¹Asia Mubashir, ¹Sarah Al Qassimi, ²Jawahir Alameri, ¹Rajaie Namas, ¹Mohamed Elarabi

¹Cleveland Clinic Abu Dhabi

Background(s): Idiopathic Inflammatory Myositis (IIM) is a systemic inflammatory disorder that classically affects the sin, muscles, and other organs, including the respiratory tract, cardiac system, and gastrointestinal tract. IIM is further divided into subgroups that vary in terms of prognoses, treatment responses and organ manifestations, thus highlighting the importance of identifying these subgroups. There is a scarcity of data in the Middle East surrounding IIM and this is the first study of its nature from the United Arab Emirates. Idiopathic Inflammatory Myositis (IIM) is a systemic inflammatory disorder that classically affects the sin, muscles, and other organs, including the respiratory tract, cardiac system, and gastrointestinal tract. IIM is further divided into subgroups that vary in terms of prognoses, treatment responses and organ manifestations, thus highlighting the importance of identifying these subgroups. There is a scarcity of data in the Middle East surrounding IIM and this is the first study of its nature from the United Arab Emirates. Our study aimed to determine the profile of IIM in the United Arab Emirates and address the clinical significance of its autoantibodies in myositis patients

Method(s): Between April 2015 to March 2023, 124 patients were retrospectively identified to have myositis through our electronic medical records’ in-built data exploration tool. Inclusion criteria included patients fulfilling the 2017 EULAR/ACR criteria for IIM. Exclusion criteria included those below the age of 17 and those who did not fulfil criteria for IIM. Data collected included patient characteristics, disease manifestations, antibody panels, investigations, and treatment.

Result(s): A total of 69 patients were identified for the study. Our cohort was predominantly female (57%) of Emirati nationality (64%) with an average age of IIM diagnosis at 28±8 (mean±SD) years. The most common diagnoses were anti-synthetase syndrome (34.8%), dermatomyositis (24.6%), connective tissue disease-related myositis (24.6%), juvenile dermatomyositis (10.1%) and polymyositis (5.8%). The most common clinical domains of IIM were dermatological (58%), neurological (55%), pulmonary (46%), musculoskeletal (45%) followed by gastrointestinal (41%) and cardiac (9%). Dermatological manifestations included Gottron’s papules (28%), rash (20%), heliotrope rash (15%) and shawl sign (14%). Neurological manifestations included muscle weakness (59%) and dysphagia (33%). Pulmonary manifestations included interstitial lung disease (35%). Musculoskeletal manifestations included arthritis (91%). The average CK level was 1640±3466 IU/L and was elevated in 39 patients (56.6%). The most common MSAs were Jo-1 (17%), PL-12 (10%), MDA-5 (7%), Mi-2 (4%), and PL-7 (3%). The most common MAAs were ANA (41%), Ro (38%), PM/Scl (7%), RNP (7%), and sm/RNP (7%). In terms of treatment, patients were given corticosteroids (77%), mycophenolate mofetil (42%), rituximab (36%) and IVIG (23%) at any given point of their disease.

Conclusion(s): Our study represents the first investigation of IIM in the United Arab Emirates with an aim to tailor management and treatment based on our population’s IIM subgroups.