Evaluation of short-term responsiveness and cutoff values of inflammatory bowel disease questionnaire in Crohn's disease.
BACKGROUND
The inflammatory bowel disease questionnaire (IBDQ) is a frequently used outcome parameter in clinical trials. Whereas the validity and reproducibility of the IBDQ have been extensively studied, there are limited data on its short-term responsiveness and cutoff values for remission and partial clinical response.


METHODS
The IBDQ score and its bowel (BD), systemic (SysD), emotional (ED), and social (SocD) dimensions were tested for responsiveness in a cohort of 224 patients with Crohn's disease (CD) treated with infliximab for refractory luminal disease. Changes in the IBDQ score and its dimensions 4 weeks after therapy were analyzed and correlated with changes in the Crohn's Disease Activity Index (CDAI). The responsiveness ratios of the IBDQ and its dimensions were analyzed. Using regression line with DeltaCDAI, the cutoff values for the IBDQ remission and response were calculated.


RESULTS
Overall, there was a good correlation between the CDAI and IBDQ at week 0 (correlation coefficient, 0.69; P < .001) and week 4 (-0.76; P < .001) and change after 4 weeks (0.74; P < .001). The correlation coefficients for DeltaCDAI and changes in BD, SysD, ED, and SocD were 0.753, 0.552, 0.620, and 0.631, respectively; all P < 0.001. The responsiveness ratios for DeltaIBDQ, BD, SysD, ED, and SocD were 2.6, 2.1, 1.9, 1.7, and 1.9, respectively. Regression line for the IBDQ (r = -0.76, P < .001) resulted in a cutoff value for remission of 168 points and for DeltaIBDQ resulted in a cutoff value of 22 and 27 points for clinical improvement based on DeltaCDAI > or = -70 and > or = -100 points.


CONCLUSIONS
The IBDQ is a responsive instrument for reflecting quick change in the quality of life of patients with CD. Cutoff values for the IBDQ remission and partial response were 168 and > or = 27 points.
University Hospital Gasthuisberg, Leuven, Belgium. tibor.hlavaty@zoznam.sk
Tibor
T
Hlavaty
Philippe
P
Persoons
Severine
S
Vermeire
Marc
M
Ferrante
Marie
M
Pierik
Gert
G
Van Assche
Paul
P
Rutgeerts
D000328:Adult; D001530:Belgium; D003424:Crohn Disease / Q000175:diagnosis* / Q000628:therapy*; D004032:Diet; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011788:Quality of Life; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome