January 11, 2013

Patients who have had a stroke are at higher risk for death from any cause if they also have depression, a new study suggests.

The study is to be presented at the American Academy of Neurology 65th Annual Meeting in March by lead author Amy Towfighi, MD, University of Southern California, Los Angeles.

"Depression is not currently routinely screened for after a patient has had a stroke," Dr. Towfighi told Medscape Medical News. "We think it ought to be, as treatment of depression could improve outcomes."

NHANES I

For the study, the researchers examined data on 10,550 individuals aged 25 to 74 years followed for 21 years (from 1971 to 1992) in the National Health and Nutrition Examination Survey I (NHANES I) Epidemiologic Follow-up Study. Of those, 73 had a stroke but not depression, 48 had stroke and depression, 8138 did not have a stroke or depression, and 2291 did not have a stroke but had depression.

Depression was defined as a score of 16 or greater on the 20-item Center for Epidemiologic Studies Depression scale. Results were adjusted for demographic (age, sex, and race) and socioeconomic (education level, income level, and marital status) factors.

In unadjusted analysis, individuals with stroke and depression had more than a 4-fold higher risk for all-cause mortality. After adjustment for sociodemographic factors, an almost 3-fold elevated risk remained.

Patients with both conditions also had an almost 4-fold increased risk for stroke mortality compared with those with neither condition.

Table. Adjusted Risk for All-Cause and Stroke Mortality With Stroke and Depression vs Neither Condition

Endpoint Hazard Ratio (95% Confidence Interval)
All-cause mortality 2.86 (1.76 - 4.64)
Stroke mortality 3.69 (1.66 - 8.22)

 

There was a strong correlation between depression and mortality in patients with stroke. "The mortality rate was doubled in patients with stroke compared with those without stroke. But mortality was tripled if depression was also present," Dr. Towfighi said.

She commented, "We found that even if the stroke had happened years beforehand, there was still an association between depression and mortality so it is important that the possibility of depression is discussed at every follow-up visit. Several simple tools can be used for diagnosing depression in the outpatient setting. The Patient Health Questionnaire 2 (PHQ2) only involves 2 questions so can be done very quickly. If this is positive, it can be extended to the 9-question PHQ9, which can also be done in just a few minutes."

Dr. Towfighi estimates that 1 in 3 patients become depressed after sustaining a stroke. It is not necessarily related to the degree of disability. Some studies have found an association between depression and functional status and others have not. "Perhaps it depends on which particular part of the brain has been affected by the stroke," she suggests.

The mechanism linking depression to increased mortality in patients with stroke is not known for sure, but it is likely to be behavioral, Towfighi believes. "If patients are depressed, they are less likely to seek help, take medications, live a healthy lifestyle, etc. Others suggest a more physiological explanation, but it's probably a combination of the two," she said.

The study was supported by an American Heart Association National Scientist Development Grant. The researchers have disclosed no relevant financial relationships.

American Academy of Neurology 65th Annual Meeting. Abstract 3498. Released January 11, 2013.

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