Declining death rate from COVID-19 in hospitals in England
June 24, 2020
Mahon J, Oke J, Heneghan C.
The UK government publishes the following data:
- The daily number of people who have died in hospital in England with a diagnosis of COVID-19;
- The daily number of people admitted to hospital in England who are diagnosed with COVID-19.
The number of people dying with COVID-19 in hospitals in England each day has fallen from a peak of 899 on the 8th April to 50 on the 15 June.
The number of people In hospital with COVID has fallen from a peak of 15,702 on the 10th of April to 2,891 on the 19th of June.
The figure shows that the number of people with COVID-19 in hospital has fallen at a slower rate than the number of people dying.
- The number of people in hospital with COVID is reducing by 2.4% every day: halving every 29 days.
- The number of deaths is reducing by 4.3% per day: halving every 16 days.
This lead to declining death rates in hospitals, which can be seen by looking at the peak Hospital Fatality Rate (HFR) on the 2nd if April and comparing to the current HFR:
On the 2nd April, there were 644 deaths in 10,737 people in the hospital with COVID-19 HFR* peaked at 6.0%.
By the 15th of June, there were 50 deaths and 3,270 people in hospital with COVID: an HFR of 1.5%.
*HFR (hospitalized) defines a case as someone who is infected and hospitalized.
The reasons for this steep and continual decline in the deaths per day in the hospital of patients with COVID-19 are unknown and should be explored. Potential reasons could include:
- Older patients who had recovered from COVID-19 but could not be discharged to care homes have places that have over recent weeks become available. This would not, however, explain the decline that started from 9 April 2020.
- Patients with COVID-19 in late March and early April included a significant proportion of patients who caught the infection in hospital. These patients, because they were in hospital, were more likely to be sicker and more vulnerable than patients who acquired infection in the community and so more likely to die from COVID-19. As patients with community-acquired infections became a greater proportion of patients in hospital the hospital death rate fell. However, this would not explain why the death rate has fallen continually for approximately 8 weeks with no signs that the decline has yet plateaued.
- Clinicians have become more skilled and adept at treating patients with COVID-19.
- Patients overtime being admitted are becoming younger with fewer comorbidities, although there is no evidence of this in the daily hospital death data which, if anything, suggests a greater proportion of deaths in hospital are over the age of 60 than at the peak of deaths in early April.
- Patients are entering the hospital with less severe disease, which could be a reflection of either the disease becoming less severe or hospitals that are now less concerned with being unable to manage peak infections being more willing to admit patients with lower disease severity than they would admit in early April.
The reasons for the declining death rate in hospitals may be a combination of one or all of these factors or due to some other reason, we have not considered. In either case, further research is warranted to understand why the hospital death rate has declined so markedly over the past 8 weeks.
SEE BMJ News for coverage of this article:
Covid-19: Continued outbreaks in care homes risk extending pandemic, say experts
BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m2530 (Published 24 June 2020)
Correction: this page has been corrected on the 25th of June
James Mahon is an economist who holds an honorary post at the Liverpool Reviews and Implementation Group (LRiG) in the Department of Health Services Research at Liverpool University and works alongside the York Health Economics Consortium (YHEC) at the University of York.
Jason Oke is a Senior Statistician at the Nuffield Department of Primary Care Health Sciences and Module Coordinator for Statistical Computing with R and Stata (EBHC Med Stats), and Introduction to Statistics for Health Care Research (EBHC), as part of the Evidence-Based Health Care Programme.
Carl Heneghan is Professor of Evidence-Based Medicine and Director of Studies for the Evidence-Based Health Care Programmes (Full bio and disclosure statement here)
Disclaimer: the article has not been peer-reviewed; it should not replace individual clinical judgement, and the sources cited should be checked. The views expressed in this commentary represent the views of the authors and not necessarily those of the host institution, the NHS, the NIHR, or the Department of Health and Social Care. The views are not a substitute