New analysis combines data from NHS Dumfries and Galloway gathered in the first week of January with previously published figures from NHS Greater Glasgow and Clyde and NHS Grampian around the same time.
Of the 396 patients admitted with a recent diagnosis of Covid-19, 175 (44 per cent) are estimated to have been hospitalised “because of” the virus.
This is lower than the 60 per cent reported early this month, but uses a different data definition.
The proportion of people admitted “because of” as opposed to “with” the virus is similar in patients with the Omicron and Delta variants, PHS said.
In its analysis PHS defines patients hospitalised “with Covid” as those who tested positive either in the 14 days before admission or the first 48 hours of their hospital stay, excluding those who tested positive later in hospital where the cause is likely to be hospital transmission, and those where the date of the test was unknown.
Using this definition, the report shows 63 per cent of Covid patients were admitted because of the virus.
The headline figures reported each day by PHS and the Scottish Government of people in hospital "with Covid” include those who test positive in the first 28 days of their hospital stay. Using this definition, the report found 44 per cent of studied cases were admitted “because of” Covid.
Of the 396 admissions with a recent Covid diagnosis across the three health boards, 66 were definite or probable cases of hospital transmission, while in 51 cases the date of testing positive was unknown.
The proportion of those in hospital “because of” Covid was higher in Grampian than the other two health boards, PHS said.
Those in older age groups were also more likely to be hospitalised because of the virus, with over-80s more than twice as likely to be in hospital because of Covid than with it.
National clinical director Professor Jason Leitch warned Holyrood’s Covid-19 recovery committee last week against placing too much emphasis on the distinction between hospitalisations “with” and “because of” Covid.
"Healthcare is not a single disease,” he said. “The people in hospital with Covid who are in trouble don't just have Covid. They have diabetes, they have leukaemia, they’re 87. There are all kinds of things going on.
“The death certificates often have five reasons for death, not one, and principal diagnosis versus secondary diagnosis is a matter of judgement at the time of death by the junior doctor who perhaps is filling in the death certificate.”
Prof Leitch added: “There are very few people in who are having their leg fixed because they fell over on the ice who get a positive Covid test.
“There will be some, of course, but the vast majority getting care in our hospitals with a Covid test are getting it because they've got Covid, and they've got other things going on as well.”
It comes as PHS reported that 1,571 people were in hospital with recently-confirmed Covid on Tuesday, while 44 were in intensive care.