Analysis: Hospital discharges may have increased risk of care home outbreaks by up to 50%

There is “no statistical evidence” that hospital discharges in the months March to May were associated with Covid-19 outbreaks in care homes, a report from Public Health Scotland has found.

113 patients were discharged from hospitals to care homes in March to May after having had a positive Covid-19 test.

The report, released on Wednesday, revealed that in that period March 1 to May 31, 113 patients were discharged from hospitals to care homes after having had a positive Covid-19 test but no subsequent negative test.

Of those, 52 were moved within a week of the positive test.

The data also shows there were 3,599 discharges from hospital to a care home between 1 March and 21 April, when guidance around testing changed, of which 82 per cent were not tested.

In her daily briefing on Wednesday, Nicola Sturgeon drew attention to the conclusion that the report “does not find statistical evidence that hospital discharges were associated with care home outbreaks.”

However, the report goes on to add that researchers “cannot statistically exclude” a connection between the two.

What this means is that while the numbers do not show an incontrovertible link between hospital discharges and Covid-19 outbreaks in care homes, it also does not rule it out.

In fact, those behind the report, which was drawn up in collaboration with Edinburgh and Glasgow universities, said it was likely that hospital discharges did increase the risk of care home outbreaks in a small number of cases.

It is certain that care homes which took in patients discharged from hospital were far more likely to suffer outbreaks of Covid-19 – almost three times as likely.

But conclusions are muddied by the presence of other factors: patients were more likely to be discharged to larger care homes, with more than 90 beds, and those large care homes were more likely to see virus outbreaks because of their size, as more residents means more comings and goings and opportunity for the virus to enter the home.

These larger care homes also tend to house older people, and to offer nursing care which involves more close contact and opportunities for the virus to spread.

One of the most important figures in the report is that of the increased likelihood of a virus outbreak in care homes with hospital discharges, after adjusting for these other factors such as size and residents ages.

That figure is 1.21, meaning that homes where hospital patients were discharged were 21 per cent more likely to see a virus outbreak.

However, because the data sets are so small, researchers cannot be sure of this, and that figure could be anywhere between 0.94 and 1.54.

This means that discharges could have increased the risk of outbreaks by half, or they could have had almost no effect. This is the grey area the researchers have been hemmed into – they are statisticians, and must report what the numbers tell us. And in this case the numbers are not quite certain.

What is certain is that 113 people were discharged from hospital and taken to care homes after testing positive for Covid-19, and 3,061 people were moved without any test at all.

With 1,915 Covid-related care home deaths in this three month period, the statistical ambiguities may not be enough to comfort grieving families around the country wondering what could have been done differently.

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