The NHS 111 helpline in Derbyshire is referring an increasing number of people to emergency services or calling an ambulance, prompting concerns about extra strain on A&E departments.
The latest figures released by NHS England show that Derbyshire sent 4,669 people to A&E in June 2018, 20 per cent of all callers.
This is up from 16 per cent in June 2014, when 3,061 patients were referred to casualty.
That was the first year of full service for 111.
NHS 111 is a 24-hour helpline for patients who need medical help but do not need to call 999, taking over from NHS Direct and GP out-of-hours services in 2014.
The service has become increasingly popular. Derbyshire handled 23,515 calls in June 2018, up from 19,658 four years earlier.
It referred 58 per cent of these to primary care, such as GP surgeries, pharmacies and dentists.
About four per cent of them were advised to rest at home.
The service is commissioned by local clinical commissioning groups, which make spending decisions for local health services.
The helplines are run by ambulance trusts, GP surgeries and private healthcare companies.
Nationally, there is significant variation in the number of A&E referrals by each service. Devon NHS 111 sent 28 per cent of all callers to A&E in June 2018, while Hertfordshire sent just 13 per cent.
NHS 111 replaced NHS Direct, which employed nurses and other clinical staff, in 2014.
Now, most calls are dealt with by staff with no clinical background working to a set script, although around a fifth are referred to nurses or paramedics.
Adam Steventon, director of data analytics at the Health Foundation, said: “There is broad recognition that a large number of people calling NHS 111 are being directed to A&E and NHS England have stepped up the amount of clinical input available to those seeking help through this route to try and tackle this.
“In looking at the impact of making more clinicians available in NHS 111 call centres, we found that children and young people who were reviewed by a GP were less likely to go on to A&E than other patients.
“However, the lower levels of attendances were focussed on minor treatment units, with little evidence that review by a GP reduced attendances at major A&E departments, which is where most of the pressure is.”
The Nuffield Trust, an independent health think tank, last year released an analysis warning about the increasing proportion of people being sent to A&E.
The report said: “The decision to scrap NHS Direct and replace it with the NHS 111 was strongly criticised by health professionals, and today we have learned that NHS 111 is sending more callers, and a higher proportion, to A&E than in previous years, with great variations in performance across different regions.”