LAUSR

Warfarin, the traditional oral anticoagulant (OAC), functions by inhibiting the biological activity of vitamin K, and thus inhibiting the carboxylation of coagulation factors. Meanwhile, warfarin also interacts with the formation of active vitamin K-dependent bone and cartilage proteins, including osteocalcin, matrix Gla protein and Gla-rich protein.1 2 Therefore, warfarin can be hypothesised to be associated with adverse musculoskeletal events.2 In contrast, novel OACs (NOACs) act independently of vitamin K. We have read with great interest the article by Ballal et al 3 who conducted a nested case–control study and raised the concern that warfarin was associated with significantly higher risk of hip or knee replacements compared with NOACs (adjusted OR 1.59, 95% CI 1.31 to 1.92). Another cohort study also indicated that vitamin K antagonist was associated with an increased risk of osteoarthritis (OA) incidence and progression (OR 2.50, 95% CI 1.94 to 3.20).4 As OA is a relatively rare event and current evidence on the OAC-associated OA risk was limited, we aimed to examine the association between OACs and OA risk using the Food and Drug Administration Adverse Event Reporting System (FAERS) data. We queried FAERS Database using OpenVigil V.2.1 (http://openvigil.sourceforge.net/ …