title: A disease-specific quality of life instrument for non-alcoholic fatty liver disease and non-alcoholic steatohepatitis: CLDQ-NAFLD.
abstract: Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis are the most common causes of chronic liver disease with known negative impact on patients' health-related quality of life. Our aim was to validate a disease-specific health-related quality of life instrument useful for efficacy trials involving patients with non-alcoholic fatty liver disease and non-alcoholic steatohepatitis.
  
  
  
  From a long item selection questionnaire, we selected relevant items which, by factor analysis, were grouped into domains constituting Chronic Liver Disease Questionnaire-Non-Alcoholic Fatty Liver Disease version. The developed instrument was subjected to internal validity, test-retest reliability and construct validity assessment using standard methods.
  
  
  
  For development of the Chronic Liver Disease Questionnaire-Non-Alcoholic Fatty Liver Disease version instrument, a 75-item-long item selection questionnaire was administered to 25 patients with non-alcoholic fatty liver disease. After item reduction, factor analysis found that 98.7% of variance in the remaining items would be explained by six factors. Thus, the resulting Chronic Liver Disease Questionnaire-Non-Alcoholic Fatty Liver Disease version instrument had 36 items grouped into six domains: Abdominal Symptoms, Activity, Emotional, Fatigue, Systemic Symptoms, and Worry. The independent validation group included another 104 patients with non-alcoholic fatty liver disease. The Cronbach's alphas of 0.74-0.90 suggested good to excellent internal consistency of the domains. Furthermore, the presence of obesity and history of depression were discriminated best by Chronic Liver Disease Questionnaire-Non-Alcoholic Fatty Liver Disease version scores (P<.05). The domains' correlations with the most relevant domains of Short Form-36 exceeded 0.70. Test-retest reliability in a subgroup of patients (N=27) demonstrated no significant within-patient variability with multiple administrations (all median differences were zero, all P>.15, intraclass correlations .76-.88).
  
  
  
  The Chronic Liver Disease Questionnaire-Non-Alcoholic Fatty Liver Disease version is a disease-specific health-related quality of life instrument developed and validated using an established methodology and useful for clinical trials of non-alcoholic fatty liver disease.
authors.affiliation: Center For Liver Disease, Department of Medicine, Inova Fairfax Hospital, Falls Church, VA, USA.|Betty and Guy Beatty Center for Integrated Research, Inova Health System, Falls Church, VA, USA.|Center for Outcomes Research in Liver Diseases, Washington, DC, USA.
authors.forename: Zobair M
authors.identifier: 0000-0001-9313-577X
authors.initials: ZM
authors.lastname: Younossi
authors.affiliation: Center for Outcomes Research in Liver Diseases, Washington, DC, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Stepanova
authors.affiliation: Center for Outcomes Research in Liver Diseases, Washington, DC, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: Henry
authors.affiliation: Center For Liver Disease, Department of Medicine, Inova Fairfax Hospital, Falls Church, VA, USA.|Center for Outcomes Research in Liver Diseases, Washington, DC, USA.
authors.forename: Andrei
authors.initials: A
authors.lastname: Racila
authors.affiliation: Center For Liver Disease, Department of Medicine, Inova Fairfax Hospital, Falls Church, VA, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Lam
authors.affiliation: Center For Liver Disease, Department of Medicine, Inova Fairfax Hospital, Falls Church, VA, USA.
authors.forename: Huong T
authors.initials: HT
authors.lastname: Pham
authors.affiliation: Center for Outcomes Research in Liver Diseases, Washington, DC, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Hunt
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000523:psychology*; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
keywords: non-alcoholic fatty liver disease; non-alcoholic steatohepatitis; patient-reported outcome; quality of life