Incidence of acute coronary syndrome during national lock-down: insights from nationwide data during the coronavirus disease 2019 (COVID-19) pandemic

Østergaard, Lauge; Butt, Jawad Haider; Kragholm, Kristian; Schou, Morten; Phelps, Matthew; Sørensen, Rikke; Lamberts, Morten; Gislason, Gunnar; Torp-Pedersen, Christian; Køber, Lars; Fosbøl, Emil L.

BACKGROUND: Urgent recognition and treatment are needed in patients with acute coronary syndrome (ACS), however this may be difficult during the Coronavirus disease 2019 (COVID-19) pandemic with a national lock-down. We aimed to examine the incidence of ACS after national lock-down. METHODS: The Danish government announced national lock-down on March 11 2020 and first phase of reopening was announced on April 6. Using Danish nationwide registries, we identified first-time ACS admissions in A) January 1 – May 7 2017-2019, and B) January 1 – May 6 2020. Incidence rates of ACS admissions per week for the 2017-2019-period and the 2020-period were computed and incidence rate ratios (IRR) were computed using Poisson regression analysis. RESULTS: The number of ACS admissions were 8,204 (34.6% female, median age 68.3 years) and 2,577 (34.0% female, median age 68.5 years) for the 2017-2019- and 2020-period, respectively. No significant differences in IRRs were identified for weeks 1-9 (January 1 – March 4) for 2020 compared with week 1-9 for 2017-2019. In 2020, significant lower IRRs were identified for week 10 (March 5-11) IRR=0.71 (95% CI: 0.58-0.87), week 11 (12-18 March) IRR=0.68 (0.56-0.84), and week 14 (2 – 8 April) IRR=0.79 (0.65-0.97). No significant differences in IRRs were identified for week 15-18 (April 9 – May 6). In subgroup analysis, we identified that the main result was driven by male patients, and patients ≥60 years. CONCLUSION: During the COVID-19 pandemic with an established national lock-down we identified a significant decline around 30% in the incidence of ACS admissions. Along with the reopening of society, ACS admissions were stabilized at levels equal to previous years.