Comparison of several activity indices for the evaluation of endoscopic activity in UC: Inter- and intraobserver consistency

Abstract

This study evaluated inter- and intraobserver agreement in the assessment of ulcerative colitis (UC) activity using 4 established indices and a newly designed Modified 6-point Activity Index. In all, 279 endoscopic pictures of inflammatory lesions from 93 UC patients were displayed twice to 4 expert and 4 trainee endoscopists, at an interval of 1 month. Each picture was assessed for inflammatory changes using established indices (Matts, Schroeder [a.k.a. Mayo Score], Baron, and Blackstone) and our new Modified 6-point Activity Index. Weighted kappa statistics were used to estimate intra- and interobserver variation. The Matts and Schroeder indices gave a "good" degree of concordance for expert endoscopists in terms of inter- and intraobserver agreements (0.74-0.78); this was not so evident with the Baron and Blackstone indices (0.61-0.73). For trainee endoscopists, all scores for inter- and intraobserver weighted kappa values using established indices (0.41-0.51) were lower than for the experts. The degree of concordance using the Modified 6-point Activity Index was rated as "good" for inter- and intraobserver agreements for expert endoscopists (0.65 and 0.79), and as "moderate" for trainee endoscopists (0.54 and 0.64). Accurate assessment of UC disease activity from endoscopic findings benefited from experience. For expert endoscopists, the Matts and Schroeder indices proved the most reliable of the 4 established indices. Current endoscopic technologies may be adequate for assessing UC activity, particularly if modified to permit a finer classification of disease severity based on 6 grades, as with our newly developed Modified 6-point Activity Index.