Stroke: Study examines risk, risk factors for depression

More than 10 million people had a stroke in 2013 and more than 30 million people worldwide live with a stroke diagnosis.

Merete Osler, M.D., D.M.Sc., Ph.D., of Copenhagen University, Denmark, and coauthors used data linked from seven Danish nationwide registers to examine how risk and risk factors for depression differ between patients with stroke and a reference population without stroke, as well as how depression influences death.

Among 135,417 patients with stroke, 34,346 (25.4 percent) had a diagnosis of depression within two years after stroke and more than half of the cases of depression (n=17,690) appeared in the first three months after stroke.

In a reference population of 145,499 people without stroke, 11,330 (7.8 percent) had a depression diagnosis within two years after entering the study and less than a quarter of the cases (n=2,449) appeared within the first three months, according to the results.

The risk of depression in patients during the first three months after stroke was eight times higher than in the reference population without stroke, the authors report.

Major risk factors for depression for patients after stroke and in the reference population were older age, female sex, living alone, basic educational attainment, diabetes, a high level of somatic comorbidity, history of depression and stroke severity (in patients with stroke), according to the results.

In both groups -- patients with stroke and the reference population without stroke -- depressed individuals, especially those with new onset, had increased risk of death from all causes.

Study limitations include a definition of depression that was based on psychiatric diagnoses and filling of antidepressant prescriptions, and most cases were defined by filling antidepressants, which can be prescribed for various diseases.

"Depression is common in patients with stroke during the first year after diagnosis, and those with prior depression or severe stroke are especially at risk. Because a large number of deaths can be attributable to depression after stroke, clinicians should be aware of this risk," the study concludes.