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

Abstract

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. 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. 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. 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.