Background Approximately 30–50% of neuropsychiatric (NP) events in SLE patients are attributable to lupus. Prospective studies have reported differences in the outcome of NP events depending, in part, on their attribution to SLE and non-SLE causes. The current study was performed to determine predictors for change in a patient’s NP event status, based on a multistate modelling approach and attribution rules previously described.
Methods Upon enrollment and annually thereafter, NP events as per the American College of Rheumatology case definitions, were identified and attributed to SLE or non-SLE causes. Physician determined resolution was documented over time. Factors potentially associated with onset and resolution of NP events were determined by time-to-event analysis using a multistate modelling structure.
Results Over 11 years (1999 – 2011) 1,827 patients with SLE were recruited to a disease inception cohort from five different geographic areas of the world. At enrollment 88.8% were female, the mean (SD) age was 35.1 (13.3) years, and patients had variable race/ethnicity (Caucasian 48.8%, African 16.8%, Hispanic 15.4%, Asian 15.1% and other 3.9%). The mean (SD) disease duration was 5.6 (4.2) months, SLEDAI-2K 5.3 (5.4) and SLICC/ACR damage index 0.32 (0.74). NP events occurred in 955/1,827 (52.3%) patients and 592/1910 (31.0%) unique events were attributed to SLE. For SLE NP events multivariate analysis revealed positive associations with male sex, concurrent non-SLE NP events excluding headache, active SLE and corticosteroids (table 1a). There was a negative association with Asian race/ethnicity, post-secondary education, and immunosuppressive or anti-malarial drugs. For non-SLE NP events, excluding headache, there was a positive association with concurrent SLE NP events and negative associations with African and Asian race/ethnicity. NP events attributed to SLE had a higher resolution rate than non-SLE NP events, with the exception of headache that had comparable resolution rates. For SLE NP events, multivariate analysis revealed resolution was more common with Asian race/ethnicity and for central/focal NP events (table 1b). For non-SLE NP events resolution was more common with African race/ethnicity and less common with older age at SLE diagnosis (table 1b).
Model 1 includes time invariant variables or those defined at all time points. Model 2 is restricted to transitions for which there is information as in model 1 and additional time variable explanatory variables available only for events occurring after the initial patient assessment.
Conclusions In a large and long-term study of the occurrence and resolution of NP events in SLE we identified subgroups with better and worse prognosis. The course of NP events differs greatly depending on their nature and attribution.
Acknowledgement This work was completed by members of the Systemic Lupus International Collaborating Clinics (SLICC).
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