The impact of length of antidepressant use on risk of sudden cardiac death

Patients with psychiatric disorders have an increased all-cause mortality as well as an increased risk for sudden cardiac death (SCD) across all age groups. We have previously shown that patients with depressive disorders had a 2-fold increased risk of SCD compared to the general population. However, the impact of antidepressants (AD) exposure on SCD risk is unclear.

To investigate the association between length of antidepressant use and SCD in patients aged 18-90 years in the Danish population in one year.

We examined all deaths in Denmark among residents aged 18-90 years in 2010 by reviewing all death certificates and autopsy reports. Deaths were categorized as non-SCD or SCD based on the available information. Exposure to AD was defined by redemption of a prescription for AD-medication at least 2 times in one year over a period of 12 years before the year of follow-up (2010). Furthermore, exposure time was categorized into two groups: 1-5 years and 6+ years.

Of 4.3 million residents in 2010 aged 18-90 years, there was a total of 45 701 deaths and 6 002 cases of SCD. 643 999 inhabitants were exposed to AD-medication prior to the year of follow up. The total amount of SCD in the AD cohort was 1 981 individuals. The incidence rate of SCD was significantly higher in the exposed groups compared to the general population across all age groups bar the age group 18-29 years (Figure 1).

Adjusting for age, sex, and comorbidities the hazard ratio for SCD was 1.56 (1.46-1.67 p<0.001) for 1-5 years of exposure to AD, and 2.17 (2.01-2.31 p<0.001) for 6+ years of exposure of AD.

In individuals ages 40-79 years, the SCD incidence rate ratio was significantly higher among persons with 6+ exposure of AD compared to persons with 1-5 years exposure (Figure 2).

Exposure time to antidepressants was associated with a higher risk of SCD. Adjusted HR was 1.56 for 1-5 years of AD exposure and 2.17 for 6+ years (p-value <0.001). The risk was notably higher among individuals aged 40-79 years with longer exposure time.Figure 1  Figure 2