Thursday, January 31, 2013

Insomnia.... Heart Attack

I thought this was an interesting Norwegian population study from Circulation: Journal of the American Heart Association, Oct 2011. In it, they simply did a chart review of men and women, 52 thousand of them and tried to see if there was an increased amount of heart attacks in those that don't sleep well.

They followed these people over 11.6 years worth of medical charting.
2,368 heart attacks were noted.

They split the population sleep complaints up into three groups:

1. Patients who don't fall asleep quickly (sleep onset insomnia).

2. Patients who don't stay asleep well (sleep maintenance insomnia).

3. And patients who just don't feel subjectively like they got a good night's sleep the next day for no obvious reason they are aware of... (nonrestorative sleep).

And they compared these groups to other patients who had no such sleep complaints in their charts.

1. Those who commonly couldn't fall sleep quickly at the beginning of the night were 45% more likely to have a heart attack than their counterparts without sleep onset insomnia.

2. Those who commonly couldn't stay asleep well were 30% more likely to have a heart attack than their counterparts without sleep mantenance insomnia.

3. Those who complained of nonrestorative sleep the next morning were 27% more likely to have a heart attack than their counterparts who didn't complain of nonrestorative sleep.

Interestingly, while the onset and mantenance insomnia had to be a complaint of almost every night, the nonrestorative complaint only had to be only 2 of 7 nights to see that connection to heart attacks.

That being said, let's point out some weaknesses:
-What sleep problems lead to poor sleep quality and insomnia are not addressed? The problem is likely not only the lack of sleep or quality sleep but perhaps some sleep disorder as a unifying cause of both poor sleep AND heart attacks.
-No sleep studies on any of these patients were done, or at least, not reviewed if done.
-Also, no correlate to timing of the heart attack (nighttime versus early morning versus midday) were made and might have direct relevance.
-Is this Norwegian group relevant to people at lower lattitudes with different risks of heart disease and perhaps a different prevalence of sleep disorders which might interfere with sleep quality?

The likely moral of the story is supported in a growing body of studies:
Not just sleep itself, but quality sleep is needed for your heart and vasculature to "rest" during sleep (your heart never truly "rests") or at least somehow reorient itself biochemically or mechanically for the rigors of the next day. When you don't get sleep or quality sleep, your heart is ALSO paying the price (I would argue ALL organ systems are paying the price in one way or another).

Another VERY IMPORTANT point is that the answer is MOST ASSUREDLY NOT just more sleep medication. In this study, the actual cause of WHY people had insomnia or nonrestorative sleep was not addressed, so masking it with a sleep medication will likely not fix the fact that it's not just sleep, but quality and restorative sleep that is needed.

Sleep medications do not fix a vast majority of the known sleep disorders, and should really be used only to augment therapies for sleep disorders leading to insomnia--- the underlying cause still has to be addressed.

Only about 10% of all patients complaining of insomnia have idiopathic primary insomnia which is an underlying defect in the central nervous system substrate responsible for the sleep-wake cycle and present since birth or early childhood. And only in this small group are sleep agents the first and direct approach to treatment. In those patients, it may reduce heart attack risk, but that would suggest a benefit for the minority of patients.

Below is some of the article in more detail if you would like to read it as well:
Sleepless Nights May Tax the Heart

A population-based study of more than 52,000 Norwegian men and women suggests that sleepless nights may increase the risk of a heart attack.
People who struggled to fall or stay asleep almost every night were 30% to 45% more likely to have an acute MI, Lars E. Laugsand, MD, of the Norwegian University of Science and Technology in Trondheim, and colleagues found.
The more insomnia symptoms reported, the higher the risk (P=0.003 for trend), they wrote in Circulation: Journal of the American Heart Association.
Although the observation suggests just moderate relative risks, the authors estimated that insomnia may affect as many as one third of adults and symptoms are easily recognizable.
"Therefore, evaluation of insomnia might provide additional information in clinical risk assessment that could be useful in cardiovascular prevention," they suggested in the paper.
Management can be as simple as following sleep hygiene recommendations, although targeted pharmacological and nonpharmacological therapies may be needed to help with chronic insomnia, the researchers pointed out.
They analyzed questionnaire responses from 52,610 men and women living in a single county in Norway and followed for acute MI through national hospital and vital status registries in the Nord-Tr√łndelag Health Study.
During 11.4 years of follow-up, 2,368 incident acute MIs were recorded.
Difficulties initiating sleep almost every night were reported at baseline by 3.3% of the participants; trouble maintaining sleep almost every night by 2.5%; and nonrestorative sleep more than once a week by 8.0%.
People who struggled to fall asleep almost every night were 45% more likely to have an acute MI (adjusted hazard ratio 1.45, 95% confidence interval 1.18 to 1.80) compared with those who never experienced this sleep problem.
Trouble staying asleep nearly every night was associated with 30% elevated risk (adjusted HR 1.30, 95% CI 1.03 to 1.57).
Nonrestorative sleep two or more times a week predicted 27% elevated risk of acute MI (adjusted HR 1.27, 95% CI 1.03 to 1.57).
These results had been adjusted for age, sex, education, shift work, marital status, depression, anxiety, and heart disease risk factors, such as smoking and physical activity.
Sensitivity analyses further excluding the first five years of follow-up, acute MI not hospital verified, and those with chronic somatic disorders didn't have much impact.
Potential mechanisms include common risk factors between sleep disorders and heart disease, such as increased sympathetic activation and high blood pressure, they noted.
Sleep apnea, which is well-established as a cardiovascular disorder, wasn't assessed.