Psych Drugs Linked to MI Risk in Dementia (CME/CE)
But the effect of antipsychotic drugs on the risk of acute myocardial infarction (MI) hasn't been studied in depth, Moride and colleagues noted.
To help fill the gap, they turned to data from the public prescription drug and medical services programs in the Canadian province of Quebec, which cover more than 98% of the province's citizens who are 65 and older.
For this analysis, the researchers studied 37,138 people 66 and older who lived in the community and had become new users of cholinesterase inhibitors between Jan.
Of those, Moride and colleagues reported, 10,969 (or 29.5%) started antipsychotic drugs during the study period.
For Cox proportional hazards modeling, they were matched with random sample of the members of the cohort who did not start the medications.
Overall, the researchers found, 1.3% of those who started the antipsychotics had a heart attack within a year of beginning to take the medications.
In addition to the elevated risk in the first month, the risk was also elevated for the following 60 days, at a hazard ratio of 1.62, but the 95% CI missed statistical significance, ranging from 0.99 to 2.65.
The risk became lower as time went on: HR 1.36 for the first 90 days and HR 1.15 for the first 365 days.
In both cases, the confidence intervals crossed unity, meaning the risk was not significantly different from the group that was not taking the drugs.
The researchers also conducted a self-controlled case series study among all 804 people who had a heart attack after starting antipsychotics, with a median follow-up of 47 months.
For that analysis, a participant was defined as having acute risk in the first 30 days after starting the drugs, and mid-term risk for the period from 31 to 60 and 61 to 90 days.