Three-quarters of older hospitalised patients with a delirium diagnosis were on at least one medicine at least suspected to be associated with the condition, a new study has found
Researchers from South Australia conducted a retrospective observational study, 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 aged 65 years or older with a delirium diagnosis. Nearly 23,000 of these patients were included in the study.
The researchers – Gizat M Kassie, Lisa M Kalisch Ellett, Tuan A Nguyen and Elizabeth E Roughead, cited international data showing that a significant proportion of patients diagnosed with delirium had taken medicines associated with the condition before they developed it.
For example, “Medicines have been identified as one of the precipitating factors for 35% of delirium cases in Finland among 193 delirious patients from nursing homes and geriatric wards”.
In this Australian study, published in the Australasian Journal on Ageing, the researchers identified medicines associated with delirium from two systematic reviews and three narrative reviews.
“We classified the medicines into two groups: medicines with known risk of delirium and medicines suspected to be associated with delirium based on evidence from two systematic reviews,” the authors write.
“For the purposes of this study, medicines known to be associated with delirium had to be independently associated with delirium in at least two independent studies.
“Medicines known to be associated with delirium included antipsychotics, anxiolytics, hypnotics and sedatives, opioids, tricyclic antidepressants (TCAs), barbiturates, benzodiazepines, first-generation antihistamines and other medications with high anticholinergic property. Medicines with suspected associations with delirium included dopaminergic antiparkinsonian agents, selective serotonin reuptake inhibitors, second-generation antihistamines, skeletal muscle relaxants, fluoroquinolones, non-steroidal anti-inflammatory analgesics, corticosteroids, antihypertensives and cardiac medications.”
The researchers found that of the 22,923 patients hospitalised with a primary or secondary diagnosis of delirium between 2010 and 2015, 40% were taking at least one medicine known to be associated with delirium at the time they were hospitalised.
Meanwhile, 73% were taking one or more medicines suspected to be associated with delirium.
“Among study participants who used two or more medicines either known or suspected to be associated with delirium, the most common combinations were antidepressants and antihypertensives, psycholeptics and antihypertensives, psycholeptics and antidepressants, opioids and antihypertensives, and antihypertensives and cardiac medications,” the authors write.
“Thirteen per cent of medical patients who developed delirium during hospitalisation were using psycholeptics and antidepressants concomitantly at the time of admission.”
Minimising the use of medicines which precipitate delirium should be considered as part of any strategy to prevent and manage the condition, the authors write.
“Pharmacists could play a role in reviewing patients’ medications to identify medicines that may precipitate delirium and those suitable for ceasing or tapering to reduce delirium risk.
“A survey of hospital pharmacists in Australia found that pharmacists had limited involvement in the management of delirium in older patients. However, they were interested to increase their role in the future and believed that they could assist in improving patient outcomes.
“For medical patients, pharmacists could review a patient’s current list of medications at admission and make necessary amendments according to the patient’s level of delirium risk. For patients undergoing elective surgery, medication-related interventions could be started earlier, for instance during planning for the procedure by involving pharmacists in preoperative medication review.
“This study supports such efforts by identifying the types of medicines known to precipitate delirium that are commonly used by older patients in Australia who are admitted for delirium or developed the condition in the hospital.”