International IVIg prescription patterns in idiopathic inflammatory myopathies: real-world insights from the MyoNet survey.

OBJECTIVES

Intravenous immunoglobulin (IVIg) is increasingly used in idiopathic inflammatory myopathies (IIMs), especially in cases with complex clinical presentations or resistance to conventional immunosuppressants. However, real-world prescription patterns remain poorly defined and are likely influenced by regional, institutional, and economic factors.

METHODS

A 31-item, English-language e-survey was distributed through the MyoNet registry members after pilot testing and expert review. The survey assessed institutional IVIg treatment practices in IIM, comprising indications, dosing strategies, perceived limitations, and adverse events (AEs). Regional comparisons were performed, and socioeconomic metrics including Human Development Index (HDI) and national gross domestic product (GDP) per capita were correlated with reported barriers.

RESULTS

Across 68 centres in 27 countries, IVIg was most frequently used in dermatomyositis (85.3%), immune-mediated necrotising myopathy (82.4%), and antisynthetase syndrome (66.2%). Dysphagia, refractory disease, and rapidly progressive courses were the leading indications. IVIg was predominantly used as second- or third-line treatment and commonly administered alongside glucocorticoids and steroid-sparing immunosuppressants. AEs were frequent (76.5% of centres), most commonly headaches and infusion reactions. Non-European centres more often used IVIg in seropositive patients, interstitial lung disease, and when other immunosuppressants were contraindicated. Access to IVIg significantly correlated with national development and wealth: cost and availability were more restrictive in countries with lower HDI (cost: r = -0.26, P = .03; availability: r = -0.31, P < .01) and lower GDP (cost: r = -0.27, P = .03; availability: r = -0.34, P < .01).

CONCLUSIONS

This international survey provides a current overview of real-world IVIg use in IIM. Our findings support the need for harmonised treatment guidance to promote equitable access across healthcare systems.