In AF patients on concurrent warfarin and antiplatelet therapy, spending ≥25% of time with an INR >3.0 was associated with a 2.40-fold increased risk of developing dementia (P=0.04).
Cohort (n=992)
Does increased percent time with a supratherapeutic INR (>3.0) increase the risk of dementia in atrial fibrillation patients receiving concurrent warfarin and antiplatelet therapy?
In atrial fibrillation patients on concurrent warfarin and antiplatelet therapy, spending ≥25% of time with a supratherapeutic INR (>3.0) is associated with a 2.4-fold increased risk of developing dementia.
Effect estimate: HR 2.40
p-value: p=0.04
BACKGROUND: Patients with atrial fibrillation (AF) are at higher risk of developing dementia. AF patients treated with warfarin with poor time in therapeutic ranges are significantly more likely to develop dementia. AF patients are also frequently treated with antiplatelet agents due to coexistent vascular disease. We hypothesize that AF patients with anticoagulation and antiplatelet therapies will be at higher risk of dementia, particularly with chronic exposure to over-anticoagulation. METHODS: Chronically anticoagulated patients receiving warfarin (target INR 2-3) for AF and managed by the Intermountain Healthcare Clinical Pharmacist Anticoagulation Service (CPAS) on concurrent antiplatelet agents with no history of dementia or stroke/TIA were included. The primary outcome was the presence of dementia defined by neurologist determined ICD-9 codes. Percent time with an INR>3.0 was determined and then compared by 3 strata 3 more than 25% of the time were 2.40 times more likely to develop dementia (P = 0.04). A comparison between 3 indicated no difference in risk for the development of dementia (P = 0.74). The risk was significantly increased in patients using triple antithrombotic therapy, although the number of patients within this group was small. CONCLUSION: In AF patients receiving antiplatelet and anticoagulant therapies, the percent of time exposed to over-anticoagulation increased dementia risk. These data support the possibility of chronic cerebral injury from microbleeds as a mechanism underlying the association of AF and dementia.
Jacobs et al. (Thu,) conducted a cohort in Atrial Fibrillation (n=992). Percent time with an INR > 3.0 (≥25%) vs. Percent time with an INR > 3.0 (<10%) was evaluated on Presence of dementia defined by neurologist determined ICD-9 codes (HR 2.40, p=0.04). In AF patients on concurrent warfarin and antiplatelet therapy, spending ≥25% of time with an INR >3.0 was associated with a 2.40-fold increased risk of developing dementia (P=0.04).