Intraindividual cognitive function course over time in patients with systemic lupus erythematosus

BACKGROUND: Cognitive impairment (CI) is one of the most common manifestations of neuropsychiatric systemic lupus erythematosus (SLE). This study aimed to characterise the course of CI over a 1-year period in patients with SLE and its associated factors. METHODS: 175 adult SLE patients from the University of Toronto Lupus Clinic were assessed at baseline, 6 months and 12 months using the American College of Rheumatology Neuropsychological Battery. CI was classified based on standardised z-scores in cognitive domains. Patients were categorised as persistent-CI (CI at all three time-points; T0, T1 and T2), never-CI (no CI at any time-point) or fluctuating-CI (CI at 1-2 assessments). Sociodemographic, clinical, laboratory and medication data were collected at each visit. Patients with persistent-CI were compared with never-CI patients. CI severity was determined based on the mean z-score of tests across all six domains. RESULTS: Over 1 year, 46% of patients experienced CI, with 17% showing persistent-CI, 29% fluctuating-CI and 54% never-CI. Persistent-CI patients exhibited more severe CI compared with fluctuating-CI. The most frequently affected cognitive domains were learning and memory, simple attention and processing speed, and visual-spatial construction. Factors associated with CI persistence over 1 year included Black race, older age at SLE diagnosis, divorced/separated status at T0 and higher disease-related damage at T0. CONCLUSION: This study highlights the variable nature of CI in SLE patients, with most exhibiting a stable course over 1 year. Factors such as sociodemographic characteristics and comorbidities may influence CI persistence