Accident and emergency departments are under increasing pressure, which is leading to high numbers of patients being admitted, according to a new report from the National Audit Office.

The study found many emergency admissions through A&E are avoidable and many patients stay in hospital “longer than is necessary”.

There has been a 47 per cent increase in emergency admissions over the past 15 years and this increase has primarily come from short hospital stays which have increased by 124 per cent. In comparison long stays have increased by just 14 per cent.

Only a quarter of the rise was due to an increase in the number of people attending A&E, with the rest due to a higher admission rate.

The report said: “A&E departments are facing increasing pressure and trusts told us that at times of increased pressure there is a greater tendency to admit patients.

“The increase in emergency admissions over the last 15 years has come almost entirely from patients being admitted from major A&E departments who have a short hospital stay once admitted.”

Factors putting pressure on A&E include patients finding the range of NHS services “confusing”, poor access to out-of-hours GP care in some areas and the four-hour A&E waiting time target, which means patients cannot be kept in A&E for observation.

The introduction of the 111 non-emergency telephone number for the NHS also had a negative impact on A&E.

The report said: “The number of emergency admissions to hospitals - admissions that are not planned and happen at short notice because of perceived clinical need - continues to rise at a time when NHS budgets are under significant pressure.

“In 2012-13, there were 5.3 million emergency admissions to hospitals, representing around 67 per cent of hospital bed days in England, and costing approximately £12.5bn.”

More patients attending major A&E departments are now being admitted than in the past, it said.

In 2012-13, more than a quarter of all patients attending major A&E departments were admitted to hospital, up from 19 per cent in 2003-04.

The study pointed to problems with people getting help in the community, from GP practices and other services.

“When the health and social services are not working effectively, the pressure is usually felt within A&E departments.

“For example, if patients are not accessing appropriate primary care, community care or social services, they may turn up at A&E departments, placing additional pressure on A&E services.”

It said a “confusing myriad of services” on offer to patients was making the problem worse.

“A wide range of services are now available between the GP surgery and the A&E department, including walk-in centres, urgent care centres, polyclinics, equitable access centres and GP-led health centres.

“These all offer a slightly different range of services at varying times. Faced with such a confusing myriad of services, many commentators have

The introduction of NHS 111 earlier this year - which was plagued by problems - was also “cited by a number of trusts we visited as causing an increase in A&E attendances”, the report said.

The report found that 0.8million patients were admitted to hospital by GPs in 2012/13 – down by 34 per cent since 1997/98, but there were 5 million ambulance journeys to A&E, up by 18 per cent since 2007/08.

Other factors include an increasingly frail elderly population, who are far more likely to need emergency care.

The A&E waiting time target, which says patients must be seen or discharged within four hours, “is likely to be one of the main reasons for the increase in short-stay emergency admissions”.

The report estimated that at least one-fifth of admissions could be managed effectively in the community and criticised a “lack of alignment between hospital services and other health services”, with poor seven-day care on offer outside of hospitals.

Meanwhile, inside hospitals, it said the Department of Health and NHS England should also “address barriers to seven-day working in hospitals, such as the consultants’ contract, which gives consultants the right to refuse to work outside 7am to 7pm, Monday to Friday”.

When it comes to funding commissioners have been slow to provide funding to trusts to tackle winter pressures, which has increased spending on agency staff to fill the gap, according to the report. It states: “Trusts receive additional funding from the Department [of Health], normally in December, to support the additional workload they face in winter. This short notice meant that trusts could not plan ahead and may have had to use more expensive temporary or agency staff to meet demand.”

Amyas Morse, head of the NAO, said: “Many emergency admissions to hospital are avoidable and many patients stay in hospital longer than is necessary. This places additional financial pressure on the NHS as the costs of hospitalisation are high.

“Growth in emergency admissions is a sign that the rest of the health system may not be working properly.

“Making sure patients are treated in the most appropriate setting and in a timely manner is essential to taking the pressure off emergency hospital admissions.”

Keith Willett, director for acute episodes of care for NHS England, said: “We are determined to provide the best possible care for every patient but the increase in emergency admissions is a growing concern, and must be a concern for the whole health and care system, not just for hospitals.”

He added: “As the report recommends, we must collectively take substantial steps to ensure patients receive the best possible care, preferably out of hospital but also, when necessary, in hospital.

“To achieve that, it is clear the way we provide health and social care must change so our hospitals, GP and community services have the space to do that.”

Dr Mark Porter, chairman of the British Medical Association council, said: “Too often, the NHS is put under unnecessary political pressure, including politically driven targets, which does nothing to enhance the treatment of patients.

“We must develop an environment where doctors and other healthcare professionals are trusted to use their clinical expertise and judgement to treat the individual patient in front of them.

“It is also vital that we invest in systems and measures which help to direct patients to the NHS service or setting that is right for them. This can include facilities for short, intensive diagnosis in the community or elsewhere that can, if done properly, avoid unnecessary admissions.”

Health secretary Jeremy Hunt said: “We know demand for A&E services is increasing as the population ages, with more people needing more healthcare.

“That’s why we are tackling both the short and long-term problems: transforming out of hospital care by reversing the disastrous changes to the 2004 GP contract, joining up the health and social care system, and backing A&Es with £250 million to prepare for this winter.

“Winter is always tough, but the NHS has never been more prepared, and in the face of unprecedented demand A&E performance has never been stronger.”