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

Hannah C Moorey,Sebastian Zaidman,Thomas A Jackson

doi:10.1186/s12877-016-0336-9

Hannah C Moorey, Sebastian Zaidman + Show 1 more

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https://doi.org/10.1186/s12877-016-0336-9

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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.

Highlights

Older people are commonly prescribed multiple medications, including medications with anticholinergic effects
This observational case control study has demonstrated no relationship between anticholinergic burden and polypharmacy, with delirium in older people admitted to an acute hospital
We found no relationship between either of the anticholinergic drug scales used in this study, Anticholinergic Cognitive Burden Scale (ACB) and Anticholinergic Drug Scale (ADS), and prevalent delirium on admission to hospital

Summary

Introduction

Older people are commonly prescribed multiple medications, including medications with anticholinergic effects. Polypharmacy and anticholinergic medications may be risk factors for the development of delirium. Delirium is important because it is common among older people acutely admitted to hospital and is associated with greater mortality, in-hospital falls and new institutionalization [2]. Polypharmacy has been indicated as a precipitating factor in the development of delirium [5,6,7], as has the addition of multiple drugs as an inpatient [8]. The use of specific medications or medication classes have been identified as risk factors for the development of delirium [9]. Psychotropic drugs, those with anticholinergic properties, have been implicated as precipitants [10]

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