NICOLA Sturgeon has confirmed that hospital admissions data in Scotland is being investigated amid claims that the number of Covid patients may have been overcounted.

The First Minister said she expected to be able to provide an update on the figures next week.

It comes after the Herald reported that Professor Carl Heneghan, the director of the Centre for Evidence-based Medicine at Oxford University, believed there was a a "potential substantial" issue with current data.

Prof Heneghan noted that based on figures as of August 28, there were 255 patients in hospital in Scotland who had tested positive for Covid, compared to 430 in England.

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He added that calculating the difference based on population meant that the patient rate in Scotland would be nearly nine times higher - 46.8 per million compared to 7.7 per million in England.

Prof Heneghan said the reason for the disparity was "not clear", but suggested that the number could have been inflated if Scotland was counting people in hospital as having Covid if they had tested positive at any time, as opposed to in the past 14 days.

He wrote: "This is similar to the problem with the [Public Health England] issue with deaths in England, which meant previously that everyone who has ever had Covid at any time must die with Covid too."

A previous blog by Prof Heneghan triggered a review of how PHE was recording Covid deaths after it emerged that England was the only part of the UK not to apply a 28 day cut-off.

As a result, someone who had tested positive for Covid three months previously and recovered could still be counted as a Covid death, even if they were hit by a bus.

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Referring to the Herald report during today's Covid briefing, Ms Sturgeon said the possibility that Scotland was overstating the number of people being treated for Covid in hospital was "something we have been investigating for a few weeks".

She said: "NHS boards have conducted an audit of the figures.

"This audit is trying to identify which patients have tested positive within the last 14 or 28 days, how many of them are still being treated for Covid-related illnesses, and how many - although they might have tested positive for Covid some time ago - are now actually being treated for other conditions.

"I hope to be able to give an update on that next week once we've got the full outcome of that, and therefore at that point I will be able to set out any changes in how we report hospital cases."

The hospital data also shows that while the number of people in hospital with Covid fell by 42% in England during August, it flatlined in Scotland - going from 260 on August 1 to 264 by September 1. 

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However, separate statistics from Public Health Scotland show that there were only 40 new admissions for Covid in the month to August 26.  

Professor Rowland Kao, an expert in epidemiology and data science at Edinburgh University, has examined additional data on the "primary condition" behind hospital admissions. 

This shows that by the end of May, 90% of Covid admissions were people for whom the virus was the main reason for admission to hospital.

By mid-July, this had fallen to 70%, however - meaning that nearly a third of 'Covid admissions' were people who had tested positive but were in hospital for other reasons. Up to six secondary conditions can be recorded. 

Prof Rowland said: "The proportion of people where the main reason they are in hospital is Covid-19 declines very steadily from 90% down to 70% between May and July.

"What we don't know [about this dataset] is whether secondary diagnoses can be added afterwards.

"Are their Covid diagnoses all on admission, or are some of them catching mild cases while they are in hospital which would tend to up the numbers?"

The next dataset on primary conditions, for August, will not become available until the end of September. 

However, Prof Kao added that overcounting the number of patients in hospital did not necessarily matter in terms of public safety. 

"We need to be aware of these things, but it's not necessarily cause for alarm," he said.