Depression consists of a range of symptoms -- some of which may be more predictive of death for coronary artery disease patients than others, according to a study.
Noting that many studies have observed that depressed cardiac patients are at higher risk of death than those who are not depressed, researchers at Duke University Medical Center attempted further analysis of this observation.
"The present study is an investigation of the importance of different depressive symptoms for the prediction of survival in patients with coronary artery disease," said lead author John C. Barefoot, PhD, of Duke University Medical Center, in Durham, NC. "Depression manifests itself in a variety of symptoms that do not necessarily occur together."
Barefoot and colleagues analyzed data on more than 1,200 cardiac patients whose progress had been followed for approximately 19 years. At the start of the study period, the patients were evaluated for depression.
The researchers examined a variety of symptoms, such as absence of feelings of well-being, hopelessness and negative affect -- which is a measure of downheartedness, sadness, irritability and restlessness. They also looked at the study participantsí physical symptoms of depression, including tiredness, rapid heartbeat and insomnia.
Most symptoms associated with depression seemed to adversely influence length of survival, but two symptoms had a stronger influence than the others -- negative affect and hopelessness, the researchers found.
"The risk of death for patients with many symptoms of negative affect was more than 40 percent higher than those with little negative affect," said Barefoot. "The impact of negative affect seemed particularly strong among younger patients; in patients under the age of 51, the increase in risk was approximately 70 percent," said Barefoot. "The occurrence of a coronary event may have more significant meaning for those for whom it is more unexpected and likely to result in major lifestyle changes."
"Hopelessness was a potent predictor of survival even though the measure was based on only one question that was endorsed by a relatively small number of patients," said Barefoot. More than half (55.7 percent) of the patients who indicated that they experienced feelings of hopelessness died during the follow-up period of the study, in comparison to only slightly more than one-third (36.2 percent) of patients who indicated that they did not have this symptom.
The study results appear in the November/December issue of Psychosomatic Medicine.
The findings may have treatment implications, according to the researchers, who suggested further research efforts to pinpoint the exact classes of symptoms needing attention, as well as the types of patients most likely to benefit from treatment.
This research was supported in part by grants from the National Heart, Lung and Blood Institute, the National Institute on Aging and the National Institute of Mental Health.
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