Case Rates and Outcomes in Acute MI During COVID-19 Pandemic

Quick Takes

  • There was a substantial decrease in AMI hospitalization rates in the early COVID-19 period suggesting that a significant number of patients with AMI initially avoided hospitalization during the COVID-19 pandemic, possibly related to apprehension of catching SARS-CoV-2.
  • Patients hospitalized for AMI during the COVID-19 period had an increased O/E mortality ratio, especially among patients with STEMI.
  • Additional studies are needed to identify factors associated with the higher mortality rate in patients with STEMI and to understand whether a facilitated PCI strategy with initial thrombolysis may have reduced reperfusion time and mortality risk during the pandemic.

Study Questions:

What are the changes in acute myocardial infarction (AMI) case rates, patient demographics, cardiovascular comorbidities, treatment approaches, and in-hospital outcomes during the pandemic?

Methods:

The investigators conducted a retrospective cross-sectional study and analyzed AMI hospitalizations that occurred between December 30, 2018, and May 16, 2020, in 1 of the 49 hospitals in the Providence St Joseph Health system located in six states (Alaska, Washington, Montana, Oregon, California, and Texas). The cohort included patients aged ≥18 years who had a principal discharge diagnosis of AMI (ST-segment elevation myocardial infarction [STEMI] or non–STEMI [NSTEMI]). Segmented regression analysis was performed to assess changes in weekly case volumes. Cases were grouped into one of three periods: before coronavirus disease 2019 (COVID-19) (December 30, 2018-February 22, 2020), early COVID-19 (February 23-March 28, 2020), and later COVID-19 (March 29-May 16, 2020). In-hospital mortality was risk-adjusted using an observed to expected (O/E) ratio and covariate-adjusted multivariable model. The primary outcome was the weekly rate of AMI (STEMI or NSTEMI) hospitalizations. The secondary outcomes were patient characteristics, treatment approaches, and in-hospital outcomes of this patient population. Trends among the three COVID-19 periods were compared using univariate χ2, Fisher exact, or Kruskal-Wallis tests, as appropriate, for each variable.

Results:

The cohort included 15,244 AMI hospitalizations, of which 4,955 were for STEMI (33%) and 10,289 for NSTEMI (67%) involving 14,724 patients (mean [SD] age of 68 [13] years and 10,019 men [66%]). Beginning February 23, 2020, AMI-associated hospitalizations decreased at a rate of –19.0 (95% confidence interval [CI], –29.0 to –9.0) cases per week for 5 weeks (early COVID-19 period). Thereafter, AMI-associated hospitalizations increased at a rate of +10.5 (95% CI, +4.6 to +16.5) cases per week (later COVID-19 period). No appreciable differences in patient demographics, cardiovascular comorbidities, and treatment approaches were observed across periods. The O/E mortality ratio for AMI increased during the early period (1.27; 95% CI, 1.07-1.48), which was disproportionately associated with patients with STEMI (1.96; 95% CI, 1.22-2.70). Although the O/E mortality ratio for AMI was not statistically different during the later period (1.23; 95% CI, 0.98-1.47), increases in the O/E mortality ratio were noted for patients with STEMI (2.40; 95% CI, 1.65-3.16) and after risk adjustment (odds ratio, 1.52; 95% CI, 1.02-2.26).

Conclusions:

The authors concluded that this cross-sectional study found important changes in AMI hospitalization rates and worse outcomes during the early and later COVID-19 periods.

Perspective:

This study reports a substantial decrease in AMI hospitalization rates in the early COVID-19 period, suggesting that a significant number of patients with AMI initially avoided hospitalization during the COVID-19 pandemic, possibly related to apprehension of catching severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Of note, patients hospitalized for AMI during the COVID-19 period had an increased O/E mortality ratio, especially among patients with STEMI. Given the importance of timely reperfusion of STEMI, any delay by patients, emergency medical services, the emergency department, or cardiac catheterization laboratory related to donning of personal protective equipment may have played a role. Additional studies are needed to identify factors associated with the higher mortality rate in patients with STEMI, and to understand whether a facilitated percutaneous coronary intervention (PCI) strategy with initial thrombolysis may have reduced reperfusion time and mortality risk during the pandemic.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Prevention, Interventions and ACS

Keywords: Acute Coronary Syndrome, Coronavirus, COVID-19, Hospital Mortality, Myocardial Infarction, Myocardial Reperfusion, Outcome Assessment (Health Care), Patient Discharge, Percutaneous Coronary Intervention, Personal Protective Equipment, Risk Adjustment, Secondary Prevention, ST Elevation Myocardial Infarction


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