Prevalence and clinical features of dementia associated with the antiphospholipid syndrome and circulating anticoagulants

The increasing prevalence with age of antiphospholipid antibodies (aPL), of dementia and of stroke complicates the study of a causal relationship between antiphospholipid syndrome (APS) and dementia. Prolonged aPTT due to circulating anticoagulants (CAC) may serve as a more specific laboratory marker of APS. In a hospital-based study, we examined all patients with CAC and included 23 who fulfilled standard criteria for primary APS. These patients were assessed for dementia, vascular brain disease, autoimmune disease activity and dementia risk factors. Among CAC-positive APS patients, 13 of the 23 (56%) were demented and these were significantly older (mean age±S.E., 68±3 years) than the nondemented APS group (n=10, 51±4 years; p<0.01, Student's t-test). The demented patients had significantly more pathology on computerized brain tomography (CT) and electroencephalography (EEG) studies but six of them had no clinical or CT evidence of vascular brain disease. Erythrocyte sedimentation rate was significantly lower in the dementia group, in which there was also a significant negative correlation between levels of aPL and age. CAC-positive APS patients seem to be at risk for developing dementia with age, suggesting a pathogenic role for prolonged exposure to elevated aPL.