Inappropriate Dosing of Direct Oral Anticoagulants Among Very Elderly Inpatients With Atrial Fibrillation

BackgroundAmong very elderly patients with atrial fibrillation, the frequency of inappropriate direct oral anticoagulant (DOAC) dosing, associated factors, and temporal trends in practice are unknown. ObjectiveTo investigate the frequency of inappropriate DOAC dosing, associated factors, and temporal trends in very elderly patients with atrial fibrillation. MethodsWe retrospectively enrolled consecutive very elderly inpatients ([&ge;]80 years of age) diagnosed with atrial fibrillation at Beijing Hospital from January 2018 to August 2023, and discharged on DOACs were stratified according to receipt of underdosing, overdosing, or recommended dosing. Risk factors associated with underdosing or overdosing were identified using logistic regression. Cochran-Mantel-Haenszel analyses were used to assess temporal trends. ResultsWe included 676 inpatients aged [&ge;]80 years with atrial fibrillation (mean age 84.4{+/-}3.5 years, 53.1% female) prescribed a DOAC at hospital discharge (22.9% dabigatran, 62.3% rivaroxaban, 14.8% edoxaban). Recommended dosing occurred in 338 (50.6%) patients, underdosing in 308 (45.6%), and overdosing in 30 (4.4%). The overall rate of inappropriate dosing was 49.4%. Risk factors associated with underdosing included older age (OR = 1.98, 95% CI: 1.52-2.60, p < 0.001), lower CrCl (OR = 0.98, 95% CI: 0.97-0.99, p = 0.01), and non-internal medicine ward (OR = 2.15, 95% CI: 1.33-3.45, p = 0.002). The risk factor associated with overdosing was younger age (OR = 0.38, 95% CI: 0.19-0.75, p = 0.005). Over the study period, recommended dosing increased over time with a corresponding decline in inappropriate dosing, but these changes were not statistically significant. ConclusionsInappropriate DOAC dosing, especially underdosing, remains common in very elderly AF inpatients. This issue persists despite years passing, emphasizing the need for patient-focused, collaborative AF management and thorough prognostic studies. What Is New?Among AF patients aged 80 and above, nearly half experienced inappropriate NOAC dosing, with 92.3% of these cases being underdosed. This situation has not shown significant improvement over the years. Risk factors associated with underdosing included older age, compromised renal function, and hospitalization in non-internal medicine wards. Risk factor associated with overdosing was younger age. What Are the Clinical Implications?There is an urgent need for patient-centered, multidisciplinary AF management and shared decision-making, coupled with robust prognostic research focusing on very elderly AF patients.