The large majority of coeliacs have a high degree of perceived dietary competence

Abstract

Purpose: The treatment for coeliac disease (CD) is a gluten-free diet (GFD), which impacts the health-related quality of life (HRQoL). The aim of the study was to develop the Gluten-Free Diet Perceived Competence Scale (GFD-PCS): a short and precise CD-specific patient-reported outcome measure.

Methods: The GFD-PCS was developed from the scales ‘Perceived Competence (Maintaining a Healthy Diet)’ and ‘Perceived Competence for Diabetes’. The scale was then programmed into a web-based questionnaire and distributed together with generic quality of life (WHO-5) and CD-specific HRQoL (CDQL) questionnaires.

Results: There were 931 respondents. The 831 who reported ‘diagnosed CD’ were retained. The average age was 37.6 years (SD = 16.5). There was no statistically significant difference between males (M = 5.9, SD = 1.6) and females (M = 6.2, SD = 1.4) in GFD-PCS score. Respondents younger than 18 years (n = 104) scored lower (M = 5.8, SD = 1.4) than adults (M = 6.2, SD = 1.4). The psychometric properties of the GFD-PCS showed excellent internal reliability (α = .96) and satisfied construct and criterion validity.

Conclusion: The GFD-PCS measures patient-perceived dietary competence for maintaining a GFD. The scale is psychometrically robust and provides a useful tool in assessing patients’ difficulties with a GFD.

Keywords:

• Coeliac disease
• perceived competence
• quality of life
• gluten-free diet
• scale development

Acknowledgements

The authors wish to thank all respondents and the Danish Coeliac Society.

Ethical approval

Due to the exclusive use of interview and questionnaire-based methods, the study was approved a priori by the Regional Committee on Health Research Ethics. The legislation governing ethical approval is described here.

Questionnaire and interview surveys:

Clean questionnaire and interview surveys should not be notified to the committee system. References to the law and guidelines regarding this provision are contained in:

Section 14, subsection 2:

‘Questionnaire surveys and health science registry research projects must only be reported to the Scientific Ethics Committee if the project includes human biological material’.

‘Guidance on notification, reporting obligations, etc. (health science research projects)’ of the National Science Ethics Committee 2014, section 2.8:

‘For questionnaire surveys, the same is true of the so-called register research projects, i.e., that they are only to be notified if the project involves a study of human biological material or examination of individuals (…). Interview surveys are equated with questionnaire surveys’.

Disclosure statement

T.O.K. and H.S. do not have any conflicting interests. S.H. has participated in advisory board activities at Inova, and received honorarium for oral presentations by Thermo-Fisher.