Benzodiazepines, Z-drugs do not up risk of dementia in patients with affective disorders

Use of benzodiazepines or Z-drugs is not associated with subsequent dementia, even when exposures are cumulated or divided into long- and short-acting drugs, reveals a study.

Of the 235,465 patients included, 171,287 (75.9 percent) had any use of benzodiazepines or Z-drugs, and 9,776 (4.2 percent) were diagnosed with dementia during a median follow-up of 6.1 years (interquartile range, 2.7–11).

After multiple adjustments in either the cohort analysis or a nested case-control design, no association was found between any use of benzodiazepines or Z-drugs and subsequent dementia. The cohort analysis further showed that the number of prescriptions and the cumulated dose of benzodiazepines or Z-drugs did not correlate with dementia.

On the other hand, patients with the lowest use of benzodiazepines or Z-drugs had a slightly higher risk of developing dementia (odds ratio [OR], 1.08, 95 percent confidence interval [CI], 1.01–1.15) compared with no lifetime use in the nested case-control study, where prescriptions were counted from 1995 until 2 years before the index date.

In contrast, those with the highest use had the lowest odds of developing dementia (OR, 0.83, 95 percent CI, 0.77–0.88).

“Some results were compatible with a protective effect,” the investigators said.

This cohort and nested case-control study involved patients aged >20 years who were identified in the Danish National Patient Registry as having had a first-time hospital contract for an affective disorder between 1996 and 2015.

The investigators obtained information on all prescriptions for benzodiazepines, Z-drugs and other anxiolytics from the Danish National Prescription Registry and followed patients for incident dementia, defined by hospital discharge diagnosis or acetylcholinesterase inhibitor use.