Defining relapse of ulcerative colitis using a symptom-based activity index

Background: Several tools exist to assess disease activity in patients with ulcerative colitis (UC), but a definition of relapse does not exist. The aim of the study was to determine the score in the Simple Clinical Colitis Activity Index (SCCAI) that defined relapse. The reliability and validity of the SCCAI when self-administered was also examined. Methods: Patients with UC routinely attending hospital completed the SCCAI questionnaire, which was later administered by their clinician blinded to the scoring process. In the absence of a gold standard definition of relapse, a subjective global assessment of disease status was made by the clinician. The SCCAI was evaluated in a separate cohort of patients. Results: Seventy-one presentations were analysed; mean age 48 years, 49% male, 37% relapse rate. The mean patient score was 4.2 (range 0-14) and mean physician score 3.8 (0-14). A score of 5 or more defined relapse with 92% sensitivity, 93% specificity, 88% positive predictive value and 95% negative predictive value. The difference between the scores obtained by the patient and clinician (0.35, 95% Cl 0.09-0.62) was small. Correlation with a more complex symptom and laboratory-based activity index was very high (r = 0.79, P < 0.01). The index was quick to use and comparative results for sensitivity and specificity were recorded in the second cohort of patients. Conclusions: The SCCAI is a simple tool that can be accurately and quickly self-administered, correlates well with a more complex disease activity index, and can be used to define relapse of UC with high specificity and sensitivity.