It’s not clear whether the increase is due to the action of the drug or the underlying disease.
A population-wide study has found a greatly increased risk of sudden cardiac death among people who take antidepressants, the annual meeting of the European Heart Rhythm Association has heard, with the size of the increase depending on age and length of exposure.
Danish researchers presenting at the conference said they knew from previous work that people with psychiatric disorders had at least double the risk of sudden cardiac death across all age groups, but it was not known what role antidepressants might play in that increased risk.
They examined all deaths in Denmark in 2010 of people aged 18-90, looking for sudden cardiac death and antidepressant exposure.
Incident rate ratios for SCD were significantly higher for those on antidepressants in all age groups except for 18-29-year-olds, where the association was not significant.
Adjusted for age, sex and comorbidities, those who had been on antidepressants for one to five years had a 56% higher risk of SCD, while those who had been on antidepressants for six or more years had 2.2 times the risk.
The risk gap varied by age group and decreased with age.
In people in their 30s, one to five years’ exposure was associated with triple the risk of SCD, and six or more years’ exposure with five times the risk.
For those aged 50-59, those differences were double and four times respectively, while people aged 70-79 had an 83% greater risk and 2.2 times the risk respectively.
A separate study of all deaths in Denmark the same year found around 6900 of 54,000, or 13%, were definite, probably or possible sudden cardiac deaths. The incidence rate of definite sudden cardiac deaths was 11 per 100,000 person-years. Fifty per cent had no diagnosed cardiovascular disease.
Sudden cardiac death is any unexpected death attributed to a cardiac cause within an hour of symptom onset if witnessed or 24 hours if unwitnessed. In the young it is usually due to a cardiomyopathy or electrophysiological fault, while in older people it is more likely due to coronary artery disease.
A co-author of the present study, Dr Jasmin Mujkanovic of the Rigshospitalet Hjertecentret in Copenhagen, said: “The increased risk of sudden cardiac death may be attributed to the potential adverse effects of the antidepressants. However, the exposure time to antidepressants might also serve as a marker for more severe underlying illness.
“Additionally, the increase could be influenced by behavioural or lifestyle factors associated with depression, such as delayed healthcare seeking, and poor cardiovascular health. Further research is warranted.”
In their previous work the team found that out of all the psychiatric disorders, schizophrenia came with the highest rate of sudden cardiac death.
They estimated that an 18-year-old with any psychiatric disorder had a 10-year reduction in life expectancy compared with a healthy 18-year-old.
