A Nationwide Study of Patients Hospitalized with Indeterminate Colitis: a Comparison with Crohn's Disease and Ulcerative Colitis

Purpose: Indeterminate colitis (IC) is subtype of colonic inflammatory bowel disease (IBD) that has features of both Crohn's disease (CD) and ulcerative colitis (UC). There have also been no studies to date examining patients hospitalized with IC in the United States (US).

Methods: We examined the demographic and clinical characteristics of patients admitted with IC and compared them with patients admitted with CD and UC. We also analyzed trends in cost and length of stay (LOS).

Results: Patients admitted with IC tended to be female (58%), Caucasian (72%), and younger [39 (SD: 23) years]. Patients with IC underwent lower endoscopy at higher rates (26%; CD: p < 0.001, UC: p = 0.08) but bowel surgery at lower rates compared to those with CD (11% vs. 16%; p = 0.04). Patients with IC were found to have a higher rate of bowel obstruction (4% vs. 0.7%, p = 0.004) than those with UC, but lower rates of abscess and obstruction compared to patients with CD (p < 0.001). When the analysis was confined to patients who underwent bowel surgery, IC patients still demonstrated higher rates of lower endoscopy (p = 0.03) but lower rates of abscess compared to CD patients (p = 0.049). Costs increased significantly over time for CD- and UC-related hospitalizations, but not for admissions related to IC.

Conclusion: This is the first nationwide US study illustrating the demographics and clinical characteristics of patients hospitalized with IC. We conclude that IC has notable differences in hospitalization characteristics compared to the main two IBD subtypes.