Validation of the Spanish version of the Inflammatory Bowel Disease Questionnaire on ulcerative colitis and Crohn's disease

The objective of this study is to validate the Spanish translation of the I nflammatory Bowel Disease Questionnaire (SIBDQ) on ulcerative colitis and C rohn's disease by assessing its convergence validity, discriminatory power, reliability and sensitivity to change. For that purpose, 211 patients with inflammatory bower disease (116 with ulcerative colitis and 95 with Crohn' s disease) completed the SIBDQ, the Psychological General Well-Being Index and the EuroQol. SIBDQ was repeated in those patients who remained in stabl e remission and in those with changes in clinical activity. Clinical activi ty was assessed by the Rachmilewitz and Harvey-Bradshaw indices. Correlatio ns among scores of SIBDQ, EuroQol, Psychological General Well-Being Index a nd clinical indices of activity were all positive and comparable for both d iseases (r = -0.50 to r = -0.70, p < 0.01). Analysis of variance showed tha t SIBDQ discriminates between different clinical degrees of activity. Cronb ach's alpha was 0.96 in ulcerative colitis and Crohn's disease. SIBDQ was a lso highly reliable when it was repeated in clinically stable patients with ulcerative colitis (intraclass correlation coefficient = 0.82) and Crohn's disease (intraclass correlation coefficient = 0.86). SIBDQ was sensitive t o clinical changes in ulcerative colitis and in Crohn's disease, whether pa tients entered remission (effect size -1.88 and -1.81, respectively) or rel apsed (effect size 1.70 and 8.04, respectively). In conclusion, the Spanish version of the IBDQ has proven to be a valid, reliable and sensitive instr ument to detect clinical changes in patients with ulcerative colitis and Cr ohn's disease.