May 21, 2015 | Louise Gagnon
“We noticed that they were quite frequently used in patients with delirium, which is one of the things that sparked our interest in this topic,” said Michael Serna, MD, Kaweah Delta Health District, Visalia, California, on May 16. “We wanted to look at what medications these patients [with delirium] were prescribed after the diagnosis.”
Treatment for delirium is not well established, and why this particular population was prescribed benzodiazepines is unclear.
“There is not much evidence to show benefit in this population," said Dr. Serna.
The researchers reviewed the records of 908 patients aged ≥18 years who had been admitted to hospital over a 2-year period. They looked at the association between the use of benzodiazepines and drugs with anticholinergic properties and mortality and length of stay in hospital.
A total of 112 patients died. Patients who were given benzodiazepines had greater mortality than those who did not take them (27.7% vs 10.6%; P < .001; odds ratio [OR] = 3.24). Mortality was also higher in patients prescribed drugs with anticholinergic properties and in those who received vancomycin (26.9% vs 7.9%; P < .001; OR = 4.17).
Vancomycin use was also linked to longer mean hospital stay (P < .001). The impact of vancomycin in terms of poor outcomes might be explained by infection rather than the anticholinergic characteristics of the glycopeptide antibiotic, noted Dr. Serna.
The retrospective design of the study is a limitation of the finding, stressed Dr. Serna, noting the limited data on the specific doses of benzodiazepines that were administered when drugs were titrated. The investigators did not control for comorbidities in the study population, which included many patients aged ≥65 years.
Patients with delirium are known to have an increased risk of mortality compared with patients without delirium, but the possible role of medications hastening mortality should be explored, said Dr. Serna.
“We would like to look at this in a future study and look at the impact of dose,” said Dr. Serna. “We don't have that information and would like to look at the relationship between dose and outcomes like mortality.”
[Presentation Title: Benzodiazepines and Drugs With Anticholinergic Activity Increase Mortality in Patients With Delirium. Abstract P2-85]