Development of a Crohn's index for survey research.

Current Crohn's disease activity indices are not suitable for survey research because they rely on information from the laboratory or physical examination. We used data from a multicenter controlled trial of adjuvant sulfasalazine to develop an index of Crohn's disease activity based on information which could be obtained exclusively by interview. The study population consisted of 89 actively symptomatic patients seen on 1082 occasions in eight medical centers. Multiple regression analyses identified three variables which predicted the ratings of physicians: stool frequency, abdominal pain and sense of well-being. The new index correlated very well (r = 0.87, p less than 0.001) with the Crohn's Disease Activity Index from which it was derived. The index may be used in epidemiologic studies to accurately place patients into quartiles of disease severity which correspond to similar quartiles of the CDAI.