A survey-based index was validated for measuring disease activity in inflammatory bowel disease. An evaluation study.
OBJECTIVE
Crohn's disease is a highly distressful chronic disorder, characterized by frequent relapses. A symptom-based disease activity index was developed for use in epidemiological research.


METHODS
One hundred and six consecutive patients presenting to a tertiary referral hospital in Southern Germany in 2004-2005 participated in a questionnaire-based survey. As a reference standard, disease activity was assessed using a clinical index (Crohn's Disease Activity Index [CDAI], based on symptoms reported to physician, laboratory markers, and physician assessed signs). A linear regression equation was calculated based on the survey data on severity of symptoms (dependent variable: CDAI). Survey index scores (S-CDAI) were then calculated using the estimated coefficients for pain, stools, and general well-being in an independent data set.


RESULTS
S-CDAI and CDAI showed moderate agreement (kappa=0.57 for relapse vs. remission). High activity (high S-CDAI) correlated negatively with high quality of life (disease specific: Short Inflammatory Bowel Disease Quality-of-Life Questionnaire; r=-0.67; generic: Short Form 36 physical summary score, r=-0.47). Test-retest reliability and sensitivity for change were good (intraclass correlation coefficient 0.81).


CONCLUSIONS
A useful, valid, and reliable disease activity score was developed, which will facilitate meaningful survey research in this chronic disorder.
Timmer
Antje
A
Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. antje.timmer@helmholtz-muenchen.de
Kemptner
Daniela
D
Takses
Angela
A
Klebl
Frank
F
Jöckel
Karl-Heinz
KH
D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003424:Crohn Disease / Q000175:diagnosis* / Q000534:rehabilitation; D004812:Epidemiologic Methods; D006801:Humans; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life; D012008:Recurrence; D012720:Severity of Illness Index; D055815:Young Adult