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Stress linked to mortality in CHD patients

CHD patients with moderate or severe stress have higher CVD and all-cause mortality

Louise Prime

Wednesday, 28 June 2017

Moderate to severe psychological distress identified at a single assessment is associated with a substantial increase in risk of cardiovascular and all-cause mortality in people with stable coronary heart disease (CHD), research has suggested. But authors of the study,* published in Heart, said there was no such association for persistent mild or occasional distress over the long term. The writer of an accompanying editorial** said although there could be other non-causal explanations for the association, doctors should routinely include screening for mental distress in their patients with CHD.

Researchers in New Zealand and Australia analysed data on 950 participants aged 31-74 years in the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) trial, who had completed at least four General Health Questionnaires (GHQ-30) at baseline and after ½, 1, 2 and 4 years; all had had a heart attack or been admitted to hospital for unstable angina in the 3- 36 months before study entry.

As part of the GHQ-30 participants had answered questions to gauge their levels of mental distress, which was graded according to severity and the length of time it lasted at each of the assessments: never distressed; occasional (of any severity); persistent mild distress on three or more occasions; and persistent moderate distress on three or more occasions.

Participants’ health and survival were monitored for an average of 12 years, during which 398 people died from all causes and 199 died from cardiovascular disease.

About a quarter (27%) of participants said they had experienced occasional distress of any severity, and 62% said they had not been distressed at any of the assessments. Around one in 10 (8%) said they had experienced persistent mild distress, and 35 people (3.7%) complained of persistent moderate distress. Those in this last group were nearly four times as likely to have died of cardiovascular disease and nearly three times as likely to have died from any cause as those who said they had not been distressed at any of the assessments. The researchers found no such associations for people who had experienced persistent mild distress, or who said they had only experienced it occasionally. These results held true even after taking account of other potentially influential risk factors.

The researchers pointed out that as theirs was an observational study, it could not show cause and effect, and they added that confining the assessments to a period of four years might have underestimated the true impact of persistent distress. But they concluded that the increase in risk of death was “substantial” and that: “In patients with stable [CHD], long-term mortality risk is related to the cumulative burden of psychological distress.”

The author of a linked editorial pointed out that although the GHQ-30 is very reliable it cannot pinpoint the specific nature of stress and is no longer widely used for assessing it; and also that the researchers didn’t account for the impact of traumatic life events or socioeconomic factors. He said: “The possibility is real that [CHD] itself is the source of distress and a determinant of poor outcome.”

However, he added that mental distress activates the sympathetic nervous system and boosts stress hormone levels, which, if persistent, can produce potentially harmful physiological changes, some of which may be permanent; and distress can also prompt unhealthy behaviours.

He concluded: “Clinicians should make the screening of psychological distress, a constituent part of the routine assessment of patients with CHD. Strict implementation of secondary prevention measures and referral of distressed subjects to mental health profes­sionals to strengthen their stress-coping aptitude should be included in the strategy of care, principally for subjects with CHD and persistent moderate-to-high distress.”

* Stewart RAH, Colquhoun DM, Marschner SL on behalf of the LIPID Study Investigators, et al. Persistent psychological distress and mortality in patients with stable coronary artery disease. Heart, published online first: 26 June 2017. doi: 10.1136/heartjnl-2016-311097

** Ndrepepa G. Psychological distress and mortality in stable coronary heart disease: persistence of high distress means increased risk. Heart, published online first: 26 June 2017. doi: 10.1136/heartjnl-2017-311610

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