MedWire News: Researchers have developed a new instrument specifically for measuring quality of life (QoL) in patients with celiac disease (CD).
D A Drossman (University of North Carolina at Chapel Hill, USA) and co-authors explain: “Previous studies on CD-related QoL have been limited by their use of a ‘generic’ rather than CD-specific assessment instruments.
“Unlike generic QoL surveys and health status measures, the condition-specific and needs-based CD-QoL considers the difficulties imposed by a stringent gluten-free diet, which, in the United States, can be quite expensive and difficult to follow.”
Through a series of focus groups, the researchers identified 48 items from patients that related to questions about the specific nature of their disease and its impact. These items were reviewed by experts and other patients with CD (average 9-year duration) and reduced to 24 items.
A 5-point Likert Scale was then developed, refined, and administered to 387 patients on a gluten-free diet from both community-based support groups and a tertiary care referral center. A formal validation study was then conducted to assess the psychometric properties of the CD-QoL.
Following factor analysis, four items were removed from the initial 24-item questionnaire spanning four clinically relevant subscales (Limitations, Dysphoria, Health concerns, and Inadequate Treatment) because they contributed little variance to the factor analysis, correlated poorly with the total scale, or were considered redundant.
Correlations performed between the CD-QoL, the single health-related QoL, and the psychometric measures showed mild-to-moderate correlates in the expected direction and within the ideal correlation range.
Patients with higher self-rating of health had higher CD-QoL total scores as well as higher CD-QoL subscale scores. Likewise, those with less daily impairment, lower psychological distress, and less abdominal pain had higher CD-QoL scores.
The researchers say that the CD-QoL they developed has high internal consistency, reliability, and discriminate validity. “The CD-QoL is a valid measure of health-related QoL for [CD] and is likely to be a useful tool for evaluating patients on a gluten-free diet with this disorder,” concludes the team in the journal Alimentary Pharmacology and Therapeutics.
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