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POS1173 CLINICAL PRESENTATION AND TREATMENT OF STERNOCOSTOCLAVICULAR HYPEROSTOSIS (SCCH): A SYSTEMATIC REVIEW AND META-ANALYSIS OF SCATTERED EVIDENCE

Sternocostoclavicular hyperostosis (SCCH) is an inflammatory bone disorder within the spectrum of chronic non-bacterial osteomyelitis. SCCH can be a manifestation of SAPHO syndrome, standing acronym for synovitis, acne, pustulosis, hyperostosis and osteitis, but also appears as an isolated clinical entity without joint and skin involvement1,2. Consensus on nomenclature, diagnostic classification, and therapy for SCCH is currently lacking3. Literature is diffuse, and spreads over a wide range of medical disciplines, calling for a first systematic overview.We critically appraised literature with the aim to i) gain overview on the clinical presentation of SCCH and features leading to diagnosis and to ii) evaluate different treatment modalities and treatment response. We focused on the clinical entity of SCCH in adults, either isolated or as a part of SAPHO syndrome.We conducted a systematic review and meta-analysis according to the PRISMA guidelines on the clinical presentation and therapeutic modalities applied in adult SCCH patients. Studies covering these respective domains were selected. Risk of bias was assessed using validated tools according to study type. Untransformed numerical data and double-arcsine transformed proportional data were analyzed in a random effects model in R-4.0.5; pooled proportions were reported with 95% confidence intervals (95%CI). Treatment response was categorized as good, partial, or none.28(i) and 12(ii) studies were included, containing heterogeneous data on 1818 patients. A female predisposition (67%, 95%CI 60-73) and major diagnostic delay (5 years 95%CI 3-7) were noted. Clinical presentation was marked by anterior chest pain (89%, 95%CI 79-96), and swelling (79%, 95%CI 62-91). Pustulosis palmoplantaris was present in 53%, 95%CI37-68, whereas acne (8%, 95%CI4-13) and peripheral arthritis (24%, 95%CI 11-39) were less prevalent. Inflammatory markers were inconsistently elevated and autoantibodies and HLA-B27 prevalence normal. Histopathology was unspecific, and cultures almost exclusively negative. Increased isotope uptake (99%, 95%CI96-100) was the most consistent imaging finding. Amongst manifold treatments (see Figure 1), NSAIDs were mainly partially effective. Pamidronate and biologicals (mainly TNF-α inhibitors) yielded good, though heterogeneous, response in 83%, 95%CI 60-98 and 56%, 95%CI 26-85 respectively.Figure 1.Treatment modalities applied in SCCH and their effects on bone pain (data from trials and several cohort studies combined)Literature on SCCH is extremely heterogeneous. Timely diagnosis proves challenging and mainly follows from the increased isotope uptake on nuclear examination. Biopsies, autoantibodies and HLA-status are non-contributory, and inflammatory biochemical profiles only variably detected. Pamidronate and TNF-α inhibitors emerged as promising therapies, but powered, placebo-controlled research with standardized measures of response is warranted. Inherently, international consensus on SCCH’s diagnostic classification and name appears critical to improve scientific collaboration on this rare disease, and to advance the development of clinical guidelines.[1]Saghafi M, Henderson MJ and Buchanan WW. Sternocostoclavicular hyperostosis. YSARH 1993; 22: 215-223. 10.1016/0049-0172(93)80070-v. DOI: papers3://publication/doi/10.1016/0049-0172(93)80070-v.[2]Carroll MB. Sternocostoclavicular hyperostosis: a review. Therapeutic advances in musculoskeletal disease 2011; 3: 101-110. 10.1177/1759720X11398333. DOI: papers3://publication/doi/10.1177/1759720X11398333[3] Kalke S, Perera SD, Patel ND, et al. The sternoclavicular syndrome: experience from a district general hospital and results of a national postal survey. Rheumatology 2001; 40: 170-177. 10.1093/rheumatology/40.2.170. DOI: papers3://publication/doi/10.1093/rheumatology/40.2.170The authors would like to thank Drs. J.W. Schoones, information specialist at the Walaeus Library, Leiden University Medical Center, for his contribution to the search strategy and selection of studies.None declared