To Örebro University

OBJECTIVES: We aimed to investigate gender-based differences in idiopathic inflammatory myopathies (IIMs), with a particular focus on patient-reported outcomes, utilizing data obtained through the international COVID-19 vaccination in autoimmune disease (COVAD) e-survey.

METHODS: Patient-reported outcomes including fatigue, pain, and physical function were extracted from the COVAD database and compared between genders, adjusting for demographics and IIM subgroups by multivariable analysis. Inclusion body myositis (IBM) was analysed separately because of substantial differences in outcomes.

RESULTS: 1197 complete responses from patients with IIMs as of 31 August 2021 were analysed. Seventy percent were women. Women were younger (58 [48-68] vs. 69 [58-75] years old, median [IQR], p < 0.001) and more likely to suffer from autoimmune multimorbidity, defined as three or more autoimmune diseases in an individual patient (11.4% vs. 2.8%, p < 0.001). In non-IBM IIMs, fatigue visual analogue scale scores were higher in women (5 [3-7] vs. 4 [2-6], median [IQR], p = 0.004), whereas no significant gender-based differences were noted in IBM. Multivariable analysis in non-IBM IIMs revealed women, residence in high-income countries, overlap myositis, and autoimmune multimorbidity were independently associated with increased fatigue.

CONCLUSIONS: Women with IIMs suffer from autoimmune multimorbidity and experience increased fatigue compared to men.