Serum Rheumatoid Factor Levels at Acute Phase of Ischemic Stroke Are Associated with Poststroke Cognitive Impairment

Background: The effect of serum rheumatoid factor (RF) on poststroke cognitive impairment remains unknown. We aimed to investigate the association of serum RF in the acute phase with cognitive impairment at 3 months after ischemic stroke onset.

Methods: Our study was based on a random sample from the China Antihypertensive Trial in Acute Ischemic Stroke, a total of 582 patients from 7 of 26 participating sites of the trial with serum RF levels were included in this analysis. Cognitive impairment was defined as Mini-Mental State Examination less than 27 or Montreal Cognitive Assessment less than 25.

Results: According to Mini-Mental State Examination score, the multivariate-adjusted odds ratio and 95% confidence interval of cognitive impairment for the highest tertile of serum RF was 1.79 (1.08-2.99) compared with the lowest tertile. Each standard deviation increase of log-transformed RF was associated with 33% (95% confidence interval: 7%-66%) increased risk of cognitive impairment, and a linear association between serum RF and risk of poststroke cognitive impairment was observed (P for linearity < .01). Adding log-transformed RF to a model containing conventional risk factors improved the predictive power for poststroke cognitive impairment (net reclassification improvement: 26.21%, P < .01; integrated discrimination index: 1.24%, P = .02). Similar significant findings were observed when cognitive function was defined by Montreal Cognitive Assessment score.

Conclusions: Elevated serum RF levels in the acute phase were independently associated with 3-month cognitive impairment among ischemic stroke patients. Further studies are needed to replicate our findings and to clarify the potential mechanisms.