1Departments of *Medicine, and †Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; ‡Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and §Departments of Medicine and Public Health Sciences, Pennsylvania State College of Medicine, Hershey, Pennsylvania.
The Crohn's Disease Activity Index (CDAI) and Mayo score for ulcerative colitis (UC) require symptom recall and/or use of a symptom diary. We examined patients' abilities to recall their symptoms and the day-to-day variability of symptoms.
Patients with UC or CD completed a questionnaire including items from the short CDAI (sCDAI) and the 6-point Mayo score. Patients were randomized to receive a follow-up questionnaire testing recall of the bowel symptom items between 1 and 7 days later. In a second study, patients completed a 7-day electronic diary recording their symptoms. sCDAI and 6-point Mayo scores were computed. Analyses estimated daily variability in the indices and misclassification rates when using fewer than 7 days of data.
100%, 82%, and 90% of CD participants recalled the same disease activity status (i.e., active versus remission) as reported on the initial survey when the follow-up questionnaire was administered 1 to 2, 3 to 5, and 6 to 8 days later, respectively. Compared with using 7 days of data, when using only day 7 data, 3.7% of patients with CD were misclassified as active or inactive. Disease activity was misclassified in 2.8%, 4.9%, and 3.3% of patients by using the last 2, 3, or 4 days, respectively. Results were similar for patients with UC.
Patients with CD and UC demonstrated good recall of bowel symptoms for up to 8 days. Additionally, bowel symptoms have relatively little variability within a 7-day period allowing for accurate computation of the sCDAI and 6-point Mayo score using 1 to 3 days of data.