P114 A service evaluation of the Myositis clinic at London North West University Healthcare Trust

Abstract

Abstract Background/Aims The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare diseases, primarily characterised by inflammation of skeletal muscle which leads to muscle weakness, but often involving several other organ systems. The myositis service at London North West University Healthcare Trust (LNWUH) was created in 2017 with the aim of standardising care and improving clinical outcomes for patients. The International Myositis Assessment and Clinical Studies Group (IMACS) established disease activity core set measures to validate clinical response to treatment in studies, but the optimal treatment and real world data on clinical outcomes for patients with IIM is not well described. We undertook a service evaluation to understand the cohort, assess the effectiveness of the service, and in order to inform future service improvements for patients with IIM. Methods We performed a retrospective analysis of the IIM cohort at LNWUH as of January 2021, which consisted of 40 patients. Data were gathered from electronically stored notes and results. Results 65% of our cohort were female, 35% were male. The age range was 18-85. The most common subgroup was dermatomyositis (22.5%). The presenting symptoms included muscle weakness (82.5%), dysphagia (32.5%) and interstitial lung disease (ILD) (27.5%). The most common primary antibody was HMG-CoA reductase, followed by anti-Jo1. More than one antibody was present in 47.5% of patients. three patients had no detectable antibody. 1 in 5 patients had a normal creatine kinase (CK) at baseline. 89% had a raised troponin at baseline, with only two of these having confirmed cardiac involvement on imaging (echocardiogram or cardiac MRI). 30% of the cohort are currently taking mycophenolate mofetil (MMF), 27.5% are taking methotrexate, and 20% are taking hydroxychloroquine. 30% of patients have received rituximab, 20% intravenous immunoglobulin (IVIg), and 7.5% cyclophosphamide. Normalisation of CK was seen in 80% of patients, compared with 20% for pulmonary function tests (PFTs). 63% of patients were in clinical remission one year after diagnosis. Three patients died, two from MDA5-positive rapidly progressive interstitial lung disease. Conclusion In our cohort of patients with IIM, most patients had a significant improvement in their CK and muscle strength with treatment, but there remain challenges. We have established a baseline demographic and clinical outcome data for our cohort that will be used to make service improvements in line with the BSR guideline in development “Adult patients with idiopathic inflammatory myopathy”, and to assess future performance of the service. Disclosure I. Welding: None. A. Isaacs: None.