"Missing" acute coronary syndrome hospitalizations during the COVID-19 era in Greece: Medical care avoidance combined with a true reduction in incidence?

Abstract

Background: Reports from countries severely hit by the COVID-19 pandemic suggest a decline in acute coronary syndrome (ACS)-related hospitalizations. The generalizability of this observation on ACS admissions and possible related causes in countries with low COVID-19 incidence are not known.

Hypothesis: ACS admissions were reduced in a country spared by COVID-19.

Methods: We conducted a nationwide study on the incidence rates of ACS-related admissions during a 6-week period of the COVID-19 outbreak and the corresponding control period in 2019 in Greece, a country with strict social measures, low COVID-19 incidence, and no excess in mortality.

Results: ACS admissions in the COVID-19 (n = 771) compared with the control (n = 1077) period were reduced overall (incidence rate ratio [IRR]: 0.72, P < .001) and for each ACS type (ST-segment elevation myocardial infarction [STEMI]: IRR: 0.76, P = .001; non-STEMI: IRR: 0.74, P < .001; and unstable angina [UA]: IRR: 0.63, P = .002). The decrease in STEMI admissions was stable throughout the COVID-19 period (temporal correlation; R² = 0.11, P = .53), whereas there was a gradual decline in non-STEMI/UA admissions (R² = 0.75, P = .026) following the progressively stricter social measures. During the COVID-19 period, patients admitted with ACS presented more frequently with left ventricular systolic impairment (22.2 vs 15.5% control period; P < .001).

Conclusions: We observed a reduction in ACS hospitalizations during the COVID-19 outbreak in a country with strict social measures, low community transmission, and no excess in mortality. Medical care avoidance behavior is an important factor for these observations, while a true reduction of the ACS incidence due to self-isolation/quarantining may have also played a role.

Keywords: COVID-19; acute cardiac care; acute coronary syndrome; myocardial infarction; public health.

FIGURE 1

Number of acute coronary syndrome (ACS)‐related hospitalizations during the COVID‐19 outbreak (6‐weeks: 2 March 2020 to 12 April 2020 [orange bars]) are significantly reduced compared with the corresponding control period in 2019 (blue bars) overall and separately for ST‐segment elevation myocardial infarction (STEMI), non‐STEMI (NSTEMI) and unstable angina (UA). P values are derived from Poisson regression analysis

FIGURE 2

A, The overall number of admissions for acute coronary syndromes (ACS) on a week‐per‐week basis showed a gradual decline during the COVID‐19 period. B, The incidence rate ratio of admissions (ie, relative change in COVID‐19 compared with the control period) per week assessed separately for ST‐segment elevation myocardial infarction (STEMI) and non‐STEMI/unstable angina (UA) showed a temporal trend for NSTEMI/UA (P = .026) but not for STEMI (P = .53) which remained stable throughout the study period. Best‐fit curves (logarithmic) with the coefficients of determination (R²) are demonstrated

FIGURE 3

Cumulative number of acute coronary syndrome (ACS) hospitalizations plotted over the 42 days (6‐weeks) during the COVID‐19 outbreak (2 March 2020 to 12 April 2020 [orange]) and the corresponding period in 2019 (blue). The corresponding trend lines by linear regression are also shown. The numbers started to diverge substantially between March 16th (lockdown for over 80% of business type activities; yellow vertical line) and March 23rd (complete national lockdown with restriction of freedom of movement; red vertical line). There was an overall significant difference in the slopes of the regression lines between the COVID‐19 and control periods (17.3 vs 25.7 admissions/day, respectively; ratio of slopes: 0.68, 95% CI: 0.66‐0.70, P < .001)