Different methods, different results--how do available methods link a patient's anticholinergic load with adverse outcomes?
OBJECTIVE
Anticholinergic drugs are known to cause physical and cognitive impairment, particularly in older patients. The total of all anticholinergic influences to which a patient is exposed is referred to as anticholinergic load. Because the anticholinergic load is defined in various ways, this review aimed to describe differences in the development and evaluation of available methods calculating the anticholinergic load.


METHODS
From September 2014 to August 2015, two reviewers performed a literature search in PubMed considering relevant items of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. We aimed to identify articles which calculated the anticholinergic load with a scale or equation and investigated its association with patient-related outcomes. From the included studies, we descriptively analyzed the identification and scoring criteria of the scales and equations with a main emphasis on their association to the reported outcomes.


RESULTS
Out of 465 articles, 55 were included referring to 12 scales and one equation. Main discrepancies were located in eight different identification criteria for anticholinergic drugs, two different scoring principles, and 118 tests used for assessing outcomes. The methods most frequently detecting a significant association between the anticholinergic load and outcomes took into account the drugs' dosages and anticholinergic potencies. Interestingly, none of the methods included the patient's susceptibility for anticholinergic effects and they only rarely considered modulators of drug exposure.


CONCLUSIONS
Due to hugely varying tests for assessing outcomes, the methods are scarcely comparable. For a more valuable comparison, the anticholinergic load should be calculated with all scales and the equation and correlated with patient-related outcomes.
Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.|Cooperation Unit Clinical Pharmacy, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
Tanja
T
Mayer
Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.|Cooperation Unit Clinical Pharmacy, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
Walter E
WE
Haefeli
Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany. hanna.seidling@med.uni-heidelberg.de.|Cooperation Unit Clinical Pharmacy, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany. hanna.seidling@med.uni-heidelberg.de.
Hanna M
HM
Seidling
D018680:Cholinergic Antagonists / Q000009:adverse effects*; D003072:Cognition Disorders / Q000139:chemically induced*; D006801:Humans
D018680:Cholinergic Antagonists
Adverse drug reactions; Anticholinergic drugs; Drug Burden Index