Direct oral anticoagulant plasma concentrations according to the time elapsed since the last dose and to renal function: a retrospective study in geriatric patients with hip fractures

BACKGROUND Early surgery for hip fractures in elderly patients is recommended to reduce morbidity and mortality. In patients treated with direct oral anticoagulants (DOACs), early surgical management raises pharmacological and safety concerns. Current guidelines recommend using plasma anticoagulant levels to guide perioperative management, but data describing the time course of DOAC plasma concentrations after the last dose in geriatric patients with hip fracture remain limited. OBJECTIVE(S) To describe the time course of DOAC plasma concentrations according to the estimated time since last intake in elderly patients admitted for hip fracture, and to compare residual concentrations at 24 h between patients with preserved and impaired renal function. DESIGN Single-centre retrospective observational study. SETTING Secondary care hospital; emergency admissions for hip fracture surgery. Study period: January 1st, 2022 to March 31st, 2025. PATIENTS Patients aged ≥65 years treated with DOACs and admitted for hip fracture following a low-energy traumatic event. Patients receiving inappropriate DOAC dosing or DOACs despite formal contraindications were excluded from the main analysis. INTERVENTION(S) None. MAIN OUTCOME MEASURES The primary outcome was the proportion of patients with a plasma DOAC concentration ≥100 ng ml −1 at 24 h after the last estimated dose. Renal impairment was defined as estimated glomerular filtration rate (eGFR)