Casemix, resource use and geriatric medicine in England and Wales - Commentary

Age and Ageing,  Jan, 1995  by Gillian F. Turner,  Alistair Main,  G. Iain Carpenter

• E-mail
• Print
• Link

'The care you provide for your patients costs too much'

'Your length of stay is longer than the regional average'

'The cost per patient is greater than it was last year, and we are going to overspend'

These statements opened the editorial, Measuring Casemix, in the British Medical Journal in April 1992 [1], written by Dr Hugh Sanderson, Director of the National Casemix Office. They are sure to ring a bell in all of us. He continued: 'How can we ensure comparisons are fair? Are different kinds of patient being treated? Are the patients in our unit more likely to require expensive care because they have more complicated illnesses?'. The problem is how to determine the proportion that is due to differences in patient characteristics - the difference in the casemix. Casemix measures would fulfil two needs: enable contracts between providers and purchasers which are more sensitive than the current block or cost and volume contracts and also help to define a 'starting point' of care so that the Government's 'league tables' of outcome become more meaningful.

In the United States, since 1983 when the Medicare Prospective Payment System (PPS) for acute hospitals was introduced, there have been attempts to introduce a method of producing groupings of patients or cases linked to a payment system that would closely reflect the resources used in caring for them [1]. Diagnosis related groups (DRGs) have become the most widely used system [2].

Over the past five years, the National Casemix Office (NCMO) of the NHS Management Executive has been developing healthcare resource groups (HRGs) as a casemix system for use in the NHS [3]. Developed from DRGs, the system uses data, such as age, sex, diagnosis and procedure, information available from the computerized hospital discharge record, to allocate patients to groups that have similar lengths of stay. HRGs look set to become the standard casemix system in this country [4].

It is acknowledged that DRGs (and HRGs) work best in acute surgical specialties and less well in acute medicine, where the discharge diagnosis may bear little relationship to the reason for admission or the costs of caring for the patient. These difficulties are compounded in rehabilitation, a fact that led to the exemption of these facilities from the United States PPS. The National Association of Rehabilitation Facilities (NARF) in the States is currently developing alternative casemix measurements [5].

In continuing care the same problems have been recognized. In the USA, the late 1980s saw a search for suitable casemix measurements for this mainly nursing-home setting. A comprehensive review by Weissert and Musliner [6] demonstrated that most of these measures are based on functional independence.

The challenge for Geriatric Medicine in the UK is twofold. Firstly, although more relevant to British practice, HRGs, like DRGs, may be useful for 'acute' specialties, and patients with straightforward clinical conditions, but are virtually useless for care of elderly people as they do not take account of multiple pathology, 'frailty' and confounding circumstances. Secondly, 'geriatric' encompasses the whole spectrum of services - acute, rehabilitation and long-stay.

The ideal casemix measurement for use in Geriatrics would have the following characteristics:

Reliable and consistent groupings for the same types of patients, defined by patient characteristics (although the groups will have been developed initially according to the resources used);

Groupings explain a significant percentage ([greater than] 30%) of the variation in costs between the groups;

The number of groups is sufficient to ensure that each is unique and homogeneous, yet not so many that the system is unmanageable;

Groups must make clinical sense; it may cost as much to manage a 'death on arrival' in A&E as it does a cut finger but putting these two cases in one group would be nonsensical;

Easy to use; the information needed in order to group patients should either be collected routinely or easily accessible from the patients' records;

It should be versatile; ideally a casemix system would be used not only for resource management but also for quality assurance;

It should recognize severity of illness; functional dependence could serve as a proxy for severity of illness;

It should not be dependent on diagnosis; many of our patients have nonspecific disease (e.g. frailty) and multiple and incomplete diagnoses are common.

Patients need to be grouped according to how severely affected they are by their illness(es), which is likely to relate to their functional dependence rather than their specific diagnosis(es). Functional related groups (FRG) rather than DRGs have been proposed [5]. It is also likely that other variables such as the behaviour of the patient (more staff are required to manage a wandering patient than an immobile one) and the likelihood of return to functional independence (it takes nurses more time to help someone help themselves than to do it for them) will be important in the assignation to casemix groups.