Sleeping Pills May Claim Half a Million Lives Annually

The use of hypnotic sleep aids is associated with a three- to five-fold higher mortality risk when compared with the risk for nonusers, according to a new study.

Researchers at the Scripps Clinic (La Jolla, CA, USA) reviewed electronic medical records (EMRs) and conducted a one-to-two matched cohort survival analysis of 10,529 patients (mean age 54 years) who received hypnotic prescriptions and 23,676 matched controls with no hypnotic prescriptions. The participants were followed for an average of two and a half years, between January 2002 and January 2007. The main outcome measures were Hazard ratios (HRs) for death, adjusted for age, gender, smoking, body mass index (BMI), ethnicity, marital status, alcohol use, and prior cancer.

The results showed that overall 6.1% of hypnotic users died during observation, compared with 1.2% of the nonusers. For groups prescribed 0.4–18, 18–132, and over 132 doses per year, the HRs were 3.60, 4.43, and 5.32, respectively, demonstrating a dose–response association. Separate analyses for several common benzodiazepine hypnotics, barbiturates, and sedative antihistamines also demonstrated elevated HRs. Hypnotic use in the upper tercile was also associated with a significant elevation of incident cancer, with a HR of 1.35. The results were robust within each comorbidity group, indicating that the associations were not attributable to preexisting disease. The study was published on February 27, 2012, in BMJ Open.

“We cannot be certain what portion of the mortality associated with hypnotics may have been attributable to these drugs, but the consistency of our estimates across a spectrum of health and disease suggests that the mortality effect of hypnotics was substantial,” said lead author Daniel Kripke, MD. “Rough order-of-magnitude estimates ... suggest that in 2010, hypnotics may have been associated with 320,000 to 507,000 excess deaths in the US alone.”

More than two dozen studies have examined the mortality risk associated with hypnotics use, and two-thirds of them demonstrated significant associations. The first was conducted more than 30 years ago, which showed that both cigarette smoking and hypnotic use were associated with excess mortality; however, the link to hypnotics was largely discounted because the study was not designed primarily to examine these drugs.

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