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New prescriptions of benzodiazepines after hospitalisation, which are often given to elderly people, may lead to chronic use, with its associated risks, says a new Canadian study.
“Our data demonstrate that about half of patients dispensed benzodiazepines within the first week after hospital discharge fill another prescription in the next six months,” said the study's principal investigator, Chaim Bell, an adjunct scientist with the Institute for Clinical Evaluative Sciences in Toronto.
In the retrospective cohort study, the researchers used linked, population based administrative data to track the use of benzodiazepines among Ontario citizens aged 66 years or older who were living in the community and who had stays in hospital between 1 April 1992 and 31 March 2005 (Journal of General Internal Medicine 2007;22:1024-9).
A total of 405128 hospitalised patients were included. Only people who had not been prescribed benzodiazepines in the year before their hospital stay were selected.
The researchers classed 12484 people (3.1%) as early benzodiazepine users (those who were given a new prescription of a benzodiazepine within seven days of discharge from hospital) and 29207 (7.2%) as late benzodiazepine users (those given a new prescription between eight days and six months of discharge). A total of 6136 (1.5%) were classed as new chronic benzodiazepine users—those who were given a new prescription of a benzodiazepine within seven days of discharge and an additional one between eight days and six months after discharge.
The most commonly prescribed benzodiazepine was lorazepam, and oxazepam was the second most common.
The proportion of new chronic benzodiazepine users fell over the study period from 1.8% in the first year to 1.2% in the final year (P<0.001). Multivariate logistic regression showed that the odds ratio for being a new chronic benzodiazepine user was higher among women; patients who were admitted to intensive care units or non-surgical wards; patients with longer stays in hospital, higher overall comorbidity, or a prior diagnosis of alcoholism; and patients who were taking a higher number of prescribed drugs. The likelihood of being a new chronic user fell with increasing age.
“The use of benzodiazepines has been linked to serious adverse events such as residual daytime sedation, cognitive impairment, fall related injuries, including hip fractures, and motor vehicle collisions, particularly when combined with other drugs or alcohol,” said Dr Bell. “As well, an important but often overlooked issue is that long term use of benzodiazepines can lead to dependence.
“Initiatives such as the development of electronic medical records and more formal medication lists, or models of care that facilitate communication and coordination between hospital and community based physicians, may help to further reduce the risk of new chronic benzodiazepine prescriptions, particularly when targeted to the higher risk patients identified in our study.”