Correlations between endoscopic and clinical disease activity indices in intestinal Behcet's disease

AIM: To develop a novel endoscopic severity model of intestinal Behcet's disease (BD) and to evaluate its feasibility by comparing it with the actual disease activity index for intestinal Behcet's disease (DAIBD). METHODS: We reviewed the medical records of 167 intestinal BD patients between March 1986 and April 2011. We also investigated the endoscopic parameters including ulcer locations, distribution, number, depth, shape, size and margin to identify independent factors associated with DAIBD. An endoscopic severity model was developed using significant colonoscopic variables identified by multivariate regression analysis and its correlation with the DAIBD was evaluated. To determine factors related to the discrepancy between endoscopic severity and clinical activity, clinical characteristics and laboratory markers of the patients were analyzed. RESULTS: A multivariate regression analysis revealed that the number of intestinal ulcers (≥ 2, P = 0.031) and volcanoshaped ulcers (P = 0.001) were predictive factors for the DAIBD. An endoscopic severity model (Y) was developed based on selected endoscopic variables as follows: Y = 47.44 + 9.04 × non-Ileocecal area + 11.85 × ≥ 2 of intestinal ulcers + 5.03 × shallow ulcers + 12.76 × deep ulcers + 4.47 × geographicshaped ulcers + 26.93 × volcano-shaped ulcers + 8.65 × ≥ 20 mm of intestinal ulcers. However, endoscopic parameters used in the multivariate analysis explained only 18.9% of the DAIBD variance. Patients with severe DAIBD scores but with moderately predicted disease activity by the endoscopic severity model had more symptoms of irritable bowel syndrome (21.4% vs 4.9%, P = 0.026) and a lower rate of corticosteroid use (50.0% vs 75.6%, P = 0.016) than those with severe DAIBD scores and accurately predicted disease by the model. CONCLUSION: Our study showed that the number of intestinal ulcers and volcano-shaped ulcers were predictive factors for severe DAIBD scores. However, the correlation between endoscopic severity and DAIBD (r = 0.434) was weak.