Among health professionals, they're known as "frequent flyers" - the patients who regularly go to hospital with conditions ranging from asthma to arthritis.
Until now, the Department of Health had only a patchy picture of how many there are or how much was spent on their treatment. But today, new research shows there are nearly half a million frequent flyers, and that they cost the health service about £2.3bn a year - nearly four times the national deficit of the NHS.
While there is no suggestion the visits are unnecessary, the research could help patients avoid costly and often traumatic stays in hospital by offering them treatment at local clinics or GP surgeries.
The report, the first from research company Dr Foster Intelligence, set up by the DoH and Dr Foster, an independent provider of healthcare information, has data on some 439,000 people who were admitted to hospital as emergencies at least three times in one year - a quarter of the total annual emergency admissions to NHS hospitals. The Guardian has seen the database - which compiles a single patient record from all available hospital and GP files - on an anonymised basis.
The database documents every contact a patient had with the NHS, their treatment and the cost to the taxpayer. The government is backing the research, which ties in with ministers' ambitions for the NHS to provide more healthcare locally, set out in a white paper last month.
It also offers the potential of saving money, something local health authorities will be interested in as they battle with the £623m net deficit.
National figures show that £253m is spent on emergency treatment for people diagnosed with emphysema-type respiratory illnesses and £64m is spent on emergency asthma admissions. Some £20m is spent on emergency treatment for people suffering from anaemia - a condition caused primarily by poor diet.
The majority of these emergency admissions are made for one of 19 illnesses, conditions such as asthma, diabetes and congestive heart failure, which are believed to be manageable to the point that some emergency admissions can be avoided. These visits to hospitals alone cost the NHS £1.3bn a year, the data shows. The database includes records of a patient who was hospitalised weekly for asthma attacks because they had not been prescribed an inhaler.
The report says: "Many of these emergency admissions could be avoided and people supported to manage their condition outside of hospital through the right combination of health and social care provided at the right time. By focusing on these people, there is an opportunity for the NHS to support and improve their quality of life and to do so in a way that makes better use of scarce health resources. This is an immediate and achievable challenge with more than £2.3bn of NHS money at stake."
The researchers have compiled a graphic illustration of the links between ill health and social class: those most likely to be frequent flyers are low-income families and pensioners living in council housing in the inner city. More prosperous professionals living in the suburbs are least likely to need so many emergency admissions.
Health authorities in large northern and urban areas spend the most on repeat admissions. South Birmingham primary care trust has the highest bill: £20.75m spent on repeat emergency treatment for 9,811 patients, followed by similar amounts for Newcastle, Northumberland Care, Nottingham City, Central Liverpool and Sunderland Teaching PCTs. Southwark in London and areas of central Birmingham are in the top 20 out of the 300 PCTs.
The lowest include small rural PCTs such as Royston, Buntingford and Bishop's Stortford PCT, which spent £2.16m on 852 patients, followed by Uttlesford, Staffordshire Moorlands and North East Oxfordshire.
The research predicts that costs will soar over the next 20 years as the population ages and more people are diagnosed with chronic conditions. The number of emergency admissions to hospitals for people with the 19 conditions is predicted to surge to 900,000 by 2028 at a cost of £1.86bn.
Richard Bautrey, of the British Medical Association's GP committee, said some PCTs were already collating information for GPs on the way patients use the NHS. The research was useful but had not yet proved its worth, he said. "People's medical needs change very rapidly in the NHS and a new group of high demand users will come along the minute you redirect the existing ones. The population target changes quickly; the data has to keep up."
Denise Lievesley, chief executive of the DoE's Health and Social Care Information Centre, said: "Information is critical to making improvements to the way we deliver and manage services. People at the frontline need better information products to understand how they can make those improvements."
Emergency numbers
439,000 The number of people admitted to hospital as emergencies at least three times in one year
£2.3bn The cost of their treatment to the NHS
£623m The NHS's net deficit
5% The resources the government wants shifted from hospitals to local surgeries over the next 10 years
