West London's Lillie Road Health Centre - the practice patients must join to access the GP at Hand service - saw its total list more than double from 4,970 on 1 November 2017 to 11,867 just a month later, statistics from NHS Digital reveal.
Of the 6,897 new patients that joined the service, 89.6% were aged between 20 and 45 years old, analysis by GPonline reveals.
The number of patients in this age range at the practice almost tripled in the one-month period after the service launched in early November - rising 178% from 3,475 to 9,652, the data reveal.
A spokesman for Babylon Health, the company that supplies the technology behind the GP at Hand service, told GPonline that registrations from patients keen to make use of the video GP service were responsible for the sharp increase in the Lillie Road practice's list size.
The high proportion of younger patients signing up for the service appears to confirm GPs' fears that it would 'cherry pick' younger patients. Although NHS rules bar traditional GP practices from refusing to register patients based on factors including their age, disabilities or medical conditions, the GP at Hand service reserves the right to reject patients such as women who are or may be pregnant, people with complex physical, psychological and social needs, or older people with 'conditions related to frailty'.
The Babylon Health spokesman said: 'We've had people from across the ages sign up, from children, to people over 80, to people with complex health needs, as well as people in good health.' He added that the service had a 95% approval rating from patients.
Age range of patients
Analysis by GPonline found that numbers of patients aged over 80 years old were static in the one-month period - with one patient less listed in the 80-84 age group, and one extra in the 85-89 group - suggesting the extra over-85 may have been simply a patient moving beyond his or her 85th birthday, rather than a new registrant.
Five new patients joined in the 75-79 age group, but the vast majority of new patients came among younger age groups. The number of patients registered in every five-year age group from 15-19 years old to 45-49 at least doubled.
The number of patients aged 20-29 more than tripled from 1,599 on 1 November to 4,967 on 1 December, the data reveal - increasing from 27% of the practice population to 42%.
GPC chair Dr Richard Vautrey told GPonline: 'This does clearly show that this service is cherry picking young healthy patients with the risk that this could destabilise other practices and indeed the CCG itself as the population they cover and are responsible for could change dramatically.'
When the service launched last month, Dr Vautrey warned that it 'risks undermining the quality and continuity of care and further fragmenting the service provided to the public'.
He said: 'It is also delivered by a private company that is primarily cherry picking younger, generally healthier people and excluding many others. It will do nothing to help the growing number of older, vulnerable patients who need well funded services that can provide the specialist care they need in the community.'