Prehospital Anticholinergic Burden Is Associated With Delirium but Not With Mortality in a Population of Acutely Ill Medical Patients.

OBJECTIVES

Anticholinergic drugs have several side effects, and they have been associated with adverse outcomes, particularly in older patients. The aim of this study was to analyze anticholinergic burden and its relationship to delirium and mortality in older acutely ill medical patients.

DESIGN

Cohort study.

SETTING AND PARTICIPANTS

Patients 65 years of age and older who were admitted to an Internal Medicine ward between August 1 and December 31, 2016.

METHODS

Anticholinergic drug use, outpatient and inpatient, was assessed using the Anticholinergic Cognitive Burden Scale (ACB). Prevalent delirium was diagnosed by the Short Confusion Assessment Method (Short-CAM).

RESULTS

Of the 198 patients, 28.3% developed delirium. Mortality rate was 13.6% in-hospital and 45.6% at 12 months. In multivariate analysis, outpatient ACB was associated with delirium, with an odds ratio (OR) of 1.65 [95% confidence interval (CI) 1.09-2.51]. Those with delirium had longer hospital stays (median 13 vs 8 days; P = .01), received more drugs (median 18 vs 15; P = .02), and presented a higher inpatient ACB (mean 3.9 vs 3.1; P = .034). No increased risk was found for in-hospital or 12-month mortality with drug use, ACB, or delirium.

DISCUSSION

In the population studied, we found an association between anticholinergic burden as measured by the ACB and the presence of delirium, but not with mortality at 12 months. A very high 12-month mortality rate might have been an obstacle for association recognition.

CONCLUSIONS AND IMPLICATIONS

Clinician awareness of possible drug side effects, especially in older populations, is crucial. As part of medication reconciliation at the time of hospitalization, ACB of prehospitalization medications should be routinely calculated by inpatient pharmacy services and made available to medical teams.