[1] The CDAI was developed by WR Best and colleagues from the Midwest Regional Health Center in Illinois, in 1976.
The components and weighting factors are the following:[citation needed] *One point each is added for each set of complications: Remission of Crohn's disease is defined as CDAI below 150.
[2] Most major research studies on medications in Crohn's disease define response as a fall of the CDAI of greater than 70 points.
[7][8] A key criticism of the CDAI is that it does not incorporate a subjective assessment of quality of life, endoscopic factors, or systemic features, such as fatigue into its calculation.
In a study of 305 patients in Ontario, the IBDQ was found to correlate well with the CDAI in assessing disease activity, but had the added benefit of being a more robust tool for determining the effect of symptoms on perceived quality of life.