Carl Heneghan & Tom Jefferson

Following the evidence for hospital admissions

Following the evidence for hospital admissions
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The recent warnings of exponential growth of Covid-19 cases, inevitably followed by a rise in hospital admissions, is one focus of the Government's Covid messaging. Jeremy Hunt described this spike in admissions as a 'wake-up call' for the Government. But while this year the disease is newly identified, warnings of a winter crisis in the NHS occur annually. So should we be worried?

For 20 years, 'influenza' has been blamed for putting hospitals under pressure in winter. Now, this fear has been substituted by 'Covid'. Yet both are one-track, one-pathogen scenarios, which ignores the reality that there are scores of different pathogens that cause respiratory infections across a community at different times of the year. As a consequence, cases of respiratory disease fluctuate throughout the year and so do related hospital admissions and, unfortunately, deaths. This is what gives rise to the seasonal effect where more people die in the winter compared to the summer.

However, causes of admission to hospital for acute respiratory infections are as varied as the pathogens causing them. Few have specific drugs to negate their impact, so we rely on general care and support measures and if there is superimposed bacterial infection, antibiotics. In severe cases of Covid-19, dexamethasone can be used to good effect in those on intensive care.

The question though is this: should we rely on dire warnings that we are heading in the 'wrong direction', or do we need to rely on modelling and other forms of predictions to fathom what lays ahead? Or is there an alternative way to look at the data in a context that can help the Government interpret what might happen next? Everyone in the northern hemisphere knows that with the onset of autumn acute respiratory infections go up and so do unplanned hospitalisations.

In 2017, in an answer to a Parliamentary Question, Philip Dunne MP, the then-minister of state at the Department of Health, provided the number of unplanned accident and emergency attendances resulting in an admission and a primary (main) diagnosis of respiratory condition between 2010-11 and 2016-17 (the downloadable file, helpfully, shows the data for admissions in England by month, age category and by year).

The data show that the worst month was December in six out of the seven years when approximately 1,000 respiratory admissions per day occur in the NHS in England. A rise that starts in September and peaks in December-January and then tails off as we go into Spring, reaching the bottom in Summer. In a good year, we see admissions go below the 15,000 mark.

The seasonal effect should be the barometer for planning and future actions. The figures are based on Government data. We can use them as a benchmark for the severity of what is going on by month and what might be around the corner.

The month of September sees around 21,000 cases of unforeseen attendances and admissions, which works out at around 700 unplanned admissions per day. However, by the end of September 2020, around 300 patients with covid were admitted in England per day. This is less than half of what we would normally expect. The difference is marked, especially with the complete absence of alarm in September 2015 which 'topped the September charts' with over 21,000 admissions.

And what about Covid? There is a golden opportunity for the government to prospectively test all those who are admitted, not just for Covid, but for the other common pathogens. It is possible that searching only for one pathogen may miss the others. We know for instance that some 17 per cent of respiratory infections are caused by more than one pathogen. Testing for more than just Covid would help us to find out what is making people sick, and put the Covid admissions data into context.

The biggest impact on admissions takes place at the beginning and ends of our lives. Significant increases over the year are seen in those under the age of one, and those over 85 years. Over 16,000 babies (under the age of one) get admitted for respiratory conditions every year; there’s a near six-fold increase from August to December.

The seasonal effect also has a big impact on deaths. In the 2017 to 2018 winter period, there were 50,100 excess winter deaths in England and Wales. Over 85-year-olds can account for over 5,000 admissions in December and the observed variations in deaths each year are largely driven by this age group.

The current Covid projections need to be placed into context of the impact of the seasonal effect of the other respiratory pathogens. If we don’t, then we may jump to inappropriate conclusions.

Written byCarl Heneghan & Tom Jefferson

Carl Heneghan is professor of evidence-based medicine at the University of Oxford and director of the Centre for Evidence-Based Medicine Tom Jefferson is a senior associate tutor and honorary research fellow at the Centre for Evidence-Based Medicine, University of Oxford

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