Gastroenterol Res

Gastroenterology Research, ISSN 1918-2805 print, 1918-2813 online, Open Access

Article copyright, the authors; Journal compilation copyright, Gastroenterol Res and Elmer Press Inc

Journal website http://www.gastrores.org

Original Article

Volume 10, Number 2, April 2017, pages 106-115

Differential Simultaneous Liver and Kidney Transplant Benefit Based on Severity of Liver Damage at the Time of Transplantation

Figure 1. Correlation between serum creatinine and MELD score categories at the time of transplantation. Analysis of variance (ANOVA): mean serum creatinine in each MELD group (P = 0.0001). A linear correlation between increasing MELD score and serum creatinine (Pearson correlation coefficient 0.04, P = 0.0001).

Figure 2. Prevalence of renal dysfunctions at the time of transplantation. Prevalence of patients with renal dysfunctions creatinine > 1.5 in overall study cohort and in each MELD group. A trend of increasing prevalence from low to high MELD groups (Pearson correlation R 0.46: P = 0.0001 (two-tailed)). One-way analysis of variance was used to determine the differences among the groups. All the groups are statistically significant from each other (P = 0.001).

Figure 3. Distribution of patients receiving transplantation base on MELD categories. Proportion of patients receiving simultaneous liver kidney (SLK) or liver alone (LA) transplant in each MELD group and in overall study population. A trend of increasing prevalence from low to high MELD groups (Pearson correlation R 0.11: P = 0.00001 (two-tailed)). Analysis of variance was used to determine the differences among the groups. High MELD group (MELD 36 - 40) is statistically significantly different (P ≤ 0.05) compared to other groups except MELD group 31 - 35 (P = 1.0).

Figure 4. Kaplan-Meier patient survival analysis at 1 year based on MELD category. In each MELD category survival was compared among three transplant recipient groups (group 1: creatinine < 1.5 receiving liver alone, group 2: creatinine > 1.5 receiving liver alone and group 3: creatinine > 1.5 receiving simultaneous liver kidney. Log rank test P values (statistically significant < 0.05) are: 16 - 20 (1 vs. 2); 21 - 25 (1 vs. 2 and 1 vs. 3); 26 - 30 (1 vs. 2); 31 - 35 (1 vs. 2 and 1 vs. 3); 36 - 40 (1 vs. 2 and 1 vs. 3).

Figure 5. Analysis of deceased patients. Distribution of death within 1 year based on MELD score. (a) Proportion of post-transplantation deaths based on MELD score at transplantation in overall study cohort. (b) Proportion of post-transplantation deaths based on MELD score at transplantation in patients with and without renal dysfunctions.

**Table 1.** Clinical Characteristics at Transplantation
Clinical feature	n = 30,928	Clinical feature	n = 30,928
SD: standard deviation; n: sample number; MELD: model for end-stage liver disease; BMI: body mass index; LTA: liver transplantation alone; SLKT: simultaneous liver and kidney transplantation; LOS: length of stay.
Age recipient: mean ± SD	51.58 ± 11.17	Hepatic encephalopathy
Age donor: mean ± SD		None, % (n)	21.8% (6,732)
Gender recipient: male, % (n)	64.8% (20,034)	Mild to moderate, % (n)	59.8% (18,505)
Gender donor: male, % (n)	59.8% (18,495)	Severe, % (n)	17.4% (5,396)
Race recipient		Unknown, % (n)	1% (295)
White, % (n)	71.3% (22,066)	Final MELD, mean ± SD	27.366 ± 8.48
Others, % (n)	28.7% (8,862)	MELD groups
Race donor		16 - 20, % (n)	25.2% (7,806)
White, % (n)	67.5% (20,862)	21 - 25, % (n)	24.4% (7,549)
Others, % (n)	32.5% (10,066)	26 - 30, % (n)	17.8% (5,500)
Ethnicity recipient		31 - 35, % (n)	13.6% (4,214)
Non-Hispanic, % (n)	86.4% (26,735)	> 36, % (n)	18.9% (5,859)
Hispanic, % (n)	13.6% (4,193)	Child-Pugh score
BMI, mean ± SD	28.30 ± 7.10	Class A, % (n)	1.7% (518)
Creatinine at Tx, mg/dL, mean ± SD	1.93 ± 1.56	Class B, % (n)	25.9% (8,025)
Dialysis at Tx, % (n)	16.4% (5,084)	Class C, % (n)	67.1% (20,759)
Albumin at Tx, mean ± SD	2.84 ± 0.73	Missing, % (n)	5.3% (1,626)
INR at Tx, mean ± SD	2.2 ± 1.7	Distribution of patients based on renal functions
T. bilirubin at Tx, mg/dL, mean ± SD	12.27 ± 12.5	Creatinine 1.5 or less, % (n)	52.5% (16,249)
Ascites		Creatine > 1.5 non-dialysis LTA, % (n)	28.1% (8,701)
None, % (n)	12.9% (3,986)	Creatine > 1.5 non-dialysis SLKT, % (n)	2.9 % (894)
Mild to moderate, % (n)	48.9% (15,129)	Creatine > 1.5 dialysis LTA, % (n)	10.2% (3,161)
Severe, % (n)	37.2 (11,520)	Creatine > 1.5 dialysis SLKT, % (n)	6.2% (1,923)
Unknown, % (n)	0.9% (293)	LOS, mean ± SD	18.91 ± 24.46)

Table 1. Clinical Characteristics at Transplantation

Clinical feature

n = 30,928

Clinical feature

n = 30,928

SD: standard deviation; n: sample number; MELD: model for end-stage liver disease; BMI: body mass index; LTA: liver transplantation alone; SLKT: simultaneous liver and kidney transplantation; LOS: length of stay.

Age recipient: mean ± SD

51.58 ± 11.17

Hepatic encephalopathy

Age donor: mean ± SD

None, % (n)

21.8% (6,732)

Gender recipient: male, % (n)

64.8% (20,034)

Mild to moderate, % (n)

59.8% (18,505)

Gender donor: male, % (n)

59.8% (18,495)

Severe, % (n)

17.4% (5,396)

Race recipient

Unknown, % (n)

1% (295)

White, % (n)

71.3% (22,066)

Final MELD, mean ± SD

27.366 ± 8.48

Others, % (n)

28.7% (8,862)

MELD groups

Race donor

16 - 20, % (n)

25.2% (7,806)

White, % (n)

67.5% (20,862)

21 - 25, % (n)

24.4% (7,549)

Others, % (n)

32.5% (10,066)

26 - 30, % (n)

17.8% (5,500)

Ethnicity recipient

31 - 35, % (n)

13.6% (4,214)

Non-Hispanic, % (n)

86.4% (26,735)

> 36, % (n)

18.9% (5,859)

Hispanic, % (n)

13.6% (4,193)

Child-Pugh score

BMI, mean ± SD

28.30 ± 7.10

Class A, % (n)

1.7% (518)

Creatinine at Tx, mg/dL, mean ± SD

1.93 ± 1.56

Class B, % (n)

25.9% (8,025)

Dialysis at Tx, % (n)

16.4% (5,084)

Class C, % (n)

67.1% (20,759)

Albumin at Tx, mean ± SD

2.84 ± 0.73

Missing, % (n)

5.3% (1,626)

INR at Tx, mean ± SD

2.2 ± 1.7

Distribution of patients based on renal functions

T. bilirubin at Tx, mg/dL, mean ± SD

12.27 ± 12.5

Creatinine 1.5 or less, % (n)

52.5% (16,249)

Ascites

Creatine > 1.5 non-dialysis LTA, % (n)

28.1% (8,701)

None, % (n)

12.9% (3,986)

Creatine > 1.5 non-dialysis SLKT, % (n)

2.9 % (894)

Mild to moderate, % (n)

48.9% (15,129)

Creatine > 1.5 dialysis LTA, % (n)

10.2% (3,161)

Severe, % (n)

37.2 (11,520)

Creatine > 1.5 dialysis SLKT, % (n)

6.2% (1,923)

Unknown, % (n)

0.9% (293)

LOS, mean ± SD

18.91 ± 24.46)

**Table 2.** Distribution of Patients Based on Serum Creatinine Status at Liver Transplantation
MELD group	Creatinine ≤ 1.5 mg/dL	Creatinine > 1.5 mg/dL	LT alone	SLK	Death at 1 year
MELD: model for end-stage liver disease; LT: liver transplant; SLKT: simultaneous liver and kidney transplant.
16 - 20 (%)	6,584 (21.3%)	1,222 (4.0%)	7,594 (24.6%)	212 (0.7%)	664 (2.2%)
21 - 25 (%)	4,952 (16.0%)	2,597 (8.4%)	6,793 (22.0%)	756 (2.4%)	847 (2.7%)
26 - 30 (%)	2,832 (9.2%)	2,668 (8.6%)	4,902 (15.9%)	598 (1.9%)	731 (2.4%)
31 - 35 (%)	1,289 (4.2%)	2,925 (9.5%)	3,695 (12.0%)	519 (1.7%)	632 (2.0%)
35+ (%)	592 (1.9%)	5,267 (17.0%)	5,127 (16.6%)	732 (2.4%)	1,091 (3.5%)
Total (%)	16,249 (52.5%)	14,679 (47.5%)	28,111 (90.9%)	2,817 (9.1%)	3,965 (12.8%)

Table 2. Distribution of Patients Based on Serum Creatinine Status at Liver Transplantation

MELD group

Creatinine ≤ 1.5 mg/dL

Creatinine > 1.5 mg/dL

LT alone

SLK

Death at 1 year

MELD: model for end-stage liver disease; LT: liver transplant; SLKT: simultaneous liver and kidney transplant.

16 - 20 (%)

6,584 (21.3%)

1,222 (4.0%)

7,594 (24.6%)

212 (0.7%)

664 (2.2%)

21 - 25 (%)

4,952 (16.0%)

2,597 (8.4%)

6,793 (22.0%)

756 (2.4%)

847 (2.7%)

26 - 30 (%)

2,832 (9.2%)

2,668 (8.6%)

4,902 (15.9%)

598 (1.9%)

731 (2.4%)

31 - 35 (%)

1,289 (4.2%)

2,925 (9.5%)

3,695 (12.0%)

519 (1.7%)

632 (2.0%)

35+ (%)

592 (1.9%)

5,267 (17.0%)

5,127 (16.6%)

732 (2.4%)

1,091 (3.5%)

Total (%)

16,249 (52.5%)

14,679 (47.5%)

28,111 (90.9%)

2,817 (9.1%)

3,965 (12.8%)

**Table 3.** Cox Proportional Hazard Analysis
Variables	Un-adjusted analysis	Adjusted analysis^a
HR: hazard ratio; CI: confidence interval; MELD: model for end-stage liver disease; BMI: body mass index; LTA: liver transplantation alone; SLKT: simultaneous liver and kidney transplantation. ^aAdjusted for patient’s ascites grade, albumin, bilirubin, Cr, INR, MELD, dialysis, gender, race and age, donor’s age and gender, and type of transplant.
Dialysis at transplantation: yes	0.001	1.401	1.321	1.485	0.001	1.204	1.119	1.297
Recipient race: non-White	0.061	1.051	0.998	1.106	0.001	1.137	1.066	1.213
Donor race: non-White	0.027	1.058	1.006	1.112	0.016	1.064	1.012	1.119
Ethnicity: non-Hispanic	0.037	0.927	0.864	0.995	0.001	0.811	0.743	0.885
Recipient gender: male	0.164	1.036	0.986	1.088
Donor gender: male	0.124	0.963	0.918	1.01
Recipient age > 65	0	1.332	1.227	1.445	0.001	1.287	1.185	1.397
Donor age > 55	0	1.335	1.266	1.409	0.001	1.372	1.3	1.449
BMI < 20	0.431
BMI 21 - 25	0.31	0.945	0.846	1.056
BMI 26 - 30	0.242	0.937	0.84	1.045
BMI 31 - 35	0.072	0.898	0.799	1.01
BMI 36 - 40	0.521	0.956	0.834	1.096
BMI > 40	0.881	1.013	0.859	1.193
Child-Pugh Class A	0.001
Child-Pugh Class B	0.269	0.901	0.748	1.084
Child-Pugh Class C	0.811	1.022	0.852	1.226
Creatinine > 1.5 mg/dL	0.001	1.417	1.352	1.485
Creatinine ≤ 1.5 mg/dL	0.001
Creatinine > 1.5 mg/dL LTA	0.001	1.531	1.457	1.608	0.001	1.401	1.32	1.486
Creatinine > 1.5 mg/dL SLKT	0.001	1.338	1.232	1.454	0.004	1.158	1.049	1.277
MELD 16 - 20	0.001
MELD 20 - 25	0.001	1.162	1.083	1.246	0.013	1.095	1.02	1.175
MELD 26 - 30	0.001	1.294	1.202	1.394	0.001	1.164	1.077	1.258
MELD 31 - 35	0.001	1.342	1.239	1.453	0.018	1.11	1.018	1.21
MELD 36 - 40 and higher	0.001	1.514	1.41	1.626	0.005	1.131	1.038	1.233

Table 3. Cox Proportional Hazard Analysis

Variables

Un-adjusted analysis

Adjusted analysis^a

P value

95.0% CI for HR

P value

95.0% CI for HR

Lower

Upper

Lower

Upper

HR: hazard ratio; CI: confidence interval; MELD: model for end-stage liver disease; BMI: body mass index; LTA: liver transplantation alone; SLKT: simultaneous liver and kidney transplantation. ^aAdjusted for patient’s ascites grade, albumin, bilirubin, Cr, INR, MELD, dialysis, gender, race and age, donor’s age and gender, and type of transplant.

Dialysis at transplantation: yes

0.001

1.401

1.321

1.485

0.001

1.204

1.119

1.297

Recipient race: non-White

0.061

1.051

0.998

1.106

0.001

1.137

1.066

1.213

Donor race: non-White

0.027

1.058

1.006

1.112

0.016

1.064

1.012

1.119

Ethnicity: non-Hispanic

0.037

0.927

0.864

0.995

0.001

0.811

0.743

0.885

Recipient gender: male

0.164

1.036

0.986

1.088

Donor gender: male

0.124

0.963

0.918

1.01

Recipient age > 65

1.332

1.227

1.445

0.001

1.287

1.185

1.397

Donor age > 55

1.335

1.266

1.409

0.001

1.372

1.3

1.449

BMI < 20

0.431

BMI 21 - 25

0.31

0.945

0.846

1.056

BMI 26 - 30

0.242

0.937

0.84

1.045

BMI 31 - 35

0.072

0.898

0.799

1.01

BMI 36 - 40

0.521

0.956

0.834

1.096

BMI > 40

0.881

1.013

0.859

1.193

Child-Pugh Class A

0.001

Child-Pugh Class B

0.269

0.901

0.748

1.084

Child-Pugh Class C

0.811

1.022

0.852

1.226

Creatinine > 1.5 mg/dL

0.001

1.417

1.352

1.485

Creatinine ≤ 1.5 mg/dL

0.001

Creatinine > 1.5 mg/dL LTA

0.001

1.531

1.457

1.608

0.001

1.401

1.32

1.486

Creatinine > 1.5 mg/dL SLKT

0.001

1.338

1.232

1.454

0.004

1.158

1.049

1.277

MELD 16 - 20

0.001

MELD 20 - 25

0.001

1.162

1.083

1.246

0.013

1.095

1.02

1.175

MELD 26 - 30

0.001

1.294

1.202

1.394

0.001

1.164

1.077

1.258

MELD 31 - 35

0.001

1.342

1.239

1.453

0.018

1.11

1.018

1.21

MELD 36 - 40 and higher

0.001

1.514

1.41

1.626

0.005

1.131

1.038

1.233

**Table 4.** Death by Cr (> 1.5 vs. ≤ 1.5) and MELD Score (≥ 30 vs. < 30)
Group	Transplant phase	At 1-year post-transplantation^b
^aAdjsuted for bilirubin, INR, dialysis, patient’s gender, BMI and type of transplant via logistic regression. ^bAfter excluding those who died at transplantation.
Cr ≤ 1.5 and MELD < 30	85 (0.62%)	< 0.001	2,510 (18.34%)	< 0.0001
Cr > 1.5 and MELD < 30	53 (0.89%)	1,524 (25.72%)
Cr ≤ 1.5 and MELD ≥ 30	21 (0.92%)	429 (18.94%)
Cr > 1.5 and MELD ≥ 30	120 (1.37%)	2,238 (25.89%)

Table 4. Death by Cr (> 1.5 vs. ≤ 1.5) and MELD Score (≥ 30 vs. < 30)

Group

Transplant phase

At 1-year post-transplantation^b

Number of deaths (%)

Adjusted P-value^a

Number of deaths (%)

Adjusted P-value^a

^aAdjsuted for bilirubin, INR, dialysis, patient’s gender, BMI and type of transplant via logistic regression. ^bAfter excluding those who died at transplantation.

Cr ≤ 1.5 and MELD < 30

85 (0.62%)

< 0.001

2,510 (18.34%)

< 0.0001

Cr > 1.5 and MELD < 30

53 (0.89%)

1,524 (25.72%)

Cr ≤ 1.5 and MELD ≥ 30

21 (0.92%)

429 (18.94%)

Cr > 1.5 and MELD ≥ 30

120 (1.37%)

2,238 (25.89%)