A top NSH doctor has been checking the stats and made some interesting observations.
I spent Friday morning (when I should have been operating) running over the PHE released stats up to Oct 1st – they are obviously not up to date but there is quite a lot of info on here, though the data on the complex spreadsheet isn’t as granular as one would like, so definitive conclusions are difficult to draw.
However, there are some interesting findings.
Firstly, the number of people admitted with an already positive test is quite low as a percentage of the whole – about 20% in the last week of September.
Most ‘admissions’ are admitted without a positive test and only become ‘positive’ after two to five days when the test comes back. But about 6% to 9% test positive after eight days in hospital and these may be hospital acquired covid – Hennegan has access to more up to date figures and says in the DT today that this percentage of late positive tests is rising, possibly suggesting more hospital acquired infection.
Some of those positive swabs will be people with covid symptoms – but many are admitted with other things and the positive swab is an incidental finding as they don’t have any covid symptoms – I have heard this from anecdotal discussions, For example every patient admitted (irrespective of the reason for admission) is swabbed on admission, again at five days and weekly thereafter – any positive swab puts them into the ‘covid admission’ column regardless of reason for admission.
So the reported number of covid admissions is not the same as the number of patients with covid symptoms – in some ways it could be the same testing artefact as with the community asymptomatic tests.
The age breakdown of positive swab tests also shows a disparity in the last week of September – the positive admission swabs are skewed to a younger age group. I’m not sure what the significance of this could be as we don’t know if all these admitted patients were symptomatic for covid or not (I suspect not).
I thought the number of daily discharges of covid patients also interesting – there is quite a ‘churn’ of patients in and out of hospital with covid – again this may be asymptomatic patients or people admitted for treatment who get better quickly. Of note is that the percentage of discharges per day is higher in September (15% – 20% per day) than it was in April (8% to 10 % per day) – this might mean that a proportion of these people discharged in September were not covid symptomatic patients – i.e., admitted for routine reasons and discharged with a positive swab as an incidental finding. You can clearly see the ‘weekend effect’ in the sheet (highlighted in red) – it is more marked in September than in April as well.
The percentage of patients on ventilators is pretty constant at between 11% and 13% of the total in September (the figure for Sept 12th is clearly a counting error) – there is no age breakdown on these figs and they are a small proportion of total ventilator available beds. I’m also told that this time round there will be more scrutiny on decision making so that a greater number of patients who have minimal chance of survival will be ventilated (whereas last time round there was a cap on the ceiling of care for people with minimal chance of survival). The percentage of people in ventilated beds in April was a bit higher at about 15-16%. Also note that just because a patient is in a ventilator capable bed, it does NOT necessarily mean that the patient IS ventilated – they could quite easily be on a face mask – its one way of massaging the data… I do know that the ‘planners’ are assuming that we will not be short of ventilators this time and that more patients can be managed by CPAP – this is important as the main issue last time was managing a lot of intubated patients and the lack of ITU nurses – much easier to manage if they aren’t tubed. This has major implications as last time the critical skills shortage in London was ICU nurses. I wrote a paper about it in May suggesting that over the summer we needed to rapidly upskill the junior ICU nursing cohort – predictably, nothing has been done.