The Crohn's Disease Activity Index (CDAI) is utilized in clinical trials to assess disease activity in Crohn's.

CDAI scores can range from 0 to ~600.

A cut-off value of <150 was selected so that most patients below this threshold would be rated by physicians as 'very well'.

The delineator between active and very severe disease was defined as a cut-off value of 450 points.

CDAI scores of 150–219 has been labelled as mildly active disease and scores of 220–450 as moderately active disease.

CDAI has some limitations, which include:

• interobserver variability
ratings of 'general well being' and 'intensity of abdominal pain' are subjective
• stool frequency is based on a diary filled in by the patient for 7 days before evaluation which doesn't generally get done in routine clinical practice
• it is not accurate in patients with fistulizing and stenosing disease
• it is not useful in patients with previous extensive ileo-colonic resections or stoma

References


Best WR.
Predicting the Crohn's disease activity index from the Harvey-Bradshaw Index.
Inflamm Bowel Dis. 2006 Apr;12(4):304-10.

Best WR, Becktel JM, Singleton JW, Kern F Jr.
Development of a Crohn's disease activity index. National Cooperative Crohn's Disease Study.
Gastroenterology. 1976 Mar;70(3):439-44.