NHS Worcestershire's scheme, run in partnership with three CCGs, pays GPs to work with the local ambulance service in-hours, and aims to treat patients in their homes.
NHS Worcestershire medical director and Bromsgrove GP Dr Jonathan Leach, who pioneered the scheme, said that since it began about 86% of patients who called 999 in-hours had been treated at home.
According to the PCT, before the scheme was introduced, just 37% of patients across the county were treated at home after calling for an ambulance.
Hospital admissions cost about £2,000 on average, he said, and 'you only need to keep one patient out per shift' to cover the cost of GP involvement. The scheme works by pairing a GP with the local West Midlands Ambulance NHS Trust crew from lunchtime until about 8pm. At weekends two GPs work with the crew.
GPs are paid locum rates and can be called by the ambulance team to attend the patient at home or to give advice by telephone.
Dr Leach said the GPs usually attended patients with complaints such as stomach pain and non-cardiac chest pain, as well as seeing bariatric patients.
PCT data show that 188 patients were seen and treated by the GPs in the first two months after the scheme began on 5 October 2012. About 70 further patients received clinical advice from a GP by telephone.
NHS Worcestershire said GPs' fees were currently paid for with funding for 'managing winter pressures'.
Dr Leach said that the scheme would be 'at least' cost-neutral.
'If in one shift we can keep one patient out of hospital, then that shift has paid for itself,' he said. 'It is at least cost-neutral, but we actually think it's cheaper.'
Dr Leach said local GPs had been 'very happy' with the scheme.