Background: The ulcerative colitis Endoscopic Index of Severity (UCEIS) is an endoscopic index of disease activity, applied to the most severely affected region of the rectosigmoid, developed for use in adult ulcerative colitis (UC) patients. Given that most paediatric UC cases involve extensive colitis, we hypothesized that a pancolonic adaptation of the UCEIS may be more appropriate for children. We aimed to compare such an adapted version and the traditional UCEIS to clinical and biological markers of disease activity in this population.
Methods: In this single-centre prospective study, Paediatric UC Activity Index (PUCAI), physician global assessment (PGA), fecal calprotectin (FC) and C-reactive protein (CRP) were measured in consecutive paediatric UC patients undergoing colonoscopy. Colonoscopies were scored by 2 blinded IBD physicians using the traditional rectosigmoid UCEIS and a pancolonic adaptation derived by summing individual UCEIS scores applied to the rectum, left colon, transverse colon and right colon, and dividing by the number of visualized segments. Spearman correlations were calculated between variables. The ability of both UCEIS versions to discriminate between disease activity, reflected by PUCAI, was assessed graphically.
Results: 35 UC patients were enrolled (53% male, median age 12.7 years, 72% pancolitis). Median PUCAI score, FC and CRP were 15 (range 0–75), 1435 (range 29–16782) μg/g and 1.4 (range 0.1–17.1) mg/L, respectively. Spearman correlations are shown in Table 1. Both versions of the UCEIS demonstrated similar correlations with PGA, PUCAI, FC and CRP. Both scores were most highly correlated with PUCAI, and moderately correlated with PGA and FC. Correlations were lower with CRP. The boxplot in Figure 1 illustrates the distribution of the rectosigmoid and pancolonic UCEIS per disease activity category defined by established PUCAI cut-offs. Based on this, the rectosigmoid UCEIS appears to discriminate disease activity better than the colonic UCEIS.
Conclusions: The traditional UCEIS applied to the rectosigmoid region and an adapted pancolonic version performed similarly in this paediatric UC cohort when compared to various symptom-based and biological markers of disease activity. This likely relates to the usually homogeneous pattern of disease in paediatric UC in the rectum and more proximally in the colon.