Comparison of Safety Profiles of New Oral Anticoagulants with Warfarin Using the Japanese Spontaneous Reporting Database

Abstract

The development of new oral anticoagulants (NOACs) has led to an alternative to treatment with warfarin. However, real-world data on comparing safety profiles of NOACs and warfarin are insufficient. The purpose of this study was to compare safety profiles of warfarin and NOACs using a spontaneous reporting system database. Adverse event reports spontaneously submitted to the Pharmaceuticals and Medical Devices Agency (Japan) between April 2011 and January 2017 were analysed. We performed disproportionality analyses, calculating the reporting odds ratio (ROR) with 95% confidence interval (CI). The database comprised 3445 reports associated with warfarin, and 14,269 reports with NOACs. A large number of bleeding complications were detected with the use of both warfarin and NOACs. As for cerebral haemorrhage, the signal scores were greater for NOACs as a class (ROR 25.1, 95% CI 23.3-27) and individual agents (edoxaban: ROR 23.6, 95% CI 18.6-29.9; rivaroxaban ROR 23.9, 95% CI 21.4-26.8; apixaban ROR 28.1, 95% CI 25.4-31.1) than for warfarin (ROR 18.9, 95% CI 16.4-21.7), but showed the lowest value for dabigatran (ROR 9.26, 95% CI 7.76-11). Gastrointestinal haemorrhage had stronger signals for NOACs (ROR 19.4, 95% CI 17.8-21.1) than warfarin (ROR 12.2, 95% CI 10.2-14.6). With respect to calciphylaxis, the association with warfarin was noteworthy (ROR 190; 95% CI, 126-287), but no reports were detected involving NOACs. Our results may provide useful information for treatment with oral anticoagulants, although further studies with more data are needed.