Plasma exchange in adult idiopathic inflammatory myositis: a systematic review and meta-analysis.

objectivesTo systematically evaluate the efficacy and safety of plasma exchange (PE) in adult patients with idiopathic inflammatory myopathies (IIM).

methodsA systematic review was conducted in accordance with PRISMA guidelines and registered on PROSPERO. MEDLINE, Embase and Web of Science were searched from inception to 17 January 2025. Studies involving adult patients with IIM treated with PE were included. Baseline demographics, clinical characteristics, treatment outcomes and adverse events were extracted.

resultsThirty-five studies involving 473 patients were included, of whom 361 received PE. Most studies were observational, and PE was predominantly used as adjunctive or rescue therapy alongside immunosuppressive treatment. Across included studies, PE was reported to be associated with improvements in organ-specific outcomes, including muscle strength, dysphagia, pulmonary manifestations and biochemical markers such as creatine kinase, ferritin, KL-6 and myositis-specific autoantibody titres. A meta-analysis of seven comparative studies did not demonstrate a statistically significant mortality benefit associated with PE in patients with refractory or rapidly progressive interstitial lung disease (RR 0.41, 95% CI 0.16-1.06, I

conclusionPE has a biologically plausible but clinically selective role in adult IIM and is most commonly used as an adjunctive therapy in severe or refractory disease. Evidence is heterogeneous and largely observational, limiting causal inference. Prospective studies with standardised outcome measures are required to better define the role of PE in IIM.