Depressive Symptoms and Risk of Acute Stroke INTERSTROKE Case-Control Study

Background and Objectives Depression has been reported to be a risk factor of acute stroke, based largely on studies in high-income countries. In the INTERSTROKE study, we explored the contribution of depressive symptoms to acute stroke risk and 1-month outcome across regions of the world, within subpopulations and by stroke type. Methods The INTERSTROKE is an international case-control study of risk factors of first acute stroke, conducted in 32 countries. Cases were patients with CT- or MRI-confirmed incident acute hospitalized stroke, and controls were matched for age, sex, and within sites. Standardized questions asked about self-reported depressive symptoms during the previous 12 months and the use of prescribed antidepressant medications were recorded. Multivariable conditional logistic regression was used to determine the association of prestroke depressive symptoms with acute stroke risk. Adjusted ordinal logistic regression was used to explore the association of prestroke depressive symptoms with poststroke functional outcome, measured with the modified Rankin scale at 1 month after stroke. Results Of 26, 877 participants, 40.4% were women, and the mean age was 61.7 ± 13.4 years. The prevalence of depressive symptoms within the last 12 months was higher in cases compared with that in controls (18.3% vs 14.1%, p < 0.001) and differed by region (p interaction <0.001), with lowest prevalence in China (6.9% in controls) and highest in South America (32.2% of controls). In multivariable analyses, prestroke depressive symptoms were associated with greater odds of acute stroke (odds ratio [OR] 1.46, 95% CI 1.34-1.58), which was significant for both intracerebral hemorrhage (OR 1.56, 95% CI 1.28-1.91) and ischemic stroke (OR 1.44, 95% CI 1.31-1.58). A larger magnitude of association with stroke was seen in patients with a greater burden of depressive symptoms. While preadmission depressive symptoms were not associated with a greater odds of worse baseline stroke severity (OR 1.02, 95% CI 0.94-1.10), they were associated with a greater odds of poor functional outcome at 1 month after acute stroke (OR 1.09, 95% CI 1.01-1.19). Discussion In this global study, we recorded that depressive symptoms are an important risk factor of acute stroke, including both ischemic and hemorrhagic stroke. Preadmission depressive symptoms were associated with poorer functional outcome, but not baseline stroke severity, suggesting an adverse role of depressive symptoms in poststroke recovery.