Benzodiazepines may confer dementia risk for elderly patients

Patients who started taking benzodiazepines after age 65 had a greater risk of developing dementia than those who never used the drugs, a study found.

Researchers examined 3,777 community-dwelling French people age 65 years and older in a prospective cohort study on brain aging. They observed the subjects for three to five years to identify factors that led to benzodiazepine initiation, and then followed them for 15 years. Eligible subjects (n=1,063, mean age 78.2 years) were dementia-free and didn't start taking benzodiazepines until at least the third year of follow-up. The main outcome was incident dementia confirmed by a neurologist.

Results were published online by BMJ Sept. 27.

Nearly 9% (n=95) of patients started taking benzodiazepines during the study. These new users were more likely to be single or widowed, have less education, have more significant depressive symptoms, use antihypertensives, use platelet inhibitors or oral anticoagulants, and consume wine less regularly.

About 24% (n=253) of all patients developed dementia, including 30 benzodiazepine users and 223 non-users. Starting benzodiazepines was associated with a significant increase in the risk of developing dementia (hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.08 to 2.38), a result that was basically unchanged when adjusted for depressive symptoms (HR, 1.62; 95% CI, 1.08 to 2.43).

In absolute numbers, the chance of dementia occurring was 4.8 per 100 person-years in the group that took benzodiazepines versus 3.2 per 100 person-years in the non-using group.

Benzodiazepines are useful for treating acute anxiety and persistent insomnia, but evidence is mounting that their use may have adverse outcomes in the elderly, including falls, fall-related fractures and now dementia, the authors wrote.

The effect on dementia in this study remained after adjustment for potential confounders, including cognitive decline before starting benzodiazepines and clinically significant symptoms of depression, they noted. They noted, too, that their study included “a run-in time of at least three years to allow adjustment for factors associated with starting benzodiazepines, thus reducing the possibility of reverse causation.”

“Physicians should carefully assess the expected benefits of the use of benzodiazepines” and limit prescriptions to a few weeks when possible, they said. “In particular, uncontrolled chronic use of benzodiazepines in elderly people should be cautioned against,” they wrote.