Scale Analysis

The Coeliac Disease Quality of Life (CDQL) questionnaire was developed in 2017 by Skjerning and colleagues as part of the Health Services Research Unit at Oxford University. It is a specialized questionnaire designed for coeliac disease, based on the HRQoL (Health-Related Quality of Life) questionnaire. It is intended for children, adolescents, adults, and individuals with a proxy. Therefore, the questionnaire should be as brief and understandable as possible, allowing it to be completed by patients.

Purpose

This scale was created to determine the quality of life of individuals diagnosed with coeliac disease (CD) and to analyze their feelings about the disease. Their reactions when diagnosed with CD, their emotions, and the difficulties they face vary among patients.

Question Scoring

The questionnaire consists of three broad sections: Sociodemographic Characteristics: This section includes questions related to the participants’ gender, age, residential area, duration of CD, adherence to the gluten-free diet (GFD), concerns about CD symptoms, and the perceived severity of CD symptoms. There is also a question asking whether the questionnaire was completed with the help of someone else or entirely on their own.
HRQoL Questions: The second section consists of HRQoL questions, which may relate either generally or specifically to CD. Specifically, this section includes 2 general questions and 30 specific ones. The specific questions are divided into 8 scales, each of which was analyzed separately for validity.
Open-Ended Question: The third section contains a single open-ended question, allowing participants to provide free comments.
The questions in the questionnaire are accompanied by 5 or 7 response options, with or without text and “smiley faces,” which were presented and evaluated by the participants.

Statistical Analysis

In the study conducted by the creators of the questionnaire, the participants were initially divided into two age groups: those under 18 years of age and those 18 and older. Additionally, participants were divided into three broader age categories: children (0-12 years), adolescents (13-17 years), and adults (18 years and older). Statistical analysis was performed using SPSS and R software, with validity and sensitivity assessed through ANOVA tests.

Validity and Reliability

In the study conducted by the creators of the questionnaire, the reliability of each scale in the questionnaire was calculated. According to the analysis, the questions in each scale showed high correlation, with a Cronbach’s Alpha coefficient of 0.93 for the entire set of questions, indicating high internal consistency and reliability.

Bibliography

Skjerning, H., Hourihane, J., Husby, S., & DunnGalvin, A. (2017). A comprehensive
questionnaire for the assessment of health-related quality of life in coeliac disease (CDQL). Quality of Life Research, 26(10), 2831-2850.

Keywords: CDQL, Coeliac Disease