A recent American study, published in February 2022 in the scientific journal Nature Medicine, reports an increased risk of cardiovascular problems in the 12 months following a COVID-19 infection, including in mild forms without hospitalization. Prof. Hubert Cochet, head of the Technology for Health Department at the Liryc Institute, who has conducted two studies on the subject, shares his views to better understand the conclusions of this study.
A proven excess risk of cardiovascular disorders
In this study, teams from Washington University in St. Louis used a large database extracted from the American health system. They studied the occurrence of cardiovascular events within 12 months of COVID-19 infection in a cohort of more than 150,000 patients, compared to subjects who did not have the infection, or at least did not report it. The results showed an increased risk of cardiovascular events within one year of COVID-19 infection, including heart rhythm disorders and heart failure. The risk appears to be greatly increased in individuals with severe infection and hospitalization, which has been reported in previous studies. The novel result, however, is that an impact is already present, although weaker, in subjects who had a non-severe infection without hospitalization.
The strength of this publication lies in the very large number of people included in the study. Unlike the studies conducted at Liryc, which focus on a "patient" approach, and whose objective is to assess the risk at the level of the "sick" individual and to deduce a management plan, this study allows a more macro view. This is what is called "public health study", i.e. it analyses the impact of the disease on health systems.
Medico-economic consequences on health systems, more than on individual health
The results must therefore be interpreted with caution, in a public health framework. Indeed, an impact may be considered negligible at the individual level, but represent a major public health issue. For example, for an individual, the annual risk of developing atrial fibrillation in France is around 4 per 1000. The American study reports that in the aftermath of a non-severe COVID-19 infection, this risk could increase by 30% in the 12 months following the infection, i.e. between 5 and 6 per 1000. On an individual level, this risk remains minimal and should not lead to the systematic performance of additional examinations and cardiological assessments following the infection. This is also confirmed by the Liryc COVID-CMR study, which should be published shortly, in which we did not find a significant number of silent cardiac lesions after non-severe COVID 19, despite the use of advanced MRI methods.
On the other hand, this recent US study highlights the need for governments and healthcare systems worldwide to prepare for the increasing burden of cardiovascular disease, because although the excess risk is low at the individual level, it is high at the population level. Indeed, a significant proportion of our populations had nonsevere COVID 19 infection. If the results reported in this study were to be confirmed and if they were to persist over time (beyond 12 months after infection), the pandemic could profoundly modify the epidemiology of cardiovascular diseases, with in particular a significant increase in cases of heart failure, sudden death or stroke.
What are the solutions?
The solutions must be brought to the scale of the problem, i.e. to that of the population. The first one is preventive, based on the vaccination strategy associated with social distancing measures in the phase of epidemic rebound. The challenge is to limit the number of infected patients, but also to reduce the severity of infections, since there is a strong link between the severity of the infection and the increased cardiovascular risk. But the circulation of the virus is such that we must also prepare our health systems for this significant increase in cardiovascular disease. Because of the chronic nature of these diseases, the consequences should be long-lasting, with an impact on the training of health professionals and the organization of care.