Relationship of Antiphospholipid Antibodies to Risk of Dementia: A Systematic Review

Antiphospholipid antibodies (aPL) are well-known risk factors for venous and arterial thrombosis, but their association with cognitive dysfunction has not been widely investigated in the general population and in patients with primary and secondary antiphospholipid syndrome (APS). We performed a systematic review searching MEDLINE via PubMed and Cochrane (CENTRAL) databases for observational studies reporting on the association between aPL and dementia in the general population, in subjects carrying aPL, in patients with cognitive disorder/dementia, and in primary and secondary APS. Prevalence of anticardiolipin (aCL) IgG ranged from 5.9% to 31.1% in the general population, with aCL titers being more elevated in subjects with functional decline of cognitive functions or with neurological alterations as detected by imaging. The prevalence of aPL ranged from 6.0 to 56.6% in patients with vascular dementia. Regarding patients with primary and secondary APS, a severe cognitive deficit has been described in up to 60% of patients, 33.3% of systemic lupus erythematosus (SLE)-APS and 22.2% of SLE patients without aPL. Five studies included patients with primary APS with divergent results, while 18 studies investigated the association between aPL and cognitive impairment in patients with SLE. Of these, 14 reported a positive association between aPL, mostly aCL and LAC, and cognitive impairment while little evidence on anti β2-Glycoprotein I exists. Mechanisms leading to cognitive dysfunction are not well characterized and may include vascular aPL-induced micro and macro-thrombosis and immune-mediated neuronal toxicity pathways in the cerebral district.