Efficacy and safety of direct oral anticoagulants versus vitamin K antagonists in patients on chronic dialysis

Background: Clinical trials of direct oral anticoagulants (DOAC) are scarce and inconclusive in patients who are receiving dialysis, for whom DOAC are not labelled in Europe. In a French nationwide registry study of patients on chronic dialysis, we compared the effectiveness and safety of off-label DOAC use vs approved vitamin K antagonist (VKA).

Methods: Data on patients on dialysis were extracted from the French Renal Epidemiology and Information Network (REIN) registry and merged with data from the French national healthcare system database (Système National des Données de Santé, SNDS). Patients on dialysis who had initiated treatment with an oral anticoagulant between 1 January 2012 and 31 December 2020, were eligible for inclusion. The primary safety outcome was the occurrence of major bleeding events and the primary effectiveness outcome was the occurrence of thrombotic events. Using propensity score-weighted cause-specific Cox regression, we compared the safety and effectiveness outcomes for DOAC and VKA.

Results: A total of 8954 patients received an oral anticoagulant (483 DOAC and 8471 VKA) for the first time after the initiation of dialysis. Over a median (interquartile range) follow-up period of 1.7 (0.8-3.2) years, 2567 patients presented a first thromboembolic event and 1254 patients had a bleeding event. After propensity score adjustment, the risk of a thromboembolic event was significantly lower in patients treated with a DOAC than in patients treated with a VKA {weighted hazard ratio (wHR) [95% confidence interval (CI)] 0.66 (0.46; 0.94)}. A non-significant trend toward a lower risk of major bleeding events was found in DOAC-treated patients, relative to VKA-treated patients [wHR (95% CI) 0.68 (0.41; 1.12)]. The results were consistent across subgroups and in sensitivity analyses.

Conclusions: In a large group of dialysis patients initiating an oral anticoagulant, the off-label use of DOACs was associated with a significantly lower risk of thromboembolic events and a non-significantly lower risk of bleeding, relative to VKA use. This provides reassurance regarding the off-label use of DOACs in people on dialysis.