Ab0788 Coexistence of Sarcoidosis and Spondyloarthritis: A Rare and Intriguing Association

Background: A recent systematic literature review found good evidence of the association between spondyloarthritis (SpA) and sarcoidosis. Objectives: We aimed to describe a cohort of patients being diagnosed with both diseases. Methods: All centres included in two large multicentre registries (the Sjögren Syndrome Big Data Consortium and the Sarco- GEAS-SEMI Registry) were contacted via e-mail asking for patients seen in clinical practice with a potential coexistence between SpA and sarcoidosis. The inclusion criterion was defined as the fulfilment of current classification criteria for both diseases. Results: We identified twenty-two patients (13 females and 9 males) with a mean age of 44 years at diagnosis of SpA and of 45 years at diagnosis of sarcoidosis. (Table 1). Sarcoidosis was histologically confirmed in 19 (86%) patients. In 8 patients, sarcoidosis was diagnosed after SpA (group 1), in 8 patients sarcoidosis preceded SpA (group 2) and in 6 patients the diagnosis were concurrent (group 3). A median of 2 years occurred between the diagnosis of the two diseases in Groups 1 and 2. None of the patients had familiar history of SpA or sarcoidosis. In group 1, all patients fulfilled ASAS axial criteria. Six (75%) patients with SpA developed symptoms that led to the diagnosis of sarcoidosis while in 2 individuals pulmonary abnormalities were detected at chest X-ray performed for other reasons. In group 2, 7 (87%) patients with sarcoidosis developed inflammatory back pain (IBP) during follow up which was associated with sacroiliac involvement on X-ray and/or MRI in over 70% of patients but only 2 of them displayed HLA-B*27. Five patients (71%) of group 2 fulfilled ASAS axial criteria and 3 patients fulfilled ASAS peripheral criteria. Regarding sarcoidosis, lung, skin and extra-thoracic lymph nodes were the most frequent manifestations in all 3 groups. Conversely, eye involvement was numerically more frequent in group 3 (concurrent SpA and sarcoidosis) compared to the other 2 groups. In group 3 angiotensin converting enzyme was rarely increased and blood calcium level was always normal whereas they were more frequently abnormal in the other groups. In all groups sarcoidosis was mainly managed with GC. Immunosuppressants and bDMARDs for sarcoidosis were rarely used due to the good response to GC. Conversely, bDMARDs were used in half of the patients for the management of SpA with variable clinical response. At last follow up only one of the 22 patients was deceased due to malignant melanoma. Conclusion: Patients with axSpA should be carefully monitored particularly within the first 5 years after diagnosis as they may develop sarcoidosis. Likewise, articular symptoms, mainly IBP, in patients with sarcoidosis should prompt clinical and imaging assessment for SpA. In these patients, axial involvement is a diagnostic challenge as it can be difficult to differentiate between involvement caused by sarcoidosis and the existence of an associated SpA. REFERENCES: [1] Cadiou S et al. Spondyloarthritis and sarcoidosis: Related or fake friends? A systematic literature review. Joint Bone Spine 2020;87(6):579-587 [2] Brito-Zerón P, et al. Coexistence of immune-mediated diseases in sarcoidosis. Frequency and clinical significance in 1737 patients. Joint Bone Spine. 2021 Dec;88(6):105236. Acknowledgements: NIL. Disclosure of Interests: None declared.