Different kinds of neuropsychiatric (NP) events in patients with systemic lupus erythematosus (SLE) have substantial variability in their occurrence, resolution, and recurrence over time, as well as in their predictors, according to new research from a large, prospective, international, inception cohort study.
Because “multiple NP events due to different causes may present concurrently in individual patients, the findings emphasize the importance of recognizing attribution of NP events as a determinant of clinical outcome,” John G. Hanly, MD, of Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, N.S., and colleagues wrote in Arthritis & Rheumatology.
In a previous study of the same group of 1,827 patients with SLE, NP events occurred in about half and approximately one-third of these events were deemed disease related. They also “occurred most frequently around the diagnosis of SLE and had a significant negative impact on health-related quality of life,” the researchers wrote.
Researchers involved with the Systemic Lupus International Collaborating Clinics recruited the 1,827 adults with SLE over an 11-year period during 1999-2011 from a total of 31 sites in Europe, Asia, and North America. The average age of the patients at study enrollment was 35 years, 89% were women, and 49% were White. The mean disease duration was 5.6 months, and 70% of patients were taking corticosteroids at enrollment.
Over an average follow-up period of 7.6 years, 955 patients (52.3%) experienced a single neuropsychiatric event, and 493 (27.0%) experienced two or more events; the total number of unique NP events was 1,910. Most of these unique events (92%) involved the central nervous system, and 8.4% involved the peripheral nervous system.
The researchers used multistate models to attribute NP events to SLE based on factors that included the temporal onset of NP events in relation to SLE diagnosis, concurrent non-SLE factors, and NP events that are common in healthy controls. The four states in the multistate models were no NP events, no current NP event but a history of at least one event, new or ongoing NP events, and death. The results included a multivariate analysis of a model involving 492 observed transitions into new or ongoing NP events.
In the multivariate analysis, factors positively associated with SLE-attributed NP events included male sex (hazard ratio, 1.35; P = .028), concurrent non-SLE NP events excluding headache (HR, 1.83; P < .001), active SLE based on the Systemic Lupus Erythematosus Disease Activity Index 2000 (HR, 1.19; P = .012), and corticosteroid use (HR, 1.59; P = .008). The researchers also found that SLE-attributed NP events were negatively associated with Asian race/ethnicity, postsecondary education, and use of immunosuppressive drugs.
Another multivariate analysis found that non-SLE NP events were positively associated with only concurrent SLE-attributed NP events excluding headache (HR, 2.31; P < .001), but negative associations were seen with non-U.S. African race/ethnicity and Asian race/ethnicity.
The researchers found that SLE-attributed NP events had higher rates of resolution, compared with non-SLE NP events, with the exception of headache, which had similar resolution for both event groups.
“Resolution of SLE events was more likely in patients with Asian race/ethnicity and those with Central/Focal nervous system disease with no effect seen for age at diagnosis,” the researchers noted. “For non-SLE NP events, African race/ethnicity at non-U.S. sites and younger age at diagnosis was associated with a better outcome.”
The study findings were limited by several factors including the predominantly White patient population and the clustering of NP events into limited categories, which may have reduced the identification of more specific associations, the researchers noted. Also, the assessment of NP event outcomes did not include patient perceptions, and the relatively short follow-up period does not allow for assessment of later NP events such as cerebrovascular disease. However, “despite these limitations the current study provides valuable data on the presentation, outcome and predictors of NP disease in SLE patients enrolled in a long-term, international, disease inception cohort,” the researchers concluded.
The study received no outside funding. Dr. Hanly was supported by a grant from the Canadian Institutes of Health Research but had no financial conflicts to disclose. Several coauthors received grant support from various institutions, but not from industry, and had no financial conflicts to disclose.