Anti-depressants could increase the risk of sudden cardiac death up to five-fold, suggest Danish researchers, who found patients taking the medications for between one and five years had a 50% higher risk of dying from an unexpected heart issue.
And taking the mood-boosting drugs for six years or more was found to increase the risk by slightly more than 100%, they said.
Several psychiatrists told MailOnline the findings were a “shocking” example of the hazards of giving the drugs to millions, adding that “patients need to be warned”, but other experts urged caution, urged patients not to quit taking their medication without discussing it with their doctors.
In the study, a sudden cardiac death was defined as the unexpected fatality of a person from a heart-related issue, between one and 24 hours of the onset of symptoms.
The Danish team, which analysed all deaths recorded in the UK in 2010, found 6 002 cases of sudden cardiac death, one-third of which were among patients taking anti-depressants.
Overall, they found individuals prescribed anti-depressants had a far higher chance of dying this way than non-users, with the risk increasing the longer the patients took the drugs.
But the increased risk was higher in certain age groups.
The highest increased risk was seen among 30-39-year-olds, who had triple the risk of sudden cardiac death if they took anti-depressants for one to five years, and a five-fold increased risk if they took them for six years or more.
Study co-author Dr Jasmin Mujkanovic, from Rigshospitalet-Copenhagen University Hospital, said the reason behind this increased risk of dying remained unclear.
“However, the exposure time to anti-depressants might also serve as a marker for more severe underlying illness.
“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.”
University College London psychiatrist Professor Joanna Moncrieff told MailOnline that medics had known, for years, that these drugs were “cardio-toxic”, meaning they damage the heart.
She said the study was the strongest evidence yet that this was leading to deaths.
“It’s another shocking example of an adverse effect that’s taken too long to come out even though we had good reason to suspect that these drugs are cardio-toxic,” she said.
“We know they affect the heart, they change the way the heart beats, the heart’s rhythm. It’s an adverse effect doctors and patients haven’t been sufficiently aware of in the past, so people need to be warned about it.”
Moncrieff highlighted that while the overall risk of sudden cardiac death was low in the study, about one per 1 000 each year, the scale at which medics were dishing out anti-depressants meant thousands of patients could be at risk.
But other experts have urged caution of the findings, arguing that the increased risk of sudden cardiac death could be due to the depression the drugs are designed to treat rather than the medication.
Dr Paul Keedwell, psychiatrist and fellow of the Royal College of Psychiatrists, said: “Depression is associated with high levels of heart disease, including sudden cardiac death, 60% higher than non-depressed, life-threatening abnormal heart rhythm, a 50%-90% increase in risk, and for heart attack, roughly double the risk.”
He added that patients with depression also tended to be in poorer physical health in general, a factor that could increase their risk of serious heart problems.
He also suggested that even if the risk of cardiac deaths from the drugs were real, the risk of suicide among these patients would still be greater, meaning the drugs would still be recommended.
“Sudden cardiac death is a relatively rare event in the total population of depressed people, especially those under 40, while the absolute risk of early death from suicide and other physical health problems is likely to be much higher,” he said.
“More research is needed to directly compare the life expectancy in treated and untreated depression, but, as things stand, the weight of evidence supports the conclusion that the risk of early death is much higher when depression is left untreated than when it is treated.”
Questions
Moncrieff added that there were unanswered questions on the link between cardiac health risks and anti-depressants that needed further research.
This included unpicking how much of this increased risk could be linked to the drugs themselves or depression as a condition, as well as whether different types of anti-depressants carried different levels of risk.
The Danish study was presented at the recent annual congress of the European Heart Rhythm Association in Vienna, Austria.
Study details
The impact of length of anti-depressant use on risk of sudden cardiac death
J Mujkanovic, PE Warming, LV Kessing, LV Koeber, BG Winkel, TH Lynge, J Tfelt-Hansen.
Abstract
Background
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 anti-depressants (AD) exposure on SCD risk is unclear.
Purpose
To investigate the association between length of anti-depressant use and SCD in patients aged 18-90 years in the Danish population in one year.
Methods
We examined all deaths in Denmark among residents aged 18-90 years in 2010 by reviewing all death certificates and autopsy reports. Deaths were categorised 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 two times in one year over a period of 12 years before the year of follow-up (2010). Furthermore, exposure time was categorised into two groups: 1-5 years and 6+ years.
Results
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).
Conclusion
Exposure time to anti-depressants 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.
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