Patients with coronary heart disease who are both highly stressed and depressed may be at much higher risk of heart attack or death.
Past studies have shown that stress and depression separately may have negative health implications for patients with coronary heart disease. In November 2014, for example, Medical News Today reported on a study revealing that emotional stress reduces blood flow in people with coronary heart disease - particularly women.
But the researchers of this latest study - led by Carmela Alcántara, associate research scientist at Columbia University Medical Center for Behavioral Cardiovascular Health in New York, NY - say few studies have assessed how stress and depression combined affect coronary heart disease patients.
To find out, the team assessed 4,487 patients aged 45 and older who had been diagnosed with coronary heart disease. All patients were part of the REasons for Geographic and Racial Differences in Stroke (REGARDS) study.
Between 2003 and 2007, the patients received home visits and were asked to complete a series of questionnaires about stress and depression. To gauge levels of depression, patients were asked how often they felt depressed during the past week, whether they had felt sad or lonely, and whether they experienced crying episodes.
To determine stress levels over the past month, patients were asked how often they felt overwhelmed, how often they felt they were unable to control important factors in their lives, whether they felt confident in handling personal problems and whether they felt things were going their way.
'Perfect storm' of stress, depression increased risk of heart attack, death by 48%
Over the average 6-year follow-up period, around 6% of patients reported both high levels of stress and depression. During this time, there were 1,337 deaths or heart attacks.
Compared with patients who reported low levels of stress and depression, the team calculated that patients with high stress and depression levels were at 48% increased risk of heart attack or death in the 2.5 years after their initial home visit.
This finding remained even after researchers accounted for patients' demographic factors, medical history, medication use and health risk behaviors.
The researchers say the increased risk identified was most strongly linked to death, but further research indicated that these deaths are likely to have been cardiovascular-related, though additional studies are needed to confirm this.
Increased risk of heart attack and death was not found among patients who experienced either high levels of stress or depression. The team says this validates the theory of a "psychosocial perfect storm," in that increased risk was only identified when both high levels of stress and depression were present.
Last month, a Spotlight feature by MNT looked at some of the other ways in which stress may affect our health.