Prevalence of Cognitive Disorders in Patients with Systemic Lupus Erythromatosus; a Cross-sectional Study in Rasoul-e-Akram Hospital, Tehran, Iran.

BACKGROUND: Neuropsychological manifestations are present in 60% of patients with Systemic Lupus Erythematosus (SLE) among which cognitive dysfunction is the most common. This study aims to determine the prevalence of cognitive disorders in SLE patients, and the relationship between cognitive disorder domains and depression and anxiety.

METHODS: In this cross-sectional study, 54 patients with SLE and 48 healthy subjects were included. Mini-Mental State Examination (MMSE), Clock Drawing Test (CDT) and Trail Making Test part A (TMT-A) were used to screen for cognitive impairments. All subjects were evaluated with the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI) to determine depression and anxiety as probable confounding variables.

RESULTS: The mean MMSE scores in SLE and control group patients (26.12 ± 3.58 and 28.01 ± 1.99, respectively) were significantly different (P = 0.001). The sub-scores in all areas assessed with MMSE were lower in SLE patients; however, it was only significant in the areas of orientation, recall and language (P < 0.05). SLE patients showed a significantly poorer performance in TMT compared to healthy controls (P = 0.01). The CDT according to the Watson scoring system showed significant difference between the two groups (P = 0.03). The Sunderland scoring system also indicated poorer performance in the SLE group, but the difference was not significant.

CONCLUSION: Our study showed that cognitive disorders are more than 3-fold higher in SLE patients compared to normal subjects. The most impaired domains include orientation, Memory (recall), Language, Executive function, and psychomotor speed. Anxiety and depression are mostly correlated with domains included in the MMSE test.