How to best measure quality of life in coeliac disease? A validation and comparison of disease-specific and generic quality of life measures

Abstract

OBJECTIVE: Health-related quality of life (HRQoL) is an important outcome in chronic disease. Generic HRQoL questionnaires may not adequately reflect disease-specific challenges in coeliac disease. We investigated whether disease-specific HRQoL questionnaires add relevant information to generic measures that will better help to identify patients experiencing problems. PATIENTS AND METHODS: We performed a cross-cultural validation of the Celiac Disease Quality Of Life-survey (CD-QOL), next we developed and validated a new disease-specific HRQoL questionnaire, and finally compared their predictive validity with the disease-generic RAND SF-36/SF-12 in 825 patients (mean age: 56.1+/-15.8 years) with (reported) biopsy-proven coeliac disease. Internal consistency and convergent, discriminative and predictive validity of the questionnaires was determined. RESULTS: Two Dutch versions of the CD-QOL were validated, consisting of 14 and six items, respectively (CD-QOL-14-NL, CD-QOL-6-NL). We developed and validated the CeliacQ-27, which has 27-items across three subscales (Limitations, Worries and Impact on daily life), and a short seven-item version, the CeliacQ-7. All questionnaires had excellent psychometric properties and differentiated well between active disease and clinical remission and strict versus poor dietary adherence. The added value of the disease-specific questionnaires to the generic HRQoL measure to the explained variance of symptom burden and dietary adherence was limited. CONCLUSION: HRQoL in patients with coeliac disease can easily be assessed by brief generic as well as disease-specific measures. Disease-specific questionnaires, however, provide more explicit information on disease-relevant areas of functioning.