Use of oral anticoagulants associated with reduced risk of dementia
A systematic review recently showed that the use of oral anticoagulants (OACs) in atrial fibrillation (AF) is associated with a reduced risk of dementia.
In the systematic review and meta-analysis, researchers explored the association between OAC use and subsequent dementia development in AF patients by searching databases from their inception to February 2018. The pooled adjusted risk ratios (RRs) from six studies suggested a protective effect of OAC use in reducing dementia risk (RR, 0.79; 95 percent confidence interval [CI], 0.67 to 0.93; I2= 59.7 percent; p=0.005). [Neurosci Biobehav Rev 2018;96:1-9]
The study also showed that a high percentage of time in therapeutic range (TTR) was associated with a decreased risk of dementia (RR, 0.38; 95 percent CI, 0.22 to 0.64; I2=81.8 percent; p<0.001).
“The results of the study provide up-to-date evidence, which has implications for clinical decision-making. Our findings support the importance of OAC use in AF patients, not only for the prevention of thromboembolic complications, but also for reducing the risk of developing dementia,” the authors stated.
There was, however, no statistically significant difference in the occurrence of dementia between patients taking novel oral anticoagulants (NOACs) and those taking vitamin K antagonists (VKAs) (RR, 0.97; 95 percent CI, 0.67 to 1.40; p=0.871).
In subgroup analyses by study design, the pooled RR for observational studies showed a significant association between OAC use and decreased risk of dementia (RR, 0.75; 95 percent CI, 0.67 to 0.83; I2=33.6 percent; p<0.001), while results for randomized controlled trials demonstrated no significant association with OAC use (RR, 1.31; 95 percent CI, 0.79 to 2.18; p=0.297).
Literature search for the systematic review used the terms atrial fibrillation, antithrombotics, anticoagulants, antithrombin, factor Xa inhibitors, platelet aggregation inhibitors, and dementia as keywords, text words or Medical Subject Headings (MeSH) terms.
Using these terms, six studies were included for analysis, including a randomized controlled trial, two prospective observational studies, and three retrospective observational studies. [Stroke 2014;45:1381-1386; Thromb Haemost 2004;2:1873-1878; Circulation 2013;128:1341-1348; Eur Heart J 2018;39:453-460; Mayo Clin Proc 2018; 93:145-154; Am Heart Assoc 2016;5:e003932]
Dementia or cognitive impairment in the included studies were diagnosed based on clinical judgement, mental state examinations, cognitive status testing, neuropsychological and physiological testing, established diagnostic criteria for dementia including the Diagnostic and Statistical Manual of Mental Disorders (DSM)-III, DSM-IV, DSM-V, or diagnosis based on international classification of diseases codes (ICD), or United Kingdom (UK) Read codes.
Assessment of publication bias using data of any OAC use and risk of dementia was performed, which showed no evidence of publication bias by Begg’s (p=0.221) and Egger’s tests (p=0.219).
“Research in this area can be improved by performing studies that adjust for confounding factors and include periods of longer follow-up. Moreover, assessment of associations between OAC use and dementia/cognitive impairment can be stratified by age, risk of thromboembolic complications, and medical history. Dose-response relationship between the duration of untreated AF and the development of dementia and assessment of the benefits of individual OACs such as NOACs could also be interesting directions of future studies,” the authors commented.