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Insomnia and Heart Failure Risk: Something to Lose Sleep Over?

In Neuropsychology, Neuroscience, Psychiatry on Tuesday, 21 May 2013 at 06:55

Insomnia and Heart Failure Risk: Something to Lose Sleep Over?

By: Shelley Wood

Clinical Context

Insomnia can lead to activation of the neuroendocrine system, which in turn may promote a higher risk for cardiovascular disease. The authors of the current study previously used the same study cohort to evaluate the risk for acute myocardial infarction (AMI) associated with insomnia. Their results, which were published in the November 8, 2011, issue of Circulation, demonstrated that mild, intermittent sleep problems were not associated with a higher risk for AMI. However, insomnia almost every night and nonrestorative sleep experienced more than once per week were associated with increases in the risk for AMI of more than 40%.

The current study by Laugsand and colleagues examines whether insomnia can affect the risk for incident heart failure.

Study Synopsis and Perspective

Insomnia symptoms in middle age are strongly associated with the subsequent development of heart failure, a large Norwegian cohort study has found[1]. The analysis, which considered over 54 000 men and women, linked insomnia symptoms and heart failure, even in subjects who had never experienced a coronary event.

While the study does not demonstrate causation, researchers led by Dr Lars E Laugsand (Norwegian University of Science and Technology, Trondheim) say their findings have important implications for patient management and, potentially, reducing progression to heart failure.

“If subsequent studies confirm our findings and if causality is better established, the observed prospective association between insomnia and HF [heart failure] risk could have implications for cardiovascular prevention, since insomnia is an easily recognizable and potentially manageable condition,” the authors write.

Speaking with heartwire , Laugsand stressed that the findings do not have immediate implications for physicians, beyond the fact that sleep is important to good health generally.

“I think cardiologists should talk to their patients about sleep problems, but I think it’s a little too early to say that anything should be implemented in the CV [cardiovascular] risk assessment,” he said. “More research is clearly needed to evaluate the possible underlying mechanisms.”

For example, he continued, the chronic activation of stress responses seen in insomnia could be expected to have an impact on the heart. “Patients who are stressed both at night and during the day have increased BP [blood pressure], increased release of stress hormones, increased heart rate, etc, and all of these factors are related to HF, so that’s a potential link between the neuroendocrine system and the sympathetic nervous system. We cannot say this is the case from our study,” but it’s a plausible link, he said.

Community-Based Analysis

Laugsand et al reviewed baseline data relating to insomnia symptoms from the Nord-Trøndelag Health Study on the 54 279 patients enrolled between 1995 and 1997, none of whom had HF at the study outset. By 2008, 1412 patients had developed heart failure.

In a range of analyses that took into account different factors, such as age, cardiovascular disease risk factors, or psychological factors, insomnia symptoms remained strongly correlated with new-onset heart failure, with more symptoms linked with higher risk. For example, subjects who reported having “difficulty initiating sleep” on “almost every night” had a 27% to 66% risk of developing heart failure (depending on the model used), compared with subjects with no insomnia symptoms. By contrast, patients who reported “difficulty initiating sleep” on a frequent basis, in addition to “difficulty maintaining sleep” and feeling that their sleep was “nonrestorative,” had a risk of heart failure that ranged from two to five times higher than in subjects with no insomnia symptoms.

Women were at an increased risk of having heart failure in relation to certain insomnia risk factors and for cumulative measures of insomnia, compared with men, but Laugsand was reluctant to make much of this observation. “You cannot say from these numbers that insomnia is more dangerous for women than men when it comes to having heart failure,” he said. They have a higher relative risk, but that might be due to their lower baseline risk of HF.”

The next step, said Laugsand, would be a trial treating patients for insomnia to see whether such a strategy could mitigate the development of heart failure.

“That would be the ultimate goal, to do a randomized controlled trial. This study is an observational study and saying anything too firm about causality is difficult,” he cautioned. “But from the studies done in insomnia and other sleep problems, we know that sleep problems affect the physiology of the heart.”

References

  1. Laugsand LE, Strand LB, Platou, et al. Insomnia and the risk of incident heart failure: A population study. Eur Heart J 2013; DOI: 10.1093/eurheartj/eht019. Available at: http://eurheartj.oxfordjournals.org.

Study Highlights

  • Study data were derived from the Nord-Trøndelag cohort, which reflects the general population of Norway. Study recruitment began in 1995. The current study focused on individuals between 20 and 89 years old without a history of heart failure.
  • Participants completed a thorough examination at the outset of the study, including questions regarding insomnia and the use of hypnotic medications. The insomnia history focused on difficulty falling asleep (early insomnia), waking during sleep (middle insomnia), and nonrestorative sleep. A laboratory assessment was also part of the initial examination.
  • The main study outcome was incident heart failure, which was identified from hospital diagnoses and national death registers.
  • The study analyzed the risk for heart failure associated with insomnia, and researchers adjusted their analyses to account for demographic data and traditional cardiovascular risk factors. Researchers also performed an analysis that accounted for patients’ other chronic diseases.
  • 54,279 participants provided study data. The rates of severe insomnia in the study cohort varied between 2.5% and 8.1%, depending on which domain of insomnia was being queried.
  • Older adults and women were more likely to have insomnia. Insomnia was closely related to depression, anxiety, and the presence of cardiovascular risk factors.
  • During a mean evaluation period of 11.3 years, there were 1412 incident cases of heart failure. 408 of these cases were reported from the death registry.
  • In fully adjusted analyses, including psychiatric diagnoses, the presence of early insomnia, middle insomnia, or nonrestorative sleep individually did not significantly increase the risk for heart failure, even when these symptoms were severe.
  • However, there was a dose-dependent positive effect on the risk for heart failure with a greater number of insomnia symptoms. The presence of 1 insomnia symptom was associated with a hazard ratio (HR) for heart failure of 0.96 (95% [confidence interval] CI, 0.57 – 1.61). Having 2 or 3 of these symptoms was associated with respective HRs of 1.35 (95% CI, 0.72 – 2.50) and 4.53 (95% CI, 1.99 – 10.31).
  • The presence of nonrestorative sleep was associated with a higher risk for incident heart failure among women vs men.
  • Exclusion of cases of heart failure diagnosed early during follow-up failed to significantly alter the main study outcome.

Clinical Implications

  • A previous study of the current cohort of adults found that severe, but not mild, insomnia was independently associated with a higher risk for AMI.
  • In the current study by Laugsand and colleagues, only the presence of multiple insomnia symptoms was significantly associated with a higher risk for incident heart failure.

Retrieved from: http://www.medscape.org/viewarticle/781692

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