A symptom severity questionnaire for patients suffering from functional gastrointestinal disorder: FGI-Checklist

Background and aim: A well-validated, comprehensive checklist of functional gastrointestinal (FGI) disorder (FGID) symptom severity for tracking symptom profile changes over time is lacking. We aim to develop and validate a comprehensive symptom severity checklist for FGID.

Methods: A 20-item scale, including both upper and lower gastrointestinal symptoms, was generated to measure the symptom severity commonly found in FGID. Patients who experienced at least monthly symptoms of FGID with negative endoscopy findings were invited to complete the FGI-Checklist, Patient Health Questionaire-9 for assessing depressive symptoms, and Patient Health Questionnaire-15 for assessing somatic symptoms at baseline. A subset of patients who met Rome III diagnostic criteria of gastroesophageal reflux disease, functional dyspepsia, and irritable bowel syndrome received medication treatment for 8-12 weeks and completed the FGI-Checklist again at a follow-up visit. Exploratory factor analysis was performed for subscales formation and psychometric properties were measured.

Results: Six hundred and forty-one patients were recruited for current study and 108 (16.8%) of them completed the FGI-Checklist again at follow-up. Exploratory factor analysis identified a five-factor solution accounting for 66.8% of the total variance. The five factors are named esophageal syndrome, reflux syndrome, functional dyspepsia syndrome, nausea and vomiting syndrome, and abdominal and bowel syndrome. The FGI-Checklist total score correlated with Patient Health Questionaire-9 and Patient Health Questionnaire-15 (all P < 0.001), which demonstrated good construct validity. Good item-internal consistency was found (Cronbach's alphas: 0.69-0.87). Responsiveness for reflux syndrome subscale, functional dyspepsia syndrome subscale, and abdominal and bowel syndrome subscale after medication treatment was significant (paired-t-test: all P < 0.01).

Conclusion: The instrument, Checklist, is valid and reliable.