Myocardial Infarction incidence during national lockdown in two French provinces unevenly affected by COVID-19 outbreak: An observational study

BACKGROUND: A reduction of admission for MI has been reported in most countries affected by COVID-19. No clear explanation has been provided. METHODS: To report the incidence of myocardial infarction (MI) admission during COVID-19 pandemic and in particular during national lockdown in two unequally affected French provinces (10-million inhabitants) with a different media strategy, and to describe the magnitude of MI incidence changes relative to the incidence of COVID-19-related deaths. A longitudinal study to collect all MIs from January 1 until May 17, 2020 (study period) and from the identical time period in 2019 (control period) was conducted in all centers with PCI-facilities in northern “Hauts-de-France” province and western “Pays-de-la-Loire” Province. The incidence of COVID-19 fatalities was also collected. FINDINGS: In “Hauts-de-France”, during lockdown (March 18–May 10), 1500 COVID-19-related deaths were observed. A 23% decrease in MI-IR (IRR=0.77;95%CI:0.71–0.84, p<0.001) was observed for a loss of 272 MIs (95%CI:−363,−181), representing 18% of COVID-19-related deaths. In “Pays-de-la-Loire”, 382 COVID-19-related deaths were observed. A 19% decrease in MI-IR (IRR=0.81; 95%CI=0.73–0.90, p<0.001) was observed for a loss of 138 MIs (95%CI:−210,−66), representing 36% of COVID-19-related deaths. While in “Hauts-de-France” the MI decline started before lockdown and recovered 3 weeks before its end, in “Pays-de-la-Loire”, it started after lockdown and recovered only by its end. In-hospital mortality of MI patients was increased during lockdown in both provinces (5.0% vs 3.4%, p=0.02). INTERPRETATION: It highlights one of the potential collateral damages of COVID-19 outbreak on cardiovascular health with a dramatic reduction of MI incidence. It advocates for a careful and weighted communication strategy in pandemic crises. FUNDING: The study was conducted without external funding.