Development and validation of the Diabetes Bowel Symptom Questionnaire

Background: Although gastrointestinal symptoms occur frequently, there is no validated measure of gastrointestinal symptoms in patients with diabetes mellitus. Aim: To develop the Diabetes Bowel Symptom Questionnaire. Methods: A questionnaire derived from previously validated symptom measures was compiled to assess all relevant gastrointestinal and diabetes items. Face and content validity were ascertained by expert review. One hundred and sixty-eight patients with diabetes mellitus completed the instrument, and reliability was evaluated by a test-re-test procedure 1 week later. Concurrent validity was evaluated by an independent physician interview (n = 33). Measures of glycaemic control (glycated haemoglobin and plasma glucose) were compared with self-reported glycaemic control on a five-point Likert scale in diabetic out-patients (n = 166). Results: The questionnaire had adequate face and content validity. There was good to excellent test-re-test reliability for the gastrointestinal and diabetes items (median kappa: 0.63 and 0.79, respectively); concurrent validity was good to excellent (median kappa: 0.47 and 0.65, respectively), except for the items assessing the severity of gastrointestinal symptoms. Both glycated haemoglobin (P < 0.0001) and plasma glucose (P = 0.005) correlated significantly with self-reported glycaemic control. Conclusion: The Diabetes Bowel Symptom Questionnaire appears to be a useful measure of gastrointestinal symptoms and glycaemic control in diabetes mellitus, and should have applicability in epidemiological and clinical studies.