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Depression Boosts Stroke Risk
 
 
  By Kristina Fiore, Staff Writer, MedPage Today
Published: September 20, 2011

Being depressed may increase an individual's risk of stroke and stroke death, a meta-analysis found.

In a review and meta-analysis, depression was associated with a 45% increased risk of total stroke and a 55% higher risk of fatal stroke, Frank Hu, MD, PhD, of Harvard School of Public Health, and colleagues reported in the Sept. 21 issue of the Journal of the American Medical Association.

Action Points

· Note that this study was a review and meta-analysis of prospective studies assessing the association between depression and risk of developing stroke in adults.

· Point out that depression was associated with a significantly increased risk of total stroke in terms of both morbidity and mortality.

· Note that most studies did not have information on depression treatment and the use of antidepressant medication use so that the role of depression treatment in modulating the subsequent risk of stroke could not be determined.

"Given the high prevalence and incidence of depression and stroke in the general population, the observed association between depression and stroke has clinical and public health importance," they wrote.

Several studies have suggested that depression is tied to an increased risk of stroke, but results have been inconsistent.

So Hu and colleagues conducted a review and meta-analysis of prospective studies conducted through May 2011 that have examined the relationship.

They included 28 studies involving 317,540 patients. Eight of the studies focused on fatal stroke, three on nonfatal stroke, six on ischemic stroke, and two on hemorrhagic stroke.

There were 8,478 stroke cases over a follow-up that ranged from two to 29 years.

Overall, depression was tied to a 45% greater risk of total stroke (95% CI 1.29 to 1.63), though there was high heterogeneity among the studies, the researchers said.

Depressed patients had a greater risk of fatal stroke as well (HR 1.55, 95% CI 1.25 to 1.93), and there was "moderate" heterogeneity across the eight studies assessing this outcome.

There was also a greater risk of ischemic stroke among this population (HR 1.25, 95% CI 1.11 to 1.40), and heterogeneity was low across the six studies assessing this outcome.

Hu and colleagues found that results for nonfatal stroke and hemorrhagic stroke were not significant, although the number of studies that separately addressed these outcomes was small, they noted.

They estimated that the absolute risk differences associated with depression were 106 cases for total stroke, 53 cases for ischemic stroke, and 22 cases for fatal stroke per 100,000 patients per year.

Using the most recent statistic of 9% of adults meeting criteria for current depression, the researchers estimated that 3.9% of stroke cases in the U.S. could be attributable to depression.

Depression remained associated with a greater risk of stroke when evaluated by subgroup, the researchers reported, although risk was more evident for several circumstances -- when using a clinical diagnosis to define depression, having a high study quality, having shorter follow-up, including younger participants among Asian studies, and when not controlling for smoking status or body mass index (BMI).

For instance, reports that controlled for smoking showed a 28% increased risk of stroke in depressed patients compared with a 92% greater risk for those that did not control for this potential confounder. Controlling for BMI had similar effects, they said.

Hu and colleagues wrote that their results are consistent with a previous meta-analysis of 10 studies published before 2005.

"Our current meta-analysis, with five times more cases, provides strong evidence that depression is associated with increased risks of total stroke, fatal stroke, and ischemic stroke," they wrote.

They added that the results are also consistent with those of the INTERSTROKE study, which found self-reported depression to be associated with a significant 35% greater risk of stroke.

Depression may contribute to stroke via a variety of mechanisms, including known neuroendocrine and immunological/inflammatory effects, its association with poor health behaviors that could increase cardiovascular risk, and its correlation with other major comorbidities that raise the risk of stroke, such as diabetes and hypertension.

They said antidepressants may contribute to the increased risk of stroke as well, though they may only be a marker of severity of disease and not causally associated with the condition.

Hu and colleagues called for more studies to explore the potential mechanisms underlying the relationship.

The study was limited by the heterogeneity among included studies and by the potential for publication bias among those studies.

 
 
 
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