Cardiovascular factors, including hypertension, associated with risk for severe stroke

Key takeaways:

• Diabetes, diet quality and lack of physical activity were linked to increased odds of stroke.
• Those with non-severe stroke were younger than those with severe stroke by country income level.

Hypertension, atrial fibrillation and smoking were most strongly associated with an increased risk for severe compared with non-severe stroke, according to analysis from the INTERSTROKE study.

“Public health interventions to reduce the burden of stroke may reasonably prioritize the prevention of disabling stroke,” Catriona Reddin, MB, BCh, BAO, MSc, of the School of Medicine at the University of Galway in Ireland, and colleagues wrote in Neurology. “Accordingly, a detailed knowledge of whether the magnitude of association of traditional vascular risk factors with acute stroke differs by stroke severity may refine global stroke prevention strategies.”

Reddin and colleagues sought to determine whether individual risk factors for acute stroke differed by stroke severity. They analyzed the results of INTERSTROKE, an international case-control study, which showed that 10 potential modifiable risk factors were associated with 90% of the study population’s attributable risk for stroke when controlling for both age and sex.

INTERSTROKE recruited more than 13,000 individuals with stroke and more than 13,000 matched controls from 32 countries between 2007 and 2015, for which stroke severity was measured by modified Rankin Scale (mRS) score (with severe stroke defined as scores 4 to 6 and non-severe 0 to 3) within 72 hours of hospital admission.

Risk factors associated with stroke were measured via self-reported standardized questionnaires that collected baseline demographics and a range of lifestyle-related stroke risk factors, including blood pressure, diabetes risk, smoking, cardiovascular health, stress, depression, exercise and diet quality.

The researchers conducted a matched case-case analysis based on age, sex, country and primary stroke subtype to determine if a significant difference existed in prevalence of risk factors among study individuals with severe and non-severe stroke.

From 13,460 enrollees with stroke, 64% (n = 8,612) reported mRS scores of 0 to 3 and 36% (n = 4,848) reported scores of 4 to 6.

According to the results, hypertension (OR = 3.21; 95% CI, 2.97–3.47 for severe stroke; OR = 2.87; 95% CI, 2.69–3.05 for non-severe stroke), atrial fibrillation (OR = 4.7; 95% CI, 4.05–5.45 for severe stroke; OR = 3.61; 95% CI, 3.16–4.13 for non-severe stroke) and smoking (OR = 1.87; 95% CI, 1.72–2.03 for severe stroke; OR = 1.65; 95% CI, 1.54–1.77 for non-severe stroke) had a stronger association with severe stroke compared with non-severe stroke.

Reddin and colleagues also found that diabetes, lower diet quality and lack of physical activity were associated with increased odds of both severe and non-severe stroke, with no significant difference in odds among both groups; alcohol use was associated with increased odds of non-severe but not severe stroke.

Data additionally showed that individuals with non-severe stroke were younger than those with severe stroke when analyzed by country income level.

“All risk factors were significantly associated with both severe and non-severe stroke symptoms but to varying magnitudes,” Reddin and colleagues wrote. “Our findings emphasize the importance of hypertension control in stroke prevention.”