Saturday, March 03, 2012

Do Sleeping Pills Kill?

A recent study published in BMJ Open found that the prescription of sleeping pills (hypnotics) was associated with a greater than threefold increase in the risk of death. The abstract and full article are available (free) here:

http://bmjopen.bmj.com/content/2/1/e000850.full

There are a number of problems with this study, as mentioned by Dr. Nancy Collop, President of the American Academy of Sleep Medicine:

"Although the study found that the use of hypnotic medication, or sleeping pills, was associated with an increased risk of mortality, a cause-and-effect relationship could not be established because the study only analyzed an insurance database... it was impossible for them to control for psychiatric conditions and anxiety, which is an area of significant concern to this study population..." http://www.medscape.com/viewarticle/759336?src=mpnews&spon=17

The major problem that I have with the study is that, as I far as I can see looking at the full article, the presence of insomnia was not controlled for (most of the comparison group did not have insomnia). Insomnia itself is associated with increased mortality (in some but not all studies) and morbidity (illness). To further illustrate why this is a problem, consider a hypothetical study in which the use of insulin was associated with an increased death rate. It is well known that dibetes itself increases the risk of death. If the comparison group in this hypothetical study did not have diabetes, I don't think much if anything could be learned from the study.

This new sleeping pill study doesn't add much new information to the field of sleep medicine, although it does add to the literature suggesting that insomnia is a serious problem. I did find this earlier editorial by Dr. Kripke (primary author of the current study) which sums up the problem with this current study:
"Numerous previous studies have shown an association of hypnotic use to mortality, which can become confounded with insomnia. Was mortality controlled for hypnotic usage in examining the association with insomnia?" http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079930/?tool=pubmed
To fully apply to the current study, that last statement can be changed to: Was mortality controlled for insomnia in examining the association with hypnotic usage?

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Edit: The association between insomnia and death is a complex issue. It is clearly associated with illness/morbidity. This abstract sums up the issues: http://www.ncbi.nlm.nih.gov/pubmed/15600216

Some studies have found that while a subjective complaint of insomnia is not associated with an increased risk of death, short sleep time is.

6 comments:

Adjustabeds said...

Interesting.. I see the issue with the psychiatric conditions of the "control group" being uncontrollable. It would be enlightening to see a follow up study with a greater degree of control.

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janisek said...

Well, I was told once by my close friend and doctor that every pill is potentially poisonous.
I don't know if hypnotics kill, but they are habit forming. I've tried Lunesta before and for me it lost its effectiveness within 3 days only!!! I tried it again after couple years and even 3 times higher dose didn't work for me! Lunesta is supposed to be a long term sleep aid. It might work for someone else, but not for me. It is the only hypnotic I've tried so far and unless I'm absolutely desperate I'm not trying any other brand. I'm been searching for some natural sleep aid which would solve insomnia I've been dealing with for 4 1/2 years already, but no luck so far. :(

Orin said...

While the study might not be conclusive it is still a little bit unnerving to say the least.

There are a lot of things you can do to sleep better, one of which includes getting a comfortable mattress especially if you suffer from insomnia caused by a poor sleep surface.

Ayaz Ahmad said...

Insomnia, defined as trouble falling asleep or staying asleep is experienced by more quarter of adult population in America.Its horrible experience when whole world around you is sleeping and you are trying to sleep most of the patient complain about the side effects like Sleeping Walk , Episodes to Hallucinations , Violent Outbursts etc and research is going to confirm that sleeping pills can produce cancer
Medical biller certification Southern California

AlexV said...

Restrospective studies and chohorts have weaknesses. Association can be demonstrated but not causality. A double blind randomized placebo controlled trial would not be ethical and would not be accepted at the IRB of most developed countries.

An additional study with similar findings was published last month at the Mayo Clinic Proceedings. Full text can be found at:

http://download.journals.elsevierhealth.com/pdfs/journals/0025-6196/PIIS0025619612003059.pdf

Currently, I still prescribe hypnotics to patients who choose this modality of treatment over CBTI. All patients are screened for contraindications and given a disclosure about these two studies.