Serum anticholinergic activity in hospitalized older persons with delirium: a preliminary study.
OBJECTIVE
To evaluate the relationship between total serum anticholinergic activity (SAA) and the presence or absence of delirium in older hospitalized persons on general medical wards.


METHODS
Case-control study and within-subjects repeated-measures in recovered delirious patients.


METHODS
Minneapolis Veterans Affairs Medical Center medical wards.


METHODS
Eleven male delirious patients (DSM-III-R criteria) aged 60 or older and 11 comparably aged male nondelirious controls.


METHODS
Radioreceptor bioassay of total SAA using tritiated quinuclidinyl benzilate (QNB) binding to muscarinic receptors. Results are expressed in terms of atropine equivalents (nM).


RESULTS
Mean SAA was significantly elevated in the delirious group (mean +/- SD = 6.05 +/- 2.97 nM atropine equivalents) compared with the controls (3.38 +/- 2.49; t(20) = 2.28, P < .05). At study entry, mean SAA was significantly higher in delirious subjects whose symptoms eventually resolved completely (mean +/- SD = 7.77 +/- 2.37) compared with subjects whose delirious symptoms persisted (3.99 +/- 2.30; t(9) = 2.68, P < .05). All six patients in whom delirium resolved completely had a decrease in serum anticholinergic activity when measured during delirium (7.77 +/- 2.37) and after symptom resolution (3.92 +/- 2.61; t(5) = 3.29, P < .05).


CONCLUSIONS
Our findings suggest that serum anticholinergic activity may play a role in delirium in medical inpatients. The relationships between SAA and delirium in medical patients and between total SAA and medication use warrant further study.
Mach
J R
JR
Geriatric Research Education and Clinical Center (GRECC), VA Medical Center, Minneapolis, MN 55417, USA.
Dysken
M W
MW
Kuskowski
M
M
Richelson
E
E
Holden
L
L
Jilk
K M
KM
D000368:Aged; D016022:Case-Control Studies; D018680:Cholinergic Antagonists / Q000097:blood*; D003693:Delirium / Q000097:blood*; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011869:Radioligand Assay
D018680:Cholinergic Antagonists