The impact of TNF inhibitors on glucocorticoid use among patients with inflammatory arthritides: A nationwide cohort study

Objectives: Tumour necrosis factor inhibitors (TNFi) effectively treat inflammatory arthritides and may reduce glucocorticoid dependence. This study investigates the impact of TNFi on glucocorticoid usage. Methods: This nationwide study involved biologic-naïve adults with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and other spondyloarthritis (SpA) registered in ICEBIO who commenced TNFi treatment from 2005 to 2018. Patients were matched by age, sex, and calendar time to five randomly selected general population comparators. Data on filled oral glucocorticoid prescriptions for two years before and after TNFi initiation were obtained from nationwide registries, quantified by filled prescriptions (NP) and defined daily doses. Glucocorticoid users were categorised by their average defined daily doses (DDDs) before TNFi initiation into three groups: "Very Low Doses," "Low Doses," and “High Doses." Multivariable regression models were utilised to estimate incidence rates and odds ratios. Results: We extracted data from 1,290 patients. The mean DDD significantly decreased after TNFi initiation (191.3 to 152.23, p<0.01), particularly in the highest user group (738 DDD to 398 DDD, p<0.001). Nearly 20% continued to receive glucocorticoids two years post-initiation. Factors linked to higher DDDs included age, pre-TNFi glucocorticoid doses, RA diagnosis, and elevated HAQ and DAS28-CRP scores at baseline and 18 months. Methotrexate use did not influence glucocorticoid use. Conclusions: TNFi treatment in inflammatory arthritis decreases the use of glucocorticoid therapy and reduces cumulative dosages, particularly among high-dose users. Disease activity influences higher glucocorticoid dosages. However, many patients still utilise glucocorticoids long-term, despite guidelines recommending rapid tapering after initiating TNFi or avoiding glucocorticoids altogether .