From the European Heart Journal
Cardiovascular disease (CVD) and depression are common. Patients with CVD have more depression than the general population. Persons with depression are more likely to eventually develop CVD and also have a higher mortality rate than the general population. Patients with CVD, who are also depressed, have a worse outcome than those patients who are not depressed. There is a graded relationship: the more severe the depression, the higher the subsequent risk of mortality and other cardiovascular events.
It is possible that depression is only a marker for more severe CVD which so far cannot be detected using our currently available investigations. However, given the increased prevalence of depression in patients with CVD, a causal relationship with either CVD causing more depression or depression causing more CVD and a worse prognosis for CVD is probable. There are many possible pathogenetic mechanisms that have been described, which are plausible and that might well be important.
However, whether or not there is a causal relationship, depression is the main driver of quality of life and requires prevention, detection, and management in its own right. Depression after an acute cardiac event is commonly an adjustment disorder than can improve spontaneously with comprehensive cardiac management. Additional management strategies for depressed cardiac patients include cardiac rehabilitation and exercise programmes, general support, cognitive behavioural therapy, antidepressant medication, combined approaches, and probably disease management programmes.
Cardiovascular disease (CVD) and depression are currently the two most common causes of disability in high-income countries and expected to become so for countries of all income levels by 2030. The key health system and economic indicators relating to CVD and depression reveal rising medical costs, increased health service utilization,and lost productivity. Additionally, CVD and depression profoundly impact the overall quality of life, even more so for heart failure patients. One could argue that depression is probably the most important driver of overall quality of life.
The prevalence of unrecognized depression in cardiac patients has been noted for more than 40 years. In a seminal paper from Australia by Wynn in 1967, of patients with perceived disability after myocardial infarction, 40% were depressed and in many of them this had not been previously recognized. In 1972, Cay et al. found symptoms of depression and anxiety in two-thirds of consecutive patients after admission for cardiac events.
The patient burden of co-morbid CVD and depression would seem to warrant targeted intervention. In this review, we clarify the prevalence, aetiology, and prognosis of depression in CVD patients. We also explore the relationship between depression and other psychosocial factors, such as anxiety and social isolation. Drawing on the most recent research evidence, we examine psychosocial and pharmacological intervention strategies to manage depression in the context of CVD, noting the need for ongoing randomized controlled trials. Finally, we review the potential benefits of using an integrated, multi-disciplinary approach to CVD patient care and management.
Diagnostic issues: characterizing depression in cardiovascular disease
The word ‘depression’ has many meanings ranging from a transient feeling of flat mood, through to serious clinical syndromes that can be severe, disabling, and recurrent. In addition, some persons seem to have a more distressed, enduring personality including some features of depression.11 Depression generally involves symptoms such as a feeling of depressed mood, a loss of interest or pleasure in activities, sleep disturbance, fatigue, or impaired concentration.
Mostly the severity of what is experienced as depression occurs as a continuous variable. However, sometimes we use specific criteria for dichotomizing data. This allows us to organize information into useful ‘diagnostic’ groups. There are a number of ways in which this is done. One of the most commonly used is the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) of the American Psychiatric Association that has evolved over a number of decades. Certain criteria are used to classify an individual as having dysthymia (a disorder of mood), grief (a reaction to loss), adjustment disorder with depressed mood (a time limited reaction to an event) or major depressive disorder (MDD—with a greater number and severity of symptoms associated with depression). All of these syndromal clusters can occur in cardiac patients.
There are a number of psychological reactions that can potentially occur after acute medical events. Depressed mood is commonly experienced as a reaction to an acute coronary event, or for that matter to any illness or operation perceived to threaten one’s life and well-being. If patients are comprehensively managed, this depression can be of a temporary nature and therefore, classified as an adjustment disorder. Thus, the most common form of depression experienced after acute coronary events is an ‘adjustment disorder with depressed mood’. This is seen in the non-treatment control groups of randomized trials treating depression in cardiac patients, in whom there is a marked reduction in depression over time.
While preventing and managing any depression is important for all cardiac patients, patients who fulfill criteria for MDD are at high risk for further events and have particularly poor quality of life. Thus, these patients especially require sensitive detection, accurate diagnosis, and careful management.
The reported prevalence of depression in patients with cardiac disease is quite variable It has long been recognized that mild forms of depression are found in up to two-thirds of patients in hospital after acute myocardial infarction (AMI),with major depression generally being found in ∼15% of CVD patients. This prevalence is over two to three times that found in the general population, although perhaps not much greater than the predicted life-time prevalence for the general population. It is even more prevalent in chronic heart failure (CHF) patients, generally over 20%, with the prevalence being related to the severity of the functional class, ranging from 10% in asymptomatic patients to 40% in those with severe functional impairment. Depression in CHF patients is also an independent predictor of mortality and rehospitalization.
Two years after receiving an implantable cardioverter defibrillator, over one quarter of patients are depressed, those patients experiencing more shocks being significantly more likely to be depressed. On average, it would appear that of patients have major depression after coronary artery bypass surgery and probably another 15% experience minor depression or significantly depressed mood.