title: Risk of epilepsy in patients with systemic lupus erythematosus - a retrospective cohort study.
abstract: BACKGROUND
  Systemic lupus erythematosus (SLE) affects central and peripheral nervous systems, manifesting neuropsychiatric 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.
  
  
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Institute of Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan ; Department of Pediatrics, Chung Shan Medical University and Hospital, Taichung, Taiwan.
authors.forename: Jeng-Dau
authors.initials: JD
authors.lastname: Tsai
authors.affiliation: Institute of Clinical and Medical Science, China Medical University, Taichung, Taiwan ; Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Department of Family Medicine, China Medical University School of Medicine, Taichung, Taiwan ; Division of Family Medicine, China Medical University Hospital, Taichung, Taiwan ; Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Institute of Clinical and Medical Science, China Medical University, Taichung, Taiwan ; Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan ; Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Institute of Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan ; Department of Pediatrics, Chung Shan Medical University and Hospital, Taichung, Taiwan.
authors.forename: Ko-Huang
authors.initials: KH
authors.lastname: Lue
keywords: cohort study; epilepsy; health insurance data; incidence; lupus