American Society of Hirudotherapy

The Impact of NOACS versus VKAS on Absolute and Relative Cognitive Function Decline Over Time: A Machine Learning Approach

Research article published in Thrombosis and haemostasis (2025)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportClinical TrialsFerrantelli S et al. · Thrombosis and haemostasis, 2025

Abstract

Atrial fibrillation (AF) is the most common arrhythmia in older adults and is associated with an increased risk of cognitive impairment and dementia, even in patients without prior stroke. Nonvitamin K antagonist oral anticoagulants (NOACs) offer a better safety profile than vitamin K antagonists (VKAs), but their cognitive benefit remains uncertain.To assess the impact of NOACs versus VKAs on cognitive decline in elderly AF patients using a machine learning approach.This multicenter prospective cohort study included 983 AF outpatients enrolled between 2008 and 2022 at the Geriatrics Department, University of Catanzaro, and the ProMISE Department, University of Palermo. Stroke and bleeding risks were assessed using CHA2DS2-VASc and HAS-BLED scores. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). Cognitive decline was defined as a decrease in MMSE score between baseline and follow-up. Patients with prior anticoagulant therapy (OAT), severe dementia, or comorbidities affecting cognition were excluded. Multivariable logistic regression and a random forest classifier were used to assess whether anticoagulant type independently predicted cognitive decline. Class imbalance was addressed using both class-weighted learning and the synthetic minority over-sampling technique (SMOTE), with model performance evaluated through repeated stratified cross-validation and threshold optimization.At baseline, cognitive performance was comparable between groups (p = 0.11). After a mean follow-up of 7.2 ± 3.4 years, MMSE scores declined significantly more in VKA-treated patients (-1.7 vs. -0.3 points, p < 0.001). In logistic regression, NOAC use was independently associated with a lower risk of cognitive decline (odds ratio: 0.322; 95% confidence interval: 0.221-0.469; p < 0.0001). The random forest classifier achieved a mean cross-validated AUC of 0.8719 (standard deviation: 0.0273) and a test-set AUC of 0.880. Threshold adjustment and SMOTE improved sensitivity (recall increased: 0.47-0.84), with a precision-recall AUC of 0.763. Permutation importance analysis identified "OAT" as the top predictor. Predicted probabilities of cognitive decline were significantly higher in VKA users (median = 0.70) than in NOAC users (median = 0.09), confirmed by a Kolmogorov-Smirnov test (KS = 0.385, p < 0.001).NOAC use is associated with a lower predicted probability of cognitive decline, suggesting potential cognitive benefits over VKAs.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article

Summary

Atrial fibrillation (AF) is the most common arrhythmia in older adults and is associated with an increased risk of cognitive impairment and dementia, even in patients without prior stroke. Nonvitamin K antagonist oral anticoagulants (NOACs) offer a better safety profile than vitamin K antagonists (VKAs), but their cognitive benefit remains uncertain.

Why This Matters for Hirudotherapy

This multicenter prospective cohort of 983 elderly atrial-fibrillation outpatients used logistic regression and a random-forest model to compare cognitive decline on non-vitamin-K oral anticoagulants (NOACs) versus vitamin-K antagonists (VKAs); over a mean 7.2-year follow-up, MMSE scores fell significantly more in VKA-treated patients (-1.7 vs -0.3 points) and NOAC use was independently associated with lower odds of decline (OR 0.322). For ASH, the value is contextual rather than direct: it documents the long-term burden and class-dependent trade-offs of systemic oral anticoagulation that medicinal-leech-derived antithrombotics (hirudin, calin, destabilase) are sometimes positioned against, underscoring why the leech secretome remains of drug-discovery interest as a source of localized, mechanistically distinct anticoagulant peptides. Honest caveat: this is an observational cohort with a machine-learning analysis showing association, not causation, and it studies pharmaceutical oral anticoagulants only -- it makes no claim about leeches or hirudotherapy and cannot be read as evidence for any leech-based treatment.

Citation

The Impact of NOACS versus VKAS on Absolute and Relative Cognitive Function Decline Over Time: A Machine Learning Approach.

Ferrantelli S et al. · Thrombosis and haemostasis, 2025

Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026

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