Out-of-hospital cardiac arrest risk high in patients with mental disorders

Patients with bipolar disorder or schizophrenia are more likely to experience out-of-hospital cardiac arrest (OHCA) compared with the general population, with a recent study pointing to cardiac disease, cardiovascular risk factors, and antipsychotic use as important underlying mechanisms.

The nested case-control study included 35,017 OHCA patients and 175,085 matched controls (median age, 72 years; 66.9 percent male).

Multivariable Cox regression analysis revealed that during the study period (2001–2015) OHCA occurred with greater frequency among patients with bipolar disorder and those with schizophrenia versus controls (hazard ratio [HR], 2.74, 95 percent confidence interval [CI], 2.41–3.13 and HR, 4.49, 95 percent CI, 4.00–5.10, respectively).

The association remained significant among patients with both cardiac disease and cardiovascular risk factors at baseline (bipolar disorder: HR, 2.14, 95 percent CI, 1.72–2.66; schizophrenia: HR, 2.84, 95 percent CI, 2.20–3.67) and among those without known risk factors (bipolar disorder: HR, 2.14, 95 percent CI, 1.09–4.21; schizophrenia: HR, 5.16, 95 percent CI, 3.17–8.39).

The findings were confirmed in subgroup analyses limited to OHCA patients presenting with shockable rhythm or receiving an autopsy.

Finally, antipsychotic use contributed to increased OHCA hazard compared with nonuse in both mental disorders. In contrast, antidepressants, lithium, or antiepileptics (the last two evaluated only in bipolar disorder) showed no association with OHCA.