Trends in COVID-19 in-hospital mortality: Insights from the AHA COVID-19 CVD registry

Information on the survival trends of hospitalized COVID-19 patients is important for physicians to identify trends and track the efficacy of hospital-based care in real-world practice. The American Heart Association’s (AHA) COVID-19 Cardiovascular Disease (CVD) Registry was put in place in April 2020 with the objective of improving nation-wide surveillance of hospitalized patients with COVID-19.1 Early data derived from this registry were presented at scientific sessions #AHA20 last year. This blog summarizes a more recent analysis by Gregory A. Roth and colleagues, looking at trends in patient characteristics and COVID-19 in-hospital mortality in the United States during the pandemic.2

This retrospective study published in JAMA Network Open included 20 736 hospitalized patients from the AHA COVID-19 CVD registry at 107 hospitals in 31 states. Undertaken as part of the Global Burden of Disease Study, the objective was to quantify changes in in-hospital mortality rates during the first 9 months of the pandemic, and understand if any observed changes were associated with differences over time in the characteristics of presenting patients. The data were analyzed to show comparative trends across 4 periods in 2020: March and April; May and June; July and August; and September through November.

There was a gradual decline in the numbers of admitted patients in the registry, with 11 901 patients admitted in March or April, down to 2010 patients in September through November. In terms of the patient demographics, 45.9% were women, the proportion of which slightly increased over time. The mean age was 61.2 ±17.9 years which decreased from March -April through September-November. 58.4% of patients were hypertensive. 35% were diabetic, and 18.3% had pulmonary disease. The mean BMI was in the obese range (30.8 ± 8.5) and increased a small amount through November.

Almost a quarter of patients were receiving supplemental oxygen on admission. This proportion increased from 23% in March – April to 35.9% in September through November. This was despite the presence of interstitial infiltrates on admission decreasing from 70.7% of patients to 60.8% during the corresponding periods. In contrast to supplemental oxygen, however, the use of mechanical ventilation decreased substantially from 23.3% to 13.9% during the same periods. The use of glucocorticoids and remdesivir increased substantially, potentially reflecting the emergence of randomized evidence of its efficacy during that time and the US Food and Drug Administration (FDA) announcement of remdesivir emergency use authorization on May 1, 2020.3 The mean duration of hospital stay also showed a reduction from 10.7±12.1 days to 7.5 ± 6.8 days.

A total of 3271 in-hospital deaths recorded from March through November 2020, corresponding to overall in-hospital mortality of 15.8%. In-hospital mortality rates declined as time progressed, with 19.1% in March-April, 11.9% in May-June, 11% in July-August, and 10.8% in September- November. Adjusted odds for in-hospital death were also significantly lower for all 3 later time periods studied, compared with March-April. Increasing age was the factor most strongly associated with death, with the figure depicting the adjusted odds ratios across different age groups [Figure 1]. Male sex, BMI > 45, and presences of comorbidities, specifically cancer, cerebrovascular disease, diabetes, and heart failure were independently associated with in-hospital death.

The greatest reduction in the in-hospital mortality rates occurred between March and May 2020, with high mortality rates falling by a massive 38% from March and April 2020 by May and June, followed by a modest further decrease by November. Notably, this difference in mortality rates persisted even after adjusting for age, sex, medical history, and COVID-19 disease severity. In the face of only minor changes in the characteristics of admitted patients described above, the authors have thus put forward some hypotheses that might explain these trends of decreasing mortality rates over time.

One of them is the extremely high hospital census and rapid implementation of new measures (i.e. isolation and personal protection procedures) especially in locations with very high rates of COVID-19 in March and April. This is consistent with the observation of the most rapid declines in mortality rates between the months of March – April and May – June, when health care workers gradually became more familiar with new procedures.

Changes in treatment protocols may also have contributed to this decreased mortality. The observed increased use of supplemental oxygen and decreased use of mechanical ventilation in the registry data could be explained by trends in respiratory care that emerged as the pandemic progressed, particularly the efficacious modalities of noninvasive ventilation, high flow nasal oxygen, and prone positioning, although these modalities were not captured in the registry. Substantially increased use of steroids and remdesivir may also have contributed to better outcomes.

Few limitations exist: the analysis was retrospective, with varying sample sizes due to the voluntary nature of enrolment in the registry. Certain treatment modalities were not captured. There was potential for bias due to confounding from unobserved or unrecorded characteristics in the estimation of associations, and as such causality cannot be inferred. Furthermore, it is important to note that this analysis included data from before the rollout of vaccines, and it would be interesting to see these more contemporary trends from the AHA COVID-19 CVD registry in future analyses.

Needless to say, such registry-based analyses provide important data on trends in mortality and contemporary management practices in the face of rapidly evolving hospital dynamics during the pandemic. While randomized controlled trials are essential to investigate potential treatments and inform evidence-based practice, the utility of such registries in identifying mortality and treatment trends in real-world practice, and indeed using this information to implement best practices, cannot be understated.


  1. Alger HM, Rutan C, Williams JH IV, et al. American Heart Association COVID-19 CVD Registry powered by Get With The Guidelines. Circ Cardiovasc Qual Outcomes. 2020;13(8):e006967.
  2. Roth GA, Emmons-Bell S, Alger HM, et al. Trends in Patient Characteristics and COVID-19 In-Hospital Mortality in the United States During the COVID-19 Pandemic. JAMA Netw Open. 2021;4(5):e218828.
  3. US Food and Drug Administration. Emergency Use Authorization (EUA) for emergency use of Veklury® (remdesivir) for the treatment of hospitalized patients with severe 2019 coronavirus disease (COVID-19). Published October 22, 2020. Accessed June 4, 2021.


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