CHOROIDAL THICKNESS AS A BIOMARKER OF SYSTEMIC INFLAMMATION IN PATIENTS WITH POLYMYALGIA RHEUMATICA

Laura Trives-Folguera^1,2,3*Santiago Muñoz-Fernández^1,2Maria del Mar Esteban-Ortega^1,2Raquel Coca-Serrano¹TATIANA COBO-IBÁÑEZ^1,2Cristina Vergara-Dangond^1,2Liz Romero-Bogado^1,2Isabel de la Cámara-Fernández^1,2Patricia Richi^1,2Maria Beatriz Paredes^1,2Ana Esteban-Vázquez^1,2Ana Valeria Acosta¹Gabriela Cueva Nájera¹Marco Algarra San José¹Jorge Juan González-Martín³Karen N Franco Gomez³Patricia Bogas Schay³Tamara Shukair Harb³Israel Thuissard-Vasallo²Martina Steiner^1,2

• ¹Hospital Universitario Infanta Sofia, San Sebastián de los Reyes, Spain
• ²Universidad Europea de Madrid SLU, Madrid, Spain
• ³Hospital Universitario HM Sanchinarro, Madrid, Spain

Objective: Choroidal thickness (CT) varies with systemic inflammatory activity in diseases such as spondyloarthritis, suggesting its potential role as a biomarker. This study aimed to evaluate changes in CT in patients recently diagnosed with Polymyalgia Rheumatica (PMR) who are undergoing corticosteroid therapy, over a six-month follow-up period. Methods: It is a prospective, observational, longitudinal pilot study including 20 patients with recent PMR diagnosis from two centres. All participants met PMR classification criteria. Participants underwent three visits: at diagnosis (baseline), at 3 and 6 months after starting corticosteroids. Each visit included physical examination, musculoskeletal ultrasound (MSK US) of shoulders and hips, blood tests including C-reactive protein (CRP) and erythrosedimentation rate (ESR) and CT measurement by optical coherence tomography (OCT). Disease activity was assessed using the PMR Activity Score (PMR-AS) and its imputed version. This is a provisional file, not the final typeset article Results: Mean baseline CT was 242.10 ± 79.05 µm. Choroidal thickness decreased significantly after 3 months (229.85 ± 79.01 µm, p = 0.017) and after 6 months (220.37 ± 75.96 µm, p = 0.014) of corticosteroid treatment. We found a significant decrease in all laboratory and clinical parameters. Concordance between CT, CRP, and PMR-AS was 95%. Rotator cuff pathology does not appear to influence on evolution of MSK US bicipital tenosynovitis inflammatory findings neither in pain. Conclusion: We found that CT was high in patients with recent diagnosis of PMR and decreases significantly after 3 and 6 months of corticosteroid therapy. There is a 95% of concordance between CT and CRP as well as between CT and PMR activity scores. Our findings suggest that CT is useful as a noninvasive, imaging-based biomarker of systemic inflammation in patients with PMR. More studies are needed to confirm these preliminary results.