Loneliness Linked to Higher Rates of Mortality in Cardiac Patients

Among men and women with a wide range of cardiac diagnoses, loneliness was associated with a more than twofold increased risk of death from all causes, according to a new Danish analysis.

Loneliness, a subjective measure highlighting “perceived deficiencies in one’s social relationships,” was a much stronger predictor of all-cause mortality than the objective measure of living alone, report investigators. For men with cardiac disease who lived by themselves, there was an increased risk of all-cause mortality at 1 year (HR 1.39; 95% CI 1.05-1.85), but there was no such relationship observed in women, report investigators.  

“We know that psychosocial factors do play a large role in the development of cardiovascular disease but also in the prognosis after a diagnosis of cardiovascular disease,” Anne Vinggaard Christensen, PhD (Copenhagen University Hospital, Denmark), told TCTMD. “We’ve mostly studied anxiety and depression and the link they have to cardiovascular disease and mortality. We haven’t looked that much into loneliness and social networks, but there is quite an extensive amount of previous research that links loneliness or social isolation to poor health outcomes, broadly speaking.”

Several studies have shown that a lack of social support may play a role in the progression of cardiovascular disease, explain the researchers. For example, a recent meta-analysis suggested that poor social support had a negative impact on cardiac and all-cause mortality in patients with coronary heart disease.

In this analysis of 13,443 patients discharged from the hospital with a diagnosis of ischemic heart disease, arrhythmia, heart failure, or valve disease, loneliness, which was assessed on a questionnaire from the Danish National Health Survey, was associated with a nearly threefold increased risk of death at 1 year in women (HR 2.92; 95% CI 1.55-5.49) and a more than twofold higher risk in men (HR 2.14; 95% CI 1.43-3.22).

The association between living alone and mortality at 1 year was not observed in women, a finding consistent with prior studies. “Living alone seems like it’s a risk among men only,” said Christensen. She pointed out that living alone and loneliness, while they appear similar, are different variables, with loneliness a subjective measure that varies between individuals.

In terms of mechanisms, the researchers say there are several plausible reasons for the association, among them behavioral, psychological, and biological pathways. Loneliness and social isolation may be associated with a stress response that leads to heightened cardiovascular reactivity, as well as adverse changes in neuroendocrine or immune function, said Christensen. From a behavioral perspective, loneliness could have a direct effect on health behaviors that can affect heart health, such as not exercising, making unhealthy food choices, smoking, or not adhering to medical therapy.

The researchers also note that social relationships increase feelings of safety and trust, which are “buffers” that can partly offset biological stress-induced responses.

To TCTMD, Christensen said physicians should address social isolation and feelings of loneliness in their cardiac patients as part of clinical risk assessment. “As far I know, based on my experience in our clinic, it’s not something we would normally talk to the patient about,” she said. “In terms of what to do, though, it’s very difficult.”

While the researchers are performing some exploratory work with interventions designed to combat loneliness and social isolation, it’s challenging “because people don’t really want to ask for help,” Christensen said. One possible intervention might include contact with fellow cardiac patients, she suggested. “It’s a way of sharing experiences and feeling like they’re part of something, but there’s no simple answer.”