Change in The Extent of Colonoscopic and Histological Involvement in Ulcerative Colitis Over Time

OBJECTIVE: Colonoscopy has replaced barium enema as the method for determining the extent of disease in patients with ulcerative colitis (UC). Normally, the extent of disease is determined by direct visualization of the mucosa, but biopsies are also used with increasing frequency. Very little is known about the extent to which these two ways of assessing the extent of disease are correlated and whether the correlation differs over time. The aim of this study was to determine the changes in extent of disease assessed by direct visualization and by histological examination of the mucosa at the time of diagnosis and after 1 yr of follow-up in a cohort of incident cases of UC patients. METHODS: All new cases of UC in a defined population were identified during a 4-yr period (496 patients). Of these, 384 patients (78%) were available for follow-up and were subjected to a second colonoscopy with representative biopsies taken from both normal and affected mucosa. RESULTS: After 1 yr there were macroscopical signs of progression in 14%; 22% showed regression, and 30% had a normal colonoscopy. The histological changes from diagnosis until follow-up showed progression in 20%, 24% showed regression, and 24% had normal histological findings. Histological examination showed more extensive disease than did direct visualization in 4% of patients at diagnosis and in 28% at follow-up, whereas direct visualization showed more extensive disease than did histological examination in 18% of patients at diagnosis and 12% at follow-up. The best correlation at both diagnosis and follow-up was seen in pancolitis (99% and 88%, respectively). CONCLUSIONS: With regard to the extent of colonic involvement in the UC patients, we found less agreement between endoscopic and histological evaluation at the follow-up examination than at the start of the study. This could indicate that biopsies represent a better indicator than endoscopical examination for long term prognosis. Further studies are needed to confirm this finding.