BACKGROUND AND AIM: Safety concerns and medication shortages may influence prescribing practices in rheumatology. This study aimed to explore the impact of Janus kinase inhibitor (JAKi) safety warnings and the COVID-19 pandemic on biologic and targeted-synthetic disease-modifying antirheumatic drug (b/tsDMARD) prescription patterns from 2002 to 2024 in the western region of Melbourne. METHODS: A retrospective audit was conducted on data from rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS) patients who attended Western Health and Western Rheumatology clinics between 2002 and January 2024 inclusive. b/tsDMARD switching was analysed based on the first date of b/tsDMARD prescription using interrupted time series analysis, with ethics approval granted by the Western Health Office for Research (HREC/23/WH/101783). RESULTS: There were 3124 new b/tsDMARD prescriptions. Following the 2021 United States JAKi boxed warning, the JAKi prescription rate decreased to -0.04/month (-0.20, 0.11) from 0.30/month (0.18, 0.42), P = 0.002. Supply shortages during the COVID-19 pandemic led to 44 b/tsDMARD switches. The most common cause of switching was inefficacy (32.6% of new prescriptions for AS, 42.6% for RA and 46.1% for PsA (P < 0.001)). Less than 5.4% of new prescriptions were from adverse events, underscoring b/tsDMARD safety. CONCLUSIONS: b/tsDMARD switches were primarily driven by inefficacy. Black box warning issuance led to decreased JAKi prescriptions. The COVID-19 pandemic led to minimal b/tsDMARD switches. Switching due to adverse events was infrequent, highlighting the overall safety of b/tsDMARDs in clinical practice.
Kwan et al. (2026) studied this question.