Supplementary Material for: Use of Systemic Corticosteroids for Reasons Other than Asthma in Subjects with Asthma

<b><i>Backgrounds:</i></b> Recent studies have reported increased risks of adverse events from systemic corticosteroids even with only low-dose or short-term use. Some patients with asthma experience complications requiring systemic corticosteroids. However, few studies have examined issues associated with administration of systemic corticosteroids for reasons other than asthma among subjects with asthma. <b><i>Objectives:</i></b> We investigated patterns of systemic corticosteroid exposure for reasons other than asthma in subjects with asthma. <b><i>Method:</i></b> We retrospectively reviewed the records of adult subjects with asthma followed up for &gt;1 year at Yokohama City University Hospital from January 1, 2010, to December 31, 2019. We investigated patterns and reasons for systemic corticosteroid use during follow-up. In addition, factors related to systemic corticosteroid use for reasons likely other than asthma were investigated. <b><i>Results:</i></b> Among the 568 subjects with asthma analyzed, 326 (57.4%) had received systemic corticosteroids for some reason. Among those 326 patients, 120 (36.8%) had received systemic corticosteroids for reasons likely other than asthma. Multivariable analysis revealed rheumatoid arthritis, eosinophilic granulomatosis with polyangiitis, other collagen vascular diseases, chronic rhinosinusitis, and malignancy as positively associated with systemic corticosteroid exposure for reasons likely other than asthma in subjects with asthma. <b><i>Conclusions:</i></b> About 40% of systemic corticosteroid use in subjects with asthma was for reasons likely other than asthma. Clinicians should be aware of their asthma patients’ exposures to systemic corticosteroids for nonasthma reasons, to avoid missing adverse events or underestimating the severity of asthma, and to reduce systemic corticosteroid use.