Summary
Background and objectives
Depression has been reported to be a risk factor for acute stroke, largely based 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 world regions, within subpopulations, and by stroke type.
Methods
INTERSTROKE is an international case-control study of risk factors for first acute stroke, conducted in 32 countries. Cases were patients with incident acute hospitalized stroke confirmed by CT or MRI, and controls were matched for age, sex, and within sites.
Standardized questions regarding self-reported depressive symptoms over the previous 12 months and use of prescribed antidepressant medications were recorded. Multivariable conditional logistic regression was used to determine the association of pre-stroke depressive symptoms with the risk of acute stroke. Adjusted ordinal logistic regression was used to explore the association of pre-stroke depressive symptoms with post-stroke functional outcome, measured with the modified Rankin Scale one month after stroke.
Results
Of 26,877 participants , 40.4% were women, the mean age was 61.7 ± 13.4 years. The prevalence of depressive symptoms in the past 12 months was higher in cases compared to controls (18.3% vs. 14.1%, p < 0.001) and differed by region (interaction < 0.001), with the prevalence higher lowest in China (6.9% of controls) and highest in South America (32.2% of controls).
In multivariable analyses, pre-stroke depressive symptoms were associated with increased odds of acute stroke (OR 1.46, 95% CI 1.34 to 1.58), which was significant for both intracerebral hemorrhage ( OR 1.56, 95% CI 1.28–1.91) as for ischemic stroke (OR 1.44, 95% CI 1.31–1.58). A greater magnitude of association with stroke was observed in patients with a higher burden of depressive symptoms.
Although preadmission depressive symptoms were not associated with a higher odds of worse baseline stroke severity (OR 1.02, 95% CI 0.94–1.10), they were associated with a higher odds of poor functional outcome one month after acute stroke (OR 1.09, 95% CI 1.01–1.19).
Discussion and Conclusions In this global study, we recorded that depressive symptoms are an important risk factor for acute stroke, including ischemic and hemorrhagic stroke. Pre-admission depressive symptoms were associated with poorer functional outcome, but not with baseline stroke severity, suggesting an adverse role for depressive symptoms in post-stroke recovery. |
Comments
People who have symptoms of depression may be at increased risk for stroke, according to a study published in Neurology ®, the medical journal of the American Academy of Neurology. The researchers also found that people with symptoms of depression were more likely to have a worse recovery after a stroke.
“Depression affects people around the world and can have a wide range of impacts on a person’s life,” said study author Robert P. Murphy, MBBS, of the University of Galway in Ireland. "Our study provides a broad picture of depression and its link to stroke risk by looking at a number of factors, including participants’ symptoms, life choices, and antidepressant use. Our results show that depressive symptoms “were associated with an increased risk of stroke and the risk was similar in different age groups and around the world.”
The study involved 26,877 adults from the INTERSTROKE study and included people from 32 countries in Europe, Asia, North and South America, the Middle East and Africa. The participants had an average age of 62 years. Of the participants, more than 13,000 suffered a stroke. They were matched with more than 13,000 people who had not had a stroke but were similar in age, sex, racial or ethnic identity.
Participants completed questionnaires at the beginning of the study about cardiovascular risk factors, including high blood pressure and diabetes. The researchers collected information about depression symptoms during the year before the study. They were asked if they had felt sad, blue, or depressed for two or more consecutive weeks during the past 12 months.
Of the study participants, 18% of those who had a stroke had symptoms of depression compared to 14% of those who did not have a stroke.
After adjusting for age, sex, education, physical activity, and other lifestyle factors, people with symptoms of depression before their stroke had a 46% increased risk of stroke compared to those who did not have symptoms of depression .
The more symptoms participants had, the higher their risk of stroke. Participants who reported five or more symptoms of depression had a 54% higher risk of stroke than those with no symptoms, while those who reported three to four symptoms of depression and those who reported one to two symptoms of depression had 58% and 35% higher risk, respectively.
While people with symptoms of depression were not more likely to have more severe strokes, they were more likely to have worse outcomes one month after the stroke than people without symptoms of depression.
“In this study we gained deeper insights into how depressive symptoms may contribute to stroke,” Murphy added. “Our results show that symptoms of depression can have an impact on mental health, but also increase the risk of stroke. Clinicians should be alert to these symptoms of depression and can use this information to help guide health initiatives focused on stroke prevention.”
A limitation of the study was that participants completed questionnaires about depression symptoms only at the beginning of the study, so the effects of depression over time could not be measured.
The study was funded by the Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Canadian Stroke Network, Swedish Research Council, Swedish Heart and Lung Foundation, AFA Insurance, The Health & Medical Care Committee of the Regional Executive Board, Region Västra Götaland, Astra Zeneca, Boehringer Ingelheim, Pfizer and Merck.
