It has been reported that the incidence of sudden death has seen a significant increase during the COVID-19 pandemic compared to the previous period.1 This fact is probably related to the higher incidence of arrhythmias and hypercoagulability after infection with the SARS-CoV2 virus.2 Attending highly competitive soccer matches causes intense “emotional tension” among attendees, which is a potential trigger for acute coronary syndrome (ACS).3 However, the effect of the COVID-19 pandemic on serious cardiovascular events in those attending high-competition soccer matches in Spain is not known. We hypothesized that serious cardiovascular events among those attending national soccer league matches would have experienced an increase following the COVID-19 pandemic in Spain. To do this, a search was carried out for the events reported in different media from August 2013 to February 6, 2024. The main online search engines (Google and Bing), the social network Twitter/X and the National Library's digital newspaper archive were used. The search keywords were different combinations of: “dies”, “fan”, “league”, “deceased”, “football”, “heart attack”, “emergency”, “stand”, “match”, “resuscitation”, “cardiorespiratory”, “stroke”. The inclusion criteria were:

• 1

  Soccer matches of the Spanish first or second division leagues (other competitions were excluded).

• 2

  Experiencing a “serious cardiovascular event” identified as cardiorespiratory arrest and/or myocardial infarction or cerebrovascular event (excluding bronchospasms, heat strokes, “fainting” with immediate recovery, “surges or drops in blood pressure,” etc.).

• 3

  Occurrence during the match, in the pregame or immediately after its end.

• 4

  The cardiovascular event occurring only to spectators, excluding security personnel, journalists, club workers, etc. For each identified fan, their sex and age were recorded.

Likewise, data on total attendance at stadiums during the analysis seasons was obtained as of 02/06/24 from the website www.transfermarkt.es. In this way, two incidence rates of cardiovascular events were calculated, one that includes the 2013/14 seasons until 2019/20, and another that includes the 2020/21 seasons until February 5, 2023/24. The cut-off point was chosen in the 2019/20 season since the first case of COVID-19 in Spain was recorded on January 31, 2020, suspending professional football competitions just 5 weeks later, which resumed in June behind closed doors.

Incidence rates were calculated as the ratio between the sum of events identified in those periods divided by the number of spectators/attendees accumulated in the respective temporal range, thus having units of events/people per time. For this analysis, a time window of 4 hours per match was considered. The rate comparison analysis was performed with the OpenEpi® software, using Fisher's exact and mid-p tests.

Table 1 shows the cardiovascular events recorded in the study. The links to the websites from which the information was obtained are shown in the Supplementary material. A total of 37 events that met the inclusion criteria were recorded, 20 for the first time period and 17 for the second. Of them, 97% occurred in men. The mean age was 65 ± 12 years, minimum 43 years old, maximum 82 years old (documented in 17 cases). The accumulated number of spectators for the first period was 96699480, while for the second it was 37248658. Overall, the incidence rate was 0.52/10000000 person-hours in the first period or pre-pandemic compared to 1.14/10000000 person-hours for the subsequent period (Fisher’s exact test p = 0.028; mid-p exact test 0.020). Our study therefore suggests a significant increase in serious cardiovascular events (incidence rate ratio 2.21).

Serious cardiovascular events are fortunately uncommon among those attending soccer matches.3 In a 2005 study carried out in the Barcelona Football Club stadium, the incidence rate of SCA was 0.56/10000000 person-hours, very similar to what we reported in the pre-pandemic stage.3 The confluence of intense emotions, copious amounts of meals, alcohol, tobacco and perhaps a recent or current SARS-Cov-2 infection mean that football stadiums may be a prone setting for cardiovascular events.

Our study presents the limitations of a retrospective observational study. The limitation is that the sources of information used conditioned a certain imprecision when classifying the events. To avoid this, JAM made a general classification of all the events that LCS later confirmed. This methodology has been previously used in clinical studies.4

In conclusion, we observed a significant increase in the incidence of serious cardiovascular events among those attending national soccer league matches in Spain after the start of the COVID-19 pandemic compared to the previous period. Measures aimed at reinforcing material and human health facilities in Spanish football stadiums could be necessary given these results.