Prevalence of Sacroiliitis in Inflammatory Bowel Disease Using a Standardized CT Scoring System

Jonathan Chan¹, Ismail Sari², David Salonen³, Mark S. Silverberg⁴, Nigil Haroon² and Robert D Inman⁵, ¹Rheumatology, Spondylitis program, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada, ²Rheumatology, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada, ³Department of Medical Imaging, University Health Network, Toronto, ON, Canada, ⁴Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital IBD Group,, Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, ON, Canada, ⁵Immunlogy and Institute of Medical Science, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: Computed tomography (CT), inflammatory bowel disease (IBD) and spondylarthritis

Session Information

Date: Monday, November 9, 2015

Title: Spondylarthropathies and Psoriatic Arthritis - Comorbidities and Treatment Poster II

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Previous studies assessing the prevalence of sacroiliitis in patients with inflammatory bowel disease (IBD) using CT scans have relied on the general impression of a radiologist. These estimates have ranged between 30-45%; however, only a small proportion of these patients were symptomatic and only patients who had symptoms suggestive of spondylitis had an increased frequency of HLA-B27. To date, the prevalence of sacroiliitis in IBD patients using a standardized CT scoring system is not known.

Our aim is to determine the prevalence of sacroiliitis in patients with IBD using a validated standardized CT scoring system and to compare this prevalence to that in a non-IBD control population.

Methods:

Patients with IBD were recruited from one gastroenterology clinic and control patients were recruited from a urology clinic. The chart of each control patient was reviewed to ensure there was no history of back pain, spondylitis, psoriasis, colitis, or uveitis. Two blinded readers scored the CT scans using two diagnostic models: Model 1: ankylosis or ≥3 erosions; Model 2:ankylosis, ≥3 erosions, ≥0.5cm of iliac sclerosis, or ≥0.3cm of sacral sclerosis. These models have been developed and validated in our previous study to have a sensitivity of 91% and 94% and a specificity of 91% and 86% respectively. We also noted the presence of lumbar spine syndesmophytes and whether the reporting radiologist had noted sacroiliitis in their reporting.

Results:

The percent of patients who fulfilled the various models for sacroilitis are presented in Table 1.

Table 1: Prevalence of sacroiliitis according to each model

	Model 1	Model 2
Control (n=108)	5.6%	13%
Crohn’s disease (n=233)	15%	17.2%
Ulcerative colitis (n=83)	16.9%	21.7%

There was no significant difference in prevalence of sacroiliitis between patients with CD and UC with a Chi²test= 0.725. There was a significant difference in the number of erosions between control and IBD patients but no difference in rate of ankylosis or sclerosis.

Amongst the 49 CT scan positive patients, radiologist comments were reported on 39 images and sacroiliitis was noted in 16 cases. Only 5 of these 49 patients had been referred to the spondylitis clinic. Amongst the 267 CT scan negative patients, radiologist comments were reported on 184 images and 5 definite and 4 possible cases of sacroiliitis were noted.

Conclusion: Using a standardized CT scoring system, the prevalence of sacroiliitis in IBD patients is 16% with no difference between CD and UC patients. This indicates a 3-fold increase in prevalence over non-IBD controls. Despite a growing awareness of the high prevalence of sacroiliitis in patients with IBD, a significant proportion of patients have never been referred to a rheumatologist. Finally, there may be a small proportion of asymptomatic patients who have changes in their sacroiliac joints suggestive of sacroiliitis, though this is of uncertain clinical significance.

Disclosure: J. Chan, None; I. Sari, None; D. Salonen, None; M. S. Silverberg, None; N. Haroon, None; R. D. Inman, None.

To cite this abstract in AMA style:

Chan J, Sari I, Salonen D, Silverberg MS, Haroon N, Inman RD. Prevalence of Sacroiliitis in Inflammatory Bowel Disease Using a Standardized CT Scoring System [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/prevalence-of-sacroiliitis-in-inflammatory-bowel-disease-using-a-standardized-ct-scoring-system/. Accessed .

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