Figures published by NHS Digital comparing monthly changes in patients registered with GPs show that the registered patient population fell by 50,406 between April and May last year in the first wave of the pandemic, with further dips of 10,046 between May and June and 5,779 between August and September.
The patient population registered with GPs in England rose overall in 2020 by 282,791 - but this is less than half the increase of around 700,000 seen in each of the previous two years.
The drops in patients registered with GPs seen in 2020 are the first ever recorded by NHS Digital since it began publishing the data in April 2013 - although monthly figures have only been available since April 2017, with the data previously published quarterly.
GP registered patients
The marked slow-down in growth of GP patient lists over the past year 'is likely due to an increase in deaths, a decrease in immigration, and potentially increased list cleansing activities brought about by additional activities to contact vulnerable patients', NHS Digital says.
Figures from the Office for National Statistics show that 575,407 deaths occurred in 2020 in England - 71,677 more than the five-year average. Government figures show 89,243 'deaths with COVID-19 on the death certificate' have been registered up to 1 January UK-wide, including just over 75,000 in England.
Immigration figures for the whole of 2020 are not yet available - but government data for the second quarter of 2020 show a '97% (27.7m) decrease [in passenger journeys to the UK] compared to the same quarter in the previous year, due to the travel restrictions imposed as a result of the COVID-19 pandemic'.
Meanwhile, practices have been forced to contact around 2.2m patients on shielding lists during the pandemic - a group that accounts for almost one in 10 patients across some entire CCG areas.
The latest data from NHS Digital show that on 1 January 2021 there were 60.6m patients registered with GPs - 8% more than the 56m registered in April 2013.
The number of full-time equivalent GPs, however, has fallen by around 5% since September 2015.