Abstract
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. OBJECTIVES: 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. INTERVENTIONS: 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) <50 ml min(-1). RESULTS: Data from 186 patients were analysed. Among patients with eGFR ≥50 ml min(-1), 1 out of 49 (2.0%) had a plasma DOAC concentration ≥100 ng ml(-1) at 24 h. In contrast, 11 patients (9.4%) with eGFR <50 ml min(-1) had concentrations ≥100 ng ml(-1) at 24 h. Inappropriate DOAC dosing was significantly associated with higher residual plasma concentrations (9 patients excluded). CONCLUSIONS: Most elderly patients with preserved renal function had plasma DOAC concentrations below 100 ng ml(-1) at 24 h. Although not powered to demonstrate definitive safety, these findings suggest that systematic plasma DOAC monitoring may be unnecessary in selected geriatric patients with hip fracture and preserved renal function. These results should be considered hypothesis-generating. TRIAL REGISTRATION: Not applicable (retrospective observational study).