gender-specific differences associated with living donor liver transplantation: a review study

ORIGINAL ARTICLE

Gender-Specific Differences Associatedwith Living Donor Liver Transplantation:A Review StudyHanna C. Hermann, Burghard F. Klapp, Gerhard Danzer, and Christina PapachristouMedical Clinic for Internal Medicine and Psychosomatics, Charite–Universitatsmedizin Berlin,Berlin, Germany

Living donor liver transplantation (LDLT) has developed into an important therapeutic option for liver diseases. For living do-nor kidney transplantation (LDKT), gender-specific differences have been observed among both donors (two-thirds beingwomen and one-third being men) and recipients (two-thirds being men and one-third being women). The aim of this studywas to determine whether there is a gender disparity for LDLT. We contacted 89 national and international transplantationregistries, single transplant centers, and coordinators. In addition, a sample of 274 articles dealing with LDLT and its out-comes was reviewed and compared with the registry data. The data included the gender of the donors and recipients, thecountry of transplantation, and the donor-recipient relationship. The investigation showed that overall there were slightlymore men among the donors (53% male and 47% female). As for the recipients, 59% of the organs were distributed tomales, and 41% were distributed to females. Differences in the gender distribution were observed with respect to individualcountries. Worldwide, 80% of the donors were blood-related, 11% were not blood-related, and 9% were spouses. The dataacquired from the publications were similar to the registry data. Our research has shown that there are hardly any registrydata published, a lot of countries do not have national registries, or the access to these data is difficult. Even widely rangingpublished studies often do not give information on the gender distribution or the donor-recipient relationship. Further investi-gations are needed to understand the possible medical, psychosocial, or cultural reasons for gender distribution in LDLTand the differences in comparison with LDKT. Liver Transpl 16:375-386, 2010. VC 2009 AASLD.

Received June 30, 2009; accepted November 30, 2009.

INTRODUCTION

Liver transplantation is an important therapy forreducing the mortality in patients with terminal liverdiseases. Living donor liver transplantation (LDLT)represents a very effective alternative to deceased liverdonation and is a good possibility for expanding thedonor pool and therefore reducing the discrepancybetween needed and available organs.

The donors are mostly healthy family members orindividuals with close emotional ties to the recipients.These people are exposed to a high degree of psycho-logical pressure to make a decision because, on the

one hand, they can save a human life but, on theother hand, they will be exposed to health risks.Today, the outcome is very similar to that found fordeceased donors because of experience, consistentlyimproved matching of prospective donors, advances insurgical techniques, and the development of immuno-suppressive therapy; moreover, the outcome in chil-dren is even better than that in adults.1

Aspects of Gender

The aim of this study was to examine this topic withrespect to the aspect of the gender-specific

Additional Supporting Information may be found in the online version of this article.

Abbreviations: A, adult; CI, confidence interval; IRODaT, International Registry of Organ Donation and Transplantation; LDKT,living donor kidney transplantation; LDLT, living donor liver transplantation; MCS, multicenter study; NA, not available;P, pediatric; R, review; SCS, single-center study; UCLA, University of California Los Angeles.Address reprint requests to Hanna C. Hermann, (care of Christina Papachristou), Medical Clinic for Internal Medicine and Psychosomatics,Charite–Universitatsmedizin Berlin, Luisenstrasse 13a, 10117 Berlin, Germany. Telephone: þ49/30/450 553 278; FAX: þ49/30/450 553989;E-mail: [email protected]

DOI 10.1002/lt.22002Published online in Wiley InterScience (www.interscience.wiley.com).

LIVER TRANSPLANTATION 16:375-386, 2010

VC 2009 American Association for the Study of Liver Diseases.

distribution of the donors. The concept of gender inthe field of medicine includes not only sex, with bothits primary and secondary characteristics, but evenmuch more so the psychological, sociocultural, andspecific sexual characteristics that influence behavior.

If there is an irregular distribution, it is important tonotice it and take it into consideration because this alsoallows one to draw conclusions involving ethical, psy-chological, and behavioral aspects, which are importantfor the adequate care of both donors and recipients.

Living Donor Kidney Transplantation (LDKT)

LDKT has already been performed for over 50 years andis an established practice in treating terminal kidneydiseases. Gender-specific differences have been exam-ined in detail. Here, the majority of the donors arewomen (two-thirds), whereas women, in contrast, arerecipients of only one-third of the organs. This is thecase for all age groups and is similar in different ethnicgroups.2 According to the literature, an explanation forthis could be that men provide the main income for thefamily and that women feel more responsible for thehealth and welfare of the family and therefore considerthe act of donation to be their duty. Women are possiblymore susceptible to family pressure than men and cantherefore be persuaded more rapidly and more easily.From a medical viewpoint, it can be assumed thatwomen more frequently come into consideration asdonors because elderly women are less likely to sufferfrom cardiovascular illnesses and diabetes than elderlymen. One must say, however, that the chance of beingrejected as a donor because of existing illnesses is equalfor both men and women.3,4

Research Questions, Methods, and Aim of the

Study

One part of this study involved searching for and con-tacting registries that document transplant activity inthe different countries of the world. The other partconsisted of reviewing and summarizing the results ofprevious studies and publications dealing with LDLTto give an overview of the present literature concern-ing gender in LDLT. Subsequently, the gender-specificdifferences were examined and analyzed for both thedonors and the recipients. In the discussion, the datafrom the different national registries are comparedwith the findings in the reviewed publications. Theadvantages and disadvantages of using publicationdata, as well as the importance of looking at both theregistry data and the publication data, are discussed.Occurring problems are also presented and examinedin detail. Possible ideas concerning further interestinginvestigations that could offer more details regardingthis topic are provided. The results of this studyshould provide answers to the following questions:

1. What is the gender-specific distribution forLDLT?

2. Are there gender-specific differences with respectto geographical locations? Here, an attempt

should be made to find out what the differencesare between individual countries and/or conti-nents. Should there be differences, and whatcould be the proper explanation for them?

3. Who act as donors, for whom and how frequentlydo they act as donors (eg, women to men, womento women, men to men, and men to women), andwhat relationship do donors and recipients havewith one another?

4. Are the data presented in publications andreviews representative of the actual data pro-vided by the registries?

PATIENTS AND METHODS

Contacting and Searching for National

Registries

At first, the official Web site of the International Regis-try of Organ Donation and Transplantation (IRODaT)was examined. IRODaT is a registry that provides an-nual numbers on donation and transplantation activ-ity worldwide. National registries were sought to findout who is responsible for the data in each country. Ifthere was a Web site of a specific national registry, itwas searched for information concerning the numberof LDLT procedures performed until today, the num-ber of male and female donors as well as recipients,and the donor-recipient relationship. If there wasno information given, the registries were contacted bye-mail. The following questions were asked:

1. How many LDLT procedures have been per-formed up to now in the country?

2. How many recipients were male, and how manywere female?

3. How many donors were male, and how manywere female?

4. Is there any information about the relationshipbetween recipients and donors?

If there was no reply, the registries were contacted asecond time. In countries that do not have a nationalregistry, for which a Web site was not available inEnglish, or from which there was no reply to the sec-ond e-mail, transplant coordinators or single institu-tions were contacted.

Another way of obtaining data was the 2009 OrganDonation Congress (10th Congress of the Interna-tional Society for Organ Donation and Procurementand 16th Congress of the European Transplant Coor-dinators Organization), at which transplantation coor-dinators from different countries were contacted inorder to contact transplantation centers.

The data acquired from this research are docu-mented in Table 1.

Review Search Concerning Publications and

Reviews Dealing with LDLT

Furthermore, we conducted an article review ofpublications and reviews dealing with LDLT. In this

376 HERMANN ET AL.

LIVER TRANSPLANTATION.DOI 10.1002/lt. Published on behalf of the American Association for the Study of Liver Diseases

section, we describe how the search and selection ofarticles were carried out.

The PubMed database and the World Wide Web weresearched. Between February/March 2008 and October2009, the following MeSH headings and text words wereused: living donor liver transplantation, living donor liver

transplantation gender, living donor liver transplantationgender imbalance, living donor liver transplantation gen-der discrepancies, gender disparity, gender distribution,gender disproportion, living donation gender, living dona-tion gender discrepancies, living donation gender imbal-ance, living donation gender disparity, living donor liver

TABLE 1. Data from Registries and Transplantation Centers

Location*

Donors [n (%)]† Recipients [n (%)]‡Relationship Between the

Donors and Recipients [n %)]§

Male Female

Not

Recorded Male Female

Blood-

Related

Not Blood-

Related Spouse

Argentina — — — — — — —Austria 24 (52%) 22 (48%) 14 (30%) 32 (70%)Australia/

New Zealand23 (57%) 17 (43%) — — 35 4

Belgium 161 (49%) 166 (51%) 181 (55%) 146 (45%) 297 11 19Brazil — — — — — — —Bulgaria — — — — — — —Canada — — — — — — —China — — — — — — —Beijing, China 41 (59%) 28 (41%) 52 (75%) 14 (25%) 58 8Hong Kong,

China180 (40%) 258 (60%) 313 (71%) 125 (29%) 283 35 120

Croatia 2 (100%) 1 (50%) 1 (50%) 1 1Egypt — — — — — — —France 242 (56%) 188 (44%) 249 (58%) 181 (42%) 362 3 65Germany 429 (50%) 428 (50%) 496 (58%) 361 (42%) 713 27 117Hungary — — — — — — —India — — — — — — —Israel — — — — — — —Italy 134 (58%) 99 (42%) 1 148 (64%) 85 (36%) 206 8 20Iran — — — — — — —Japan — — — — — — —Tokyo, Japan 238 (54%) 202 (46%) 232 (53%) 208 (47%) 287 26 78Seoul, Korea

(2005-2007)1120 590 1270 440 1485 81 144

Lebanon 1 3 3 (75%) 1 (25%)Malaysia 37 (49%) 38 (51%) 41 (55%) 34 (45%) 63 12Mexico 26 (58%) 19 (42%) 20 (44%) 25 (56%) 43 1 1Netherlands 5 (36%) 9 (64%) 10 (71%) 4 (29%) 11 3Poland 50 (36%) 90 (64%) 64 (46%) 76 (54%)Portugal — — — — — — —Romania 23 (51%) 22 (49%) 13 (33%) 33 (67%) 37 2 7Saudi Arabia — — — — — — —Singapore — — — — — — —Spain — — 101 (54%) 87 (46%) 164 16 8Switzerland — — — — — — —Taiwan — — — — — — —Turkey — — — — — — —United Kingdom 87 (65%) 46 (35%) 4 81 56 132 1 2Ukraine — — — — — — —United States 1924 (49%) 1987 (51%) 2118 1792 2944 725 221Venezuela — — — — — — —Total sum 4745 (53%) 4211 (47%) 8 5407 (59%) 3701 (41%) 7121 (80%) 943 (11%) 823 (9%)

NOTE: A dash indicates that no data were provided for the category.*The country or city in which the transplants took place.†Data regarding the donors have been divided into the following categories: male, female, and not recorded.‡Data regarding the recipients have been divided into the following categories: male and female.§Data regarding the relationship between donors and recipients have been divided into the following categories: blood-related, not blood-related, and spouse.

GENDER-SPECIFIC DIFFERENCES IN LDLT 377


outcome, living donor liver transplantation Asia, livingdonor liver transplantation Korea, living donor livertransplantation Japan, living donor liver transplantationTaiwan, and donation þ gender.

After the MeSH headings and text words wereentered, a substantially different number of articleswere listed. Using the headings and abstracts of thearticles as a preliminary method for selection, weexcluded articles whose theme did not match the spe-cific exclusion and inclusion criteria.

Exclusion criteria for the preliminary selection ofpublications were as follows:

1. The article does not deal with LDLT donors/patients.

2. The article deals with very specific complications,such as biliary complications (because these com-plications do not occur in all donors/patients, thiswould represent a strong selection bias).

3. The article should be an observational study (longi-tudinal or cross-sectional) because such studiesare more likely to report data regarding the genderof donors and recipients and their type of relation-ship. Such studies also tend to be more represen-tative of the population involved. This is why thefollowing articles were excluded:a. Articles dealing with studies concerning

medications.b. Articles explaining the surgical techniques and

procedures of liver transplantation without pre-senting a recipient/donor sample.

c. Articles involving histological parameters andproteins and not the donors/recipients.

Inclusion criteria for the selection of publicationswere as follows:

1. The article includes information on the gender ofthe donors/recipients.

2. The article reports on the psychosocial outcomeof the donors/recipients, their quality of life, andthe donor-recipient relationship.

3. The article includes empirical reports from trans-plantation centers and countries.

4. The article presents the current state of affairsregarding LDLT.

To avoid counting patients twice, the selection waslimited to 1 article from each center if it was a single-center study. The article from each center that pre-sented the highest number of patients was preferred.If there were 2 publications from the same center, but1 article presented only the donors and the other pre-sented only the recipients, both were listed.

The next step was to collect all relevant informationfrom the abstracts. Each article was examined in theform of a PDF document and was searched for the termsmale, female, women, men, gender, sex, and relationship.Once again, the articles were examined with the afore-mentioned inclusion and exclusion criteria, and the inap-propriate articles were then subsequently sorted out. Forsome of the abstracts, no complete article was available,or it was available only in another language, so thesearticles were no longer considered in the sample.

From the remaining articles, information concerningthe study design, the number of donors and recipi-ents, their gender, their relationship to one another,their geographical allocation, and their age at the timeof listing was documented. Many of the articles tookonly a few of these aspects into consideration. Foreach study, the 95% confidence interval was calcu-lated for both the donors and recipients. It was usedto indicate the reliability of this survey.

In a second step, the data from articles concerningthe same country were summarized (see Table 2).

Comparison of Registry Data and Review Data

The information found in published articles was com-pared to the data acquired from the registries withrespect to the total number of donors and recipientsand the relationship between the donors and recipi-ents for selected countries.

RESULTS

Registry and Center Data

The inquiry was sent to 38 national registries, 4 inter-national registries, 32 single transplant centers, 9transplant coordinators, and 6 transplant surgeonscontacted at the 2009 Organ Donation Congress (10thCongress of the International Society for Organ Dona-tion and Procurement and 16th Congress of the Euro-pean Transplant Coordinators Organization) from 36different countries. Twenty national registries replied,and 15 provided data. All international registriesanswered, but only 1 international registry had dataavailable. Three transplant centers responded andprovided data. Eight e-mails could not be delivered.Two individuals replied, but neither was in charge ofdata. One of the persons contacted at the congressreplied and provided data for a country. Overall, thisstudy presents data from 19 countries.

In the supporting material, we present the con-tacted registries and transplant centers and theresponse rate.

Sample of the Registry Data

The registry data include official data from 17 countriesand 3 single transplant centers. The total sample consistsof 8933 LDLT cases for donors and 9108 LDLT cases forrecipients. Some registries record only the recipients.

There was only a slight difference between the gen-ders among the donors: 4745 (53%) were male, and4211 (47%) were female (Fig. 1). Of the recipients,5407 (59%) were men, and 3701 were women (41%).

Relationship Between the Donors and Recipients

Most of the blood-related donors were parents (46%),who were followed by children (24%), siblings (18%),and other relatives (12%) such as uncles, aunts, cous-ins, and grandparents (Fig. 2).

Country and Continent Comparison with Respect

to the Donors

There were regional differences (Fig. 3). In 11 coun-tries or alternatively transplant centers, there were

378 HERMANN ET AL.


TABLE

2.Data

from

theReviewedArticles

Source*

Loca

tion

Rec

ipients

(n)

95%

CIfor

Rec

ipients

†

Donors

(n)

95%

CIfor

Donors

†

Relationsh

ipBetwee

nth

e

Rec

ipients

andDonors

(n)

Stu

dy

Des

ign

Rec

ipient

Age

Male

Fem

ale

Male

Fem

ale

Biologically

Related

Not

Biologically

Related

Spouse

Jianget

al.5(2007)

Chen

gdu,China

23

30.698-0

.976

SCS

ALiu

etal.6(2009)

Chen

gdu,China

78

82

0.441-0

.597

91

14

55

SCS

NA

Liu

andFan7(2006)

HongKong,China

97

27

0.699-0

.851

50

74

0.316-0

.495

RA

Nget

al.8(2009)

HongKong,China

72

11

0.795-0

.940

SCS

AþP

Iwamoto

etal.9(2008)

Okoyama,Japan

76

61

0.472-0

.638

76

61

0.472-0

.638

SCS

AKawagishiet

al.10

(2009)

Sen

dai,Japan

29

0.046-0

.410

SCS

AþP

Ikeg

amiet

al.11(2008)

Fukuoka,Japan

15

27(24

adults)

0.221-0

.506

29

13

0.195-0

.480

39

12

SCS

AþP

Akamatsu

etal.12

(2007)

Tokyo,Japan

191

108

0.582-0

.693

179

120

0.613-0

.885

SCS

A

Moriokaet

al.13(2007)

Kyoto,Japan

167

168

0.444-0

.553

188

147

0.16-0

.478

SCS

AUed

aet

al.14(2006)

Japan

228

340

0.361-0

.443

255

313

0.408-0

.491

568

SCS

PYokoiet

al.15(2005)

Mie,Japan

13

14

0.529-0

.824

SCS

NA

Todoet

al.16(2004)

Hokkaido,Japan

246

70

0.729-0

.823

MCS

AEgawaet

al.17(2004)

Kyoto,Japan

201

339

0.331-0

.415

SCS

AþP

Yiet

al.18(2009)

Seo

ul,Korea

121

46

0.657-0

.792

120

47

0.650-0

.787

SCS

AHwanget

al.19(2005)

Seo

ul,Korea

(UlsanColleg

e)196

41

0.773-0

.873

MCS

A

Lee

etal.20(2004)

Seo

ul,Korea

(Sungkyunkwan

University)

97

44

0.606-0

.763

102

39

SCS

AþP

Chen

get

al.21(2009)

ChungGung,Taiw

an

110

35

0.689-0

.828

SCS

APolidoet

al.22(2007)

South

east

Asia

50

15

0.648;0.865

43

22

SCS

ALoet

al.23(2003)

Asia(K

orea,Japan,

andChina)

789

719

0.498-0

.549

685

823

0.507-0

.582

1197

15

137

MCS

AþP

Khalafet

al.24(2007)

Riyadh,SaudiAra

bia

(Hosp

italand

Res

earchCen

ter)

34

10

0.533;0.805

SCS

A

Abdullahet

al.25

(2005)

Riyadh,SaudiAra

bia

(NationalGuard

Hosp

ital)

17

30.621-0

.968

18

20.509-0

.689

19

1SCS

A

Yosryet

al.26(2009)

Giza,Egypt

69

50.875-0

.990

57

17

0.674-0

.866

SCS

AYosryet

al.27(2008)

Cairo,Egypt

35

30.835-1

.007

SCS

AEsm

atet

al.28(2005)

Cairo,Egypt

34

16

0.429-0

.48

SCS

AOzk

ard

esleret

al.29

(2008)

Izmir,Turk

ey69

44

0.521-0

.701

SCS

NA

Sev

mis

etal.30(2007)

Turk

ey27

19

0.683-0

.988

26

10

10

SCS

A



TABLE

2.(Continued)

Source*

Loca

tion

Rec

ipients

(n)

95%

CIfor

Rec

ipients

†

Donors

(n)

95%

CIfor

Donors

†

Relationsh

ipBetwee

nth

e

Rec

ipients

andDonors

(n)

Stu

dy

Des

ign

Rec

ipient

Age

Male

Fem

ale

Male

Fem

ale

Biologically

Related

Not

Biologically

Related

Spouse

Honget

al.31(2009)

LosAngeles

,CA

42(14

adults)

58

(27

adults)

0.323-0

.517

SCS

AþP

Taioliet

al.32(2008)

Pittsburgh,PA

70

84

0.376-0

.533

72

82

0.389-0

.546

111

39

4SCS

ACampse

net

al.33

(2008)

Colora

do

46

0.096-0

.704

82

0.552-1

.048

SCS

A

Humaret

al.34(2008)

Minnes

ota

35

34

0.389-0

.625

29

40

0.304-0

.537

45

SCS

ALaiet

al.35(2009)

New

York

42

44

0.383-0

.594

SCS

AMek

eelet

al.36(2008)

Phoen

ix,AZ

32

10.133-1

.200

11

1SCS

AFisher

etal.37(2007)

United

States

45

13

0.647-0

.875

MCS

APompose

lliet

al.38

(2006)

Burlington,MA

55

30

0.536-0

.748

SCS

A

Verbes

eyet

al.39

(2005)

United

States

31

16

0.507-0

.791

29

18

0.351-0

.632

SCS

A

Shack

letonet

al.40

(2005)

UCLA

29

13

0.195-0

.480

16

20

6SCS

A

Olthofet

al.41(2005)

Philadelphia,PA

228

157

0.541-0

.642

205

180

0.464-0

.755

MCS

AThuluva

thet

al.42

(2004)

Baltim

ore,MD

384

330

0.500-0

.575

389

325

0.481-0

.583

MCS

A

DuBayet

al.43(2009)

Ontario,Canada

69

74

0.401-0

.564

108

22

13

SCS

AShahet

al.44(2007)

Toronto,Canada

95

58

0.539-0

.698

SCS

AAyala

etal.45(2009)

Madrid,Spain

13

80.411-0

.827

11

10

0.310-0

.737

SCS

ATsu

iet

al.46(2009)

Reg

ensb

urg,Germany

23

10

0.540-0

.854

22

11

0.506-0

.828

24

35

SCS

AErim

etal.47(2007)

Ess

en,Germany

53

47

0.428-0

.631

74

49

0.432-0

.73

102

13

8MSC

AWalter

etal.48(2005)

Berlin,Germany

15

31

0.472-0

.672

SCS

AKazemieret

al.49

(2009)

Rotterdam,th

eNetherlands

30

12

21

SCS

A

Gru

ttadauriaet

al.50

(2007)

Palerm

o,Italy

34

19

0.498-0

.769

26

27

0.032-0

.651

45

53

SCS

A

Ben

tabaket

al.51

(2005)

Algeria

44

0.157-0

.843

26

0.364-0

.793

SCS

A

Konstantinovet

al.52

(2004)

Russ

ia28

36

0.314-0

.567

SCS

AþP

Totalsu

m3991

3031

2895

2673

2539

205

245

*This

isalistingofth

eauth

ors

ofallth

ereview

edarticlesprovidingdata

on

gen

der,th

eco

untriesin

which

livingdonorlive

rtransp

lantation

wasperform

ed,and

the

relationsh

ipto

therecipients.

†The95%

CIwasca

lculatedforth

edistributionofmen

towomen

;it

wasuse

dto

indicate

thereliabilityofth

ises

timate.

380 HERMANN ET AL.


more male donors than female donors (Austria; Bei-jing, China; France; Lebanon; Italy; Tokyo, Japan;Korea; Mexico; Romania; Australia/New Zealand; andthe United Kingdom). In 5 of these cases, the propor-tion of males was higher than 55% (France; Italy;Korea; the United Kingdom; Mexico; and Beijing,China), and in 2 cases, the proportion was 65% (theUnited Kingdom and Korea). In 7 countries or alterna-tively transplant centers (Belgium; Hong Kong, China;the Netherlands; Poland; the United States; Lebanon;and Croatia), more woman were donors; in 3 cases,the proportion was higher than 60% (the Netherlands,Poland, and Croatia). In 1 country (Germany), therewas a balanced distribution (Fig. 4).

Country Comparison with Respect to the

Recipients

The gender-specific distribution of the recipients var-ied in the different individual countries (Fig. 5). In 12countries or alternatively transplant centers (Belgium;France; Beijing, China; Hong Kong, China; Korea;Germany; Italy; Tokyo, Japan; Lebanon; the Nether-lands; the United States; and the United Kingdom),males were the more frequent recipients, with 5 ofthese demonstrating a proportion higher than 60%;this was especially prominent in Beijing (China), Hong

Kong (China), Korea, the Netherlands, and Lebanon,with the proportion of males being higher than 70%.The proportion of females was higher in 4 countries(Mexico, Poland, Romania, and Austria), whereas itwas balanced in Croatia.

Publication Data

In the PubMed search, no articles were found thatconcretely dealt with the topic of gender-specific dif-ferences for LDLT.

Under the search term living donor liver transplanta-tion outcome, 1150 articles were found. From this selec-tion, as presented in the Patients and Methods section,274 articles were taken into account in the morenarrow selection. Of these 274 articles, 68 stated some-thing concerning the distribution of women to men,and some also stated something concerning the rela-tionship that they had with one another. After the selec-tion was limited to 1 article from each center, 48articles from 17 different countries remained.

Sample of Publication Data

The sample includes 7 multicenter studies, 39 singleinstitution surveys, and 1 review. Thirty-five of thestudies reported adult-to-adult LDLT, 7 reported pedi-atric and adult cases, 1 reported just pediatric cases,and 2 did not give any information about the age of therecipients. Among the recipients of LDLT, 3991 (57%)were males, and 3031 (43%) were females. Of thedonors, 2667 (48%) were male, and 2899 (52%) werefemale.

An examination of only the adult-to-adult casesshowed that 2574 of the recipients (63%) were men,and 1535 (37%) were women. Of the donors, 1930(56%) were male, and 1518 (44%) were female (Fig. 6).

Relationship Between the Donors and Recipients

The data presented in the publications show that 86% ofthe donors were blood-related to the recipient (Fig. 7).

Figure 1. Gender distribution of donors and recipients:registry data.

Figure 2. Distribution of the relationship between donorsand recipients: registry data.

Figure 3. Comparison of the continents with respect to the donors.

Figure 4. Examples of unequal gender distribution withrespect to the donors.



Country Comparison: Publication Data

The data presented in the publications concerningindividual countries are summarized (Table 3).

Country Comparison with Respect to the Donors. Inthe sample, there were more male donors than femaledonors in 8 countries (Japan, Germany, Korea, SaudiArabia, Spain, Turkey, the United States, and Egypt).A proportion higher than 70% was observed in 3countries (Saudi Arabia, Korea, and Egypt). In 6countries (Algeria, Asia, Canada, China, Italy, andthe Netherlands), more women than men weredonors. In 2 countries, the proportion was higherthan 60% (Algeria and the Netherlands). In 4 coun-tries, no information was available concerning theserelationships.

Country Comparison with Respect to the Recipi-ents. The gender-specific distribution of the recipientswas different in the individual countries. In 15 coun-tries (Asia, Canada, Germany, Korea, Italy, Spain, Den-mark, Taiwan, Saudi Arabia, Singapore, Egypt, theNetherlands, China, Japan, and the United States),males were the more frequent recipients, with 7 ofthese demonstrating a proportion higher than 65%(China, Korea, Taiwan, Singapore, Saudi Arabia, Egypt,

and the Netherlands); this was especially prominent inKorea, China, Egypt, Saudi Arabia, and Singapore,with the proportion of males being higher than 75%.The proportion of females was higher in 1 country(Russia), whereas it was balanced in Algeria, and 1country did not provide information concerning theserelationships.

Comparison of the Registry Data and the

Publication Data

The results found in the publications are similar tothe registry data presented. These show that 9108LDLT cases have been carried out in the listed coun-tries until the present time. Among the 8925 donors,4728 (53%) were men, and 4197 (47%) were women.In the publications, 52% of the donors were male,and 48% were female. An examination of the recipi-ents shows that according to the registries, 59%were male, and 41% were female; in the publica-tions, 57% were male, and 43% were female. How-ever, when we considered the relationship, we foundthat there were larger differences between the regis-try data and the publication data. As for the registry

Figure 5. Comparison of the continents with respect to the recipients.

Figure 6. Gender distribution of donors and recipients:publication data

Figure 7. Distribution of the relationship between donorsand recipients: publication data.

TABLE 3. Summary and Comparison of the Literature

Data Concerning Individual Countries

Country

Recipient Donor

Male Female Male Female

China 192 41 132 150Japan 1126 1122 730 668Korea 414 131 120 47Taiwan 110 35South East Asia 50 15Asia (Korea,

Japan, andChina)

789 719 685 823

Saudi Arabia 17 3 52 12Egypt 104 8 91 33Turkey 96 63United States 936 775 763 661Canada 95 58 69 74Spain 13 8 11 10Germany 76 57 111 91Netherlands 3 0 1 2Italy 34 19 26 27Algeria 4 4 2 6Russia 28 36Final sum 3991 3031 2889 2667

382 HERMANN ET AL.


data, there were fewer blood-related donors (80%)and more donors that were not blood-related (11%)or were spouses (9%) in comparison with the publi-cation data (Table 4).

DISCUSSION

In this review, the comparison of the gender-specificdistributions of LDLT showed that slightly more menthan women were donors and that more males thanfemales were recipients. Overall, the comparison ofdifferent countries and continents showed relativelysimilar results, but still there were regional differ-ences to be observed. In the United States andEurope, the gender distribution was more balanced.However, especially in Asia, many more recipients(70%) and donors (59%) were male than female.Also, there were larger differences in the propor-tional distribution found in countries in which a lownumber of transplants had taken place. Further-more, a predominant proportion of the individualswere blood-related.

Evaluation of the Gender-Specific Differences

Between the Donors

The research shows that LDLT does not, as initiallyassumed, show the same gender distribution asLDKT, for which twice as many women have donatedthan men, as already presented in the introduction.The reason for this difference and even the fact thatthere is a discrepancy between LDLT and LDKT areunfortunately not discussed in any of the articlesfound. Possible explanations for the more balancedrelationship could be that LDLT represents a largerand also much more risky action, and the man, in hisrole as the stronger and more protective individual,feels responsible for performing this action. Further-more, it could also be possible that many women areunable to donate their livers to adults because of thesmall liver volume, so the male members of the familyhave to donate their livers more frequently than in thecase of LDKT. The motivations for this, however,would have to be clarified through the use of an in-

depth patient interview. This could be an interestingtopic for further investigations.

However, the balanced gender distribution cannotbe seen in all of the countries. For instance, in HongKong, China (60%), and Poland (65%), womendonated predominantly, whereas men were seen to bethe primary donors in Korea and the United Kingdom(65%). Explanations for this would have to be relatedto cultural and social differences because these areaspects by which they differ from the other countries.At any rate, this could be investigated and exploredmore precisely in further studies.

Evaluation of the Gender-Specific Differences

Between the Recipients

For the recipients, there was a difference to beobserved. In 59% of the cases, males were the recipi-ents. When the various individual countries were con-sidered, however, the differences varied. In the Asiaticcountries, for example, a large percentage of the recip-ients were males (70%). In contrast, the gender distri-bution was quite balanced in Europe and the UnitedStates. However, no reason for this has been cited inthe articles. It is likely that men generally suffer moreoften from liver illnesses and must undergo livertransplantation more frequently. Also in favor of thisargument is the fact that men, especially in Asia, suf-fer from liver carcinomas 3 to 4 times more often thanwomen; the most frequent reasons for this are hepati-tis C and B infections and alcoholic cirrhosis of theliver. In China, the prevalence of demonstrating a hep-atitis B antigen is 10% to 20%; this finding could alsobe responsible for the unequal distribution betweenmen and women.53 In addition, the data from theOrgan Procurement and Transplantation Networkdata bank also speak in favor of this illness beingmore frequent in men. According to this, almost two-thirds of the patients who are waiting for liver trans-plantation in the United States are male.54 Anotherreason for this distribution might be related to thetraditional role allocation. The man is the head of thefamily and is responsible for earning the primaryincome, and so his health highly correlates with thewelfare and living standard of the entire family.

Evaluation of the Relationship of the Donors

and Recipients

Most donors are blood-related to the recipients. Thiswas already assumed because these are the individu-als who have close emotional ties to the recipientsand the matching of the genetic material is often suc-cessful. The second most frequent donors are donorsnot related by blood, such as friends, and familymembers not related by blood. Another very importantgroup of donors is spouses, who have a strong inter-est in the health of their partners simply because oftheir strong emotional and social relationships. Hereregional differences can also be observed. The second

TABLE 4. Comparison of the Registry Data and

Publication Data

Registry

Data [n (%)]

Publication

Data

[n (%)]

Donors Male 3571 (50%) 2836 (52%)Female 3569 (50%) 2654 (48%)

Recipients Male 3995 (56%) 4008 (57%)Female 3140 (44%) 3050 (43%)

Relationship Blood-related

5735 (78%) 2255 (86%)

Not blood-related

824 (12%) 138 (5%)

Spouse 659 (10%) 235 (9%)



largest group was spouses in Europe and Asia anddonors not related by blood in the United States.

Evaluation of the Comparison of the Registry

Data and Publication Data

The review shows that data presented in the publica-tions and reviews can to a certain extent be represen-tative of the actual data from the registries.

It is important to know if publications that do give acertain view of LDLT performed worldwide reflect thereal situation. It is not possible for everyone to haveaccess to all the registry data. Most of the informationis primarily taken from publications because there isimmediate access and they help to enrich one’sknowledge. They also help with interpreting data, andoften explanations are given. In addition, publicationsare the only way of acquiring this sort of data forcountries that do not have a national registry or withwhich there is a lack of communication.

However, one cannot be sure that there is not a spe-cific selection of patients or that other patients areexcluded. Publication data do not give a transparentand clear look at this issue because there is alwaysbias, such as the selection of patients who volun-teered or case series that might have been small andnot representative of a given country’s distribution ofLDLT. This research shows that it is very difficult toacquire information on this topic in publications.Gender aspects and the relationship between donorsand recipients were generally not taken into consider-ation, and most of the publications did not even dis-tinguish between male and female patients.

Reflection on the Experience of Contacting

Registries and Transplant Centers

There are international registries that provide connec-tions to national transplant registries or transplantcoordinators, such as IRODaT and the EuropeanTransplantation Coordinators Organization. Theseregistries give an overview of the national registriesthat might be contacted and provide data on trans-plantation worldwide.

The response rate of contacted national registrieswas 45%, the rate for international registries was100%, and the response rate for single centers wasonly 10%. The low response rate could lead to a selec-tion bias. Asiatic countries, such as China, Taiwan,Singapore, Saudi Arabia, and Iran, especially did notreply. A further difficulty in the data selection was thata few registries charged for the information, and thusthe information was not obtained. Communication withthe European countries, the United States, and Aus-tralia was very positive. Most of these countries are rep-resented in the sample.

Overall, it can be said that contacting nationalregistries and institutions is a good way of obtainingactual data, but it is very difficult to acquire datafrom some registries, and even international registriessuch as IRODaT have difficulties with presenting data

on performed LDLT procedures for specific countriesfor each year.

Limitations and Weaknesses of This

Investigation

A difficulty of this investigation was that the only pub-licly accessible data bank to be found was in theUnited States. Other data banks and registries had tobe contacted, and there was a 55% nonreply rate.Thus, the data in this review represent most coun-tries, but not all. In particular, the Asiatic countriesare not well represented.

As for the data from the literature review, it can besaid that many authors have reported on the numberof LDLT procedures performed but have not includedinformation concerning the gender. For this reason,many articles could not be included in the evaluation,and thus bias is possible. A further problem could bethat the 7 multicenter studies might have used thesame data, so the patients and donors could havebeen occasionally counted and listed twice. However,this could not be detected in these reports and, conse-quently, could not be corrected.

In conclusion, it can be said that information con-cerning gender is frequently lacking in publicationsand even in reports from national registries. It is im-portant to pay more attention to details and toimprove documentation.

Further publications on gender aspects or dispar-ities regarding LDLT would be helpful in order tounderstand the different gender distributions of LDLTand LDKT and to look for possible answers that couldexplain the specific country differences. In addition, itwould be useful to delve more deeply into the psycho-logical and sociocultural aspects of the subjectbecause this is important for the adequate care ofboth the donors and recipients, for improvements inoutcome, and for further possible developments ofthis therapy.

Finally, the development of a worldwide, interlinkeddata bank that also includes information on the gen-der and relationship of donors and recipients wouldfacilitate access to information regarding donationrates and individual characteristics of donors andrecipients in individual countries.

ACKNOWLEDGMENTSThe authors thank the Austrian Health Institute, theAustralia and New Zealand Organ Donation Registry,Eurotransplant, the People’s Liberation Army GeneralHospital of China, the French Agency of Biomedicine,Queen Mary Hospital of Hong Kong, the NationalTransplant Center of Italy, the University of TokyoGraduate School of Medicine, the National Organiza-tion for Organ and Tissue Donation and Transplanta-tion of Lebanon, the National Transplant ResourceCenter of Malaysia, the National Transplant Center ofMexico, the Dutch Transplant Foundation, Poltrans-plant, the National Transplant Agency of Romania,

384 HERMANN ET AL.


NHS Blood and Transplant (UK), the United Networkfor Organ Sharing, and the Seoul National UniversityCollege of Medicine for providing data from theirregistries.

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gender-specific differences associated with living donor liver transplantation: a review study

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