Psychometric Characteristics of the Persian Version of the Irritable Bowel Syndrome Quality of Life Questionnaire (P-IBS-QOL)

Objectives: This study investigated the psychometric characteristics (structural, concurrent and construct validity, and internal consistency) of the Persian version of the Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire, which is commonly used across cultures.Methodology: One hundred twenty-six patients with irritable bowel syndrome (based on diagnosis by professional physicians and the Rome II criteria) were selected from patients referred to Alzahra and Noor Hospitals in Isfahan to complete the IBS-QOL questionnaire.Results: Eight subscales of the questionnaire (sum score) had acceptable internal consistency coefficients (alpha for subscales: dysphoria, 0.88; interference with activity, 0.67; body image, 0.72; health worry, 0.57; food avoidance, 0.52; social reaction, 0.71; sexual concern, 0.76; relationships; 0.62; and overall score, 0.93). In order to assess construct validity, groups of healthy persons (n = 40) and patients (n = 40) were selected. Results of an independent t-test showed a significant difference between the mean of overall score and all subscale scores (except body image subscale) of the two groups (P 0.05). Pearson correlation coefficients showed that the questionnaire has significant concurrent validity (with respect to IBS-QOL-36) (P 0.05).Conclusion: The Persian version of IBS-QOL-34 is a valid and reliable instrument and is suitable for used in research and clinical trials