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 alpha 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.
Hospital Universitari Vall d'Hebron, Barcelona, Spain.
M J
MJ
Alcalá
F
F
Casellas
G
G
Fontanet
L
L
Prieto
J-R
JR
Malagelada
D000328:Adult; D003093:Colitis, Ulcerative / Q000150:complications* / Q000473:pathology* / Q000523:psychology; D003424:Crohn Disease / Q000150:complications* / Q000473:pathology* / Q000523:psychology; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D011788:Quality of Life; D012008:Recurrence; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires