The Intensive Care National Audit and Research Centre (ICNARC) have published a report* on the first reported 775 COVID-19 patients admitted to intensive care units (ICU) in the UK, mainly focusing on the statistics related to these patients.
Prof Sir David Spiegelhalter, Chair, Winton Centre for Risk and Evidence Communication, University of Cambridge, said:
“Out of the 775 patients being studied, only 165 have left intensive care, while the outcome for the remaining 610 is not yet determined. Those 165 tend to have had short stays (median 3 or 4 days), and 48% died and 52% were discharged alive. Those discharged already, whether dead or alive, presumably comprised the most and least sick, and it remains to be seen what happens to the intermediate group still in intensive care.”
Dr Tim Crocker-Buqué, Clinical Epidemiologist, LSHTM, said:
“To say that the mortality rate of ICU patients is 50% is misleading and may induce panic.
“More accurately it shows that of the 21% of those patients who have left critical care, 48% of them had died. However, it excludes the 79% patients who do not have an outcome yet. Importantly, this is not a mortality rate, as described in some media reports, which is a complicated statistic to calculate and requires calculation based on a pre-specified population.
“The crude death rate could be calculated, but this still has to be related to an underlying population. So this would be 48% of all the people who have left critical care, but would be 10.2% of all the people who have been admitted to critical care since the start of the outbreak. Overall the population of patients with an outcome (n=165) is too small at the moment, and unlikely to be representative of all the patients admitted to critical care.
“Of note, these are very early data, so the patients who have already died have had very short stays in critical care (3-4 days), suggesting they may have deteriorated much quicker than other patients and so are unlikely to be representative and may be reflecting a higher risk of death in this early group that died.”
Prof Duncan Young, Professor of Intensive Care Medicine, University of Oxford, said:
“The Intensive Care National Audit and Research Centre (ICNARC) have released their second weekly report on patients with COVID-19 disease being treated in intensive care units (ICUs) in England, Wales and Northern Ireland.
“There had been 846 admissions of patients with COVID-19 to the ICUs by Friday 27th March. Due to the rapidly changing situation ICNARC only had good data on 775 patients.
“Three quarters of ICUs had treated at least one patient with COVID-19, the remainder have not yet admitted a case. As with last week’s report, the majority of the cases are in London and the Thames Valley areas.
“Most cases are still being treated in an ICU (609). A total of 86 patients have been discharged from the ICU, though a proportion of these have had to be readmitted. Seventy-six patients have died. As would be expected, over half the survivors were patients who did not require treatment with a ventilator and so were less severely infected.
“The average age of patients was 61, and as before there are many more male patients (70%). There is usually a slight excess of males in all patients admitted to an ICUs but not as great as seen in the COVID-19 cases. So far the discharged patients have only stayed on the ICU for around three days, but there are many patients still being treated and I would expect the average duration of ICU care to increase in future reports.
“In the last report there was a suggestion that the proportion of obese patients was greater than expected. This report shows the BMI/age distribution for the COVID-19 patients and the general population. The BMI distribution of the patients in ICU with COVID-19 matches the population, so it is not likely that obesity is linked to severe COVID-19 infection requiring an ICU admission.
“The numbers are small but there does appear to be an increased risk of death in obese patients admitted to an ICU with a COVID-19 infection. It is well known that for ICU admissions overall extremes of body mass index (BMI) are associated with worse outcomes, so whether this is a COVID-19 effect is hard to say.
“As seen elsewhere, the chances of death on the ICU with COVID-19 increase markedly with age, reaching 73% in the over 70’s.
“ICNARC has been collecting data on admissions to ICUs for many years. In this report they have given data on over 5000 patients with non-COVID viral pneumonia treated in the two years prior to the current pandemic. These patients would have had pneumonia caused by many different viruses including influenza A and B, and respiratory syncytial virus. Comparing these patients with the COVID-19 patients suggests COVID-19’s higher mortality in the old and obese was not seen with other viral pneumonias, which also caused far fewer deaths overall.
“The mortality rate (case fatality rate) is calculated as those who died divided by all cases. The patients still in the ICU may yet die or recover, so until we have many more cases the true case fatality rate for patients admitted to an ICU with COVID-19 remains unknown. Strictly ICNARC are not reporting a mortality rate, they are reporting the number of deaths. Commentators are turning this into a mortality rate.”
Prof Paul Hunter, Professor in Medicine, University of East Anglia (UEA), said:
“The ICNARC report is a welcome source of real data that gives some indication of how the outbreak will affect the NHS in general and critical care units in particular. Of particular value has been comparing the experiences of COVID-19 with viral pneumonias that occurred during the 3 years 2017 to 2019.
“To my mind some of the important information in the report include:
1. Men are substantial more likely to be admitted compared with other viral pneumonias (70.5% v 54.3%) and men with COVID-19 are more likely to die than women (53.2% v 37.5%)
2. The length of stay on critical care is actually quite short for most people. Most people who survive are discharged from critical care back to general wards in 3 days whereas most people who die do so within about 4 days. However there is likely to be a small proportion of people who need much longer care.
3. The overall death rate for COVID-19 for patients admitted to critical care is also much higher than for other viral pneumonias (47.9% v 22.2%)
4. Almost 1 quarter of cases admitted are (22.4%) are young (<50 years old)
5. The death rate increases dramatically with age (death rate in people 16 to 49 is 24.3%, for 50-69 years 40.3% and over 70 years old 73.2%)
6. The death rate higher in people who are overweight (BMI 30+ =60.9% v BMI 25-<30 41.7%)
“The value of this report is that is gives a good indication of the likely needs for critical care as the epidemic progresses. It also gives a good indication of those who are likely to do well and those who are likely to do poorly on critical care. Sadly such information may become crucial if social distancing is insufficient to reduce the size of the peak and demand for critical care beds outstrips availability over the coming months. What this report does not do is give an indication of the outcomes for people who are not considered for a critical care bed or cannot access one and we need data to be collected and reported on all patients.”
Prof Sheila Bird, formerly Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:
“The comparison with INARC’s 5,755 patients in 2017-19 with viral pneumonia is stunningly important because it shows that 70% of COVID-19 admissions were males versus 54% of INARC’s viral pneumonia admissions in 2017-19. Also statistically noteworthy is that only 3% of over 700 COVID-19 admissions were immunosuppressed compared with 9% of the viral pneumonia admissions in 2017-19.
“INARC’s weekly reporting is timely and insightful. Soon, the authors may be able to report separately on the 7-day and 14-day post-admission status for COVID-19 admissions who have reached these landmarks and to offer the corresponding results at these landmarks for their 2017-19 comparator group. Congratulations to the INARC-analysis-team and heartfelt thanks to all INARC’s healthcare teams.”
The ICNARC report on COVID-19 in critical care – 27 March 2020 was published on the ICNARC website on Friday 27th March 2020.
All our previous output on this subject can be seen at this weblink: