the results. Projected
half-lives were utilized in both the univariate Kaplan–Meier and the multi-variate Cox Regression model for allograft failure and only in the univariateKaplan–Meier for death-censored allograft failure.
Multivariate models were corrected for the same variables uses in the SRTRannual data report as described above.
Proportional hazard assumptions were tested by visually assessing log–log survival curves. The Exact method was used to handle tied outcomeoccurrences. All analyses were conducted using SAS (v.9.2, Cary, NC) anda type-one error probability of 0.05 was utilized as an indication of statisticalsignificance.
Results
Patients
We analyzed a total of 252 910 adult kidney recipientstransplanted between 1989 and 2005 excluding multior-gan transplants. Of these, 164 480 were deceased-donortransplants and 88 430 living-donor transplants. Of 164 480deceased-donor transplants 23 580 were ECD transplants.Of 140 900 deceased standard criteria donor recipients,120 675 were first transplant recipients and 20 225 wererepeat transplants.
Graft survival
Figure 1(A) shows overall graft survival for standard crite-ria deceased-donor transplants between 1989 and 2005and the respective median half-lives based on where thesurvival curve crosses the 50% survival line.
Figure 1(B) shows death-censored graft survival for stan-dard criteria deceased-donor transplants and the respec-tive half-lives.
Figure 1: (A) Kaplan–Meier cumu-
lative graft failure and (B) death-
censored graft failure, by year
of first deceased SCD transplants
from transplant year 1989–2008.
American Journal of Transplantation 2011; 11: 450–462 451
Lamb et al.
Half-lives
Table 1 displays the overall both actual or actuarial half-lives and the projected half-lives marked as ‘forecasted’in the second shaded line by transplant year. The overlapbetween the actuarial half-lives and projected half-lives rep-resents instances where still reasonable conclusions canbe drawn from the actuarial data but forecast were gener-ated in parallel. This gives a sense also about how well theforecasts might be working.
When evaluating all 164 480 deceased-donor transplantsjointly, the half-life was 6.6 years in 1989, increased toclose to 8 years in 1995, stayed around 8 years until trans-plant year 2000 and then further increased to 8.8 years in2005.
When looking only at first-donor transplants (N = 142 198)excluding retransplants, the half-life was 6.8 years in 1989,increased to 8 years in 1995 and increased to 9 years in2005.
When limiting the analysis to just standard criteriadeceased-donor transplants but including retransplants(N = 140 900) the half-lives improved from 6.7 years in1989 to 9.5 years in 2005. Slightly (but not dramatically)better half-lives were achieved in first standard criteria kid-ney graft recipients (N = 120 675). When donor and recip-ient age was limited to less than 45 (N = 40 529), grafthalf-lives improved from 7.7 years in 1989 to 11 years in2005.
First ECD transplant (N = 21 523) half-lives were dramat-ically lower with 3 years half-life for first deceased-donorECD transplants in 1989 that increased to 6.4 years in2005.
Living-donor transplant (N = 88 430) half-lives were sub-stantially higher than deceased-donor half-lives but therewas no appreciable change in living-donor half-life over theyears. Whether repeat transplants were included or nothalf-lives were 11.4 years in 1989 and 11.9–12 years in2005.
When dividing the populations into black versus nonblackrecipients the half-lives display the well-known outcomesdifference between blacks and nonblacks. There has beena similar absolute increase in graft half-lives when com-paring nonblack and black recipients, with a modest im-provement in black ECD kidney half-life when comparingan increase in 3.9 years from 1989–2005 to only 2.9 yearsin nonblack ECD half-life over the same time period. Blackstandard criteria deceased-donor (N = 39 828) transplanthalf-life increased from 4.1 years in 1989 to 7.4 years in2005; however, this was still substantially lower than non-black (N = 101 072) half-life in the same year (10.9 years).
Living-donor transplant half-lives in 1989 were 6.3 yearsin black recipients and 12.3 years in nonblack recipients.
In 2005 living-donor recipient half-lives were 7.5 years inblack versus 13.5 years in nonblack patients.
Figure 2(A) contrasts the overall half-lives betweenfirst living-donor transplants and first standard criteriadeceased-donor transplants. Figure 2(B) contrasts firststandard criteria deceased-donor graft survival betweenblack and nonblack recipients.
Table 2 displays the death-censored graft half-lives by trans-plant year. Death-censored half-lives for all deceased-donorkidneys were 10.2 years in 1989 and increased to 14.3years in 2005. Death-censored graft half-lives for standardcriteria deceased-donor transplants have increased from10.6 years in 1989 to 15.5 years in 2005. When deceased-donor transplants were limited to first transplants and bothdonor and recipient age of less than 45, death-censoredgraft half-life was 10.1 years in 1989 and 12.4 years in2005.
First ECD transplant death-censored half-lives increasedfrom 4.3 years in 1989 to 10.1 years in 2005.
Living-donor death-censored half-life was 16.5 years in1989 and 16.6 years in 2005.
Standard criteria deceased-donor half-life was 5.2 years inblack recipients in 1989 versus 12.8 years in nonblack and10 years in 2005 in black versus 21.2 years in nonblack.In contrast to cumulative graft half-life, death-censoredhalf-lives were notably more improved from 1989 to 2005in nonblack recipients as compared to black recipients.Death-censored standard criteria kidney half-life was 12.8years and forecast to be 21.2 years in 2005, resulting inan increase by 8.4 years for nonblack recipients. Death-censored black standard criteria half-life is forecast to onlyincrease by 4.8 years by 2005. Similar trends are seen indeath-censored ECD, recipient and donor age less than 45and living-donor half-lives.
Figure 3(A) contrasts standard criteria deceased-donor firsttransplants with first living-donor transplants and Figure3(B) contrasts first standard criteria deceased-donor trans-plants between black versus nonblack patients.
Table 3 displays the adjusted half-lives derived from the Coxproportional hazard models. The adjusted half-lives showsimilar patterns to the unadjusted half-lives. The adjustedstandard criteria deceased-donor half-life in 1989 was 6.6years and 9.9 years in 2005. For living-donor transplantsthe adjusted half-lives were 11.4 years in 1989 and 12.2years in 2005.
Graft attrition rates
Table 4 displays the graft attrition rates by transplant year,where both graft loss and patient death are counted as anevent. As also shown in Figure 4, for all categories the 0–1
452 American Journal of Transplantation 2011; 11: 450–462
Long-Term Renal Allograft Survival
Tab
le1:
Kap
lan–
Mei
eres
timat
esof
cum
ulat
ive
graf
tha
lf-liv
esby
tran
spla
ntye
ar
Tran
spla
ntye
ars
All
race
s19
8919
9019
9119
9219
9319
9419
9519
9619
9719
9819
9920
0020
0120
0220
0320
0420
05
EC
D/S
CD
(N=
1644
80)
6.6
6.7
7.2
7.1
7.3
7.3
7.8
7.9
8.2
8.4
8.6
8.2
EC
D/S
CD
–fo
reca
sted
8.3
8.3
8.2
8.4
8.6
8.8
8.8
8.8
1st
Tx–
EC
D/S
CD
(N=
1421
98)
6.8
6.9
7.3
7.1
7.4
7.4
88
8.3
8.5
8.6
8.4
1st
Tx–
EC
D/S
CD
–fo
reca
sted
7.3
7.8
88.
28.
38.
38.
38.
58.
78.
98.
99
SC
D(N
=14
0900
)6.
76.
97.
47.
37.
77.
88.
48.
68.
99.
09.
28.
8S
CD
–fo
reca
sted
8.8
9.0
8.7
9.0
9.4
9.5
9.7
9.5
1st
Tx–
SC
D(N
=12
0675
)7.
07.
17.
57.
47.
87.
98.
58.
89.
09.
29.
39.
0
1st
Tx–
SC
D–
fore
cast
ed8.
99.
08.
89.
19.
59.
69.
99.
91s
tTx
–R
ec/D
onLE
45(N
=40
529)
7.7
7.6
8.5
8.4
9.2
9.0
9.7
10.6
10.2
10.5
1st
Tx–
Rec
/Don
LE45
–fo
reca
sted
9.9
10.3
10.4
10.9
10.1
10.6
10.5
11.0
1st
Tx–
EC
D(N
=21
523)
33.
74.
44.
23.
74.
85
5.5
5.1
5.4
5.4
5.6
5.5
5.8
1st
Tx–
EC
D–
fore
cast
ed5.
65.
45.
55.
65.
65.
75.
86.
45.
96.
4Li
ving
dono
r(N
=88
430)
11.4
11.6
11.6
11.4
11.5
11.1
11.2
11.8
12.0
Livi
ngdo
nor
fore
cast
ed11
.110
.811
.811
.411
.912
.912
.312
.512
.713
.614
.211
.9Li
ving
dono
r1s
tTx
(N=
7657
9)11
.411
.611
.811
.411
.511
.211
.412
.012
.0
Livi
ngdo
nor
1st
Tx–
fore
cast
ed11
.311
.012
.011
.512
.312
.712
.412
.612
.913
.914
.112
.0
Non
blac
k/bl
ack1
EC
D/S
CD
(N=
1175
84/4
6896
)7.
6/4
7.5/
4.6
7.9/
57.
9/5
7.9/
5.3
8.1/
5.5
8.8/
5.7
8.8/
6.2
9.1/
6.3
9.4/
6.5
/6.4
/6.3
/6.9
EC
D/S
CD
–fo
reca
sted
9.1/
9.2/
9/6.
49.
3/6.
99.
5/7
9.6/
7.3
9.6/
7.2
9.8/
7.1
SC
D(1
0107
2/39
828)
7.8/
4.1
7.8/
4.8
8.2/
5.1
8.2/
5.2
8.4/
5.6
8.6/
5.8
9.3/
69.
5/6.
710
/6.8
9.9/
710
/7/6
.7/7
.2S
CD
–fo
reca
sted
9.8/
710
/6.9
9.5/
6.8
10/7
.310
.4/7
.410
.4/7
.710
.7/7
.710
.9/7
.41s
t–
TxE
CD
(149
56/6
567)
3.7/
1.8
4.1/
3.2
4.8/
2.9
4.6/
3.4
5.5/
2.3
5/3.
15.
5/4.
35.
8/4.
75.
7/4.
46/
4.2
6.3/
4.5
6.1/
4.1
5.8/
56.
1/4.
9/5
1st
–Tx
EC
D–
fore
cast
ed6.
3/4.
36/
5.1
6.2/
4.9
6.9/
5.2
6/5.
46.
6/5.
71s
tTx
–R
ec/D
onLE
45(N
=27
253/
1327
6)8.
9/4.
48.
8/5.
19.
8/5.
49.
7/5.
910
.9/5
.910
.6/6
.311
.5/6
12/7
.711
.9/7
.6/7
.2/7
.7/7
.9/7
.7
1st
Tx–
Rec
/Don
LE45
–fo
reca
sted
11.9
/7.3
12.2
/7.3
12.5
/7.7
14.5
/7.5
12.3
/7.5
13.2
/7.7
11.2
/7.9
16.5
/8
Livi
ngdo
nor
(N=
7564
0/12
790)
12.3
/6.3
12.1
/712
.6/8
.512
.1/7
.612
.2/7
.711
.9/7
12/7
.412
.7/7
.6/8
.7/9
.5
Livi
ngdo
nor
fore
cast
ed12
.9/
12.3
/12
.2/9
.913
.4/9
.213
/9.2
13.6
/8.5
13.4
/9.4
14.8
/9.1
14.9
/10.
813
.5/7
.51N
onbl
ack-
reci
pien
thal
f-liv
eslis
ted
befo
reha
shm
ark
follo
wed
bybl
ack
reci
pien
tsaf
tert
heha
shm
ark.
Whe
reno
half-
life
coul
dbe
obta
ined
resp
ectiv
eye
ars
are
blan
k.S
hade
dro
ws
are
proj
ectio
ns.
American Journal of Transplantation 2011; 11: 450–462 453
Lamb et al.
A
B
Figure 2: Actuarial (diamond
marker, solid line) and projected
(round marker, dotted line) cumula-
tive half-lives. (A) First SCD deceasedversus first living donor and (B) firstSCD deceased black versus nonblackrecipients.
year attrition rate improved dramatically and progressivelysince 1989. The 1–3, 3–5 and 5–10 year attrition rates showalso small but consistent improvements.
Figure 4 shows graft attrition rates for (A) standarddeceased-donor kidney recipients, (B) living-donor kidneyrecipients, (C) nonblack standard deceased-donor recipi-ents and D) black standard deceased-donor recipients.
Compared to nonblack SCD attrition rates, black SCD attri-tion rates showed a modest improvement in the attritionrates for years 1–3, 3–5 and 5–10.
Table 5 displays the death-censored graft attrition ratescounting only graft failure as an event and censoring incase of death. For donor and recipient age below 45, thedeath-censored graft attrition rates have changed very little.Three to five years graft attrition was 5.0% per year in 1989and 4.7% in 2004. Comparing black to nonblack patientsthere is a substantially higher long-term attrition rate inblack recipients. In 1989 the 3–5 year attrition rate in blackswas 8.7% versus 3.2% in nonblacks and 4.9% in blacks in2004 versus 3% in nonblacks.
Table 6 displays graft and death-censored graft attritionrates in living-donor transplants comparing black to non-black recipients. Again the dramatic improvement in 0–1 year attrition rates is evident also in living-donor trans-plants. The first year attrition rate in black recipients in1989 was 14.7% compared to 7.8% in nonblack patientsand 4.6% in black patients compared to 4.5% in nonblackpatients in 2005. Similarly for the 3–5 year attrition ratethere has been a more striking improvement in black re-cipients with an attrition rate of 10.3% per year in black
recipients in 1989 compared to 5.1% in 2004. For death-censored graft failure the gap between the outcomes inblack compared to nonblack persists until the most recentdata even when limiting to donors and recipients belowage 45.
Discussion
Long-term renal allograft survival in the United States hasmade small but measurable progress over the years. Themajority of the gain has been documented in the first yearafter transplantation. This is important progress as with im-proved 1-year survival the graft attrition starts at a higherintercept with most likely better long-term outcomes. Yetthe attrition rate has to at least stay constant to achievethis. In fact the data suggests that the long-term attritionrates have improved slightly despite of arguably more high-risk patients now at least reaching the 1-year mark. Bothprogresses combined have led to an improvement in re-nal allograft half-lives for deceased donor from 6.6 years in1989 to 8.2 years in 2000 and a continued improvement toa projected 8.8 years in 2005. These numbers corroborateprevious publications that have shown similar data (5,6).This is important as the herein presented data has signif-icantly more follow-up relative to the previous report andnow allows us to compare the previous actuarial half-lifeprojections (6) with the actual half-lives until the year 2000,which in fact does confirm the previous projections; theactuarial half-life projections beyond the year 2000 pointtoward possible small further improvements in half-lives.
As half-lives seem to be the best way to give the pa-tient a good clinical understanding of how long their
454 American Journal of Transplantation 2011; 11: 450–462
Long-Term Renal Allograft Survival
Tab
le2:
Kap
lan–
Mei
eres
timat
esof
deat
h-ce
nsor
edgr
aft
failu
reha
lf-liv
esby
tran
spla
ntye
ar
Tran
spla
ntye
ars
Rec
ipie
ntpo
pula
tion
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
EC
D/S
CD
10.2
10.6
11.1
1111
.111
.912
.812
.6E
CD
/SC
D–
fore
cast
ed11
.411
.412
.512
.112
.913
.114
14.2
15.1
14.4
14.3
1st
Tx–
EC
D/S
CD
1111
.111
.511
.411
.712
.113
.312
.91s
tTx
–E
CD
/SC
D–
fore
cast
ed11
.611
.811
.712
.712
.613
.113
.714
.414
.415
.814
.914
.6
SC
D10
.611
.011
.611
.611
.813
.014
.0S
CD
–fo
reca
sted
12.0
12.2
12.3
13.5
13.0
13.9
13.9
15.2
15.3
15.7
15.8
15.5
1st
Tx–
SC
D11
.311
.412
.012
.212
.313
.11s
tTx
–S
CD
–fo
reca
sted
12.3
12.7
12.7
13.8
13.5
14.1
14.6
15.8
15.7
16.5
16.5
16.1
1st
Tx–
Rec
/Don
LE45
10.1
10.1
11.0
11.1
11.9
11.8
12.0
12.9
1st
Tx–
Rec
/Don
LE45
–fo
reca
sted
11.2
10.6
11.5
11.5
11.4
12.5
12.9
13.5
12.3
13.1
12.5
12.4
1st
Tx–
EC
D4.
35.
96.
55.
95.
47.
47.
87.
68.
58.
79.
21s
tTx
–E
CD
–fo
reca
sted
7.7
8.3
8.3
9.1
9.5
9.1
9.6
12.8
9.9
10.1
Livi
ngD
onor
16.5
16.3
16.7
16.7
16.0
Livi
ngdo
nor
fore
cast
ed15
.615
.814
.915
.516
.416
.317
.819
.419
.419
.621
.320
.923
.616
.6Li
ving
dono
r1s
tTx
16.5
16.2
17.7
16.7
16.0
Livi
ngdo
nor
1st
Tx–
fore
cast
ed15
.815
.216
.016
.816
.418
.419
.519
.819
.822
.422
.023
.916
.8
Non
blac
k/bl
ack1
SC
D12
.8/5
.212
.7/6
.414
/7.2
14.3
/713
.8/8
15/6
.3/8
.2/9
.3/9
.3/9
.8/9
.7/9
SC
D–
fore
cast
ed14
.4/
15.1
/14
.2/
16.4
/15
.6/8
.916
.8/9
.217
.1/9
.319
.9/9
.919
.4/1
0.1
19.6
/10.
518
.8/1
1.1
21.2
/10
1st
–Tx
EC
D5.
2/2
6.6/
3.7
7.3/
3.7
6.5/
4.5
6.5/
2.9
8.7/
5.1
9/5.
68.
3/6.
69.
8/5.
99.
8/6.
2/5
.9/6
.4/7
.11s
t–
TxE
CD
–fo
reca
sted
10.7
/711
.3/6
.914
.2/1
0.1
10.4
/8.4
11.9
/7.5
1st
Tx–
Rec
/Don
LE45
12.6
/4.7
11.9
/613
.6/6
.214
.4/6
.914
.9/7
13.9
/7.8
/7.1
/9.5
/8.7
/8/9
.2/8
.71s
tTx
–R
ec/D
onLE
45–
fore
cast
ed14
/13
.9/
13.5
/13
.7/
14.1
/7.9
16.5
/816
.6/9
21.2
/8.3
15.6
/8.7
17.9
/8.9
13.8
/9.9
19.7
/8
EC
D/S
CD
12.5
/5.1
12.4
/6.3
13.3
/6.9
13.3
/6.8
12.9
/7.6
14.4
/7.8
/7.9
/8.6
/8.7
/9.2
/9.2
/8.9
EC
D/S
CD
–fo
reca
sted
13.2
/13
.7/
12.9
/15
/14
.4/
15.7
/8.5
16/8
.818
/9.3
17.6
/9.6
18.4
/10.
416
.6/1
0.6
19.2
/9.3
Livi
ngdo
nor
17.4
/9.3
17.2
/9.2
17.7
/10.
2/9
.2/9
.4/8
.9/9
.7/1
0.3
/12.
0Li
ving
dono
rfo
reca
sted
17.3
/16
.5/
17.4
/16
.9/
17.6
/8.9
18.4
/9.5
18.1
/10.
218
.9/1
2.6
21.6
/12
21.4
/12.
122
.9/1
0.8
24/1
2.5
24.4
/11.
326
.2/1
5.7
20.9
/8.4
1N
onbl
ack-
reci
pien
tha
lf-liv
eslis
ted
befo
reha
shm
ark
follo
wed
bybl
ack
Rec
ipie
nts
afte
rth
eha
shm
ark.
No
KM
half-
life
repo
rted
for
resp
ectiv
eye
arw
here
blan
k.S
hade
dro
ws
are
proj
ectio
ns.
American Journal of Transplantation 2011; 11: 450–462 455
Lamb et al.
A
BFigure 3: Actuarial (diamond
marker, solid line) and projected
(round marker, dotted line) death-
censored half-lives. (A) First SCDdeceased versus first living donor and(B) first SCD deceased black versusnonblack recipients.
future kidney transplants might actually last it is importantto break down the populations especially where substantialdifferences in outcomes are expected. Another way to gen-erate clinically useful data is to analyze death-censoredhalf-lives to give the patients an idea of how long a kidneymight last independent of the patient’s survival. This is par-ticularly important in young patients where the likelihoodof death is remote.
In fact, there are several interesting points to be madewhen looking at this data in detail. For example it is strik-ing how in the low-risk population where both donors andrecipients were below age 45 there has been a very limitedimprovement in death-censored graft survival. The cumula-tive gain in death-censored graft survival in this populationis about 2.5 years. When looking at the same populationfor overall graft survival there was a 3.3-year gain in half-life over the 16 years between 1989 and 2005. That meansthat there were small increments in graft survival and evensmaller increments in patients’ survival. This is importantto realize as in the past it has often been hypothesized thatthe lack of long-term improvement after kidney transplan-tation might be due to more risky donors and recipients.However, in actuality there is the least improvement in thelowest risk populations. This is further corroborated by theliving-donor data where half-lives have been oscillating be-tween 11 and 12 years without any appreciable era effectsince 1989.
Half-life assessments are difficult especially when half-lives are long because lengthy follow-up is needed togenerate meaningful data. In order not to have to waitfor the full length of time to understand outcomes data
half-lives can be estimated based on incomplete follow-upor even projected. Actual half-lives are derived from datawhen all patients have follow-up for at least the same timeas the half-life itself. For example if in one population thehalf-life is 8 years, a minimum follow-up of 8 years for allpatients is needed to establish an actual half-life. For anactuarial half-life, follow-up derived from a Kaplan–Meierestimated survival would rely on a minimum of onepatient with at least as much follow-up as the half-life. In ascenario where not even one patient has enough follow-upto visually forecast the half-life, projections are necessary.The projection is based on the proportion of the Kaplan–Meier curve where somewhat stable attrition rates havebeen established. The projections may be based totallyor partially on actual follow-up and to a variable extenton actuarial follow-up. It is important to realize that thereliability of the projections does decrease with the lengthof the projection. The higher the half-life, the longer theprojections are in order to estimate a half-life. Good exam-ples are the death-censored projected half-lives displayedin Table 2. With death-censored half-lives around 20 yearsfor living-donor kidney patients transplanted in 1999 thereis only 10 years of actual follow-up, thus the remaining 10years of the displayed half-lives are based on projections.For patients transplanted in 2004 the same projected half-life is only based on 5 years of actual follow-up. An indirectmeasure of the reliability of the forecasts is the year-to-yearvariation, if the half-lives projected vary widely this is prob-ably an indication that the forecasts are not reliable. Clearlythe longer the half-lives are the more imprecise the projec-tions will be. In fact the death-censored survival data havea higher variability in the predictions because the death-censored half-lives are longer than in the uncensored data.
456 American Journal of Transplantation 2011; 11: 450–462
Long-Term Renal Allograft Survival
Tab
le3:
Cox
adju
sted
estim
ates
ofcu
mul
ativ
egr
aft
failu
reha
lf-liv
esby
tran
spla
ntye
ar
Tran
spla
ntye
ars
All
race
s19
8919
9019
9119
9219
9319
9419
9519
9619
9719
9819
9920
0020
0120
0220
0320
0420
05
SC
D6.
66.
77.
37.
27.
67.
88.
38.
68.
99.
09.
38.
9S
CD
–fo
reca
sted
8.9
9.1
8.7
9.1
9.5
9.7
10.0
9.9
1st
Tx–
SC
D6.
96.
97.
47.
27.
77.
98.
58.
89.
09.
39.
39.
01s
tTx
–S
CD
–fo
reca
sted
9.0
9.1
8.9
9.3
9.7
9.9
10.2
10.2
1stT
x–
SC
D–
Rec
/Don
LE45
7.6
7.5
8.4
8.4
9.2
9.1
9.7
10.7
10.3
10.5
1st
Tx–
SC
D–
Rec
/Don
LE45
–fo
reca
sted
10.0
10.3
10.6
11.0
10.0
10.9
11.1
11.0
Livi
ngdo
nor
11.4
11.6
11.6
11.3
11.5
11.1
11.4
11.8
12.0
Livi
ngdo
nor
fore
cast
ed11
.210
.911
.911
.512
.012
.712
.312
.612
.913
.714
.312
.2Li
ving
dono
r1s
tTx
11.3
11.6
11.9
11.3
11.5
11.3
11.4
12.0
11.4
Livi
ngdo
nor
1st
Tx–
fore
cast
ed11
.411
.212
.111
.612
.312
.812
.512
.613
.114
.114
.312
.2
Non
blac
k/bl
ack1
SC
D7.
8/4.
17.
8/4.
78.
3/5.
18.
2/5.
28.
4/5.
68.
7/5.
99.
4/6
9.6/
6.7
10/6
.810
/710
/7/6
.8/7
.2S
CD
–fo
reca
sted
9.8/
710
.1/6
.99.
6/6.
810
.1/7
.310
.5/7
.410
.6/7
.711
/7.9
11.1
/7.5
1st
–Tx
SC
D8.
2/4.
38/
4.8
8.4/
5.1
8.3/
5.2
8.6/
5.6
8.7/
69.
6/6.
29.
7/6.
710
.2/6
.910
/7.1
10/7
/6.9
/7.4
1st
–Tx
SC
D–
fore
cast
ed10
/710
.1/6
.99.
9/6.
910
.2/7
.410
.7/7
.410
.8/7
.811
.2/8
.211
.6/7
.51s
tTx
–S
CD
–R
ec/D
onLE
459.
3/4.
39.
1/5.
110
.3/5
.49.
9/5.
811
.3/5
.910
.8/6
.311
.7/6
12.2
/7.7
11.9
/7.6
/7.2
/7.5
/7.9
/7.7
1st
Tx–
SC
D–
Rec
/Don
LE45
–fo
reca
sted
12.1
/7.2
12.3
/7.3
12.5
/7.7
14.3
/7.4
12.2
/7.1
13.2
/7.7
11.4
/9.1
14.4
/7.2
1N
onbl
ack-
reci
pien
tha
lf-liv
eslis
ted
befo
reha
shm
ark
follo
wed
bybl
ack
Rec
ipie
nts
afte
rth
eha
shm
ark.
No
KM
half-
life
repo
rted
for
resp
ectiv
eye
arw
here
blan
k.S
hade
dro
ws
are
proj
ectio
ns.
American Journal of Transplantation 2011; 11: 450–462 457
Lamb et al.
A
C D
B
Figure 4: Cumulative graft failure
yearly attrition rates of first kidney
transplants (A) Deceased SCD donor,(B) living donor, (C) Nonblack deceasedSCD donor and (D) black deceasedSCD donor.
An interesting area in this data is the comparison betweenblack and nonblack recipients. In general the data highlightsthe profound differences in outcomes between black andnonblack patients, which have been described previously(8). The small improvements in half-lives have been nearlyparallel between black and nonblack patients as shown inFigure 2(B). It is interesting to note though that death-censored half-lives have been somewhat more stagnant inblack patients compared to nonblack patients (Figure 3B)with the caution again that the forecasts in nonblack recipi-ents death-censored data might not be very solid becausethe half-lives are so long. On the other hand looking at thegraft attrition data in black patients who clearly have thehighest graft attrition there seems to be a more percepti-ble trend of improvement over the years as can be seenin Figure 4(D). In fact even though the absolute increase inhalf-life was only about 4 years, the half-life almost doubledfrom 1989 (4 years) to 2005 (7.4 years).
We specifically analyzed attrition rates because half-livesassess only the cumulative effect of graft loss overtime, butthere is a clear difference in the early rate of graft loss ver-sus late and the underlying pathogenetic processes mighteven be somewhat distinct. Clearly first-year attrition ratesare significantly higher for all subpopulations and have im-
proved significantly overtime. The subsequent graft attri-tion rates are fairly constant. When comparing the 1–3,3–5 and 5—10-year attrition rate there do not seem tobe dramatic differences with increasing time posttrans-plant but overall the 5—10-year attrition rate is for themost part somewhat higher. This seems to be most ev-ident in living-donor transplants where the 1–3, 3–5 and 5–10 year yearly attrition rates increase by about 1% for eachsubsequent episode in both black and nonblack patients.This phenomenon is neither evident in the death-censoreddata nor in low-risk deceased-donor transplants namelywith both donor and recipient age below 45 years. Thismeans that the mild increase in attrition rates is probablydriven by death rather than graft loss. In fact when lookingat the death-censored attrition rates there is no increase inthe attrition with increasing time posttransplant.
When comparing attrition rates between populations themost striking difference is between living- and deceased-donor recipients. Most of this difference is based on thewell-known better short-term outcomes in living-donortransplants. Long-term attrition rates are also lower inliving-donor transplants but only in nonblack patients. Inblack patients there seems to be a higher long-term attri-tion rate in living-donor transplants compared to nonblack
458 American Journal of Transplantation 2011; 11: 450–462
Long-Term Renal Allograft Survival
Tab
le4:
Kap
lan–
Mei
eres
timat
esof
cum
ulat
ive
graf
tat
triti
onra
teby
tran
spla
ntye
arfo
rfir
st-t
rans
plan
tde
ceas
eddo
nor
Tran
spla
ntye
ars
All
reci
pien
ts19
8919
9019
9119
9219
9319
9419
9519
9619
9719
9819
9920
0020
0120
0220
0320
0420
0520
0620
0720
08
0–1
Year
19.8
18.2
15.6
15.1
15.7
14.5
12.3
11.1
10.0
9.2
10.7
10.3
9.2
9.3
9.0
8.3
8.4
8.2
7.4
6.7
1–3
Year
s7.
46.
76.
16.
66.
15.
75.
45.
45.
55.
05.
25.
55.
45.
55.
45.
35.
14.
73–
5Ye
ars
6.7
7.4
7.7
7.8
6.9
7.5
7.3
6.9
6.9
6.7
6.7
6.5
6.5
6.3
5.8
6.0
5–10
Year
s7.
57.
57.
88.
07.
37.
46.
96.
96.
86.
96.
6
Rec
ipie
ntan
ddo
nor
age
belo
w45
0–1
Year
18.4
17.2
13.9
13.4
13.5
12.4
10.5
8.9
8.3
7.4
8.8
7.9
6.4
7.1
7.6
6.4
6.8
5.7
5.8
5.4
1–3
Year
s7.
56.
85.
66.
45.
85.
25.
15.
15.
14.
95.
15.
55.
05.
25.
65.
44.
64.
73–
5Ye
ars
6.3
6.9
6.4
6.9
5.5
6.6
6.6
6.5
6.4
6.3
5.5
5.6
5.3
6.4
5.2
5.7
5–10
Year
s6.
76.
86.
86.
76.
06.
46.
25.
35.
85.
75.
4
Non
blac
k/bl
ack1
0–1
Year
18.3
/24.
217
.6/2
0.2
17.9
/14.
817
.6/1
4.3
15.5
/17.
514
/15.
712
/12.
910
.4/1
2.9
9.9/
11.6
8.7/
10.7
9.9/
12.5
9.1/
138.
3/11
.48.
8/10
.48/
11.2
7.5/
10.1
7.7/
9.9
7.8/
96.
4/9.
25.
8/8.
41–
3Ye
ars
11.8
/6.2
5.5/
10.7
4.9/
9.9
5.5/
9.9
5/9.
44.
5/8.
84.
2/8.
54.
4/8
4.5/
7.9
4.3/
74.
1/8.
14.
4/8.
24.
6/7.
14.
8/7.
34.
5/7.
34.
3/7.
74.
2/7.
14.
1/6.
23–
5Ye
ars
5.7/
10.4
6.4/
10.7
6.6/
11.6
6.9/
10.8
6.1/
9.7
6.6/
10.1
6.3/
106/
9.4
5.8/
9.7
5.6/
9.8
6/8.
75.
8/8.
25.
8/8.
25.
4/8.
35.
3/7.
25.
5/7.
25–
10Ye
ars
6.8/
10.7
7/9.
47.
4/9.
47.
4/10
.26.
8/9
6.7/
9.5
6.3/
8.7
6.4/
8.4
6.2/
8.6
6.4/
8.1
6.2/
7.7
Rec
ipie
ntan
ddo
nor
age
belo
w45
0–1
Year
17.3
/21.
816
.3/1
9.8
13.1
/16.
112
.8/1
4.9
12.6
/16
12/1
3.3
10.1
/11.
47.
9/11
.17.
9/9
6.2/
9.6
7.3/
11.9
6.9/
9.7
6/7.
46.
1/8.
76.
6/9.
44.
9/9.
16.
5/7.
25.
3/6.
24.
2/8.
13.
8/7.
91–
3Ye
ars
6/12
.55.
1/11
.23.
9/10
.55/
9.9
4/10
.73.
8/8.
43.
7/8.
33.
9/7.
73.
9/7.
73.
5/7.
83.
8/7.
94/
8.2
3.9/
7.1
4/7.
34.
2/8.
14/
8.1
3.2/
6.6
3.6/
6.5
3–5
Year
s5.
1/10
.96.
1/9.
45.
1/10
.95.
6/10
.74.
6/8.
65.
4/9.
65.
4/9.
65.
3/9.
15.
1/9.
35.
1/9
4.3/
8.2
4.5/
7.8
3.5/
9.1
4.8/
9.4
4.3/
6.9
5.3/
6.5
5–10
Year
s6.
1/9.
16.
2/9
6.3/
8.4
6/8.
75.
4/8.
25.
7/8.
55.
2/8.
75/
6.4
5.1/
7.5
4.8/
7.8
5/6.
31N
onbl
ack
reci
pien
tha
lf-liv
eslis
ted
befo
reha
shm
ark
follo
wed
bybl
ack
reci
pien
tsaf
ter
the
hash
mar
k.
American Journal of Transplantation 2011; 11: 450–462 459
Lamb et al.
Tab
le5:
Kap
lan–
Mei
eres
timat
esof
deat
h-ce
nsor
edgr
aft
attr
ition
rate
bytr
ansp
lant
year
for
first
-tra
nspl
ant
dece
ased
dono
r
Tran
spla
ntye
ars
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
All
reci
pien
ts0–
1Ye
ar15
.714
.312
.311
.312
.010
.88.
27.
66.
26.
26.
86.
15.
85.
75.
65.
15.
25.
14.
34.
01–
3Ye
ars
5.5
4.7
4.1
4.4
4.1
3.5
3.4
3.3
3.4
3.0
3.1
3.4
3.0
3.4
3.2
3.2
2.9
2.8
3–5
Year
s4.
34.
64.
44.
64.
04.
64.
74.
54.
34.
24.
23.
83.
53.
63.
13.
55–
10Ye
ars
4.5
4.4
4.8
4.8
4.7
4.4
4.2
4.3
44
3.6
Rec
ipie
ntan
ddo
nor
age
belo
w45
0–1
Year
15.8
14.9
12.3
11.0
11.9
10.7
8.7
7.1
6.3
6.0
7.1
6.3
5.3
5.5
5.9
5.2
5.1
4.6
4.4
4.2
1–3
Year
s6.
35.
64.
65.
04.
84.
14.
24.
04.
34.
34.
04.
33.
94.
14.
54.
73.
64.
03–
5Ye
ars
5.0
5.4
4.4
5.3
4.2
5.2
5.6
5.5
5.4
5.5
4.7
4.6
4.6
5.1
4.2
4.7
5–10
Year
s4.
24.
34.
74.
44.
34.
34
3.8
3.6
3.7
3.3
Non
blac
k/bl
ack
0–1
Year
13.8
/21.
513
.6/1
6.6
11.4
/15
10.4
/14.
211
.4/1
3.9
10.1
/12.
37.
7/9.
67/
96.
6/7.
95.
5/7.
96/
8.8
5.2/
8.3
4.8/
8.1
5.2/
6.9
4.7/
7.5
4.3/
6.8
4.4/
6.8
4.6/
6.1
3.6/
5.9
3.4/
5.2
1–3
Year
s4.
2/9.
83.
4/8.
82.
9/7.
83.
3/7.
83.
1/7.
32.
4/6.
42.
2/6.
42.
3/6.
12.
5/5.
82.
3/4.
92/
5.8
2.4/
5.9
2.3/
4.6
2.4/
5.6
2.3/
5.3
2.3/
5.2
2/4.
82/
4.3
3–5
Year
s3.
2/8.
73.
6/8.
23.
3/8.
73.
6/8.
23.
2/6.
63.
7/7.
17.
5/3.
83.
6/7.
13.
4/6.
93.
1/7.
23.
2/6.
92.
9/6.
32.
7/5.
62.
7/5.
92.
4/4.
83/
4.9
5–10
Year
s3.
7/8.
13.
8/6.
94.
3/6.
84.
1/7.
54.
2/6.
53.
7/6.
83.
4/6.
63.
8/6
3.2/
6.5
3.5/
5.7
3.1/
5
Rec
ipie
ntan
ddo
nor
age
belo
w45
0–1
Year
14.4
/20
13.9
/17.
811
.3/1
510
.1/1
3.3
11.1
/14.
210
.2/1
1.8
8.2/
9.5
5.8/
9.8
5.8/
7.4
4.9/
8.2
5.7/
9.8
5.4/
7.9
4.9/
6.1
5/6.
45/
7.3
7.5/
3.9
4.9/
5.4
4.4/
53.
5/5.
73.
2/5.
71–
3Ye
ars
4.7/
11.5
3.9/
10.2
2.9/
9.4
3.7/
8.2
3.1/
9.5
2.9/
6.9
2.7/
7.3
2.7/
6.9
3/6.
92.
9/7.
32.
6/7.
23/
72.
9/5.
72.
8/6.
63.
2/6.
73.
2/7.
52.
6/5.
22.
7/6
3–5
Year
s3.
6/10
.34.
6/7.
82.
9/9.
33.
9/9.
13.
3/7.
14/
8.5
4.3/
8.5
4.6/
7.7
4.2/
84.
2/8.
33.
3/8
3.5/
72.
7/8.
53.
9/7.
63.
2/6.
24.
2/5.
95–
10Ye
ars
4.1/
7.9
4.4/
7.5
4.8/
7.1
4.2/
7.5
4/6.
94.
1/7.
43.
9/7.
93.
8/5.
43.
8/6.
93.
7/6.
73.
7/5.
3† N
onbl
ack
reci
pien
tha
lf-liv
eslis
ted
befo
reha
sh-m
ark
follo
wed
byB
lack
Rec
ipie
nts
afte
rth
eha
shm
ark.
460 American Journal of Transplantation 2011; 11: 450–462
Long-Term Renal Allograft Survival
Tab
le6:
Kap
lan–
Mei
eres
timat
esof
cum
ulat
ive
graf
tat
triti
onan
dde
ath-
cens
ored
graf
tat
triti
onra
teby
tran
spla
ntye
arfo
rfir
sttr
ansp
lant
livin
g-do
nor
nonb
lack
vers
usbl
ack
Tran
spla
ntye
ars
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
All
reci
pien
tsgr
aft
failu
re0–
1ye
ar8.
67.
86.
78.
27.
66.
47.
46
5.8
5.3
5.4
5.6
5.5
5.1
4.6
4.6
4.5
3.8
3.2
3.4
1–3y
ear
3.8
3.2
3.9
3.3
4.2
3.8
3.7
3.6
3.2
3.5
3.4
3.4
3.3
3.4
3.6
3.1
3.1
2.9
3–5
year
4.5
5.2
5.2
5.1
55.
24.
54.
94.
94.
84.
24.
34.
64.
24.
14
5–10
year
5.4
5.7
5.3
5.6
5.6
5.7
5.8
5.4
5.4
5.1
5.2
Non
blac
k/bl
ack
0–1
year
7.8/
14.7
7.4/
11.3
6.2/
10.2
7.5/
13.3
7.4/
8.5
5.8/
107.
1/8.
65.
4/9.
75.
7/6.
35.
1/6.
95.
1/7.
45.
3/7.
75.
3/6.
54.
8/6.
84.
6/4.
74.
3/6.
44.
5/4.
63.
6/5
3/4.
13/
61–
3ye
ar3.
4/7.
42.
9/6.
33.
5/6.
32.
9/6.
83.
9/6.
53.
4/6.
63.
2/6.
93.
1/6.
82.
8/5.
73.
3/4.
53.
1/5.
43.
2/4.
32.
8/6
3.1/
5.4
3.3/
5.4
2.8/
4.8
2.8/
4.8
3–5
year
3.9/
10.3
4.7/
9.4
4.9/
7.5
4.7/
7.9
4.3/
9.1
4.7/
8.3
4.2/
7.1
4.5/
84.
3/8.
24.
7/5.
83.
7/7.
14.
1/6.
14.
1/7.
43.
8/6.
83.
6/6.
63.
8/5.
15–
10ye
ar5.
1/8.
55.
4/8.
15.
1/7.
65.
3/8.
65.
2/7.
95.
2/9
5.4/
8.4
5.1/
7.8
5/8.
34.
9/6.
65/
6.7
All
reci
pien
tsde
ath
cens
ored
graf
tfa
ilure
0–1
year
6.9
6.1
5.1
6.3
5.2
4.9
5.2
4.4
3.8
3.4
3.7
3.6
3.6
3.2
3.2
3.1
2.9
2.4
1.9
2.1
1–3
year
2.6
2.3
2.3
2.5
32.
32.
32.
42.
22.
32.
22
22.
12.
31.
91.
91.
63–
5ye
ar3.
13.
43.
53.
43.
33.
83
3.3
3.1
2.8
2.7
2.5
2.9
2.3
2.4
2.1
5–10
year
3.5
43.
73.
73.
73.
84
3.6
3.4
3.3
3.2
Non
blac
k/bl
ack
0–1
year
6.2/
12.6
5.6/
10.2
4.6/
8.2
5.7/
10.8
5/6.
54.
3/8.
14.
9/6.
93.
8/7.
43.
8/3.
33.
3/4.
13.
4/4.
93.
5/4.
53.
4/4.
63/
4.6
3.1/
3.6
2.8/
4.5
2.8/
3.3
2.2/
3.7
1.8/
32/
3.2
1–3y
ear
2.2/
5.8
1.9/
5.3
2/4.
32.
1/5.
32.
6/5.
41.
8/5.
11.
7/5.
91.
9/5.
31.
8/4.
62.
1/3.
91.
8/4.
41.
8/3.
21.
5/4.
41.
7/4.
31.
9/4.
11.
6/3.
51.
5/3.
61.
3/3.
33–
5ye
ar2.
7/6.
62.
9/8.
33.
1/5.
93.
1/6
2.7/
73.
4/6.
52.
6/6
2.9/
6.2
2.6/
6.5
2.7/
3.7
2.3/
5.2
2.3/
4.2
2.5/
5.5
2/4.
72/
4.9
1.9/
3.2
5–10
year
3.2/
6.4
3.8/
6.2
3.4/
6.1
3.4/
6.3
3.4/
6.2
3.4/
7.3
3.6/
6.7
3.3/
5.9
3.1/
5.7
3/5.
52.
9/5
†Non
blac
kre
cipi
ent
half-
lives
liste
dbe
fore
hash
mar
kfo
llow
edby
blac
kre
cipi
ents
afte
rth
eha
shm
ark.
American Journal of Transplantation 2011; 11: 450–462 461
Lamb et al.
deceased-donor transplants and similar to black deceased-donor transplants.
Significant progress has occurred over the decades in re-nal transplantation and is mostly driven by improvementsin short-term graft and patient survival. Further improve-ment, which now has to come mainly from long-term sur-vival improvements, has been more difficult to achieve.The multifactorial nature of chronic renal allograft loss (9)makes specific interventions for populations difficult. In-creased immunosuppression has decreased acute rejec-tion rates but led to more graft loss driven by opportunis-tic infections or over-immunosuppression (6), thus keep-ing long-term graft loss a constant phenomenon not onlyin the United States but also in other countries (10). Im-munosuppression minimization strategies as a populationapproach to deal with toxicities are likely to incur the sameproblems (11). Despite these obvious difficulties and in theabsence of any good tools to individualize immunosuppres-sion to each patient, modest but measurable progress hasoccurred in long-term graft attrition resulting ultimately inlonger kidney allograft half-lives in the United States.
Acknowledgment
We would like to extend our appreciation to the Central Florida KidneyCenter, Inc. for supporting this work through the endowment of the EminentScholar Chair in Nephrology and Hypertension. We would also like to thankMelissa Smiles for editing and proof reading the manuscript. The authorsdo not have any conflicts of interest or disclosures with regards to the datapresented in this manuscript.
Disclosure
The authors of this manuscript have no conflicts of inter-est to disclosure as described by the American Journal ofTransplantation.
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3. Wolfe RA, Ashby VB, Milford EL et al. Comparison of mortality in allpatients on dialysis, patients on dialysis awaiting transplantation,and recipients of a first cadaveric transplant. N Engl J Med 1999;341: 1725–1730.
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462 American Journal of Transplantation 2011; 11: 450–462
