BackgroundJanus kinase inhibitors (JAKi) have expanded treatment options for rheumatoid arthritis (RA) by providing rapid and effective oral therapy. However, their optimal use has become increasingly complex after the emergence of safety concerns involving serious infections, herpes zoster (HZ), major adverse cardiovascular events (MACE), venous thromboembolism (VTE), and malignancy. This issue is particularly relevant in Japan, where the RA population is older and has a higher prevalence of co