The factorial structure of the Chronic Liver DiseaseQuestionnaire (CLDQ)

Karl-Heinz Schulz Æ Sylvia Kroencke ÆHeike Ewers Æ Holger Schulz Æ Zobair M. Younossi

Accepted: 12 March 2008

� Springer Science+Business Media B.V. 2008

Abstract

Objective The Chronic Liver Disease Questionnaire

(CLDQ) is a disease-specific instrument designed to assess

health-related quality of life in patients with chronic liver

disease. The aim of this paper is to present the psycho-

metric properties of a German version of this questionnaire.

A special focus is placed on the analysis of the CLDQ’s

factorial structure.

Methods Five hundred and twenty-four patients com-

pleted the CLDQ from May 1999 to October 2006. The

results were subject to item analysis, reliability and validity

assessments, and confirmatory and exploratory factor

analysis.

Results The distribution characteristics on the item and

scale level were satisfactory. Internal consistency was good

to excellent; retest reliability acceptable. Validity could be

confirmed by characteristic subscale correlations with other

quality-of-life scales. Confirmatory factor analysis could

not sufficiently reproduce the original factor structure.

Exploratory factor analysis suggested five out of six sub-

scales of the original version and yielded a new subscale:

‘‘sleep.’’

Conclusion CLDQ’s reliability and validity have been

confirmed. In addition, the demonstrated practical admin-

istration of the questionnaire suggests that it should serve

as a routine quality of life assessment of patients with

chronic liver disease.

Keywords Chronic liver disease � Liver cirrhosis �Disease-specific questionnaire � Factor analysis �Health-related quality of life � Liver transplantation �Reliability � Validity � Living liver donation

Abbreviations

CLDQ Chronic Liver Disease Questionnaire

HRQL Health-related quality of life

SF-36 36-Item Short-Form Health Survey

HADS Hospital Anxiety and Depression Scale

Introduction

Health-related quality of life (HRQL) is a multidimen-

sional construct that includes the psychological, social, and

functional aspects of an illness as well as its physical

aspects. HRQL is usually assessed with the help of self-

reported measures, which reflect the patient’s appraisal of

his or her own illness and its accompanying impairments

[1]. Generic measures allow comparisons between groups

of patients, but disease-specific instruments identify the

characteristic impairments of a specific illness and are

considered to be more responsive to change [2].

The Chronic Liver Disease Questionnaire (CLDQ) is a

specific HRQL instrument that was systematically devel-

oped by Younossi et al. [3] for patients with chronic liver

disease of all etiologies and all stages of cirrhosis. The

K.-H. Schulz (&) � S. Kroencke � H. Ewers

Department of Hepatobiliary and Transplant Surgery, Center

for Transplantation Medicine, University Medical Center

Eppendorf, Martinistr. 52, S 35, 20246 Hamburg, Germany

e-mail: khschulz@uke.uni-hamburg.de

K.-H. Schulz � S. Kroencke � H. Ewers � H. Schulz

Department of Medical Psychology, Center for Psychosocial

Medicine, University Medical Center Eppendorf, Hamburg,

Germany

Z. M. Younossi

Center for Liver Diseases, Inova Fairfax Hospital, Annandale,

VA, USA

123

Qual Life Res

DOI 10.1007/s11136-008-9332-7

original instrument was tested within a group of 133

patients and showed appropriate reliability and validity [3].

Since then, several studies have confirmed the ability of the

CLDQ to discriminate between different stages of disease

severity according to Child class [4–10]. Another study

found that the CLDQ could discern between patients with

and without comorbid diseases [11]. Furthermore, the

CLDQ has proven to be responsive after liver transplan-

tation [9, 12] as well as after application of self-care and

educational programs [13, 14]. Between 2004 and 2006, a

Thai [8], an Italian [11], a Spanish [9], and a Lithuanian

[10] adaptation of the CLDQ were published. A German

adaptation of the CLDQ was developed by Hauser et al. in

2001. The results from their sample of 203 patients with

chronic liver disease were published in 2004 [7]. In con-

trast to the Italian [11] and the Spanish [9] validation, no

factor analysis was computed in the Hauser et al. version to

analyze the factorial structure. The Thai [8] and Lithuanian

[10] validation did not include factor analysis either.

The two studies [9, 11] in which the factorial structure

of the CLDQ was reassessed yielded considerably different

results. Whereas the Spanish [9] factorial solution was

relatively close to the original [3], although a new factor,

‘‘sleep,’’ was found and some items showed higher load-

ings on other factors than the original ones, the Italian [11]

solution consisted of a five-factor model not compatible

with the original version.

Independently of the work of Hauser et al. [7], we

developed a German version of the CLDQ that was pro-

spectively applied to patients with chronic liver disease

seen in our surgical outpatient clinic and the medical

department since 1999. This paper presents the psycho-

metric properties of the questionnaire and reports our

experiences with the questionnaire in clinical practice. As

data concerning the factorial structure of the CLDQ is

inconsistent, a special focus is placed on factor analysis.

The results are compared to the original version by

Younossi et al. [3] and to the two available factorial

solutions reported by Ferrer et al. [9] and Rucci et al. [11].

Patients and methods

CLDQ

The original CLDQ is a self-administered questionnaire

that consists of 29 items on a seven-point Likert scale, with

higher scores indicating the minimum frequency of

symptoms and therefore a better HRQL. Answers reflect

the 2 weeks prior to testing. Factor analysis yielded six

subscales: fatigue, activity, emotional function, abdominal

symptoms, systemic symptoms, and worry. Means are

computed for all subscales and for the overall score.

Translation

The original CLDQ was translated in 1999 by three bilingual

professionals (two German native speakers and one English

native speaker) using the forward and backward translation

method. Differing translations were discussed until a con-

sensus was reached. Earlier versions of the questionnaire

were discussed with patients regarding understandability and

relevance of items. Additionally, we developed a slightly

modified version of the CLDQ for living liver donors.

Patients

The CLDQ was first distributed among patients with

chronic liver disease visiting the surgical outpatient clinic

in 1999. Beginning in 2000, patients from the medical

department and the surgical outpatient clinic whose disease

had advanced so that transplantation became necessary

received the questionnaire as part of their routine psycho-

logical evaluation before being admitted to the waiting list.

Liver tumor patients without cirrhosis and patients with

polycystic disease were not included in the study, because

these patients do not exhibit typical symptoms of chronic

liver disease. In 2004, we began applying the questionnaire

to the evaluation of living liver donor candidates.

Other questionnaires

Two other questionnaires were also used in the context of

the psychological evaluation for liver transplantation and

living liver donation: the 36-Item Short-Form Health Sur-

vey (SF-36), and the Hospital Anxiety and Depression

Scale—German version (HADS-D).

36-Item Short-Form Health Survey (SF-36)

The SF-36 [15] is an internationally used instrument to

measure generic HRQL. It is often used in the field of

gastroenterology [16] and is considered reliable and valid.

The German version was adapted by Bullinger and Kir-

chberger [17]. It consists of 36 items combined into eight

scales, out of which two summary scales can be computed:

‘‘physical composite score’’ and ‘‘mental composite

score.’’ Each of the eight scales results in a score ranging

from 0 to 100, with a higher score indicating a better

HRQL. T scores with a mean of 50 and a standard devia-

tion (SD) of 10 are computed for the summary scales.

Hospital Anxiety and Depression Scale—German version

(HADS-D)

The original version of the HADS was developed by

Zigmond and Snaith [18]; the German adaptation was

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123

developed by Herrmann et al. [19]. It is a widely used

instrument for assessing anxiety and depression in clinical

medicine, with good reliability and validity. Each scale is

made up of seven items, which are summed to a score

ranging from 0 to 21. Scores lower than 7 are not consid-

ered clinically relevant.

Procedure and statistical analysis

Demographics and liver disease etiology were described

for the whole sample of patients with chronic liver disease

examined between 1999 and 2006. Item analysis was based

on calculated: means, SDs, floor effects (proportion of

patients with lowest HRQL scores), ceiling effects (pro-

portion of patients with highest HRQL scores), and item

discrimination (correlation of the item with its subscale).

Furthermore, the proportion of patients who did not answer

an item (‘‘missing’’) was used as a reflection of

‘‘acceptance.’’

Further analysis was conducted on a subscale level. For

each subscale, means and SDs were calculated as well as

the observed range of item scores, floor and ceiling effects,

and the proportion of patients with missing items. Reli-

ability was assessed through internal consistency

(Cronbach’s a) and retest reliability (Pearson correlation

coefficient).

Convergent and discriminant validity were assessed

through correlations (Pearson coefficient) of CLDQ

domains with SF-36 and HADS-D subscales in a multitrait,

multimethod matrix. It was hypothesized that different

scales measuring similar constructs would show high cor-

relations, whereas scales measuring different or

noncomparable traits would not correlate strongly. High

correlations (r [ .70) were hypothesized for the following

subscales: ‘‘fatigue’’ and ‘‘activity’’ (CLDQ) with ‘‘vital-

ity’’ (SF-36); ‘‘emotional function’’ (CLDQ) with ‘‘mental

health’’ (SF-36); and ‘‘emotional function’’ (CLDQ) with

‘‘anxiety’’ and with ‘‘depression’’ (HADS-D). Low corre-

lations (r \ .50) were hypothesized for the CLDQ subscale

‘‘abdominal symptoms’’ with SF-36 scales ‘‘role-emo-

tional’’ and ‘‘mental health’’ and with ‘‘anxiety’’ and

‘‘depression’’ (HADS-D); and ‘‘worry’’ (CLDQ) with

‘‘physical functioning,’’ ‘‘role-physical,’’ and ‘‘bodily

pain’’ (SF-36).

Validity was further estimated by comparing patients

with chronic liver disease to living liver donor candidates,

a sample selected for good physical health. Comparisons of

CLDQ means were based on independent samples t test.

The demographics and etiology of liver disease were

described separately for subsamples of patients for factor

analysis and retesting, and for the sample of living liver

donor candidates. The subsamples of patients with chronic

liver disease were compared with patients who were not

included in the analysis by using independent-samples t

tests or chi-square tests (according to scale level). The

demographics of living liver donor candidates and patients

with chronic liver disease were compared using the same

tests.

A confirmatory factor analysis (CFA) was computed as

another means to assess validity. The hypothesized model

according to Younossi et al. [3] was examined with AMOS

4.0 [20] using maximum likelihood (ML) estimation. The

following model fit indices were considered: the compar-

ative fit index (CFI), the standardized root mean square

residual (SRMR), and the root mean square error of

approximation (RMSEA). To show a good fit for the

model, CFI values should be .95 or higher, and the SRMR

and the RMSEA should be less than .08 and .06, respec-

tively [21]. It is generally accepted practice to evaluate fit

through a combination of fit indices; confidence in the

results increases as agreement among the fit statistics

increases.

In addition, an exploratory factor analysis (principal

component analysis with varimax rotation) was conducted.

Only factors with an eigenvalue [1 explaining the maxi-

mum cumulative variance were interpreted.

To minimize influences of missing data on the results of

factor analyses, list-wise exclusion of cases was preferred.

This resulted in a considerably reduced sample. Therefore,

demographics and liver disease etiology were described

separately for this sample and compared with the patients

not included in this analysis (see above).

Results

The demographics and liver disease etiology of 524

patients with chronic liver disease who filled out the

questionnaire from May 1999 to October 2006 are pre-

sented in Table 1. Patients reported no special problems

related to completing the questionnaire. However, we

repeatedly observed that patients who were hospitalized for

decompensated liver disease did not return the question-

naire. Among patients who did complete the questionnaire,

many asked questions about item no. 14 (‘‘bothered by a

limitation of your diet’’).

After list-wise exclusion of cases, the subsample for

factor analysis consisted of 401 patients (Table 1). This

subsample did not differ significantly from the patients

excluded from the analysis with regard to age (t = 1.05,

P = .29), gender (v2 = .44, P = .51), or liver disease

etiology (v2 = .62, P = .89).

Retest reliability was calculated utilizing a subsample of

55 patients who filled out the questionnaire a second time

(Table 1). The mean time between testing was 82 days

(SD = 41). This subsample’s mean age did not differ

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significantly from the patients not included in this analysis

(t = .91, P = .36), but there were more women

(v2 = 4.24, P = .04) in the retest subsample. Liver disease

etiology did not differ significantly (v2 = 7.51, P = .06).

The sample of living liver donor candidates (40) is also

described in Table 1. Living liver donors were different

from patients with chronic liver disease with regard to

mean age (t = 14.94, P \ .001) but not gender (v2 = .18,

P = .68).

Item analysis (Table 2) showed that the whole range of

possible scores was utilized. There was only one item (no.

9) with a proportion of 21% of worst HRQL scores. For

all the other items, the proportion of worst HRQL scores

was lower than 15%. In comparison, there were seven

items with a proportion of best HRQL scores higher than

20% and seven more items with a proportion exceeding

even 30%. Item discrimination was good for all items.

However, two items had a noticeable number of missing

values: 41 patients did not complete item no. 14 (‘‘both-

ered by a limitation of your diet’’), and 23 patients did not

complete item no. 9 (‘‘trouble lifting or carrying heavy

objects’’).

Analysis on subscale level (Table 3) showed means

ranging between 4.11 and 5.04. No floor effects could be

determined. The subscale ‘‘activity’’ showed the largest

proportion of patients with best HRQL scores. Missing

values on this subscale were mainly related to items no. 14

and 9. For the whole questionnaire, the proportion of

patients with at least one missing item was 23.5%.

Internal consistency coefficients ranged from a = .72

for ‘‘activity’’ to a = .92 for ‘‘fatigue,’’ attaining a = .95

for the whole questionnaire. Retest reliability was also

good, with coefficients between r = .69 and r = .79,

except for the subscale ‘‘fatigue’’ (r = .58).

Table 4 shows the intercorrelations of the CLDQ sub-

scales and correlations of CLDQ subscales with SF-36 and

HADS-D subscales in a multitrait, multimethod matrix.

The CLDQ subscale intercorrelations ranged from r = .42

to r = .76. Regarding correlations of CLDQ subscales with

scales of the other two questionnaires, those hypothesized

as high showed coefficients between r = .69 and r = .85,

whereas correlations hypothesized as low were between

r = .33 and r = .48. The pattern of correlations between

the different subscales of the questionnaires is plausible

with regard to content.

Comparing patients with chronic liver disease with liv-

ing liver donor candidates (Fig. 1) yielded highly

significant differences of mean values (P \ .001) for all

subscales and for the total score.

Factor analyses

CFA revealed an only partial fit of the data: SRMR = .076

fulfilled the recommended cutoff criterion, whereas the

other two goodness-of-fit indices (CFI = .85, RMSEA =

.092) were too far out of range of the recommended cutoff

criteria for retaining a hypothesized model. On the item

level, especially items 16 and 20 in factor ‘‘emotional

function,’’ had particularly low standardized factor

loadings.

Therefore, exploratory factor analysis was conducted. It

revealed six factors with an eigenvalue[1, explaining 70%

of cumulative variance. Most items showed the highest

factor loadings on the original factors (Table 5). The scale

‘‘systemic symptoms’’ proved difficult to reproduce, with

two items (no. 3 and 6) showing higher loadings on more

than one other factor. Item no. 3 (‘‘bodily pain’’) had a

substantially higher loading on ‘‘abdominal symptoms,’’

whereas item no. 6 (‘‘shortness of breath in daily activi-

ties’’) showed almost equally high loadings on ‘‘fatigue’’

and ‘‘abdominal symptoms.’’ The scale ‘‘worry’’ corre-

sponded fully to the original. The factor ‘‘activity,’’

however, which consists of three items, could not be

reproduced at all. Item no. 7 (‘‘not able to eat as much as

you would like’’) and item no. 14 (‘‘bothered by a limita-

tion of your diet’’) had the highest loading on ‘‘abdominal

symptoms’’ and item no. 9 (‘‘trouble lifting or carrying

heavy objects’’) on ‘‘fatigue.’’ A new factor named ‘‘sleep’’

was derived from two items (no. 16 and 20) of the original

subscale ‘‘emotional function.’’

Table 1 Characteristics of patients with chronic liver disease, including subsamples, and of living liver donor candidates

All patients (N=524) Sub-sample for factor analysis (N=401) Retest subsample (N=55) Living liver donors (N=40)

Age: mean/SD 51.5/10.6 51.3/10.7 50.3/11.6 33.3/7.1

Gender: males 306 (58%) 231 (58%) 25 (46%) 22 (55%)

Etiology

Viral 127 (24%) 94 (23%) 15 (27%) –

Alcoholic 242 (46%) 187 (47%) 20 (36%) –

Autoimmunologic 100 (19%) 77 (19%) 17 (31%) –

Other 55 (11%) 43 (11%) 3 (6%) –

SD standard deviation

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Table 6 describes means, SDs, and Cronbach’s a-coef-

ficients for the new subscales according to our factor

analysis, composed of the items with the highest factor

loadings on the respective scale.

Discussion

In the following, first the results of item analysis and

on scale level are discussed. Then, results concerning

reliability and validity including factor analysis are focused

upon. Finally, general considerations and limitations of the

study are addressed.

The Hamburg version of the CLDQ demonstrated a

satisfactory distribution of item and subscale statistics. The

whole range of possible answers was utilized, and although

some items showed ceiling effects (comparatively large

proportion of patients with best HRQL scores), this was not

the case on a subscale level. Note that some patients must

Table 2 Item analysis

CLDQ items (number) Mean SD Floora (%) Ceilinga (%) Item discrimination Missingb

Fatigue

(2) Tired or fatigued 3.63 1.65 11.7 4.2 .84 4

(4) Sleepy during the day 4.02 1.71 8.0 8.2 .78 1

(8) Decreased strength 4.02 1.90 11.6 11.0 .82 8

(11) Decreased level of energy 4.01 1.78 8.1 7.9 .86 5

(13) Drowsy 5.51 1.54 .8 35.8 .64 15

Emotional function

(10) Anxious 5.47 1.62 1.9 38.5 .64 7

(12) Unhappy 4.86 1.78 4.0 22.4 .71 5

(15) Irritable 5.14 1.53 1.6 21.5 .68 8

(16) Difficulty sleeping 4.18 1.99 10.7 15.5 .63 0

(19) Mood swings 4.68 1.62 3.5 12.0 .74 6

(20) Unable to fall asleep 4.35 1.95 6.7 18.7 .62 16

(24) Depressed 4.95 1.65 2.7 21.2 .78 14

(26) Problems concentrating 5.02 1.56 2.1 18.6 .55 7

Worry

(18) Impact on family 3.88 1.83 11.7 11.1 .72 10

(22) Symptoms developing into major problems 4.01 1.82 10.6 11.2 .84 6

(25) Condition getting worse 3.88 1.79 10.0 8.3 .85 6

(28) Never feeling any better 4.68 1.85 5.4 20.6 .68 9

(29) Availability of a liver 4.08 1.96 14.6 14.6 .66 9

Abdominal symptoms

(1) Abdominal bloating 4.34 1.78 8.6 10.5 .42 2

(5) Abdominal pain 5.46 1.65 2.1 37.9 .69 7

(17) Abdominal discomfort 4.84 1.85 5.0 23.8 .67 2

Activity

(7) Not able to eat as much as you would like 5.03 2.00 7.2 33.5 .59 8

(9) Trouble lifting or carrying heavy objects 3.79 2.15 21.0 15.4 .53 23

(14) Limitation of diet 5.39 1.90 5.4 40.0 .50 41

Systemic symptoms

(3) Bodily pain 5.05 1.77 4.9 27.6 .50 9

(6) Shortness of breath in daily activities 5.16 1.83 5.2 34.0 .53 6

(21) Muscle cramps 5.32 1.69 2.9 34.4 .50 7

(23) Dry mouth 4.64 1.85 7.6 18.8 .59 8

(27) Itching 4.97 1.90 5.8 29.0 .43 6

CLDQ, Chronic Liver Disease Questionnaire; SD, standard deviationa Proportion of patients with worst (floor, item score: 1) and best (ceiling, item score: 7) HRQL scoresb Number of patients with item missing

Nmax = 524

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occupy the highest and lowest scores for the questionnaire

to cover the entire impairment range. Floor effects were not

apparent in our sample, perhaps because patients with

strongly impaired health did not feel able to fill out the

questionnaire. Although distribution and item discrimina-

tion proved satisfactory, there were problems regarding

acceptance of two items of the subscale ‘‘activity.’’ Item

no. 14 (‘‘How much of the time during the last two weeks

have you been bothered by a limitation of your diet?’’) was

not completed by 8% of patients, and no. 9 (‘‘How much of

the time during the last two weeks have you had trouble

lifting or carrying heavy objects?’’) was not completed by

4% of patients. Some patients did not feel that the

questions applied to them because they did not have a

limitation of their diet and did not even try to lift or carry

heavy objects, so they refrained from answering the ques-

tions. These items might benefit from an additional

sentence such as: ‘‘If the question does not apply to you,

please chose ‘none of the time’.’’ A considerable propor-

tion of patients with one or more items missing in the

whole questionnaire can be attributed to items no. 9 and 14.

Nevertheless, the proportion in the Hamburg sample is

relatively large compared with other reports of missing

items: 0.4% [7] and 3.4% [9], respectively. Perhaps this is

because our data were gathered over a long period in the

context of the psychological evaluation of patients for liver

Table 3 Analysis on subscale level and reliability

Subscale Mean SD Range Floora (%) Ceilinga (%) Missingb (%) Cronbach’s a Retest reliability

Abdominal symptoms 4.89 1.44 1–7 1.6 12.9 2.1 .76 .71

Fatigue 4.24 1.48 1–7 3.2 5.1 5.9 .92 .58

Systemic symptoms 5.04 1.27 1.2–7 .6 12.0 5.0 .75 .79

Activity 4.72 1.62 1–7 3.1 17.3 13.0 .72 .70

Emotional function 4.83 1.28 1.4–7 .4 9.6 8.2 .89 .69

Worry 4.11 1.56 1–7 5.1 6.9 5.9 .90 .78

Total score 4.62 1.20 1.4–7 .7 5.2 23.5 .95 .76

SD standard deviationa Proportion of patients with worst (floor, score: 1) and best (ceiling, score: 7) HRQL scoresb Proportion of patients with any item missing on the subscale

Nmax = 524

Table 4 Chronic Liver Disease

Questionnaire (CLDQ) subscale

intercorrelations and

correlations of CLDQ subscales

with 36-Item Short Form Health

Survey (SF-36) and Hospital

Anxiety and Depression

Scale—German version

(HADS-D) subscales (multitrait

multimethod matrix)

Correlations hypothesized to be

high are marked in bold.

Correlations hypothesized to be

low are marked in italic

Abdominal

symptoms

Fatigue Systemic

symptoms

Activity Emotional

function

Worry

CLDQ

Abdominal symptoms

Fatigue .63

Systemic symptoms .65 .69

Activity .60 .76 .62

Emotional function .56 .73 .65 .64

Worry .42 .58 .51 .55 .66

SF-36

Physical functioning .40 .64 .56 .69 .52 .48

Role-physical .38 .65 .52 .62 .52 .47

Bodily pain .59 .53 .62 .55 .50 .37

General health .43 .61 .48 .51 .51 .53

Vitality .54 .85 .60 .70 .67 .56

Social functioning .40 .54 .45 .53 .56 .46

Role-emotional .33 .54 .47 .51 .55 .49

Mental health .46 .62 .53 .58 .80 .61

HADS-D

Anxiety -.42 -.52 -.47 -.48 -.69 -.61

Depression -.37 -.54 -.45 -.44 -.69 -.55

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transplantation and not in the setting of a specifically

designed study where patients could get assistance in

completing the questionnaire if necessary. Ferrer et al. [9]

reported that 21% of their patients needed help completing

the questionnaire.

Internal consistency was good to excellent. Retest reli-

ability showed acceptable scores, especially when

considering the comparatively long interval between tests.

Hauser et al. [7] found slightly higher coefficients, but the

time between testing ranged from 3 to 8 days in their

sample. Ferrer et al. [9] applied the second questionnaire

after 2 weeks. Our results indicate that a longer interval for

retesting might also be acceptable. However, HRQL is

likely to worsen during this period. The fact that the sub-

scale ‘‘fatigue’’ shows a lower coefficient (r = .58) is

understandable, because ‘‘fatigue’’ is likely to be the most

unstable factor.

CLDQ subscale intercorrelations were moderate to high,

which on the one hand allows interpretation of the different

subscales but on the other hand also makes a calculation of

a global score appropriate. Whether these interrelations are

due to the structure of the instrument itself or reflect

covariance of the underlying constructs has to be deter-

mined in future studies.

The pattern of correlations between the CLDQ subscales

and SF-36 and HADS-D subscales is further evidence for

the convergent and discriminant validity of this question-

naire. Similar patterns were found by Ferrer et al. [9] and

Hauser et al. [7]. High correlations of three CLDQ sub-

scales (‘‘fatigue,’’ ‘‘activity,’’ ‘‘emotional function’’) with

two SF-36 scales (‘‘vitality,’’ ‘‘mental health’’) and of one

CLDQ subscale (‘‘emotional function’’) with HADS scales

do not contradict the assertion of the CLDQ being a dis-

ease-specific measure. However, studies with patients with

different diseases are necessary to support the disease

specificity of the instrument. Furthermore, three of the

CLDQ subscales (‘‘abdominal symptoms,’’ ‘‘systemic

symptoms,’’ ‘‘worry’’) show only low to moderate corre-

lations with the other questionnaires. Therefore, these

subscales can be regarded as adding specific information to

the generic questionnaires.

The observation that living liver donor candidates show

significantly better HRQL scores than patients with chronic

liver disease confirms the ability of the CLDQ to dis-

criminate between different groups of patients. It should be

noted that living liver donors are significantly younger than

patients with chronic liver disease. However, we believe

that this difference is due to the necessary good health

status of these subjects and that the age difference is of

only subordinate importance. Previous studies show sig-

nificant mean differences according to the severity of liver

disease [3–10] and for patients with and without comorbid

diseases [11]. In this context, additionally we point out that

there is no specific HRQL instrument for living liver

donors. A modified version of the CLDQ may be able to fill

this gap and be applied to this field as well. Because living

donors undergo liver surgery, they may develop postoper-

ative liver-related symptoms. Therefore, the questionnaire

may help to assess the impact of living liver donation and

the course of the recovery process.

Confirmatory factor analysis revealed that the factor

solution reported by Younossi et al. [3] is not sufficiently

reproducible in our sample. Therefore, an exploratory

factor analysis was conducted, yielding in a six-factor

model. The original factor structure in part was con-

firmed; however, the factor ‘‘activity’’ could not be

reproduced and a new factor, ‘‘sleep,’’ was identified. In

their sample of 149 patients, Ferrer et al. [9] were able to

reproduce all original factors. They also found a new

factor, ‘‘sleep,’’ composed of the same two items as in our

0

1

2

3

4

5

6

7

Abdominalsymptoms

Fatiguesymptoms

Activityfunction

Worry

Patients with chronic liver disease Living liver donors

Systemic Emotional Total score

Fig. 1 Mean Chronic Liver

Disease Questionnaire (CLDQ)

scores (with standard

deviations) of patients with

chronic liver disease and of

living liver donors. Higher

scores indicate a better quality

of life

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Hamburg adaptation

Original CLDQ

Factor1

FA

Factor2

WO

Factor3

EF

Factor4

AS

Factor5

SS

Factor6

Sleep

FATIGUE (FA)(2) tired or fatigued .73 .23 .32 .24 .22 .07(4) sleepy during the day .70 .16 .32 .15 .27 .13(8) decreased strength .76 .28 .23 .29 .13 .18(11) decreased level of energy .79 .21 .31 .23 .15 .12(13) drowsy .42 .16 .49 .27 .31 .07EMOTIONAL FUNCTION (EF)(10) anxious .13 .26 .58 .40 .03 .21(12) unhappy .25 .38 .64 .31 -.08 .22(15) irritable .25 .12 .69 .09 .33 .16(16) difficulty sleeping .19 .13 .21 .14 .15 .87(19) mood swings .24 .33 .72 .18 .18 .12(20) unable to fall asleep .15 .18 .22 .09 .16 .88(24) depressed .18 .40 .72 .19 .13 .18(26) problems concentrating .39 .18 .50 .08 .46 .06WORRY (WO)(18) impact on family .19 .77 .27 .12 -.02 .06(22) symptoms developing into major problems .16 .81 .27 .16 .14 .11

(25) condition getting worse .19 .84 .23 .11 .16 .09(28) never feeling any better .17 .63 .35 .14 .32 .15(29) availability of a liver .26 .75 .04 .06 .23 .10ABDOMINAL SYMPTOMS (AS)(1) abdominal bloating .21 .13 .13 .37 .49 -.09(5) abdominal pain .17 .06 .19 .83 .24 .04(17) abdominal discomfort .22 .16 .25 .72 .25 .07ACTIVITY(7) Not able to eat as much as you would like .41 .18 .14 .56 .05 .21

(9) trouble lifting or carrying heavy objects .70 .29 .04 .31 .14 .13

(14) limitation of diet .31 .27 .22 .41 -.09 .24SYSTEMIC SYMPTOMS (SS)(3) bodily pain .35 .05 .21 .57 .28 .05(6) shortness of breath in dailyactivities

.42 .16 .02 .41 .36 .24

(21) muscle cramps .12 .05 .23 .16 .64 .06(23) dry mouth .30 .15 .16 .32 .49 .23(27) itching .09 .25 .02 .09 .68 .20

NOTES: item no. in parentheses; highest factor loadings for each factor are in bold script; factor loadings corresponding to the original factors are marked with a grey background; factor loadings with a black background indicate highest loadings on other factors than the original ones; the factor “activity” could not be reproduced; a new factor “sleep” was found

Table 5 Exploratory factor analysis of the Hamburg version of the Chronic Liver Disease Questionnaire (CLDQ) (N=401)

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analysis. Even though they were able to reproduce the

factor ‘‘activity,’’ they found by far the lowest Cronbach’s

a coefficient for this subscale, and one of the three items

(no. 9) showed a substantially higher factor loading on

‘‘fatigue.’’ In our sample, ‘‘activity’’ also demonstrated

the lowest coefficient of internal consistency and item

no. 9 a high factor loading on ‘‘fatigue.’’ Furthermore, the

factor ‘‘systemic symptoms’’ was difficult to reproduce in

both studies. Ferrer et al. [9] found three items (nos. 3, 6,

23) showing considerably higher loadings on more than

one other factor. In our study, two of these items (nos. 3

and 6) showed multiple loadings on different factors.

Regarding both studies, these items could not be assigned

clearly to any dimension. Considering the factor ‘‘worry,’’

Ferrer et al. [9] identified two items (nos. 22 and 25) that

loaded higher on ‘‘emotional function,’’ although the

loadings on ‘‘worry’’ were also still high. In our sample,

‘‘worry’’ corresponded fully to the original.

Rucci et al. [11] found a five-factor solution (347)

remarkably different from the others but with some simi-

larities. A new factor, ‘‘somatic symptoms,’’ combined all

items of the scales ‘‘abdominal symptoms’’ and ‘‘fatigue,’’

all but one item from ‘‘systemic symptoms,’’ and one item

each from ‘‘activity’’ (no. 9) and ‘‘emotional function’’ (no.

26). Another factor, named ‘‘anxiety/depression,’’ consisted

of four items of the original subscale ‘‘emotional function,’’

and a new factor, ‘‘well-being,’’ combined one item from

‘‘activity’’ (no. 7) and one from ‘‘emotional function’’ (no.

12). In accordance with our findings, the factor ‘‘activity’’

could not be reproduced either. Furthermore, Rucci et al.

[11] also found a factor, ‘‘sleep problems,’’ consisting of the

same items as in our and the Spanish sample [9] plus one

item from ‘‘systemic symptoms’’ (no. 21, ‘‘muscle

cramps’’). They also found a factor, ‘‘worries,’’ corre-

sponding to the original subscale plus one item from

‘‘activity’’ (no. 14). Their relatively different factorial

structure might be explained by the fact that their sample

consisted solely of patients with hepatitis C.

As the compared factorial solutions originated from

different countries, some of the discrepancies could be due

to the linguistic adaptations and the different cultural

backgrounds. Replications of the factor analysis of the

original American version and for the different linguistic

adaptations would help to clarify this question.

We do not yet want to recommend a change of the

subscales derived from the original factorial solution

because a direct comparison between the different versions

would no longer be possible. However, there is evidence

that at least some items should be assigned differently or,

alternatively, be eliminated from the questionnaire because

of multiple loadings. Additional studies are needed to

determine which factorial structure should be favored.

For interested parties, we describe means and SDs for

the new subscales according to our factor analysis

(Table 6). Internal consistency for these subscales is very

good except for the subscale ‘‘systemic symptoms,’’ which

contains the most heterogeneous group of items.

Concerning the comparison with the German adaptation

by Hauser et al. [7], only a few discrepancies regarding the

translation of certain items can be observed. In particular,

translation of the items concerning ‘‘abdominal bloating’’

(no. 1), ‘‘drowsiness’’ (no. 13), and ‘‘limitation of diet’’

(no. 14) differed between the two versions. At present, we

recommend the use of the version described in this paper

because the factorial structure is available, which is based

on a larger sample size. As to differences to the original

American version, until now, the factorial structure repor-

ted by Younossi et al. [3] could not be sufficiently

confirmed in different countries [9, 11]. Further studies are

necessary to clarify whether these differences are due to

linguistic ambiguities or cultural differences in dealing

with the illness [22].

We found the CLDQ to be very useful in the psycho-

logical evaluation of patients for liver transplantation. In

this context, it can be applied before and after liver trans-

plantation and serve as an outcome measure in prospective

studies. It has already shown its responsiveness after liver

transplantation [9, 12] and its ability to provide additional

relevant information to generic HRQL instruments, which

lack sensitivity for liver-specific symptoms [9].

Table 6 Suggested new Chronic Liver Disease Questionnaire (CLDQ) subscales according to factor analysis (N=401)

Subscale Mean Standard deviation Cronbach’s a Items contained (no.)

Fatigue 4.11 1.54 .92 2, 4, 6, 8, 9, 11

Worry 4.07 1.57 .90 18, 22, 25, 28, 29

Emotional function 5.08 1.29 .91 10, 12, 13, 15, 19, 24, 26

Abdominal symptoms 5.14 1.41 .82 3, 5, 7, 14, 17

Systemic symptoms 4.81 1.29 .68 1, 21, 23, 27

Sleep 4.26 1.91 .94 16, 20

Total score 4.58 1.19 .95 1–29

New subscale not contained in the original CLDQ marked in italic

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Our study did have some limitations. First, no compari-

sons according to severity of liver disease (e.g., Child A, B,

and C) could be provided because this data was not avail-

able. However, comparison of different severity groups is

just one way to determine the validity of the instrument, and

several studies [4–10] have already confirmed the CLDQ’s

ability to discriminate between Child classes.

Second, the ability of the CLDQ to discriminate

between patients with chronic liver disease and living liver

donors was expected because the CLDQ has already been

shown to discriminate between different stages of disease

severity. However, this was the first time the CLDQ was

applied to living donors, and therefore, new information is

provided.

In conclusion, these data represent the largest sample of

patients assessed with the CLDQ in the literature. The

results reconfirm the reliability and validity of the CLDQ.

Furthermore, our data confirms the practical administration

of the questionnaire as part of the routine psychological

evaluation of patients with chronic liver disease. Compar-

ing the different factorial solutions, the subscales

‘‘activity’’ and ‘‘systemic symptoms’’ seem to be the most

difficult to reproduce, whereas the fact that all studies were

able to reproduce the factor ‘‘worry’’ emphasizes its

robustness. The factorial structure of the questionnaire

should be subject to international discussion and, if possi-

ble, a consensus should be reached by means of further

factor-analytical studies.

Acknowledgements This study was supported by the Deutsche

Forschungsgemeinschaft (DFG) (SCHU 974/5-1/2). We thank

Susanne Kjer and Stefanie Kraft for their help with data collection.

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