A standardized scoring system to identify sacroiliitis could enable patients with inflammatory bowel disease to get earlier rheumatology referrals and improve treatment, according to an analysis of IBD patients with pre-existing abdominal CT scans.
Of the 316 patients recruited from an IBD clinic in Toronto, the validated CT scan scoring system identified 49 with sacroiliitis, of whom only 5 had been referred to an outpatient rheumatology clinic in the city. Rates of sacroiliitis were similar between the 233 patients with Crohn’s disease (15%) and the 83 with ulcerative colitis (16.9%). The scoring system indicated sacroiliitis in 6 (5.6%) of the 108 control subjects, who were recruited from a urology clinic and had no prior history of chronic back pain, reported Jonathan Chan, MD, of the University of Toronto and his associates (Arthritis Care Res. 2017 Jul 21. doi: 10.1002/acr.23323).“Previous studies using CT scan to detect sacroiliitis have relied upon an adaptation of the [modified New York] criteria or a radiologist’s gestalt. Such an adaptation may not be appropriate since changes suggestive of sacroiliitis can be found in the healthy population due to the increased sensitivity of CT scans,” the investigators said. They developed a CT-scan scoring system in which the sacroiliac joints are divided into left/right and iliac/sacral segments. The slice with the greatest number of erosions in each of the four segments contributes that value to the total erosion score, with a score of 3 or greater identifying the presence of sacroiliitis.
By demonstrating that sacroiliitis is three times more prevalent among IBD patients and can be reliably detected in CT scans performed in the clinical care of those patients, this study suggests that “more timely referral for rheumatology assessment” could avoid unnecessary treatment with biologics, Dr. Chan and his associates wrote.
The study was supported in part by a fellowship grant from the Assessment of Spondyloarthritis International Society and in part by Janssen. The investigators reported having no conflicts of interest for the study.
