Mortality in CVD Patients Before, During, After COVID-19 Lockdown

Quick Takes

  • The COVID-19 lockdown in Denmark was not associated with increased overall mortality among patients with known CVD. However, in-hospital mortality was lower during and after lockdown as compared to the same time period in 2019, while out-of-hospital mortality was higher.
  • The stability of overall mortality in 2020 was likely a reflection of the relatively low COVID-19 burden in Denmark, as compared with the United States and other European countries. Among the Danish population of 5.8 million people, a total of 35,291 cases and 679 deaths had occurred as of October 2020.

Study Questions:

Among individuals with cardiovascular disease (CVD) in Denmark, how did the coronavirus disease 2019 (COVID-19) lockdown impact mortality rates?

Methods:

This was a nationwide registry-based cohort study. The study population comprised all adult Danish citizens with CVD, including ischemic heart disease, atrial fibrillation (AF), heart failure (HF), ischemic stroke, and peripheral arterial disease (PAD). The COVID-19 lockdown began on March 13, 2020, and the first phase of reopening began on April 15, 2020. Study follow-up ended on October 15, 2020. Overall, in-hospital, and out-of-hospital mortality rates were determined pre-lockdown, during lockdown, and post-lockdown.

Results:

The cohort comprised 340,392 Danish citizens with CVD (median age 72 years as of 2020, 59.6% male). The pre-lockdown overall mortality rate in 2020 was significantly lower than in 2019 (adjusted incident rate ratio [IRR], 0.91; 95% confidence interval [CI], 0.87-0.95). During and after lockdown, overall mortality was similar as compared to the same time period in 2019 (IRR, 0.99; 95% CI, 0.97-1.02).

The in-hospital mortality rate during and after lockdown was significantly lower than during the same period in 2019 (IRR, 0.92; 95% CI, 0.88-0.96). Compared with patients who died during hospital admission in 2019, those who died in-hospital in 2020 more often had AF (38.4% vs. 41.2%, p = 0.01). Cardiovascular hospital admissions declined during lockdown but increased back to 2019 levels following lockdown.

The out-of-hospital mortality rate during and after lockdown was significantly higher than during the same period in 2019 (IRR, 1.04; 95% CI, 1.01-1.08). Compared with 2019, those who died out-of-hospital in 2020 were more likely to have HF (21.1% vs. 22.9%, p = 0.02), PAD (10.3% vs. 9.1%, p = 0.02), and diabetes mellitus (11.4% vs. 10.2%, p = 0.04).

Conclusions:

The COVID-19 lockdown in Denmark was not associated with increased overall mortality among patients with known CVD. However, in-hospital mortality was lower during and after lockdown as compared to the same time period in 2019, while out-of-hospital mortality was higher.

Perspective:

The stability of overall mortality in 2020 was likely a reflection of the relatively low COVID-19 burden in Denmark, as compared with the United States and other European countries. Among the Danish population of 5.8 million people, a total of 35,291 cases and 679 deaths had occurred as of October 2020. The uptick in out-of-hospital death among patients with known CVD during lockdown was likely related to patient reluctance to seek medical care. The decrease in in-hospital mortality may have been related to a decrease in influenza cases during 2020, as the authors comment, or a reflection of robust hospital staffing and resources relative to hospital occupancy. Limitations of this study include lack of cause-specific mortality rates and data on disease severity.

Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Prevention, Atherosclerotic Disease (CAD/PAD), Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure

Keywords: Acute Coronary Syndrome, Atrial Fibrillation, Brain Ischemia, Cardiovascular Diseases, Coronavirus, COVID-19, Diabetes Mellitus, Geriatrics, Heart Failure, Hospital Mortality, Myocardial Ischemia, Peripheral Arterial Disease, Primary Prevention, Stroke, Vascular Diseases


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