Risk of Coccidioidomycosis Infection Among Individuals Using Biologic Response Modifiers, Corticosteroids, and Oral Small Molecules

Objective: The study objective was to examine associations between the use of biologic response modifiers (BRMs), corticosteroids, and oral small molecules (OSMs) and subsequent coccidioidomycosis infection risk among US Medicare beneficiaries with rheumatic or autoimmune diseases. Methods: This retrospective cohort study used US 2011 to 2016 Medicare claims data. We identified geographic areas with endemic coccidioidomycosis (≥25 cases per 10,000 beneficiaries). Among beneficiaries having any rheumatic/autoimmune diseases, we identified those initiating BRMs, corticosteroids, and OSMs. Based on refill days supplied, we created time-varying exposure variables for BRMs, corticosteroids, and OSMs with a 90-day lag period after drug cessation. We examined BRMs, corticosteroids, and OSMs and subsequent coccidioidomycosis infection risk using multivariable Cox proportional hazard regression. Results: Among 135,237 beneficiaries (mean age: 67.8 years; White race: 83.1%; Black race: 3.6%), 5,065 had rheumatic or autoimmune diseases, of which 107 individuals were diagnosed with coccidioidomycosis during the study period (6.1 per 1,000 person-years). Increased risk of coccidioidomycosis was observed among beneficiaries prescribed any BRMs (17.7 per 1,000 person-years; adjusted hazard ratio [aHR] 3.94; 95% confidence interval [CI] 1.18–13.16), followed by individuals treated with only corticosteroids (12.2 per 1,000 person-years; aHR 2.29; 95% CI 1.05–5.03) compared to those treated with only OSMs (4.2 per 1,000 person-years). The rate of those treated with only OSMs was the same as that of beneficiaries without these medications. Conclusion: Incidence of coccidioidomycosis was low among 2011 to 2016 Medicare beneficiaries with rheumatic or autoimmune diseases. BRM and corticosteroid users may have higher risks of coccidioidomycosis compared to nonusers, warranting consideration of screening for patients on BRMs and corticosteroids in coccidioidomycosis endemic areas.