Risk of epilepsy in patients with systemic lupus erythematosus – A retrospective cohort study

Background: Systemic lupus erythematosus (SLE) affects central and peripheral nervous systems, manifesting neuropsychiatry disorders that vary from subtle signs to life-threatening complications. This study compared the risk of epilepsy between a general population and patients with SLE.Methods: From the national insurance claims data of the Taiwan National Health Research Institutes, we identified 32,301 patients with newly diagnosed SLE from 1997-2010 and, for comparison, 129,204 randomly selected people without SLE; the frequencies of both groups were matched by sex, age, and diagnosis date. The incidence of epilepsy was estimated for both cohorts by the end of 2010.Conclusion: Patients with SLE are at higher risk of epilepsy than the general population, especially younger SLE patients. Neurologic comorbidities and psychiatric disorders increase the epilepsy risk further.Results: The incidence of epilepsy was 2.86-fold higher in the SLE cohort than in the non-SLE cohort (9.10 per 10,000 person-years versus 3.18 per 10,000 person-years), with a Cox method estimated adjusted hazard ratio (aHR) of 2.33 (95% confidence interval [CI] =1.89-2.88) for the SLE cohort. The incidence increased with age in the non-SLE cohort, while it decreased with the increase of age in the SLE cohort. Compared with the non-SLE cohort, the age-specific aHR of epilepsy for the SLE cohort decreased from 8.05 (95% CI =4.30-15.0) for those aged <20 years to 0.90 (95% CI =0.57-1.42) for those aged 60 years and above (P=0.01). Comorbidities that had a significant association with epilepsy included infarction (aHR =7.62), intracerebral hemorrhage (aHR =5.75), aseptic meningoencephalitis (aHR =5.35), and psychiatric disorder (aHR =3.31).