Original articlesA psychometric comparison of health-related quality of life measures in chronic liver disease
Introduction
Survival and clinical variables are the standard outcome measures for assessing the efficacy of medical and surgical procedures. Nowadays, health-related quality of life (HRQL), commonly defined as the quality of life in relation to a disease and/or treatment, has achieved recognition as an equally important yardstick of outcome [1]. HRQL is usually operationalised as the impact of disease and/or treatment on patients' physical, psychological, and social functioning and is commonly measured by means of self-report questionnaires.
Chronic liver disease (CLD) encompasses various types of patients with liver dysfunctioning, ranging from patients with chronic hepatitis B or C to patients with severely decompensated cirrhosis awaiting liver transplantation. HRQL has become an important issue in CLD as disease burden is heavy even in early disease stages and curative treatment facilities are limited or scarce (liver transplantation). As a result, the main goal of treatment is symptom management in order to maintain or ameliorate quality of life.
In our hospital, a HRQL instrument was needed that could be applied in cohort studies and clinical trials with various types of CLD patients. Ideally, this instrument should be feasible and it should capture HRQL in different clinical and treatment phases in a reliable and valid way. In the literature, no instrument was found that was specifically designed and validated for use in CLD patients. More often, generic HRQL instruments were employed to measure the consequences of chronic liver disease or the impact of a specific treatment on HRQL. For example, the Short-Form Health Survey (SF-36) was used to describe the impact of chronic hepatitis C (CHC) on HRQL 2, 3 and to evaluate the efficacy of treatment with interferon 4, 5. The Sickness Impact Profile (SIP) was administered in studies investigating the impact of CHC [6] and subclinical hepatic encephalopathy on HRQL [7] and in studies into the efficacy of liver transplantation 8, 9.
However, although the reliability and validity of these instruments have been established in various patient populations, they have never been evaluated in chronic liver disease. The only exception to this rule is the recent study of Bayliss and colleagues [10], who documented the psychometric properties of the SF-36 supplemented with several subscales relevant for CHC patients. Information on the psychometric performance is necessary and may enhance the choice for a specific HRQL instrument. Not only the psychometric properties may vary in different diagnostic groups [11], but also the available instruments vary in length and content. Information on the relative performance of shorter versus longer instruments may also influence this decision.
The purpose of this study was therefore 1) to evaluate the psychometric properties of existing questionnaires as applied in a group of CLD patients, and 2) to develop a questionnaire specifically suitable for CLD patients. To this end, we compared the feasibility, reliability, and the construct and known groups validity of four generic and two domain-specific HRQL instruments, and a self-developed Liver Disease Symptom Index (LDSI) in CLD patients.
Section snippets
Study design and data collection procedures
The study was carried out at the in- and outpatient clinic of the Erasmus University Hospital-Dijkzigt, Rotterdam. Consecutive chronic liver disease patients visiting the clinic, during July 1996 to June 1997, were eligible if they were 18 years or older, had given written informed consent, and were able to read and write Dutch. Patients were excluded when they 1) were not able to speak or give consistent information about their HRQL, 2) were using strong sedative drugs, or 3) had
Patients
During the data collection period, 418 patients were eligible for the study. Six patients declined participation, 27 patients did not return the questionnaires, and 11 severely ill patients died before they could fill out the questionnaires. Thus, the total study population consisted of 374 patients, of which 208 met the eligibility criteria for the test–retest study. Fourteen patients did not return the second set of questionnaires, while four patients died before completing them. Thus, data
Discussion
The main purpose of this study was to investigate and compare the psychometric properties of four generic, two domain-specific, and one disease-specific HRQL measure in CLD patients in various disease stages.
The feasibility of the instruments was good with the exception of the sexuality scale of the HOPES. All instruments could be completed within approximately 5–10 min, even by patients with more severe disease. The missing value rates were low and comparable with the results of other studies
Acknowledgements
The study was funded by the Revolving Fund. The authors thank the patients for their willingness to complete the questionnaires and Jan Passchier for his useful critical remarks on earlier drafts.
References (31)
- et al.
Test–retest reliability of health state valuations collected with the EuroQol questionnaire
Soc Sci Med
(1994) - et al.
The Multidimensional Fatigue Inventory (MFI) psychometric qualities of an instrument to assess fatigue
J Psychosom Res
(1995) - et al.
Assessment of quality-of-life outcomes
N Engl J Med
(1996) - et al.
Chronic hepatitis C virus infection causes a significant reduction in quality of life in the absence of cirrhosis
Hepatology
(1998) - et al.
Reduction of health-related quality of life in chronic hepatitis C and improvement with Interferon therapy
Hepatology
(1999) - et al.
Effect of interferon-alpha treatment of chronic hepatitis C on health-related quality of life
Dig Dis Sci
(1997) - et al.
Health assessment for chronic HCV infectionresults of quality of life
Dig Dis Sci
(1996) - et al.
Assessing health-related quality of life in chronic hepatitis C using the Sickness Impact Profile
Clin Ther
(1994) - et al.
Subclinical hepatic encephalopathy impairs daily functioning
Hepatology
(1998) - et al.
Quality of life before and after orthotopic hepatic transplantation
Arch Intern Med
(1991)