- Email: [email protected]
Validation of the Spanish version of the Liver Disease Quality of Life questionnaire in transplant patients
OUTCOMES Living Donor/Split Livers
Validation of the Spanish Version of the Liver Disease Quality of Life Questionnaire in Transplant Patients T. Casanovas, G. Vallejo, M. Herdman, A. Casado, S. Ribas, E. Rodrı´guez Farin˜a, G. Tremosa, J. M. Mencho´n, J. Figueras, and L.A. Casais ABSTRACT Objectives. Our aim was to validate Spanish and Catalan versions of the Liver Disease Quality of Life questionnaire (LDQOL) for use in liver transplant patients. Methods. The LDQOL consists of the SF-36 generic measure of health-related quality of life (HRQOL) and 12 disease-specific dimensions for liver disease patients. The Spanish and Catalan versions of the questionnaire were administered to 138 patients with a liver transplant. Cronbach’s alpha coefficients (CAC) were used to test the internal consistency of disease-specific scales. Test-retest reliability was calculated using the Intraclass Correlation Coefficient (ICC) in a sub-group of 41 patients who completed the questionnaire on two occasions 1 to 2 weeks apart. Validity was analysed by determining the instrument’s capacity to discriminate between patient groups classified according to years since transplant, disease etiology, and symptom severity. Ceiling and floor effects were also calculated. Results. Internal consistency in the disease-specific dimensions was acceptable or good (CACs 0.60 – 0.97), as was test-retest reliability in all dimensions (statistically significant CCIs of 0.62– 0.89), except the symptoms dimension (CCI ⫽ 0.46, P ⬍ .05). Few differences were found in disease-specific dimension scores between patients classified according to number of years since transplant or etiology, but differences were found in some dimensions according to symptom severity. Moderate to severe ceiling effects were found in several disease-specific dimensions. Conclusions. The Spanish and Catalan versions of the LDQOL may be useful for measuring HRQOL in this population, though it will be important to investigate further the instrument’s sensitivity to change.
© 2003 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/03/$–see front matter doi:10.1016/S0041-1345(03)00593-1
Transplantation Proceedings, 35, 1803–1805 (2003)
1803
1804
CASANOVAS, VALLEJO, HERDMAN ET AL
S
TANDARDIZED MEASURES of health-related quality of life (HRQOL) are increasingly used as means of measuring the impact of disease and the effectiveness of treatments. Such measures may be either disease specific or generic, that is, designed to measure HRQOL in a wide range of populations. The Liver Disease Quality of Life scale (LDQOL 1.0) is an American instrument developed to measure HRQOL in patients with different types of liver disease or liver transplants.1 This instrument was recently adapted into Spanish and Catalan.2 The objective of this study was to make a preliminary assessment of the psychometric properties of these new language versions. METHODS The LDQOL consists of a generic instrument (the SF-36) and 12 disease-specific scales containing 75 items. The SF-36 has previously been adapted and validated for use in Spanish,3 and the adapted and validated Spanish version of the questionnaire was incorporated directly here. The 12 disease-specific scales in the LDQOL are: symptoms of liver-disease (17 items), effects of liver disease on activities of daily living (10 items), concentration (7 items), memory (6 items), sexual functioning (3 items), sexual problems (3 items), problems with sleeping (5 items), hopelessness (5 items), anxiety about the disease (4 items), quality of social interaction (5 items), anxiety about the future (4 items), and stigma/body image (6 items). The Spanish and Catalan versions of the questionnaire were produced using the standard recommended methodology of forward and back translation followed by testing in interviews with patients.2 The Spanish and Catalan versions of the LDQOL were administered in a cross-sectional study to a sample of 138 patients with liver transplants. The questionnaires were self-administered whenFrom the Hospital Universitario de Bellvitge (Hospitalet) Barcelona (T.C., G.V., E.R.F., G.T., J.M.M., J.F., L.A.C.) and 3D Health Research Barcelona (M.H., A.C., S.R.), Spain. Address reprint requests to T. Casanovas, Digestive Disease Department, Hospital Universitario of Belvitige, c/Feixa LLarga S/N, Hospitalet, Barcelona 08907, Spain. E-mail: t.casanavas@ esub.scs.es Table 1. Patient Sociodemographic and Clinical Characteristics Mean age, in years (SD) Gender (% males) Mean time with transplant, in years (SD) Child-Pugh classification (%)**: A B C Etiology (%)**: Fulminant Hepatitis Alcohol CBP/colangitis Criptogenic Tumor SD, standard deviation. **Percentages may not sum to 100 because of missing cases.
58.9 (9.8) 61.6 5.8 (3.4) 19.6 37.0 32.6 2.2 28.3 28.3 10.1 5.8 1.4
Table 2. Internal Consistency of Disease-Specific Dimensions in the Spanish and Catalan Versions of the LDQOL 1.0 Dimension
Cronbach’s
Symptoms related to liver disease Effects of liver disease on activities of daily living Concentration Memory Sexual function Sexual problems (women) Sexual problems (men) Sleep problems Hopelessness Worries about the disease Relationships Worries about the future Stigma/body image
0.75 0.80 0.90 0.94 0.75 0.97 0.94 0.74 0.70 0.67 0.60 0.81 0.71
ever possible. Other data collected included age, gender, educational level, length of time with transplant, symptom severity, general health status, type of liver disease, and Child-Pugh classification. Reliability was analysed by studying the internal consistency of the individual disease-specific dimensions of the LDQOL as well as by studying the test-retest reliability in a sub-group of 41 patients in whom the questionnaire was administered on two occasions separated by an interval of approximately 2 weeks. Patients in this group were deemed to be clinically stable. The internal consistency of the disease-specific dimensions was assessed using Cronbach’s alpha, and test-retest reliability was assessed using the intraclass correlation coefficient (ICC).4 Preliminary validity testing was performed by analysing the questionnaire’s capacity to discriminate between groups of patients expected to differ on a given, relevant parameter, such as symptom severity. In this case, the parameters tested were symptom severity, length of time with transplant (1–5 years, 5–10 years, ⬎10 years), and type of liver disease. Ceiling and floor effects (ie, the percentage of patients with maximum and minimum scores, respectively) were also calculated for each dimension.
Table 3. Test-Retest Reliability of Disease-Specific Dimensions in the Spanish and Catalan Versions of the LDQOL 1.0 Questionnaire Dimension
ICC
Symptoms related to liver disease Effects of liver disease on activities of daily living Concentration Memory Sexual function Sexual problems (men and women) Sleep problems Hopelessness Worries about the disease Relationships Worries about the future Stigma/body image
0.46* 0.77* 0.82* 0.85* 0.71* 0.76* 0.89* 0.64* 0.72* 0.62* 0.68* 0.69*
*P ⬍ .05. n ⫽ 41 ICC, intraclass correlation coefficient.
LIVER DISEASE QUALITY OF LIFE QUESTIONNAIRE
1805
Fig 1.
RESULTS
Patient sociodemographic and clinical characteristics are shown in Table 1 The internal consistency of the diseasespecific dimensions of the LDQOI was generally very good (see Table 2), with all coefficients being over 0.60. Testretest reliability was also good in all dimensions, as shown in Table 3, the only exception being the symptoms dimension, where the coefficient was 0.42. All of the ICCs were statistically significant at P ⬍ .05. Few differences were observed between groups on the different disease-specific dimensions of the LDQOL when patients were classified by length of time since transplant or by type of liver disease. However, statistically significant differences were recorded between groups on several disease-specific dimensions when patients were classified by symptom severity (Fig 1). There were some floor and ceiling effects on several of the disease-specific dimensions, particularly on the SF-36 dimensions. DISCUSSION
As far as we are aware, this is the first time the LDQOL has been extensively tested in patients with a liver
transplant. This is also the first validation study of these new Spanish and Catalan versions of the instrument. In this sample, these new language versions of the LDQOL showed generally very good internal consistency and test-retest reliability and some capacity to discriminate between patients classified according to their symptom severity. The fact that the instrument did not discriminate between groups classified according to etiology and length of time with transplant suggests that these parameters may not be particularly relevant in determining HRQOL in this group of patients. Further testing of other types of validity as well as the instrument’s sensitivity to change are required.
REFERENCES 1. Gralnek I, Hays RD, Kilbourne A, et al: Am J Gastroenterol 95:3552, 2000 2. Casanovas T, Vallejo G, Herdman M, et al: Gastroenterologia y Hepatologia 2003 (accepted for publication) 3. Alonso J, Prieto L, Anto ´ JM: Med Clin (Barc) 104:771, 1995 4. Nunnally J, Bernstein IH: Psychometric Theory, 3rd ed. New York: McGraw-Hill; 1994, p xx
Validation of the Spanish Version of the Liver Disease Quality of Life Questionnaire in Transplant Patients T. Casanovas, G. Vallejo, M. Herdman, A. Casado, S. Ribas, E. Rodrı´guez Farin˜a, G. Tremosa, J. M. Mencho´n, J. Figueras, and L.A. Casais ABSTRACT Objectives. Our aim was to validate Spanish and Catalan versions of the Liver Disease Quality of Life questionnaire (LDQOL) for use in liver transplant patients. Methods. The LDQOL consists of the SF-36 generic measure of health-related quality of life (HRQOL) and 12 disease-specific dimensions for liver disease patients. The Spanish and Catalan versions of the questionnaire were administered to 138 patients with a liver transplant. Cronbach’s alpha coefficients (CAC) were used to test the internal consistency of disease-specific scales. Test-retest reliability was calculated using the Intraclass Correlation Coefficient (ICC) in a sub-group of 41 patients who completed the questionnaire on two occasions 1 to 2 weeks apart. Validity was analysed by determining the instrument’s capacity to discriminate between patient groups classified according to years since transplant, disease etiology, and symptom severity. Ceiling and floor effects were also calculated. Results. Internal consistency in the disease-specific dimensions was acceptable or good (CACs 0.60 – 0.97), as was test-retest reliability in all dimensions (statistically significant CCIs of 0.62– 0.89), except the symptoms dimension (CCI ⫽ 0.46, P ⬍ .05). Few differences were found in disease-specific dimension scores between patients classified according to number of years since transplant or etiology, but differences were found in some dimensions according to symptom severity. Moderate to severe ceiling effects were found in several disease-specific dimensions. Conclusions. The Spanish and Catalan versions of the LDQOL may be useful for measuring HRQOL in this population, though it will be important to investigate further the instrument’s sensitivity to change.
© 2003 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/03/$–see front matter doi:10.1016/S0041-1345(03)00593-1
Transplantation Proceedings, 35, 1803–1805 (2003)
1803
1804
CASANOVAS, VALLEJO, HERDMAN ET AL
S
TANDARDIZED MEASURES of health-related quality of life (HRQOL) are increasingly used as means of measuring the impact of disease and the effectiveness of treatments. Such measures may be either disease specific or generic, that is, designed to measure HRQOL in a wide range of populations. The Liver Disease Quality of Life scale (LDQOL 1.0) is an American instrument developed to measure HRQOL in patients with different types of liver disease or liver transplants.1 This instrument was recently adapted into Spanish and Catalan.2 The objective of this study was to make a preliminary assessment of the psychometric properties of these new language versions. METHODS The LDQOL consists of a generic instrument (the SF-36) and 12 disease-specific scales containing 75 items. The SF-36 has previously been adapted and validated for use in Spanish,3 and the adapted and validated Spanish version of the questionnaire was incorporated directly here. The 12 disease-specific scales in the LDQOL are: symptoms of liver-disease (17 items), effects of liver disease on activities of daily living (10 items), concentration (7 items), memory (6 items), sexual functioning (3 items), sexual problems (3 items), problems with sleeping (5 items), hopelessness (5 items), anxiety about the disease (4 items), quality of social interaction (5 items), anxiety about the future (4 items), and stigma/body image (6 items). The Spanish and Catalan versions of the questionnaire were produced using the standard recommended methodology of forward and back translation followed by testing in interviews with patients.2 The Spanish and Catalan versions of the LDQOL were administered in a cross-sectional study to a sample of 138 patients with liver transplants. The questionnaires were self-administered whenFrom the Hospital Universitario de Bellvitge (Hospitalet) Barcelona (T.C., G.V., E.R.F., G.T., J.M.M., J.F., L.A.C.) and 3D Health Research Barcelona (M.H., A.C., S.R.), Spain. Address reprint requests to T. Casanovas, Digestive Disease Department, Hospital Universitario of Belvitige, c/Feixa LLarga S/N, Hospitalet, Barcelona 08907, Spain. E-mail: t.casanavas@ esub.scs.es Table 1. Patient Sociodemographic and Clinical Characteristics Mean age, in years (SD) Gender (% males) Mean time with transplant, in years (SD) Child-Pugh classification (%)**: A B C Etiology (%)**: Fulminant Hepatitis Alcohol CBP/colangitis Criptogenic Tumor SD, standard deviation. **Percentages may not sum to 100 because of missing cases.
58.9 (9.8) 61.6 5.8 (3.4) 19.6 37.0 32.6 2.2 28.3 28.3 10.1 5.8 1.4
Table 2. Internal Consistency of Disease-Specific Dimensions in the Spanish and Catalan Versions of the LDQOL 1.0 Dimension
Cronbach’s
Symptoms related to liver disease Effects of liver disease on activities of daily living Concentration Memory Sexual function Sexual problems (women) Sexual problems (men) Sleep problems Hopelessness Worries about the disease Relationships Worries about the future Stigma/body image
0.75 0.80 0.90 0.94 0.75 0.97 0.94 0.74 0.70 0.67 0.60 0.81 0.71
ever possible. Other data collected included age, gender, educational level, length of time with transplant, symptom severity, general health status, type of liver disease, and Child-Pugh classification. Reliability was analysed by studying the internal consistency of the individual disease-specific dimensions of the LDQOL as well as by studying the test-retest reliability in a sub-group of 41 patients in whom the questionnaire was administered on two occasions separated by an interval of approximately 2 weeks. Patients in this group were deemed to be clinically stable. The internal consistency of the disease-specific dimensions was assessed using Cronbach’s alpha, and test-retest reliability was assessed using the intraclass correlation coefficient (ICC).4 Preliminary validity testing was performed by analysing the questionnaire’s capacity to discriminate between groups of patients expected to differ on a given, relevant parameter, such as symptom severity. In this case, the parameters tested were symptom severity, length of time with transplant (1–5 years, 5–10 years, ⬎10 years), and type of liver disease. Ceiling and floor effects (ie, the percentage of patients with maximum and minimum scores, respectively) were also calculated for each dimension.
Table 3. Test-Retest Reliability of Disease-Specific Dimensions in the Spanish and Catalan Versions of the LDQOL 1.0 Questionnaire Dimension
ICC
Symptoms related to liver disease Effects of liver disease on activities of daily living Concentration Memory Sexual function Sexual problems (men and women) Sleep problems Hopelessness Worries about the disease Relationships Worries about the future Stigma/body image
0.46* 0.77* 0.82* 0.85* 0.71* 0.76* 0.89* 0.64* 0.72* 0.62* 0.68* 0.69*
*P ⬍ .05. n ⫽ 41 ICC, intraclass correlation coefficient.
LIVER DISEASE QUALITY OF LIFE QUESTIONNAIRE
1805
Fig 1.
RESULTS
Patient sociodemographic and clinical characteristics are shown in Table 1 The internal consistency of the diseasespecific dimensions of the LDQOI was generally very good (see Table 2), with all coefficients being over 0.60. Testretest reliability was also good in all dimensions, as shown in Table 3, the only exception being the symptoms dimension, where the coefficient was 0.42. All of the ICCs were statistically significant at P ⬍ .05. Few differences were observed between groups on the different disease-specific dimensions of the LDQOL when patients were classified by length of time since transplant or by type of liver disease. However, statistically significant differences were recorded between groups on several disease-specific dimensions when patients were classified by symptom severity (Fig 1). There were some floor and ceiling effects on several of the disease-specific dimensions, particularly on the SF-36 dimensions. DISCUSSION
As far as we are aware, this is the first time the LDQOL has been extensively tested in patients with a liver
transplant. This is also the first validation study of these new Spanish and Catalan versions of the instrument. In this sample, these new language versions of the LDQOL showed generally very good internal consistency and test-retest reliability and some capacity to discriminate between patients classified according to their symptom severity. The fact that the instrument did not discriminate between groups classified according to etiology and length of time with transplant suggests that these parameters may not be particularly relevant in determining HRQOL in this group of patients. Further testing of other types of validity as well as the instrument’s sensitivity to change are required.
REFERENCES 1. Gralnek I, Hays RD, Kilbourne A, et al: Am J Gastroenterol 95:3552, 2000 2. Casanovas T, Vallejo G, Herdman M, et al: Gastroenterologia y Hepatologia 2003 (accepted for publication) 3. Alonso J, Prieto L, Anto ´ JM: Med Clin (Barc) 104:771, 1995 4. Nunnally J, Bernstein IH: Psychometric Theory, 3rd ed. New York: McGraw-Hill; 1994, p xx