Outcomes of Oral Anticoagulation with Concomitant NSAID Use: A Registry Based Cohort Study

Concomitant use of oral anticoagulants (OACs) and nonsteroidal anti-inflammatory drugs (NSAIDs) is common despite concerns about increased bleeding risk. We sought to assess the frequency of co-administering NSAIDs for patients on OAC and the impact on clinical outcomes.

We conducted a multicenter registry-based cohort study, utilizing 4:1 propensity score matching to compare patients on OAC monotherapy to those on OAC+NSAIDs therapy between 2011 and 2023 at six anticoagulation clinics of the Michigan Anticoagulation Quality Improvement Initiative. Adults on OAC for venous thromboembolism and/or atrial fibrillation were included. Patients with a history of heart valve replacement, under 3 months of follow-up, or using two or more antiplatelet drugs were excluded. The primary outcome was any bleeding. Secondary outcomes included bleeding subtypes, thrombosis/thromboembolism, healthcare utilization, and mortality.

Among the 12,083 patients receiving OAC, 449 (3.7%) were concurrently prescribed NSAIDs. The 1,796 patients on OAC monotherapy were compared to 449 patients on OAC+NSAID therapy after propensity matching. The matched groups were well balanced and followed for an average of 30 months. No significant differences were observed in bleeding event rates per 100 patient-years between the two groups, including overall (25.1 vs. 24.3, p= 0.56), major, and non-major bleeding. Rates of thrombosis, emergency room visits, hospitalizations, transfusion, and mortality were also similar.

Clinical outcomes were similar between OAC monotherapy and OAC with concomitant NSAIDs use in this real-world observational study. As there are limited treatment options for pain, further prospective research should be conducted to replicate these findings.