Ischemic Stroke Risk Elevated in Systemic Lupus Erythematosus

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The study compared the risk of incident stroke in individuals with SLE with individuals without SLE in the general population.
The study compared the risk of incident stroke in individuals with SLE with individuals without SLE in the general population.

Patients with systemic lupus erythematosus have a higher risk of ischemic stroke, particularly within the first year of diagnosis, according to recent research published in the Annals of the Rheumatic Diseases.

Elizabeth V Arkema, ScD, from the department of medicine Solna and the clinical epidemiology unit at Karolinska Institutet in Stockholm, Sweden, and colleagues identified 3390 patients in the Swedish National Patient Register with systemic lupus erythematosus (SLE) and compared them with a control group of 16,730 people identified in a total population register.

Patients were matched with the control group based on age, gender, and residential county, with follow-up visits beginning at the second SLE-coded visit and ending at death, emigration from the country, or the end of the study in December 2013.

The researchers identified ischemic strokes, intracerebral hemorrhage, subarachnoid hemorrhage, and unspecified strokes using International Classification of Diseases (ICD) codes in the Swedish National Patient Register, the Swedish Stroke Register, and the Cause of Death Register.

In the SLE group, 126 strokes were identified compared with 204 strokes in the control group from the general population. Of these cases, 87% of strokes were classified as ischemic after excluding subarachnoid hemorrhage and unspecified strokes.

Patients in the SLE group had a greater than 2-fold risk of developing an ischemic stroke compared with the control group (hazard ratio [HR] 2.2; 95% CI, 1.7-2.8), while the risk for developing an intracerebral hemorrhage was also higher in patients with SLE (HR 1.4; 95% CI, 0.7-2.8) compared with the control group.

The mean age for stroke occurrence in the SLE group was 68.4 compared with a mean age of 73.3 in the control group, with 14% of strokes in the SLE group and 4% in the control group occurring before age 50. In the SLE group, 79% of women developed a stroke compared with 68% of women in the control group.

“Younger individuals and women with SLE have an especially higher relative risk than the general population, although their absolute risk remains low,” Dr Arkema and colleagues wrote in their study.

“The increased relative risk in the first year after diagnosis highlights a time period where preventative measures could be taken.”

Summary & Clinical Applicability

“It is recommended to screen for traditional risk factors at SLE diagnosis and at least annually thereafter, but which of the SLE-specific factors are most important should be assessed in future work,” Dr Arkema and colleagues wrote in their study. “Furthermore, what actions should be taken to modify stroke risk should be clarified so that the burden of stroke can be reduced in this vulnerable population.”

Limitations & Disclosures

Using the date of the second SLE-coded visit as the date of diagnosis could allow for misclassification of patients with SLE if diagnosis took a longer period of time, misclassification of stroke could have occurred if neurological symptoms were misdiagnosed. The research also did not account for potential confounding effects of obesity or smoking in the study.

Reference

Arkema EV, Svenungsson E, Euler MV, et al. Stroke in systemic lupus erythematosus: a Swedish population-based cohort study. [published online April 11, 2017] Ann Rheum Dis. doi:10.1136/annrheumdis-2016-210973

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