Site differences in mild cognitive dysfunction (MCD) among patients with systemic lupus erythematosus (SLE)

Abstract

Background Mild cognitive dysfunction (MCD) is common in patients with systemic lupus erythematosus (MCD-SLE) but few studies have investigated potential site differences. Methods SLE patients from Denver, CO, and New York, NY, were enrolled in two different cognition studies employing similar screening methods. Using the resulting neuropsychological scores, cognitive impairment was calculated using a cognitive impairment index (CII). Results The rate of MCD-SLE was 24% at the Denver, CO, site and 60% at the New York, NY, site. The mean CII was 2.6 ± 2.3 versus 4.4 ± 2.7, respectively ( p = 0.005). The NY participants had a significantly longer disease duration ( p = 0.13) and higher American College of Rheumatology SLE criteria scores ( p > 0.001). NY participants had a higher frequency of impairment in semantic verbal fluency ( p = 0.005), visuomotor speed ( p = 0.013), and motor sequencing ( p = 0.001). A correlation was found between cognitive impairment and SLE disease duration ( p = 0.03). Conclusions The rate of MCD-SLE was greater in SLE patients from New York, NY, compared to patients in the Denver, CO, area. The greater duration of disease and higher prevalence of medical complications in the NY group might contribute to this difference. Findings suggest that MCD-SLE may differ by site, but future studies that better evaluate site or selection bias are recommended.