For more than 15 years, benzodiazepines—often prescribed for anxiety, sleep, and seizure disorders—have been linked to hip fractures among the elderly as a result of falls. These breaks may cause disability and death, particularly for women. Concern about misuse of the sedatives and their potential for causing injury has led state and national policymakers to devise regulations limiting their use even though the evidence for such policies has never been firm. Since January 2006, for example, benzodiazepines have been excluded from coverage through the Medicare Part D drug benefit.
A study in the Jan. 16 Annals of Internal Medicine reports that these restrictive policies should now be reexamined since the data show that, among Medicaid patients age 65 and older, decreasing benzodiazepine use had no effect on the risk for hip fractures.
The researchers, including first author Anita Wagner and Stephen Soumerai, compared hip fracture rates in New York before and after the 1989 start of a statewide law requiring physicians to use triplicate forms when prescribing benzodiazepines. The policy resulted in an immediate and sustained 55 percent drop in benzodiazepine use overall. The investigators also compared the New York hip fracture rates with concurrent rates in New Jersey, a neighboring, demographically similar state that does not restrict prescribing and use of benzodiazepines. The hip fracture rates did not decline in either state.
“The policy drastically decreased use of benzodiazepines in New York, and we did not see any decline in hip fracture rates compared to New Jersey; in fact, we seem to see an increase in New York over New Jersey,” said Wagner, an HMS assistant professor of ambulatory care and prevention at Harvard Pilgrim Health Care.
There are several possible explanations for the results. Most plausible are weaknesses in earlier study design that may explain why previous work identified a relationship between the medications and hip fractures. It is difficult for researchers to disentangle the effects of the drugs from other causes.
“There are many reasons why elderly patients break their hips, and most studies cannot fully examine those,” said Wagner. “Our study had the best possible design, looking at whether a policy that drastically decreased the use of the drugs also decreased hip fractures in a large stable population. We did not find that. It is possible that previous studies attributed hip fractures to benzodiazepines that were really due to other factors that we cannot easily measure, such as how much a patient smokes and how dense his or her bones are. Many elderly who use the drugs have other medical conditions linked to falls and hip fractures, such as senile dementia.”
“The challenge of disentangling the effects of benzodiazepines from other causes of hip fractures in the elderly is especially concerning when study results are used to guide policies that restrict access to medicines for huge populations,” said Soumerai, senior author of the study and an HMS professor of ambulatory care and prevention.
The findings are particularly relevant now, since the new Medicare drug benefit excludes coverage of benzodiazepines even for patients who could benefit from their use, such as those with bipolar disorder or seizures. The investigators are currently funded by the National Institute on Aging to monitor the impact of the Medicare drug benefit, and they believe the new data may shed additional light on how policies that exclude coverage for benzodiazepines may or may not affect the rate of hip fractures among older persons.
