P63 Validation of the IBD-control questionnaire across different demographic, socioeconomic and clinical subgroups: analysis of a large-scale nationwide survey

Introduction

The IBD-Control Questionnaire is a simple, generic measure of patient-perceived disease control used increasingly in clinical practice and research. We aimed to address knowledge gaps in its psychometric performance, to ensure that it can be used with confidence in a variety of contexts.

Methods

We analysed 7,341 responses to the IBD Registry COVID-19 survey, sent to 40,911 patients who completed an online self-assessment tool during the pandemic. Questions covered demographics, comorbidities, IBD sub-type, IBD-Control Questionnaire and symptom scores (CD-PRO2 or UC-PRO2). Psychometric properties of IBD-Control-8 were tested overall and within population strata (CD, UC and IBD-U; male and female; ≤65 and > 65 years; number of co-morbidities; deprivation status).

Results

Internal consistency was very strong overall (α: 0.84, ω: 0.89) and for each stratum (α range: 0.81–0.85; ω: 0.86–0.90). Construct validity was confirmed with moderate item correlations versus global rating (VAS) (r_s range: 0.47 to 0.65); strong correlation between IBD-Control-8 score and VAS (r_s=0.74); moderate-to-strong with PRO2 scores (CD: r_s = -0.718; UC: r_s = -0.602); and significantly higher IBD-Control-8 scores for PRO2 remission versus active, consistent within each stratum. Exploratory and Confirmatory Factor Analyses demonstrated a two-factor model (items loading onto Health-related Quality of Life (HRQoL) or Treatment domains). Extensive tests for factorial invariance confirmed consistency.

Conclusions

IBD-Control-8 is a psychometrically robust scale which can be used across a range of populations, offering a quick, reliable and valid method of assessing patient-perceived control. The construct of ‘control’ includes traditional HRQoL and a novel domain relating to treatment perception.