How Case Rates, Treatment Approaches, and Acute MI Outcomes Changed During COVID-19

A new study in JAMA Cardiology revealed how treatment of acute myocardial infarction (acute MI) changed during the COVID-19 pandemic.

“The coronavirus disease 2019 (COVID-19) pandemic has changed health care delivery worldwide,” the authors wrote. “Although decreases in hospitalization for acute myocardial infarction (AMI) have been reported during the pandemic, the implication for in-hospital outcomes is not well understood.”

Researchers for the retrospective cross-sectional analysis looked at more than 15,000 hospitalizations and more than 14,700 patients with acute MI from one of the 49 hospitals in the St. Joseph Health System. Patients included in the analysis had a discharge diagnosis of acute MI (STEMI or non-STEMI). The authors performed segmented regression analysis in order to determine differences in weekly case outcomes, which were separated into three groupings:  before COVID-19 (December 2018 to February 22, 2020), early COVID-19 (February 23, 2020 to March 28, 2020), and later COVID-19 (March 29, 2020 to May 16, 2020). They adjusted in-hospital mortality using an observed-to-expected ratio and a multivariable model adjusted for covariates. The primary study outcome was the weekly rate of acute MI hospitalizations, with patient characteristics, treatment approaches, and in-hospital outcomes as secondary endpoints.

According to the results, acute MI-related hospitalizations decreased at a rate of -19.0 (95% CI, -29.0 to -9.0) cases per week for five weeks during the early COVID-19 period.  That number increased at a rate of +10.5 (95% CI, 4.6 to 16.5) cases per week by the later COVID-19 period. The authors reported no differences in patient demographics, comorbidities, and treatment approaches across the study periods. The observed-to-expected ratio increased during the early COVID-19 period and was disproportionately associated with STEMI. Although it did not reach statistical significance, incraeses in the observed-to-expected ratio were reported in STEMI patients and also after adjutment for risk.

“The findings of this study show that changes in acute MI hospitalizations and in-hospital outcomes occurred during the COVID-19 pandemic periods analyzed; additional research is warranted to explain the higher mortality rate among patients with STEMI,” the authors wrote.