Cognitive function may change over time in patients with systemic lupus erythematosus (SLE), and cognitive function trajectories have not been well studied. We aimed to identify cognitive function trajectories in SLE and describe them with depressive symptoms trajectories, and we also aimed to identify baseline factors associated with class membership in the dual trajectories.
Longitudinal data from the University of California San Francisco Lupus Outcomes Study were analyzed. Two outcome trajectories were studied jointly, the Hopkins Verbal Learning Test-Revised and the Center for Epidemiologic Studies Depression Scale (CES-D) (administered annually). Univariate/multivariable logistic regression analyses examined baseline factors associated with class memberships.
A total of 755 patients were studied, and 4 latent classes were identified: 1) low CES-D scores and low cognitive scores (no depression plus cognitive impairment; 20%), 2) lowest CES-D scores and highest normal cognitive scores (no depression plus normal cognition; 48%), 3) highest CES-D scores and lowest cognitive scores (depression plus cognitive impairment; 9%), and 4) high CES-D scores and cognitive score at borderline (depression plus borderline cognition; 23%).
In all, 4 distinct classes of dual cognitive function and depressive symptoms were identified. Persistently low cognitive performance in 28% of patients (classes 1 and 3) did not significantly improve over 7 years. Cognitive impairment was associated with depression status in 9% of patients (class 3). Other factors also predicted latent class membership: ethnicity, education, disease activity, physical functioning, and bodily pain. These results highlight the importance of periodic assessment of cognitive function and of different aspects relevant for assessing and managing cognitive function over time in SLE.