Anticardiolipin antibody and anti-β2 glycoprotein I antibody are potential risk markers of ischaemic stroke in Chinese adults

Abstract

Objectives: aCL and anti-β2 glycoprotein I antibody (aβ2GPI) are autoantibodies associated with thromboembolic diseases. Here we investigated whether they are correlated with ischaemic cardiovascular disease in a Chinese population.

Methods: Serum total aCL and aβ2GPI isotypes (IgA, IgG or IgM, separately) were measured in 11 015 Chinese adults. Differences of antibody level between disease and non-disease groups were examined by t-test. The correlation between antibody and ischaemic cardiovascular disease was determined by logistic regression analysis. Performance of risk prediction models employed aCL or aβ2GPI isotypes was evaluated by C statistic, net reclassification improvement index and integrated discrimination improvement.

Results: Total aCL and aβ2GPI isotypes maintained low levels and increased with increasing age except total aCL and aβ2GPI IgG in participants older than 70 years. When distinguishing ischaemic cardiovascular disease by coronary heart disease (CHD) and ischaemic stroke, the stroke group had higher levels of aCL and aβ2GPI isotypes than the non-stroke group, while the CHD group only had a slightly higher aβ2GPI IgG than non-CHD groups. aCL and aβ2GPI were positively correlated with stroke but not with CHD, and improved the performance of conventional risk factors for stroke risk prediction, with C statistic from 0.769 (95% CI 0.744, 0.793) to 0.777 (95% CI 0.754, 0.800) (aβ2GPI IgG, P = 0.0091), and 0.778 (95% CI 0.754, 0.801) (aβ2GPI IgA, P = 0.0793). Stroke risk could be better reclassified by aCL and aβ2GPI, in association with both net reclassification improvement and integrated discrimination improvement statistics (P < 0.05).

Conclusion: aCL and aβ2GPI are associated with ischaemic stroke and have added value for stroke risk prediction.

Keywords: anti-β2GPI antibody; anticardiolipin antibody; ischaemic stroke; risk marker.