Comparing the real-world and clinical trial bleeding rates associated with oral anticoagulation treatment for atrial fibrillation

Abstract Background The prevention of stroke in patients with atrial fibrillation (AF) involves the use of oral anticoagulation, commonly in the form of direct oral anticoagulants (DOAC). However, it comes with an increased risk of bleeding and therefore, counselling patients on their individual risk is important. Although majority of patients initiated on DOAC have been represented within the clinical trials, there are some cohorts which are under-represented in whom clinicians are unable to practice evidence-based medicine. Methods Utilising the pooled clinical trial (CT) data sourced from Medidata Enterprise Data Store, 5 recent open-label industry sponsored AF trials were compared with Real-World data (RWD) was sourced from the HealthVerity Marketplace with the occurrence of bleeding events as the primary outcome of interest. Results A total of 64,421 patients were included in the analysis, with 3207 patients from the clinical DOAC trials and 61,214 patients from the RWD cohort. Overall, the patients from RWD cohort had more co-morbidities, were older (72.2 ± 11.9 vs 65.3 ±10.7 years old, p<0.001), had higher mean CHA2DS2VASc (3.98 ± 1.9 vs 2.87 ± 1.73, p<0.001) and HAD-BLED scores (2.13 ± 1.02 vs 1/04 ± 0.93, p<0.001) when compared to the trial data. When comparing the incidence of first major bleed at 12 months post treatment initiation, rates in the RWD cohort was significantly higher (10.69 vs 18.97 per 100 person-years). The impact of comorbidities such as age, CHA2DS2VASc and HAD-BLED scores were similar in both cohorts, however, there was an under-representation of older, females and more co-morbid patients within the clinical trial cohort. Conclusion DOAC treated patients have higher bleeding incidence rate in the RWD cohort as compared to clinical trials. This can be explained by the older patient age group with more complex medical histories and higher HAS-BLED scores. The under-representation of higher risk patients and lower proportion of females within clinical trials should be addressed to better translate clinical trial data into real world clinical practice.