Use of medicines that may precipitate delirium prior to hospitalisation in older Australians with delirium: An observational study

Objective To assess the use of medicines associated with delirium prior to hospital admission in older Australian patients with a recorded diagnosis of delirium. Methods A retrospective observational study was conducted using de-identified data from the Australian Government Department of Veterans' Affairs Health Care Claims Database. The prevalence of use of medicines associated with delirium was determined in people 65 years or older with a delirium diagnosis. Results Three-quarters of the total 22 923 older patients included were taking at least one medicine associated with delirium, the median number of medications per patient was two (interquartile range, 1-3). The most frequently used medicines known to be associated with delirium were psycholeptics, opioids and tricyclic antidepressants. Conclusion A substantial proportion of older hospitalised patients with a delirium diagnosis were taking medicines known or suspected to precipitate delirium prior to admission. There may be an opportunity to decrease medication-associated delirium by reducing use of risky medication.