Antipsychotic drugs and risks of myocardial infarction: a self-controlled case series study

Area of Science:

• Cardiology
• Psychopharmacology
• Epidemiology

Background:

• Antipsychotics are associated with increased stroke risk.
• The impact of antipsychotics on myocardial infarction (MI) risk is unclear due to confounding vascular risk factors.
• Self-controlled case series (SCCS) design can mitigate between-person confounding.

Purpose of the Study:

• To investigate the association between antipsychotic use and myocardial infarction risk.
• To utilize the SCCS design to eliminate confounding by indication and other between-person differences.
• To compare findings with a classical case-control study.

Main Methods:

• Employed a self-controlled case series design using UK Clinical Practice Research Datalink data.
• Identified patients with first MI and antipsychotic prescription.
• Estimated incidence rate ratios (IRR) for MI during exposure periods versus unexposed periods within individuals.
• Conducted a comparative classical case-control study.

Main Results:

• An increased risk of MI was observed within 30 days of initiating antipsychotic therapy.
• First-generation agents showed an IRR of 2.82 (95% CI: 2.0-3.99).
• Second-generation agents showed an IRR of 2.5 (95% CI: 1.18-5.32).
• Case-control analysis yielded similar results for new users of both agent types.

Conclusions:

• Initiation of antipsychotic medication is associated with an increased risk of myocardial infarction.
• This elevated risk is evident shortly after prescription and is not due to pre-existing differences between patients.
• Findings highlight the need for cardiovascular risk monitoring in patients starting antipsychotic treatment.