MI risk raised among elderly antipsychotic users
MedWire News: Older patients with dementia who use antipsychotic medications have an increased risk for myocardial infarction (MI), a study suggests.
Because antipsychotic medication use is frequent in patients with dementia, the increased MI risk observed in the current study may have major public health implications, highlighting the need for improved communication with and close monitoring of patients at risk, report Yola Moride (Université de Montréal, Canada) and team.
They identified a retrospective cohort of community-dwelling patients aged at least 66 years who started treatment with cholinesterase inhibitors (ChI) used to treat dementia, between January 2000 and December 2009.
From this source cohort, the researchers created a subcohort of all new users without any record of ChI dispensing in the 365 days before the first ChI dispensing in the study period (exposed subcohort, n=10,969), and matched each of these for index date with 10,969 nonusers (unexposed subcohort).
Within 1 year of initiating antipsychotic treatment, 138 (1.3%) antipsychotic users experienced incident MI.
Multivariate analysis showed that antipsychotic users had a 2.19-fold increased risk for MI at 30 days, 1.62-fold increased risk at 60 days, 1.36-fold increased risk at 90 days, and a 1.15-fold increased risk at 1 year.
Self-controlled case series study analysis conducted in 804 incident cases of MI among new antipsychotic medication users yielded incidence rate ratios of 1.78 for the 1- to 30-day period, 1.67 for the 31- to 60-day period, and 1.37 for the 61- to 90-day period.
The authors suggest that MI risk in dementia patients could be increased by the agitation, aggressiveness, or potentially exhausting motor behaviors associated with their delusion.
However, they also acknowledge the potential protopathic bias in their study, whereby new use of an antipsychotic for a dementia patient who is agitated serves as a marker for an atypical presentation of acute illness subsequently recognized as MI, note editorialists Sudeep Gill and Dallas Seitz (Queen's University, Kingston, Ontario, Canada).
In an accompanying commentary, Gill and Seitz say that physicians should limit the prescription of antipsychotic drugs to dementia patients and instead use other techniques such as environmental and behavioral strategies, to keep patients "safe and engaged."
The authors conclude: "Further investigations with larger sample sizes should be undertaken to identify high-risk subpopulations."
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By Piriya Mahendra