Delirium is not associated with anticholinergic burden or polypharmacy in older patients on admission to an acute hospital: an observational case control study

Abstract

BackgroundOlder people are commonly prescribed multiple medications, including medications with anticholinergic effects. Polypharmacy and anticholinergic medications may be risk factors for the development of delirium.MethodsPatients from a medical admission unit who were over 70, with DSM-IV diagnosed delirium and patients without delirium, were investigated. Number of drugs prescribed on admission and anticholinergic burden using two scales (the Anticholinergic Cognitive Burden Scale [ACB] and the Anticholinergic Drug Scale [ADS]) were recorded from electronic prescribing records. The relationship and predictive ability of these were explored.ResultsThe sample included 125 patients with DSM-IV diagnosed delirium and 122 patients without delirium. The mean age of the sample was 84.0 years. The median number of drugs prescribed was 7: 79.8 % were prescribed ≥5 drugs and 29.0 % ≥10 drugs. The median ACB score was 1 and the median ADS score was 1.5. 73.4 % of patients had an ACB score of ≥1 and 73.0 % had a ADS score ≥1. There was no association between: number of drugs prescribed, rate of polypharmacy, rate of excessive polypharmacy, ACB score and ADS score, and a diagnosis of delirium on admission. Only acetylcholinesterase inhibitor use predicted delirium (OR 3.86, p = 0.04) and the number of drugs prescribed was negatively correlated with age (spearman rho = −0.18, p = 0.006).ConclusionNeither number of drugs prescribed, polypharmacy or anticholinergic burden were associated with delirium on admission, questioning the clinical usefulness of anticholinergic drug scales. Further research is needed to unpick fully the relationship between, drugs, anticholinergic burden, age, and prevalent delirium in older patients and whether there is any role for these scales in clinical practice.Electronic supplementary materialThe online version of this article (doi:10.1186/s12877-016-0336-9) contains supplementary material, which is available to authorized users.

Risk Factors and Outcomes of Delirium in Older Patients Admitted to Postacute Care with and without Dementia

“…On the other hand, although polypharmacy in older hospitalized patients is associated with delirium in many studies [10, 28, 29], our study did not confirm this association. This could be consistent with data by Moorey et al [30], showing that the number of prescribed drugs inversely correlated with age. Along the same line, our dementia patients (who were also older) had less polypharmacy than those without dementia.…”

Anticholinergic drug exposure is associated with delirium and postdischarge institutionalization in acutely ill hospitalized older patients

“…Our finding that anticholinergic drug exposure measured with the ARS is associated with delirium, is in agreement with the results of previous studies performed in critically ill patients (Wolters et al 2015), palliative care patients (Zimmerman et al 2014), patients with Parkinson's disease (Crispo et al 2016) and older nursing home residents (Landi et al 2014). Also, previous studies found no association between anticholinergic drug exposure, measured with the ACB or the Anticholinergic Drug Scale, and delirium in older hospitalized patients (Moorey et al 2016;Campbell et al 2011;Wolters et al 2015). These findings strengthen the observation that results may differ depending on which scale is used when assessing anticholinergic drug exposure.…”

“…Also, previous studies found no association between anticholinergic drug exposure, measured with the ACB or the Anticholinergic Drug Scale, and delirium in older hospitalized patients (Moorey et al. ; Campbell et al. ; Wolters et al.…”

Anticholinergic burden in the Japanese elderly population: Use of antimuscarinic medications for overactive bladder patients

“…In contrast, other investigations have not identified an association between AC burden and specific clinical adverse effects (e.g. delirium) . Although differences exist between findings, the Beers criteria, from the American Geriatrics Society, state that the use of medications that are classified as strong ACs should be avoided in the elderly due to an increased risk of confusion, dry mouth, constipation and other AC effects or toxicity .…”

“…delirium). 6,7 Although differences exist between findings, the Beers criteria, from the American Geriatrics Society, state that the use of medications that are classified as strong ACs should be avoided in the elderly due to an increased risk of confusion, dry mouth, constipation and other AC effects or toxicity. 8 If alternative treatments with similar efficacy, but no associated AC side effects, are available for use in a particular therapeutic area, it might be possible to reduce the AC burden experienced by the patient.…”