The report, by the Intensive Care National Audit and Research Centre (ICNARC) shows that out of 165 admissions to critical care units, 79 patients have died and 86 were discharged.
A further 609 patients were last reported as still being in intensive care.
The study includes data on all confirmed cases of Covid-19 reported to the centre up to midnight on March 26 from 285 critical care units in England, Wales and Northern Ireland taking part in an ICNARC programme.
It says the early data submitted shows that: "Of the 775 patients, 79 patients have died, 86 patients were discharged alive from critical care and 609 patients were last reported as still being in critical care."
No detail of the other case was given.
The study shows that 70.5% of those admitted to critical care with Covid-19 were men, and 29.5% were women.
The average (mean) age of those admitted was 60.2 years.
The data also shows that the mortality rate is currently higher for men than women, and increases with age.Of the 79 who have died, 21 were women and 58 were men.
An age breakdown of this group shows that nine were aged between 16-49, 29 were aged 50-69 and 41 were 70 or older.
Critical care units involved in the initiative are asked to notify ICNARC as soon as they have an admission with Covid-19 and provide data at different points of their treatment.