Depression and cognitive impairment in newly diagnosed systemic lupus erythematosus

Abstract

Objective: Cognitive impairment is present in 80% of patients with systemic lupus erythematosus (SLE) 10 years after diagnosis. The natural history of cognitive dysfunction in newly diagnosed SLE is unknown. We examined the association of depression and cognitive performance in newly diagnosed SLE.

Methods: A multicenter cohort of 111 patients newly diagnosed (within 9 months) with SLE underwent cognitive function testing using an automated battery [Automated Neuropsychological Assessment Metrics (ANAM)] with 9 subtests. Depression was measured using the Calgary Depression Scale (CDS).

Results: The patient cohort was 97.3% female, 55.9% white, 15.3% African American, 20.7% Hispanic, mean age 37.8 years, mean education 15.2 years. CDS score ranged from 0 to 18 (mean 5.0 ± 4.6). CDS score did not differ by age, sex, ethnicity, or prednisone dose. Higher Krupp Fatigue Severity Scale scores and presence of fibromyalgia were significantly associated with higher CDS score (p < 0.001; p = 0.006, respectively). Depressed patients, defined by a CDS score > 6, had significantly poorer performance on 5 ANAM throughput measures: code substitution (p = 0.03), continuous performance (p = 0.02), matching-to-sample (p = 0.04), simple reaction time (p = 0.02), and the Sternberg memory test (p = 0.04). Adjusting for age, sex, ethnicity, education, and prednisone dose, a higher CDS score remained significantly associated with poorer performance on 3 measures, but the association was slightly attenuated for code substitution and matching-to-sample. Depression was not associated with mathematical or spatial processing.

Conclusion: Depression, a modifiable risk factor, is associated with significantly poorer function in several cognitive domains in patients newly diagnosed with SLE. Treatment of depression when the CDS score is greater than 6 may improve cognitive functioning and should be further studied.