Sudden Cardiac Death in Young Adults With Previous Hospital-Based Psychiatric Inpatient and Outpatient Treatment: A Nationwide Cohort Study From Denmark

Introduction: Psychiatric patients have premature mortality compared to the general population. The incidence of sudden cardiac death (SCD) in psychiatric patients is unknown in a nationwide setting. The aim of this study was to compare nationwide SCD incidence rates in young individuals with and without previous psychiatric disease.

Method: Nationwide, retrospective cohort study including all deaths in people aged 18-35 years in 2000-2006 in Denmark. The unique Danish death certificates and autopsy reports were used to identify SCD cases. Psychiatric disease was defined as a previous psychiatric hospital contact and was identified using The Danish Psychiatric Central Research Register. All diagnoses in Danish registries are coded according to ICD-8 or ICD-10. All hospital records were retrieved manually.

Results: Among 5,178 deaths, 395 were due to SCD and autopsies were performed on 262 (66%). In 77 SCD cases, a previous psychiatric hospital contact was identified. The SCD incidence rate in psychiatric patients was 14.8 (95% CI, 11.7-18.5) per 100,000 person-years versus 3.8 (95% CI, 3.4-4.3) per 100,000 person-years in individuals without psychiatric hospital contact (incidence rate ratio = 3.9; 95% CI, 3.0-5.0; P < .01). Incidence rates per 100,000 persons-years were the highest in patients with schizophrenia-spectrum disorders (38.9; 95% CI, 26.4-55.2) and substance-related disorders (31.6; 95% CI, 19.3-48.8). SCDs in psychiatric patients compared to nonpsychiatric patients were more often unexplained (65% vs 40%, P = .02), and cardiac symptoms were reported prior to death in 46% of psychiatric patients.

Conclusions: Patients with prior psychiatric hospital contact have a 4-fold increased risk of SCD. Since almost 50% had possible cardiac symptoms prior to death, cardiovascular risk monitoring and management in the mentally ill are essential.