Researchers have warned that obesity appears to significantly increase the risk of death tied to sleeping pills,nearly doubling the rate of mortality even among those prescribed 18 or fewer pills in a year.
The findings emerged from a Scripps Clinic-led study of almost 40,000 patients.
Obesity emerged as a marker of increased vulnerability, said Robert Langer,M.D.,M.P.H.,a family physician and epidemiologist with the Jackson Hole Center for Preventive Medicine in Jackson,Wyo.
The associations between sleeping pills and increased mortality were present,and relatively stronger,even in people aged 18 to 54, stated Dr. Langer.
Study co-author Daniel Kripke,M.D.,a psychiatrist with Scripps Clinics Viterbi Family Sleep Center in San Diego,said,Obese patients appear particularly vulnerable,perhaps through interaction with sleep apnea.
He noted that sleeping pills were previously associated with more and longer pauses in breathing in people with sleep apnea.
Among obese patients,use of sleeping pills was associated with about one extra death per year for every 100 people who were prescribed the medications,Dr. Langer said.
Additionally,men who took sleeping pills were about twice as likely to die as women who received the medications,after accounting for other factors,he said.
The initially findings of the study was published in late February in the open-access online journal BMJ Open.
The research was the first to show that eight of the most commonly used hypnotic drugs were associated with increased hazards of mortality and cancer,including the popularly prescribed medications zolpidem (known by the brand name Ambien) and temazepam (also known as Restoril),Dr. Kripke said.
Those drugs had been thought to be safer than older hypnotics because of their shorter duration of action but were found to have associations with excess deaths no different from the older drugs they have largely replaced.
To eliminate the possibility that other factors led to the results,study participants who were prescribed sleeping pills were matched with control patients of similar ages,gender and health who did not receive hypnotics.
For obese patients in the study who had an average body mass index of 38.8,the risk of death was 8.1 times higher on average among those who were prescribed the smallest number of pills (18 or fewer annually) when compared with similar study participants who did not take the medications. The mortality rate was 9.3 times higher on average among obese patients receiving the largest number of pills (132 or more annually).
Death was 4.6 times more likely on average among all patients who received any amount of sleeping pills.
The study cast a shadow over a growing segment of the pharmaceutical industry that expanded by 23 percent in the United States from 2006 to 2010 and generated about 2 billion dollars in annual sales.
Using data stored in an electronic medical record that has been in place for more than a decade,the researchers obtained information on almost 40,000 patients cared for by a large integrated health system in the northeastern United States.
The research included 10,531 sleeping pill users who were prescribed the medications for an average of 2.5 years and 23,674 control participants who were not prescribed the drugs. Information came from outpatient clinic visits conducted between January 1,2002,and September 30,2006.
It is important to note that our results are based on observational data,so even though we did everything we could to ensure their validity,its still possible that other factors explain the associations, said co-author Lawrence E. Kline,D.O.,who is medical director of the Viterbi Family Sleep Center.
We hope our work will spur additional research in this area using information from other populations, he added.
The research should prompt physicians to consider alternatives to hypnotic medications,Dr. Kline said.
When insomnia results from emotional problems such as depression,doctors should treat the psychological disorder rather than prescribe sleeping pills that could prove to be harmful,Dr. Kripke suggested.
The newest findings were presented at the annual American Heart Associations Epidemiology and Prevention | Nutrition,Physical Activity and Metabolism 2012 Scientific Sessions in San Diego.