Comparison of Sacroiliac CT Findings in Patients with Skin Psoriasis, Without Rheumatological Manifestations: A Retrospective Observational Study.

Background: To describe CT characteristics of sacro-iliac joints (SIJs) in patients with psoriasis (PsO) without rheumatological manifestations, and compare them with controls of the same age and sex.

Methods: A monocentric, retrospective, observational study was conducted using the medical records of the rheumatology and dermatology departments of the Tertiary Medical Center in France. We included patients with psoriasis, without rheumatological manifestations, who underwent a CT scan including the SIJs. Each patient was matched with an age- and sex-matched control who had undergone a CT scan for rheumatological reasons. CT scan slices were interpreted by two independent rheumatologists, a resident and an expert, using a modified score. Joint space narrowing (JSN), erosions, sclerosis, and intra-articular gas were scored.

Results: Sixty patients and 57 controls were included. Global SIJs score was higher in the PsO group (6.63 ± 10.7) than in the control group (2.84 ± 4.87). Erosion and sclerosis did not differ between groups; however, the joint space narrowing score was higher in the PsO group (4.15 ± 10.8 vs. 0.873 ± 4.62, P =.035). There were no correlations between the global score and the disease duration or the severity of psoriasis. The number of gestations, active smoking, alcohol intake, and physical work had no impact on the global score.

Conclusion: The CT characteristics of SIJ from patients with PsO were different from those of age- and sex-matched controls, essentially secondary to joint space narrowing.