title: Stroke in systemic lupus erythematosus: a Swedish population-based cohort study.
abstract: OBJECTIVE
  To study the occurrence of ischaemic and haemorrhagic stroke in systemic lupus erythematosus (SLE) compared with the general population by age, sex and time since SLE diagnosis METHODS: Adults with incident SLE were identified from the Swedish National Patient Register (NPR, n=3390) and general population comparators from the Total Population Register were matched on age, sex and county (n=16730). Individuals were followed prospectively until first of death, December 2013, emigration or incident stroke (identified from the NPR, Cause of Death Register and the Stroke Register). Incidence rates, rate differences and HR were estimated comparing SLE with non-SLE. Estimates were stratified by sex, age and time since diagnosis.
  
  
  RESULTS
  We observed 126 strokes in SLE and 304 in the general population. Individuals with SLE had a twofold increased rate of ischaemic stroke compared with the general population (HR 2.2; 95% CI 1.7 to 2.8). The HR for intracerebral haemorrhage was 1.4 (95% CI 0.7 to 2.8). There was effect modification by sex and age, with the highest HRs for females and individuals <50 years old. The HR for ischaemic stroke was highest in the first year of follow-up (3.7; 95% CI 2.1 to 6.5).
  
  
  CONCLUSIONS
  The relative risk of ischaemic stroke in SLE was more than doubled compared with the general population, and importantly, the highest relative risks were observed within the first year after SLE diagnosis. Thus, the first encounter with patients presents an opportunity for rheumatologists to screen for risk factors and intervene.
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Arkema
authors.affiliation: Department of Medicine Solna, Rheumatology Unit, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Svenungsson
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.|Stroke Research Network at Södersjukhuset, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mia
authors.initials: M
authors.lastname: Von Euler
authors.affiliation: Clinical and Experimental Medicine, Rheumatology/Division of Neuro and Inflammation Sciences, Linköping University, Linköping, Sweden.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sjöwall
authors.affiliation: Department of Medicine Solna, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden.|Department of Health Research and Policy, Division of Epidemiology, Stanford School of Medicine, Stanford, California, USA.|Department of Medicine, Division of Immunology and Rheumatology, Stanford School of Medicine, Stanford, California, USA.
authors.forename: Julia F
authors.initials: JF
authors.lastname: Simard
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002545:Brain Ischemia / Q000453:epidemiology*; D016022:Case-Control Studies; D002543:Cerebral Hemorrhage / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D020521:Stroke / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology
keywords: cardiovascular disease; epidemiology; systemic lupus erythematosus