COVID-19 Mortality Rate Declining: New studies show a big drop in COVID-19 deaths in a promising sign of virus attenuation
In a promising sign of coronavirus attenuation, two new peer-reviewed studies are showing a big drop in coronavirus deaths among hospitalized COVID-19 patients. The research, an earlier version of which was shared online as a preprint in August, will appear next week in the Journal of Hospital Medicine.
Dr. Leora Horwitz, a doctor who studies population health at New York University’s Grossman School of Medicine, is an author of one of the studies. After looking at thousands of patients from March to August, she found that the death rate has gone down substantially. She said the sharp drop is seen in all groups, including older patients and those with underlying conditions, suggesting that physicians are getting better at helping patients survive their illness.
Below is the abstract of the study.
Early reports showed high mortality from Covid-19; by contrast, the current outbreaks in the southern and western United States are associated with fewer deaths, raising hope that treatments have improved. However, in Texas, for instance, 63% of diagnosed cases are currently under 50, compared to only 52% nationally in March-April. Current demographics in Arizona and Florida are similar. Therefore, whether decreasing Covid-19 mortality rates are a reflection of changing demographics or represent improvements in clinical care is unknown. We assessed outcomes over time in a single health system, accounting for changes in demographics and clinical factors.
The study, which is titled, “Trends in Covid-19 risk-adjusted mortality rates in a single health system,” finds that mortality has dropped among hospitalized patients by 18 percentage points since the pandemic began. Patients in the study had a 25.6% chance of dying at the start of the pandemic; they now have a 7.6% chance. Patients in the study had a 25.6% chance of dying at the start of the pandemic; they now have a 7.6% chance.
It’s not all good news. Horwitz said the COVID-19 death rate “is still higher than many infectious diseases, including the flu,” She added that those who recover can suffer complications for months or even longer. “It still has the potential to be very harmful in terms of long-term consequences for many people.”
“The people who are getting hospitalized now tend to be much younger, tend to have fewer other diseases, and tend to be less frail than people who were hospitalized in the early days of the epidemic,” Horwitz says.
The second study was conducted by Bilal Mateen, a data science fellow at the Alan Turing Institute in the United Kingdom. In his research of 21,000 hospitalized COVID-19 patients in England, he found a similarly sharp drop in the death rate. The objective of his study was to determine the trend in mortality risk over time in people with severe COVID-19 requiring critical care (high intensive unit [HDU] or intensive care unit [ICU]) management.
Mateen and a team of scientists accessed national English data on all adult COVID-19 specific critical care admissions from the COVID-19 Hospitalisation in England Surveillance System (CHESS), up to the 29th June 2020 (n=14,958). His work, which will soon appear in the journal Critical Care Medicine and was released earlier in preprint, shows an unadjusted drop in death rates among hospitalized patients of around 20 percentage points since the worst days of the pandemic.
Mateen and a team of scientists found that “there was subsequently a sustained decrease in mortality risk until the end of the study period. As a linear trend from the first week of April, adjusted mortality risk decreased by 11.2% (adjusted HR 0.89 [95% CI 0.87 – 0.91]) per week in HDU, and 9.0% (adjusted HR 0.91 [95% CI 0.88 – 0.94]) in ICU.”
In the end, the authors concluded with the following:
There has been a substantial mortality improvement in people admitted to critical care with COVID-19 in England, with markedly lower mortality in people admitted in mid-April and May compared to earlier in the pandemic. This trend remains after adjustment for patient demographics and comorbidities suggesting this improvement is not due to changing patient characteristics. Possible causes include the introduction of effective treatments as part of clinical trials and a falling critical care burden.