Shortened questionnaire on quality of life for inflammatory bowel disease

Questionnaires for measuring quality of life in patients with inflammatory bowel disease usually include a large number of items and are time‐consuming for both administration and interpretation. Our aim was to elaborate and validate a short quality‐of‐life questionnaire with the most representative items from the Spanish version of the 36‐item Inflammatory Bowel Disease Questionnaire (IBDQ‐36) using the Rasch analysis. The responses to 311 IBDQ‐36 questionnaires from 167 patients with ulcerative colitis (UC) and 144 with Crohn's disease (CD) were analyzed. IBDQ‐36 was shortened with successive Rasch analyses until all the remaining items showed acceptable separation and goodness‐of‐fit properties. Validation of the short questionnaire was studied in a new group of 125 patients by determining its validity and reliability. A 9‐item short questionnaire was obtained (IBDQ‐9). Its correlation with IBDQ‐36 was excellent (r = 0.91). Correlation between IBDQ‐9 and clinical indices of activity was statistically significant in UC (r = 0.70) and CD (r = 0.70). IBDQ‐9 score discriminates adequately between patients in clinical remission or relapse (P < 0.01). Sensitivity to change was determined in 14 patients who improved clinically, showing significant IBDQ‐9 changes between both determinations (P < 0.01), with an effect size of −2.67 in UC and −5.29 in CD. IBDQ‐9 was also homogeneous, with a Cronbach's α of 0.95 in UC and 0.91 in CD. In 35‐clinically stable patients, test‐retest reliability was good, with a statistically‐significant correlation between both questionnaires (r = 0.76 in UC and 0.86 in CD, P < 0.01) and an intraclass correlation coefficient of 0.82 in UC and 0.84 in CD. In conclusion, a short and valid questionnaire to measure quality of life in patients with inflammatory bowel disease was obtained using a new measurement model. Its use should facilitate comprehension of the impact of inflammatory bowel disease.