LAUSR

SAPHO syndrome (Synovitis, Acne, Palmoplantar Pustulosis, Hyperostosis and Osteitis) is a radio-clinical entity associating joint, bone and inflammatory skin disorders. The clinical presentation is very heterogeneous making the diagnosis difficult. The therapeutic strategy in SAPHO syndrome is poorly defined. The first-line treatment remains NSAIDs on demand, which are effective in treating painful flare-ups but rapidly become insufficient in 60% of cases during the course of the disease. TNF-αNF-O syndrome (S necrosis factor-alpha) are reserved for refractory forms and their efficacy is uncertain [1]. Bisphosphonates (BPs) seem to have potential interest [2].The main objective of this study was to investigate the response to treatment with BPs and/or immunosuppressive drugs (DMARDs - Disease modifying anti-rheumatic drugs), conventional synthetic cs-DMARDs or biologic (b-DMARDs), according to the clinical form of rheumatological SAPHO (bony predominantly versus articular or mixed predominantly.All patients aged 18 years or older with SAPHO syndrome meeting Benhamou’s criteria whose clinical, biological and radiological data were available in the files and who received at least one DMARD or BP treatment for their disease were included in Rouen (thanks to the health data warehouse), Caen, Le Havre/Lillebonne and Dieppe Centres. Each imaging examination was reviewed blinded to the treatments by a radiologist with expertise in osteoarticular disease. Patients were classified into 2 groups (bony versus joint/mixed) according to imaging data and clinical history. The response to treatment was considered positive if symptoms were improved by at least 50% (cut-off used in the literature). An χ2 patients aged 18 years or older with SAPHO syndrome meeting Benhamou’s criteria whose clinical, biological and a Mann-Whitney test for quantitative variables using SPSS software.Thirty-four patients with SAPHO who had received DMARD or BP treatment were included and classified as follows: 13 in the bone group and 21 in the joint or mixed group. The 2 groups were comparable on demographics, duration of follow-up, previous chest involvement, existence of associated dermatological or inflammatory bowel disease, exposure to smoking, duration of exposure to a previous NSAID or antibiotic. Only the age of onset of symptoms differed between the two groups, with a younger onset of disease in the bone group (p=0.043). The prescribers’ therapeutic attitude differed significantly between the 2 groups (p=0.043) with a greater prescription of BPs as first line in the bone group (5/13 patients) and a DMARD in the joint/mixed group (19/21). Regarding treatment efficacy, 10/13 patients had effective treatment without escape during their follow-up in the bone group, which was not significantly different from the joint/mixed group (17/21). BPs achieved escape-free efficacy in significantly more cases in the bone group than DMARDs in the joint or mixed group (p= 0.002). The bone group used significantly fewer specific treatment lines (DMARDs or BP) than the joint/mixed group (1 specific line vs. at least 2) (p =0.046).BPs appear to be more effective in SAPHO with predominantly bone involvement. This appears to be easier to treat compared to SAPHO with articular or mixed forms.[1]Daoussis D, Konstantopoulou G, Kraniotis P, et al. Biologics in SAPHO syndrome: A systematic review. Seminars in Arthritis and Rheumatism 2019;48:618–25. doi:10.1016/j.semarthrit.2018.04.003[2]Wu N, Zhao Y, Tao W, et al. A single cohort, open-label study of the efficacy of pamidronate for palmoplantar pustulosis in synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome. Clin Exp Rheumatol 2020;38:1263–4.None declared