Ultrasound-Guided Synovial Biopsy Can Be Effectively and Safely Performed in Different Clinical Settings Favouring a Widespread Application of Precision Medicine in Rheumatoid Arthritis: A Post-hoc Analysis of Three Clinical Trials

<b>Objectives</b>: In the perspective of an increasingly widespread application of precision medicine in rheumatoid arthritis (RA), this study aimed to compare efficacy and safety of ultrasound-guided synovial biopsy (US-SB) performed in an experienced rheumatology and community hospital setting. <b>Methods</b>: A post hoc analysis of R4RA, STRAP and STRAP-EU trials was performed, comparing US-SB performed in a radiology department of a community hospital without experience in RA (<i>n</i> = 14), versus a rheumatology academic centre with a high expertise in RA management and US-SB (<i>n</i> = 16). Suitability of specimens for histological and transcriptomic analysis (tissue and RNA quality) was analyzed as the main outcome. <b>Results</b>: Demographic and clinical features of the two patients' groups were similar, except of disease duration (<i>p</i> < 0.05). No differences were recorded regarding site and ultrasound of the biopsied joint. Suitability for histological (% of gradable tissue) and transcriptomic analysis (RIN >3) was similar in the two cohorts (both 85.7% vs. 87.5%, <i>p</i> = 0.88). Proportion of gradable biopsies in total (59.2% vs. 59.5%, <i>p</i> = 0.96) and for each patient (52% vs. 56.15%, <i>p</i> = 0.77), were similar in both cohorts. Adverse events were rare (two in community hospital cohort, one in rheumatology cohort, <i>p</i> = 0.54), none considered severe. Seven patients in the community hospital experienced mild or severe pain, only two referred the same in the rheumatology cohort (<i>p</i> = 0.04). <b>Conclusions</b>: US-SB can be safely and effectively performed in a community hospital without experience in RA. A larger diffusion of this technique could allow to pursuit a tailored approach also in ordinary rheumatology outpatient clinics.