In- and out-of-hospital mortality for myocardial infarction during the first wave of the COVID-19 pandemic in Emilia-Romagna, Italy: A population-based observational study

Abstract

Background: The COVID-19 pandemic has put several healthcare systems under severe pressure. The present analysis investigates how the first wave of the COVID-19 pandemic affected the myocardial infarction (MI) network of Emilia-Romagna (Italy).

Methods: Based on Emilia-Romagna mortality registry and administrative data from all the hospitals from January 2017 to June 2020, we analysed: i) temporal trend in MI hospital admissions; ii) characteristics, management, and 30-day mortality of MI patients; iii) out-of-hospital mortality for cardiac cause.

Findings: Admissions for MI declined on February 22, 2020 (IRR -19.5%, 95%CI from -8.4% to -29.3%, p = 0.001), and further on March 5, 2020 (IRR -21.6%, 95%CI from -9.0% to -32.5%, p = 0.001). The return to pre-COVID-19 MI-related admission levels was observed from May 13, 2020 (IRR 34.3%, 95%CI 20.0%-50.2%, p<0.001). As compared to those before the pandemic, MI patients admitted during and after the first wave were younger and with fewer risk factors. The 30-day mortality remained in line with that expected based on previous years (ratio observed/expected was 0.96, 95%CI 0.84-1.08). MI patients positive for SARS-CoV-2 were few (1.5%) but showed poor prognosis (around 5-fold increase in 30-day mortality). In 2020, the number of out-of-hospital cardiac deaths was significantly higher (ratio observed/expected 1.17, 95%CI 1.08-1.27). The peak was reached in April.

Interpretation: In Emilia-Romagna, MI hospitalizations significantly decreased during the first wave of the COVID-19 pandemic. Management and outcomes of hospitalized MI patients remained unchanged, except for those with SARS-CoV-2 infection. A concomitant increase in the out-of-hospital cardiac mortality was observed.

Funding: None.

Fig. 1

Daily number of admissions for MI. The graph on the left represents the number of daily hospital admissions for MI from January 2017 to June 2020. The orange line is the expected trend (based on seasonality), whereas the red line is the observed trend. The first six months of the year 2020 are highlighted in the light blue box. The upper portion of the light blue box shows the trend of cases who resulted positive for SARS-CoV-2 infection. The lower portion shows the trend of daily hospital admissions for MI in the first six months of the 2020. The violet range represents the national lockdown (from March 9 to May 3, 2020). The dotted black lines the dates associated with significant changes in the trend of daily admission for MI. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 2

Thirty-day mortality of patients hospitalized for MI. The upper portion of the Figure shows the monthly 30-day mortality of patients admitted to hospital for MI from January 2017 to June 2020. The lower part of the Figure shows the ratios between observed and expected 30-day deaths of MI patients. The expected number was computed based on data from the years 2017–2019 and after adjustment for confounding factors.

Fig. 3

Out-of-hospital cardiac death. The graph on the left represents the number of out-of-hospital cardiac deaths from January 2017 to June 2020. The orange line is the expected trend based on seasonality. The black line is the observed trend. The first six months of the year 2020 are highlighted in the light blue box (upper right). The lower portion on the right shows the ratios between observed and expected out-of-hospital cardiac deaths. The expected numbers were computed based on data from the years 2017–2019 and after adjustment for age and sex. The national lockdown was from March 9 to May 3, 2020. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)