Neuropsychiatric lupus: the prevalence and autoantibody associations depend on the definition: results from the 1000 faces of lupus cohort

Objectives: The (ever) prevalence of neuropsychiatric systemic lupus erythematosus (NPSLE) can vary widely depending on the definition used. We determined the prevalence of NPSLE in 1000 Faces of Lupus, a large multicenter Canadian cohort.

Methods: Adults enrolled at 10 sites who satisfied the American College of Rheumatology (ACR) classification for systemic lupus erythematosus (SLE) were included. NPSLE was defined as (i) NPSLE by ACR classification criteria (seizures or psychosis), (ii) ACR, SLEDAI (seizure, psychosis, organic brain syndrome, cranial nerve disorder, headache, and cerebrovascular accident (CVA)), SLAM (CVA, seizure, cortical dysfunction, and headache), and SLICC (cognitive impairment, psychosis, seizures, CVA, cranial or peripheral neuropathy, and transverse myelitis) with and (iii) without minor nonspecific NPSLE manifestations (including mild depression, mild cognitive impairment, and electromyogram-negative neuropathies), and (iv) by ACR and SLEDAI neuropsychiatric (NP) indexes alone. Factors associated with NPSLE were explored using regression models.

Results: Cohort size was 1253, with mean disease 12 ± 10 years, mean age 41 ± 16 years, and 86% female. Subgroup size was dependent on the specific definition of NPSLE. Prevalence of NPSLE was 6.4% in group (i), n = 1253 (n = 80); 38.6% in group (ii), n = 681(n = 263); 28.7% in group (iii), n = 586 (n = 168); and 10.2% in group (iv), n = 1125 (n = 115). In univariate analysis, Aboriginals had a nearly 2-fold increase in frequency of NPSLE in all groups. Education level and income were not associated with NPSLE (P = 0.32 and 0.03, respectively). As well, number of ACR criteria, SLAM, age at diagnosis, disease duration, and gender were not associated with NPSLE. Anti-Ro was significantly associated in groups (i) and (iv) and antiphospholipid antibodies (aPL) were increased in groups (i), (ii), and (iii); however, this lost significance when thromboembolic events were excluded from SLICC, SLEDAI, and SLAM indexes. In group (iv), absence of anti-Sm was significant. In multivariate analysis, anti-Ro and aPL (i) and anti-Ro+ and lack of anti-Sm (iv) were significant. NPSLE was not increased in those with +anti-DNA, La, or ribonucleoprotein (RNP), lupus anticoagulant (LAC), or anticardiolipin (aCL) antibody.

Conclusions: The prevalence and factors associated with NPSLE varied depending on the definition used, was highest in Aboriginals, and may be higher if +anti-Ro or aPL are present. SLAM and SLICC include mild subjective disease manifestations, which contributed to a 10% higher prevalence of NPSLE compared to a more strict definition. NPSLE may be less in this database than other publications as its overall prevalence may be decreasing, or because of selection bias inherent to those who enter an observational cohort. NPSLE was associated with aPL and often anti-Ro and varied by ethnicity.