Patients who manage their depression through psychological therapy are at reduced risk for cardiovascular diseases. This is the outcome of a large cohort study conducted in the United Kingdom. “Those whose depression symptoms improved after therapy were 10% to 15% less likely to experience a cardiovascular event than those whose did not,” reported the authors in the European Heart Journal.
“There is the assumption, and also some indications, that treating depression could help to protect against cardiovascular diseases, but there is no conclusive evidence,” Heike Spaderna, PhD, professor of health psychology with a focus on prevention and rehabilitation at the University of Trier, Trier, Germany, told Medscape Medical News. “Of course, this retrospective study is also not proof of a causal relationship, but it is the first large-scale study to offer any plausible evidence that this could be the case.”
Higher Cardiovascular Risk
Depression and cardiovascular disease are both highly prevalent; therefore, it is possible that they occur independently of each other. But study data show that there is interaction between the diseases. Cardiovascular diseases contribute to depression, and depression contributes to cardiovascular diseases.
“The risk of cardiovascular diseases is approximately 72% higher among people with major depressive disorders,” primary author Céline El Baou, PhD, a research assistant at University College London, London, United Kingdom, told Medscape. “Our study suggests that successful outcomes of evidence-based psychological interventions may extend beyond psychological health and have long-term physical health benefits, particularly for those aged under 60,” she added.
Seven Years’ Follow-Up
El Baou and her research group analyzed the data from 636,955 adults who had received a course of psychotherapy (for example, cognitive behavioral therapy) for depression and who were initially without cardiovascular disease. The average age of these adults was 55 years, and two-thirds were female.
Improvement in depression symptoms was measured as a reduction (≥ 6 points) in the Patient Health Questionnaire-9 (PHQ-9) score without a deterioration in anxiety symptoms. The latter criterion was intended to prevent the therapy from being considered successful if an improvement in depression coincided with a worsening of anxiety. The patient follow-up started 1 year after the last therapy session and ran for a median of 3.1 years, at maximum 7 years.
Cardiovascular Risk Reduction
The symptoms of depression improved in 59% of patients. Cardiovascular events were experienced by 49,803 study subjects, and 14,125 died. The improvement in depression was associated with a 12% reduction in the risk for cardiovascular diseases.
The risk for coronary heart disease (CHD) was 11% lower, and the risk for stroke was 12% lower. All-cause mortality was 19% lower in patients with improved symptoms than in those whose psychotherapy had been unsuccessful.
In the analyses, the researchers considered variables such as age, ethnicity, sex, socioeconomic status, and other health restrictions that could have affected the associations.
Lifestyle, Inflammatory Processes
The study does not show the ways in which the improvement in depression may have led to a reduction in cardiovascular risk. However, Spaderna offered two possibilities. “One mechanism could be that by improving the depression, the patient’s lifestyle also improves. This applies particularly to physical activity. Both the association with depression and the protective effect on cardiovascular health are well proven here.”
On the other hand, there is also the theory that depression encourages inflammatory processes in the body, including in the walls of blood vessels. This may also affect cardiovascular health, Spaderna added.
El Baou and her coauthors also reported that the associations between the improvement in depression and the risk for cardiovascular diseases were pronounced in 45- to 60-year-olds. For this group, the improvement in depression was associated with a 15% decrease in cardiovascular diseases. In patients over 60 years of age, there was only a 6% decrease.
Moreover, with respect to all-cause mortality, the 45- to 60-year-olds benefited more from a reduction in symptoms of depression. Their mortality risk underwent a 22% reduction. This reduction was only 15% in the adults over 60.
“Our results are consistent with previous research, in that [they show that] cardiovascular risk reduction interventions in general may be less effective in older adults,” commented El Baou.
“Older adults may find it harder to lead a more active life, even if the depression has improved,” said Spaderna. But it would still be worth it. “Even in older adults, behavioral changes can have a positive effect on health and life expectancy.”
However, all-cause mortality could also play a role in older adults. “The elderly often have other conditions, such as high blood pressure or diabetes, that could have an influence on cardiovascular risk. In this case, the improvement in depression may not have any resounding effect on cardiovascular health,” added Spaderna.
Access to Psychotherapy
The authors conceded that the study cannot prove definitively that the improvement in depression led to a reduction in cardiovascular diseases. Lifestyle factors such as smoking and a lack of physical exercise, for which no data were collected, may also have influenced the results.
Nevertheless, El Baou is convinced that “it is extremely important to facilitate access to psychotherapists to promote mental and physical health.” This is particularly true for communities that find it difficult to access psychotherapeutic care and that are simultaneously at high risk for cardiovascular diseases.
“It is deplorable that in Germany, many patients find it extremely difficult to find therapy,” said Spaderna. “This must be rectified urgently.” People must also be made more aware of the fact that mental illnesses such as depression should be treated at an early stage, according to the psychologist. “The correlations between depression and cardiovascular diseases are still not known to a sufficient extent,” she said.
This article was translated from Medscape’s German edition.
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