Autoimmune multimorbidity and fatigue in women with idiopathic inflammatory myopathies: an international, patient-reported, e-survey

Abstract

<h2>Abstract</h2><h3>Background</h3> Idiopathic inflammatory myopathies are a group of rare systemic autoimmune rheumatic diseases with substantial heterogeneity. We aimed to investigate gender differences in patient-reported outcomes and treatment regimens of people with idiopathic inflammatory myopathies. <h3>Methods</h3> This international, patient-reported, e-survey was conducted worldwide. We used data from the COVID-19 vaccination in autoimmune disease (COVAD) study, a large-scale, international, self-reported e-survey assessing the safety of COVID-19 vaccination in patients older than 18 years with autoimmune rheumatic diseases, including idiopathic inflammatory myopathies. The COVAD study was conducted in more than 80 health-care centres, including hospitals, clinics, and universities located in more than 50 countries worldwide and on social media platforms, such as Facebook and Twitter. The COVAD e-survey was open between April 1, 2021, and Dec 31, 2021. We extracted survey data regarding demographics; autoimmune rheumatic disease diagnosis; autoimmune multimorbidity (three or more autoimmune rheumatic disease diagnoses for each patient); current corticosteroid or immunosuppressant use; and patient-reported outcomes, including fatigue and pain Visual Analogue Scale (VAS), and PROMIS short form-physical function 10a (PF-10a). Gender was reported by participants with three options (men, women, or do not wish to disclose). Patient-reported outcomes and corticosteroid or immunosuppressant use were compared between men and women. Participants with inclusion body myositis were analysed separately due to the substantial difference in treatment and disease outcomes compared with other idiopathic inflammatory myopathy subtypes. Factors affecting each patient-reported outcome were determined using multivariable analysis. <h3>Findings</h3> The survey data were extracted on Aug 31, 2021, and 1202 complete responses from participants with idiopathic inflammatory myopathies were analysed. Five patients who did not wish to disclose gender were excluded. 845 (70·6%) of the remaining 1197 were women. Women were younger than men (median 58 years [IQR 48–68] <i>vs</i> 69 years [58–75]; p=0·00010). Autoimmune multimorbidity was more common in women than in men (94 [11·1%] of 845 <i>vs</i> 11 [3·1%] of 352; p<0·0001). Corticosteroid use was similar in men and women with idiopathic inflammatory myopathies (except for inclusion body myositis), whereas the distribution of immunosuppressants was different, with higher hydroxychloroquine use in women (131 [18·3%] of 717 <i>vs</i> 11 [6·9%] of 159 in men; p=0·0082). The median fatigue VAS was significantly higher in women than in men (5 [IQR 3–7] <i>vs</i> 4 [2–6]; p=0·0036), whereas the gender difference in pain VAS (median 3 [IQR 1–5] in women <i>vs</i> 2 [0–4] in men; p=0·064) and PROMIS PF-10a scores (38 [31–45] <i>vs</i> 39 [30–47]; p=0·29) was non-significant. There were no significant differences in patient-reported outcomes and treatment in participants with inclusion body myositis. The multivariable analysis of idiopathic inflammatory myopathies (except for inclusion body myositis) revealed that female sex, residence in high-income countries, a diagnosis of overlap myositis, and autoimmune multimorbidity were independent risk factors for higher fatigue VAS. <h3>Interpretation</h3> Women with Idiopathic inflammatory myopathies frequently have autoimmune multimorbidity and increased fatigue compared with men, calling for greater attention and further research on targeted treatment approaches. <h3>Funding</h3> None.