Description of the inflammatory bowel disease natural history in Tehran province, Iran: Mixed panel approaches.

Aim: Description of the inflammatory bowel disease natural history in Tehran province.

Background: Inflammatory bowel disease (IBD) is a non-homogeneous disorder with an unpredictable natural history that impairs a patient's quality of life over the course of their life. As a result, providing evidence for efficient patient management is critical.

Methods: In this case series study, 198 IBD patients who were visited in our clinic at least three times routinely from Oct 2015 to May 2020 were included. Then, two panel-based approaches, the Multi-State Model (MSM) and random-effect ordered logistic, were used to deduce the clinical course of IBD, which included remission, mild, moderate to severe, and surgical states.

Results: For ulcerative colitis (UC), women had a slightly poorer condition for remission but better for moderate to severe and a faster transition from moderate to severe to mild (HR=1.490, 95% CI: 1.02-2.16) compared to men. For Crohn's disease (CD), they had a better condition for remission but a slightly poorer condition for the severe state and higher transition from mild to moderate to severe (HR=1.221, 95% CI: 0.471-3.22) than men. Oral 5-ASA had better efficacy in people with remission and/or mild states but not for those with moderate to severe states, especially in CD (mild to moderate to serve, HR=1.526, 95% CI: 0.59-3.89). Immunosuppressive drugs were better for patients with lower disease severity, especially with UC (mild to remission, HR=1.258, 95% CI: 0.75-2.09).

Conclusion: Panel approaches have the potential efficacy to tackle the unpredictable clinical course of IBD (UC/CD). Hence, we highly recommend that our findings be included into the Iranian routine clinical environment of IBD and/or that related studies be conducted in Iran and other regions to gain a better understanding of the natural history of IBD.