Objective Increased risk of serious adverse events (AEs) was reported for tofacitinib relative to tumour necrosis factor inhibitor therapy in patients with rheumatoid arthritis (RA) aged ≥50 years enriched for cardiovascular (CV) risk (ORAL Surveillance). We assessed post hoc the potential risk of upadacitinib in a similar RA population. Methods Pooled safety data from six phase III trials were evaluated post hoc for AEs in patients receiving upadacitinib 15 mg once a day (with or without conventional synthetic disease-modifying antirheumatic drugs), adalimumab 40 mg every other week with concomitant methotrexate (MTX), or MTX monotherapy in the overall trial population and in a subset of patients with higher CV risk (aged ≥50 years, ≥1 CV risk factor). Higher-risk patients from a head-to-head study of upadacitinib 15 mg versus adalimumab (SELECT-COMPARE) were assessed in parallel. Exposure-adjusted incidence rates for treatment-emergent AEs were summarised based on exposure to upadacitinib or comparators. Results A total of 3209 patients received upadacitinib 15 mg, 579 received adalimumab and 314 received MTX monotherapy; ~54% of the patients were included in the overall and SELECT-COMPARE higher-risk populations. Major adverse cardiovascular events (MACE), malignancy (excluding non-melanoma skin cancer (NMSC)) and venous thromboembolism (VTE) were more frequent in the higher-risk cohorts versus the overall population but were generally similar across treatment groups. Rates of serious infections in higher-risk populations and herpes zoster (HZ) and NMSC in all populations were higher with upadacitinib 15 mg than comparators. Conclusions An increased risk of MACE, malignancy (excluding NMSC) and VTE was observed in higher-risk populations with RA, yet risk was comparable between upadacitinib-treated and adalimumab-treated patients. Higher rates of NMSC and HZ were observed with upadacitinib versus comparators across all populations, and increased rates of serious infections were detected in upadacitinib-treated patients at higher CV risk.< Réduire