It is already known that depression can complicate and slow down recovery from a heart attack. However, new research has found that after a heart attack, those with depression are also 50% more likely to suffer a stroke compared to those without depression.

US researchers analysed the health records of over 495,000 people who had suffered a heart attack between 2015 and 2021. This makes it one of the largest studies ever undertaken into the link between depression and heart disease.

Despite the patients having similar health and demographic backgrounds, the study found a major difference in stroke rates between those with and without depression.

“The only difference between these two cohorts is that one has depression. There could be a multitude of depression-related factors that are leading to these outcomes. What we’re seeing in this data is very troubling and we need to dig deeper to understand the causes and effects,” commented the study’s lead author, Dr Frank Annie, of the Charleston Area Medical Center in Charleston, West Virginia.

Among the people assessed, 51,000 (10.5%) had a diagnosis of depression after their heart attack. The majority of these were first diagnosed with depression after the heart attack, with just one in six diagnosed beforehand.

The researchers compared the 51,000 patients with depression with a group of other heart attack survivors in the same data set who did not have depression. The participants were matched in terms of characteristics such as health and demographic background.

The study found that the risk of suffering a stroke after a heart attack was almost 50% higher if a person had depression.

Dr Annie said there may be a number of reasons for this. For example, having depression could interfere with a person’s ability to attend medical appointments or take their medication properly. Depression can also negatively impact sleep and concentration, making it a challenge to eat healthily and exercise regularly.

The study noted that those with depression tended to have higher rates of hypertension, coronary artery disease, diabetes, heart failure and COPD. They were also more likely to have a higher BMI and to smoke.

However, the association between depression and a subsequent stroke remained significant even after accounting for these variables.

Dr Annie said that there is increasing evidence that getting treated for depression improves outcomes in those with heart disease.

“A multidisciplinary approach is required. Based on these data, if there’s someone who has a history of heart disease and depression, I would advocate for devoting special attention within the healthcare system to making sure that these individuals are making their appointments and that they’re seeing the right providers within the health system,” he commented.

He called for further research to better understand how depression affects a person’s heart health and risk of stroke.

“We do answer a few questions, but we’re raising a lot more,” he added.

These findings will be presented at the American College of Cardiology’s 71^st Annual Scientific Session in Washington DC in April.