Disease-specific quality of life: the Gallstone Impact Checklist.

Objective: To develop a disease-specific quality-of-life scale for symptomatic cholelithiasis for use in clinical trials, and to evaluate its reliability, construct validity and responsiveness.

Design: Questionnaire.

Participants: Health care professionals, patients with symptomatic cholelithiasis and their significant others.

Interventions: A 114-item questionnaire was developed from open-ended questions completed by the participants. Questions dealt with physical symptoms, activities of daily living, job performance, leisure activities, emotional factors, marital and sexual relations, support networks and financial situation. The questionnaire was administered by an interviewer to 50 subjects booked for elective cholecystectomy: frequency-importance products were calculated for each of the 114 items. A final shortened scale (the Gallstone Impact Checklist [GIC]) contained 41 items and was completed by patients with symptomatic cholelithiasis on two occasions, 4 to 6 weeks apart.

Results: The checklist requires 10 to 15 minutes to complete. Reliability of the questionnaire and its four subscales was assessed by Cronbach's alpha (overall questionnaire 0.88, pain 0.60, dyspepsia 0.73, emotional impact 0.78 and food and eating 0.84). Construct validity was established by comparison of questionnaire subscales with global ratings of physical and emotional health. Among subjects who reported a difference in their symptoms attributed to gallstones, there was a significant change in total GIC score and in each of the four subscales. Among patients who had undergone cholecystectomy, the absolute value of the effect size was 1.63.

Conclusions: The GIC has content validity and appears to be a reliable, responsive measure of within-person change for subjects with symptomatic cholelithiasis.