Cognitive dysfunction is common but heterogeneous across domains among patients with systemic lupus erythematous (SLE), according to study results published in Journal of the International Neuropsychological Society.
Prevalence of cognitive dysfunction in SLE ranges between 20% and 81%. Despite its potential high prevalence, cognitive screening is rarely performed during clinical assessment of SLE.
The aim of the study was to describe the prevalence and characteristics of cognitive dysfunction in SLE.
Patients with SLE and control participants were enrolled in the study from the Monash Lupus Clinic in Australia between 2018 and 2020. Participants underwent cognitive testing with a battery of verified instruments.
The prevalence of cognitive dysfunction was defined as more than 2 standard deviations (SDs) below the normative data for each test; trends in cognitive dysfunction were determined using a cluster analysis.
A total of 95 and 48 patients were included in the SLE and control groups, with a median age of 45 and 46 years; 93% and 92% were women; and 62% and 58% were White, respectively. The SLE vs control group had higher instances of depression, anxiety, and any psychiatric illness (all P £.003).
On all the 15 cognitive tests, the SLE vs control group performed significantly worse. The group differences in performance had very large or large effects in verbal fluency, Letter-Number Sequencing, Rey-Ostrrieth Complex Figure Test recall, Coding California Verbal Learning Test list learning, and interference cognition.
The percentage of patients who had 2 SDs below the control mean in 2 or more tests was 19%. Using a more relaxed definition, (1.5 SDs), 49% of the SLE group had cognitive impairment.
The variability, severity, and pattern of cognitive dysfunction among patients with SLE differed; however, there were few clear patterns.
In the cluster analysis, the optimal number of clusters was 2. The clusters did not reveal distinct types of cognitive dysfunction, but segregated individuals on the basis of the magnitude of dysfunction.
In cluster 1 vs 2, patients were younger (mean, 49 vs 48 years; P =.0015), had higher premorbid intellectual quotient (IQ) score (mean, 111 vs 104; P <.0001), had a lower prevalence of psychiatric illness (38% vs 62%; P =.026), and performed better on the cognitive tests (mean Z-score range, -0.14 to -0.7 vs -0.9 to -2.3 SDs of control group).
A major limitation of this study was the small sample size due to which it was not possible to perform a cluster analysis among the subset of patients with cognitive impairment.
The study authors concluded, “Despite significant variability in performance of cognitive tests among individual patients, our unbiased mathematical approach has shown that on a group level patients cluster into impaired and unimpaired groups, supporting the use of a binary definition of cognitive dysfunction that could be applied in future studies.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Raghunath S, Glikmann-Johnston Y, Vincent FB, Morand EF, Stout JC, Hoi A. Patterns and prevalence of cognitive dysfunction in systemic lupus erythematosus. J Int Neuropsychol Soc. 2023;1-10. doi:10.1017/S1355617722000418