Retrospective Analysis of the Effectiveness of a Reduced Dose of Idarucizumab in Dabigatran Reversal.

Background:  The recommended dose of idarucizumab, the specific reversal agent for dabigatran etexilate, is 5 g. However, published data showed biochemical reversal after an initial 2.5 g dose.

Objectives:  This study aims to retrospectively compare the clinical effectiveness of 2.5 and 5 g doses of idarucizumab used in dabigatran reversal in three hospitals in Auckland, New Zealand.

Methods:  All patients receiving idarucizumab for dabigatran reversal between April 1, 2016 and December 31, 2018 were included. The primary outcome was the likelihood of receiving a second dose of idarucizumab during the same admission. Secondary outcomes included normalization of coagulation profiles, and 30-day thrombotic, bleeding, and mortality rates.

Results:  Of 329 patients included, 206 received an initial 2.5 g dose and 123 received a 5 g dose. The median age was 78 years and median creatinine clearance was 50 mL/min. Most patients (62.6%) required idarucizumab for an urgent procedure, while 37.4% presented with bleeding. A 2.5 g dose was not associated with an increased rate of receiving a second dose (odds ratio [OR]: 0.686, 95% confidence interval [CI]: 0.225-2.090). A similar proportion of patients in each group achieved a normal activated partial thromboplastin time (73.8 vs. 80.0%,  = 0.464) and dilute thrombin clotting time (95.9 vs. 91.4%,  = 0.379) following idarucizumab infusion. There was no increase in the rate of death (OR: 0.602, 95% CI: 0.292-1.239), thrombosis (OR: 0.386, 95% CI: 0.107-1.396), or bleeding (OR: 0.96, 95% CI: 0.27-3.33) in the 2.5 g dose group compared with the 5 g dose group.

Conclusion:  An initial 2.5 g dose of idarucizumab appears effective for dabigatran reversal in the real-world setting.