Background: Measurement of the severity of dyspepsia symptoms before and after treatment and determining what is a significant change is a major problem in designing dyspepsia treatment studies.
Objectives: To assess the reproducibility, validity and responsiveness to treatment of a dyspepsia questionnaire to be used in clinical and population-based studies.
Methods: Seventy-three dyspeptic patients (35 male, 38 female; mean age 52 years) and 75 healthy volunteers (32 male, 43 female; mean age 52 years) were included. Subjects were interviewed for the presence/absence and severity/frequency of 19 gastrointestinal symptoms. Severity was measured on a 5-point scale. Frequency was also recorded on a 5-point scale. A global symptom index (severity x frequency) was calculated for the eight most severe symptoms; a mean global symptom index (8-MGSI) was considered for the evaluation of the instrument. To evaluate intra-observer variation, one author interviewed subjects (T0) and then repeated the interview 1 week later (T1). For inter-observer variation, two authors interviewed patients. VALIDITY was measured by comparing 8-MGSI of the dyspepsia patients to those of healthy volunteers. Responsiveness was assessed by comparing mean global symptom index before and 1 month after appropriate therapy.
Results: Reproducibility: The mean 8-MGSI was 4.5 at T0 and 3.7 at T1 with a correlation coefficient of 0.62. As for inter-observer variation, the average 8-MGSI was 4.8 by the first author and 3.9 by the second with a correlation coefficient of 0.60.
Validity: The mean 8-MGSI was, respectively, 1.4 in healthy volunteers and 4.8 in dyspeptic patients (p = 0.001). Responsiveness: After treatment, a significant improvement in 8-MGSI was detected (p = 0.001).
Conclusions: This questionnaire is a reliable, valid and responsive instrument for measuring the presence, severity and frequency of dyspepsia.