Apixaban Lead-In Versus Lead-In Omission in Hospitalized Adults with Acute Venous Thromboembolism: A Retrospective Safety Analysis.

BACKGROUND: Apixaban for acute venous thromboembolism (VTE) is dosed with an intensified 7-day lead-in to decrease recurrence. The optimal initiation dosing in hospitalized patients remains unknown. This study compares the safety and efficacy of apixaban maintenance versus lead-in dose initiation in hospitalized patients with acute VTE. METHODS: This IRB-approved, retrospective, single center, cohort study was conducted at a quaternary referral, academic medical center. Adult patients diagnosed with acute VTE who received ≥1 apixaban dose during hospitalization were eligible for inclusion. Patients initiated on apixaban ≥7 days from VTE or anticoagulated within 3 months prior to admission were excluded. Patients were grouped into 2 cohorts: (1) maintenance dose (MD) - no apixaban 10 mg dose and (2) lead-in dose (LD) - received ≥1 apixaban 10 mg dose. Outcomes were assessed for 3 months following apixaban initiation. The primary outcome compared a composite endpoint of major and non-major clinically relevant bleeding (NMCRB) between groups. The secondary outcome compared a composite endpoint of recurrent VTE and all-cause mortality (VTE-M) between groups. RESULTS: A total of 200 (28 MD, 172 LD) patients were included. Patients were 61 (48-72) years old and admitted 5 (2-12) days. Baseline characteristics were similar between groups. Parenteral anticoagulation was administered in 90% (25 [89%] MD, 156 [91%] LD) of patients prior to apixaban initiation. Time on parenteral anticoagulation was longer in MD (61 [37-88] hours] compared to LD (40 [18-65] hours) patients (P = .02). Composite major and NMCRB occurred in 6 (21.4%) MD and 21 (12.2%) LD patients (P = .19). Composite VTE-M occurred in 2 (7.1%) MD and 16 (9.3%) LD patients (P = .71). CONCLUSION: This study found no difference in bleeding or VTE-M in hospitalized patients with acute VTE receiving apixaban MD versus LD. The high incidence of bleeding suggests caution is needed with apixaban initiation in this population.