P282 Influence of phenotype at diagnosis and of other potential prognostic factors on the prognosis of Crohn’s Disease in Chinese population

Xiao, Z.(1,2);Wu, L.(1);Cao, Q.(1);

(1)Sir Run Run Shaw Hospital- School of Medicine- Zhejiang University, Inflammatory Bowel Disease Center, Hangzhou, China;(2)Quzhou People's Hospital, Department of Gastroenterology, Quzhou, China;


L4 Crohn’s disease (CD) is defined as any lesion location proximal to terminal ileum according to Montreal classification. L4 disease was considered to associated with poor prognosis. However, the outcome of CD patients with esophagogastroduodenal disease and small intestinal lesions remains to clarified. Our aim was to confirm whether the outcome diffs among the patients with different L4 disease.


Our study included 670 patients who confirmed CD between January 2014 and December 2020 retrospectively. As similar as Paris classification, we divide L4-disease in adult into L4a and L4b with a ligament of Treitz as a boundary. The primary outcome was defined as intestinal surgery. Clinical manifestation and outcomes were compared among L4a, L4b, and non-L4 disease.


Totally 237(10.0%) patients had isolated L4 disease or L4 disease concomitant non-L4 disease. Among them, 67(10.0%) patients suffered from L4a disease and 168(25.1%) patients has a L4b disease. Patients with L4b disease were more likely to undergo intestinal surgery compared to L4a and non-L4 disease (41.7% versus 9.0% and 21.8%,  respectively, both p<0.0001). However, L4a wasn’t a risk factor for intestinal surgery than non-L4 disease(9% versus 21.8%, p=0.074). At diagnosis, L4b group has a higher percentage of intestinal obstruction than L4-GD and non-L4 group (39.3% versus 17.9% and 22.4%, respectively, p=0.0021 and p<0.0001). Results of multivariate analysis also showed that intestinal obstruction at diagnosis, disease behavior and disease location was a independent predictors for intestinal resection , and L4b (HR 1.786; 95%CI 1.302-2.303, p=0.0032) show significant differences between non-L4 disease.


Within L4 disease, L4b disease was a risk factor associated a poor prognosis compared to non-L4 disease. But the same result can’t be found in L4a disease. It might indicate that we need divide L4 phenotype of Montreal classification into L4a subgroup and L4b subgroup, and treat patients with L4-intestnal disease with biological agents earlier.