A small research study by investigators at the Biomedical Research Institute of Málaga and Nanomedicine Platform, Spain, has shown that inflammatory activity from rheumatoid arthritis (RA) can cause cognitive impairment including diminished visuospatial abilities, recall, abstract thinking, and the executive functions of working memory, concentration, and inhibition. Their findings are published in the journal RMD Open.
Past research has drawn associations from the inflammation of RA with a range of systemic effects, including on the brain, but details on how these effects might influence cognition have not been defined.
For their research, the investigators enrolled 140 people—70 with RA (80% women with an average age of 56) being cared for at one hospital and 70 people without RA as controls, matched for age, sex, and education. Of the patients with RA, nearly three-quarters (49 patients) had chronic moderate to high levels of systemic inflammatory activity, which as measured by protein markers of the disease, and the degree of joint inflammation despite receiving drug treatments. On average these people had RA for 10.5 years.
Data for other factors that could influence brain function such as age, sex, smoking, alcohol use, high blood pressure, obesity, blood fat levels, diabetes, and a history of cardiovascular disease were also collected.
Between June 2022 and June 2023, all 140 participants in the study received comprehensive neurological and psychological evaluations, a range of cognitive tests, and assessment of mood and quality of life. Areas of evaluation included visuospatial abilities, naming attention, language, abstract thinking, delayed recall and orientation. Also assessed were the executive function of working memory, concentration and inhibition.
The patients were then scored on the Montreal Cognitive Assessment (MoCA), with scores of less than 26 (out of a maximum of 30) defined as cognitively impaired.
The team’s findings showed that those exhibiting cognitive impairment tended to be older, have lower educational attainment and more comorbidities such as obesity, higher cholesterol, and high blood pressure, than those higher MoCA scores. When comparing RA patients to the healthy controls, however, those with RA had lower MoCA scores and lower scores for executive function. Further, 60% of RA patients showed cognitive impairment versus only 40% of the healthy volunteers.
The RA patients also scored significantly higher on mental health measures of anxiety and depression.
Cognitive impairment and depression were more prevalent in those with more substantial and persistent inflammation related to RA. The factors that were associated with higher risk of cognitive impairment were obesity—with risk levels more than six times higher—and inflammatory activity that persisted over the course of the study (nearly double the risk).
“These findings highlight the importance of controlling inflammatory activity and comorbidity in the systemic management of RA,” the researchers wrote. “Our results underline the importance of earlier and more stringent control of the activity of arthritis and the need for new therapeutic strategies aimed at associated factors with the aim of mitigating the risk of cognitive impairment in patients with RA. Similarly, the connection between psychosocial factors and cognitive impairment highlights the need for a holistic approach to RA.”
