Objective: To determine factors affecting the severity of cognitive impairment in systemic lupus erythematosus (SLE) and to analyze its anatomic location.
Methods: Fifteen cognitive functions grouped into 8 domains were evaluated in 52 patients with SLE and 20 with rheumatoid arthritis. Patients were classified according to severity of impairment as normal, mild, or moderate/severe. Multivariate analysis was performed to identify the main factors affecting severity of cognitive deficits. The most likely anatomic site of damage according to neuropsychological performance was compared with the lesion's location on magnetic resonance imaging (MRI).
Results: In SLE patients, a stepwise regression analysis showed that the number of impaired functions (dependent variable) was associated with antiphospholipid antibody positivity (aPL+; P = 0.04), the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI; P = 0.001), hypertension (P = 0.032), and was inversely related to educational level (P = 0.021). Including MRI, the number of impaired functions was associated with severity of MRI (P < 0.001), the SDI (P = 0.013), and the presence of Raynaud's phenomenon (P = 0.04). The contemporary presence of aPL+ and Raynaud's phenomenon resulted in a higher probability to develop moderate/severe cognitive deficits (P = 0.015). Two logistic multiple regression analyses identified hypertension (P < 0.05), the SDI (P < 0.01), and moderate/severe MRI findings as main predictors of moderate/severe impairment (dependent variable). The damage site hypothesized through neuropsychological testing corresponded with MRI findings in 71.7% of SLE patients K = 0.42, P = 0.005).
Conclusion: Hypertension, aPL+, accumulated damage, and MRI lesions are the main factors affecting severity of cognitive impairment in SLE. The hypothesized sites of central nervous system involvement according to neuropsychological testing correlated with MRI findings in most patients.