Stress. Who isn’t affected by it almost on a daily basis? Sure some more than others, but we are all familiar with it and aware of the health risks which are commonly associated with it. A recent study investigated whether intermittent and/or persistent stress, depression and anxiety are linked to an increased risk of long term cardiovascular (CV) disease and total mortality in people with stable coronary artery disease (CAD).
Numerous prognostic and aetiological studies in the past have identified that stress, particularly depression and anxiety, are associated with an increase in the risk of major CV events such as stroke, heart failure, uncontrolled hypertension (high blood pressure) and pulmonary embolism (blood clot). This has led experts to conclude that stress is likely to increase the risk of adverse coronary artery disease (CAD) events. However, it remains unclear how to help patients and what intervention strategies can be introduced to help reduce stress and help in the prevention of CAD events.
CAD is the most common cause of heart disease and occurs when there is a build-up of plaque (deposits containing cholesterol combined with fat, calcium and other substances) over time and leads to the hardening and narrowing of the arteries which supply blood to the heart. Due to the restriction of blood flow to the heart, this can lead to blockages and result in angina (chest pain) or a heart attack. Prevention and treatment of CAD is often up to the individual as a healthy lifestyle (diet and physical activity) can make a significant impact on disease progression.
Previous studies are limited as they have only assessed the psychological well-being of patients typically only after an acute coronary event. The main issue is the results are limited in helping conclude the impact psychological distress has on a patient’s long-term health as symptoms of stress often improve directly after such an event. The severity of stress symptoms can vary over time for a number of reasons. Hence this led Stewart and colleagues to design a study which investigated the psychological distress of patients with stable coronary artery disease over a longer period of time, with multiple assessments to evaluate the effect persistence and severity of stress has on patients’ health and ultimately mortality.
This novel study, published in the British Heart Journal, assessed 1130 participants over 4 years by having them complete a General Health Questionnaire (GHQ) at baseline and then after 6 months, 1 year, 2years and 4 years. Follow up for the next 12 years was also done to assess CV and all-cause mortality in patients who participated in the study. Of the 1130 original participants, 85 died before the 4 years were completed and another 95 did not complete 4 or more questionnaires.
The remaining 950 participants in the study were included in the analysis. They were aged between 31-74 years old and had a history of acute myocardial infarction (heart attack) or had been recently (in the last 3-36 months) hospitalised for unstable chest pains. Patients with heart failure were excluded. Participants were from 36 countries around the world, including New Zealand and Australia. The GHQ contained 30 questions to assess “distress” related to depression, anxiety or both.
The results showed that of the 950 participants, 62% reported no distress at any of their visits, 27% reported mild or greater distress at one or two assessments and 8% had mild distress on at least 3 of the 5 visits. Only 3.7% of the participants reported having moderate distress.
Those with persistent mild or moderate distress were reported to more likely have angina or dyspnoea (shortness of breath), however, they were not more likely to have a history of heart attacks.Also, distress of any severity, but only present on one or two visits and persistent mild distress were not clearly linked to any increases in CV and all-cause mortality.
During the 12 year follow up, there were 398 deaths and 199 CV deaths (defined as deaths resulting from events such as heart failure, stroke, sudden cardiac death, blood clots and complications of blood circulation disorders). Patients with moderate or severe distress were associated with a two to fourfold increase in both CV and total mortality.
Overall, the burden of stress on one’s health is evident, particularly for those with stable CAD. The cumulative burden of stress is linked to an increased risk of mortality as shown in this investigation. The results of this study are supported by evidence from previous studies conducted with the general population (where it was unknown if participants had a CV disease).
Limitations of this analysis include that it was an observational study, therefore it cannot be determined if the association between persistent psychological stress and mortality was casual. Also, the occurrence of traumatic life events was not included in the assessment, which can have a significant impact on the stress levels of people.
Patients with persistent and moderate to severe stress could greatly benefit from the results of this study. It is evident more intervention is needed and perhaps primary health givers would be best poised to identify these patients and help to improve their psychological well-being. Further randomised controlled studies are needed to determine if interventions which reduce persistent stress can, therefore, result in decreasing the risk of mortality.
Written by Lacey Hizartzidis, PhD
Stewart RAH, Colquhoun DM, Marschner SL, Kirby AC, Simes J, Nestel PJ, Glozier N, O’Neil A, Oldenburg B, White HD, Tonkin AM; LIPID Study Investigators. Persistent psychological distress and mortality in patients with stable coronary artery disease. Heart. 2017 Jun 26. pii: heartjnl-2016-311097. doi: 10.1136/heartjnl-2016-311097