Antipsychotics and the Risks of Sudden Cardiac Death and All-Cause Death: Cohort Studies in Medicaid and Dually-Eligible Medicaid-Medicare Beneficiaries of Five States.

Context: Antipsychotic drugs have been linked to QT-interval prolongation, a presumed marker of cardiac risk, and torsade de pointes.

Objective: To examine the associations between antipsychotics and 1) outpatient-originated sudden cardiac death and ventricular arrhythmia (SD/VA) and 2) all-cause death.

Design: Two retrospective cohort studies.

Setting: Medicaid programs of California, Florida, New York, Ohio and Pennsylvania.

Patients: Incident antipsychotic users aged 30-75 years.

Main outcome measures: 1) Incident, first-listed emergency department or principal inpatient SD/VA diagnoses; and 2) death reported in the Social Security Administration Death Master File.

Results: Among 459,614 incident antipsychotic users, the incidences of SD/VA and death were 3.4 and 35.1 per 1,000 person-years, respectively. Compared to olanzapine as the referent, adjusted hazard ratios (HRs) for SD/VA were 2.06 (95% CI, 1.20-3.53) for chlorpromazine, 1.72 (1.28-2.31) for haloperidol, and 0.73 (0.57-0.93) for quetiapine. Adjusted HRs for perphenazine and risperidone were consistent with unity. In a subanalysis limited to first prescription exposures, HRs for chlorpromazine and haloperidol were further elevated (2.54 [1.07-5.99] and 2.68 [1.59-4.53], respectively), with the latter exhibiting a dose-response relationship. Results for death were similar.

Conclusions: Haloperidol and chlorpromazine had less favorable cardiac safety profiles than olanzapine. Among atypical agents, risperidone had a similar cardiac safety profile to olanzapine, whereas quetiapine was associated with 30% and 20% lower risks of SD/VA and death, respectively, compared to olanzapine. These measured risks do not correlate well with average QT prolongation, further supporting the notion that average QT prolongation may be a poor surrogate of antipsychotic arrhythmogenicity.