Diuretics and Electrolyte Disturbances in 1000 Consecutive Geriatric Admissions

Old people are commonly receiving diuretics on admission to hospital. Diuretics are recognized as a risk factor for electrolyte disturbances; controversy exists about the relative risks of different combinations (in particular, co-amilozide [Moduretic]). We recorded the drug history and serum electrolytes in 1000 consecutive admissions to a geriatric hospital, and examined the relative prescribing rates of various diuretics in the community.

Full results were obtained in 929 patients. A history of diuretic prescription was present in 353 (38%) of the patients; the mean serum sodium in this group (95% CI 136.0–137.1 mmol/1) was lower than in the 586 not prescribed diuretics (137.1–137.9 mmol/1). The difference was small but statistically significant (95% CI difference=0.3–1.6 mmol/1; P<0.01).

Hyponatraemia (serum sodium < 130 mmol/l) was not significantly commoner in the 41 patients prescribed co-amilozide than in patients prescribed other diuretics. In general patients prescribed potassium-retaining diuretics had a lower serum sodium than the others.

There was a significant positive correlation between the serum potassium and the log [serum urea) (r=0.26, P < 0.001) and a weak negative correlation existed between sodium and potassium (r= −0.14; P < 0.001). There was an association between the prescription of potassium-retaining diuretics and a higher serum potassium; also an association between the prescription of a loop or thiazide diuretic and a lower serum potassium. These interactions were shown by multiple regression analysis to be independent and additive.

Co-amilozide formed a significantly higher proportion of all diuretics prescribed in the community group than in the inpatient group (18% versus 12%; P < 0.05).

Hyponatraemia was mild and mainly associated with potassium-retaining diuretics in our patients. Our study was unable to confirm or refute any specific dangers of co-amilozide compared with other potassium-retaining diuretic combinations.

Modelling decisions of a multidisciplinary panel for admission to long-term care

This paper describes a modelling study of a multidisciplinary review panel which is responsible for matching levels of long-term care to the needs of older people. The study aims to understand the decision making process of the review panel and to predict placement decisions based on an applicant's attributes. Data were collected from cases notes presented to the London Borough of Merton review panel. A model predicting placement of an individual to residential home, nursing home or long-stay nursing care was built using logistic regression. and correctly predicts 78% of placement decisions. The model can be used as a means of checking the consistency of the review panel's placement decisions.

Modelling patient duration of stay to facilitate resource management of geriatric hospitals

A fundamental aspect of health care management is the effective allocation of resources. This is of particular importance in geriatric hospitals where elderly patients tend to have more complex needs. Hospital managers would benefit immensely if they had advance knowledge of patient duration of stay in hospital. Managers could assess the costs of patient care and make allowances for these in their budget. In this paper. we tackle this important problem via a model which predicts the duration of stay distribution of patients in hospital. The approach uses phase-type distributions conditioned on a Bayesian belief network.

Developing a Bayesian belief network for the management of geriatric hospital care

Resource management is an essential feature of hospital management. This is especially true for geriatric services, as older people often have complex medical and social needs. Hospital management should benefit from an explanatory model that provides predictions of duration of stay and destination on discharge. We describe how a Bayesian belief network models the behaviour of geriatric patients using predictive variables: personal details, admission reasons and dependency levels. This approach is illustrated using data on 4,722 patients admitted to geriatric medicine at St. George's Hospital, London; distributions of the patient outcome given typical values of the predictive variables are provided.

Modelling hospital and social care bed occupancy and use by elderly people in an English health district

The paper confirms that exponential equations can be used to model the total system and sub-systems of institutional health and social care for elderly people using bed occupancy census data for 6,068 elderly aged 65 and over. Two streams of flow were present in NHS acute hospitals, Local Authority residential homes and independent sector nursing homes. Three streams of flow were present in the overall data set and in the NHS geriatric hospital beds, NHS psychiatry beds and independent sector residential care homes. In total 22% of patients/residents stayed an average of 24 days (short stay), 69% for 825 days (medium stay) and 9% for 3,384 days (long stay). In both sexes, the older a patient/resident, the longer the time they occupied short stay beds and the shorter the time they occupied long stay beds.

The right person? the right place? the right time? a pilot study of the appropriateness of nursing home placements

The appropriate use of health services is a key challenge for the NHS. Older people have been consistently identified as being disproportionately represented amongst those defined as 'inappropriately' located within the acute health sector. Prior to the introduction of community care it was hypothesised that older people were entering nursing home care inappropriately. With the requirement for assessment prior to entry into nursing homes now a feature of the system such 'inappropriate' admissions should not occur. This pilot study investigates the feasibility of determining inappropriate admissions and the extent of this phenomenon in nursing homes used by three inner London Boroughs. To determine the number of 'inappropriate' placements in nursing homes in three London Boroughs (Lambeth, Southwark & Lewisham). Retrospective audit of nursing home case notes using standardised data collection method. New local authority funded admissions to nursing homes from LSL during the period 1 April 1993-31 March 1995. One hundred and fifty seven people entered the 25 nursing homes identified. For 65% nursing home placement was appropriate, 14% were apparently more suited to residential care and 17% for community care. Documentation concerning clients held by the nursing homes was generally poor. Despite the introduction of the Community Care Act and the clear requirement for assessment before entry into nursing home care, approximately one-third of the placements reviewed were inappropriate and did not meet the individual's care needs. Further research is underway to determine if these findings apply nationally.

Measuring and modelling surgical bed usage

Surgical departments treat two groups of inpatients--the simple and the complex--consequently a single average fails to describe the use being made of the occupied beds. Using decision support techniques, we show why indicators such as the average length, the average occupancy and the average admissions mislead. Furthermore, by analysing the fluctuating pattern of weekly admissions we show how weekends and the Christmas holiday periods impact on bed usage. Next, we demonstrate that flow process models can be used to describe how the in-patient workload concerns two groups of patients. On an average day, 71.4% of the beds contained patients who will have an average (exponential) stay of 4.8 days, and the other beds, 28.6%, contain patients who will have an average (exponential) stay of 22.8 days. The article concludes by demonstrating the short and long-term impact on daily admissions of a 10% change in four different parameters of the model. The data used come from a surgical department in Adelaide, as UK data sets report finished consultant episodes rather than completed in-patient spells.

Application and comparison of two modelling techniques for hospital bed management

The use of the bed occupancy management and planning system (BOMPS) and the Sorensen multi-phased bed model were used to assess the implications of a hospital expanding its emergency facility. BOMPS flow modelling generates resource utilisation data dependent on the best visual and statistical fit between mixed exponential equations and time of bed occupancy; the Sorensen model creates models based on probabilities and length of stay distributions. Both models identified the presence of two streams of flow. However, there were differences in the number of beds identified as being short and longer stay. The advantage of flow modelling is that it enables decision-makers to pre-test their decisions.

Ethical decisions at the end of life

A conference organised by Dr Gillian Ford, on behalf of the College Ethical and Palliative Medicine Committees, was held at the Royal College of Physicians of London on 24 March 1999. It attracted over 200 delegates, two-thirds of whom were doctors. Issues covered included hydration and dehydration in the dying patient, talking to patients and their families, the management of futility, caring for patients at home, listening to children, the limits of autonomy and a debate on the principle of 'double effect'.

Evaluating the costs of alternative options for dementia services

In the next decade the number of demented people is likely to increase. This has a financial impact on the resources allocated for health and social care. Classical methodologies for dealing with dementia include the historic model that has been criticised for its poor co-ordination between general practitioners, psychiatrists, social workers and the treatment services, and the needs-based approach that, although it involves a co-ordinating needs manager, does not prevent leapfrogging of patients. In order to overcome these problems we propose an annual screening of patients to take place in the needs-based models and compare this with a more sophisticated model in which after being screened patients are investigated for potential drug treatment. We also consider mix intervals for under 75 and over 75. Decision analysis is used to assess the different screening options. Assuming a 20% reduction by treatment of the cost of care we find optimal the investigation/treatment of all patients after screening. Sensitivity analysis shows that even an 8.5% reduction would make the needs-based models non-optimal.

A simulation modelling approach to evaluating length of stay, occupancy, emptiness and bed blocking in a hospital geriatric department

The flow of patients through geriatric hospitals has been previously described in terms of acute (short-stay), rehabilitation (medium-stay), and long-stay states where the bed occupancy at a census point is modelled by a mixed exponential model using BOMPS (Bed Occupancy Modelling and Planning System). In this a patient is initially admitted to acute care. The majority of the patients are discharged within a few days into their own homes or through death. The rest are converted into medium-stay patients where they could stay for a few months and thereafter either leave the system or move on to a long-stay compartment where they could stay until they die. The model forecasts the average length of stay as well as the average number of patients in each state. The average length of stay in the acute compartment is artificially high if some would-be long-term patients are kept waiting in the short-stay compartment until beds become available in long-stay (residential and nursing homes). In this paper we consider the problem as a queueing system to assess the effect of blockage on the flow of patients in geriatric departments. What-if analysis is used to allow a greater understanding of bed requirements and effective utilisation of resources.

An analysis of admission, discharge and bed occupancy of stroke patients aged 65 and over in English hospitals

Stroke illness is a common problem in the UK. Factors such as incidence, age, and ethnicity have already been shown to affect admission patterns and discharge outcomes. Our analysis of an English Hospital Episode Statistics database shows that weekends and public holidays also influence the admission and discharge patterns of elderly stroke patients. We discuss the possible reasons for this.

A three compartment model of the patient flows in a geriatric department: a decision support approach

As users of long term geriatric services occupy the beds for prolonged periods of time it is important that decision makers understand how clinical and social decisions interact to influence long term care costs. A flow modelling approach enables us to estimate current inpatient activity and to test different care options, thereby optimising decision making. In previous work we developed a two compartment model of patient flows within a geriatric hospital, where patients are initially admitted to an acute or rehabilitative state from which they either are discharged or die or are converted to a long-stay state. Long-stay patients are discharged or die at a slower rate. This initial research discussed the use of a compartmental model to describe flows through the hospital system. We now discuss a three compartment model where the compartments may be described as consisting of acute care, rehabilitation and long-stay care. A Markov model is then used to count and cost the movements of geriatric patients within a hospital system. Such an approach enables health service managers and clinicians to assess performance and evaluate the effect of possible changes to the system. By attaching costs to various parts of the system we may facilitate the evaluation and comparison of different strategies and scenarios. Using the model, we show that a geriatric medical service that improved the acute management of in-patients became more cost-efficient. Hospital planners may thus identify cost-effective options.

Performance comparison in geriatric medicine: a study in one department

It is now commonplace to base performance comparison on productivity measurements. Yates recommended the use of Barber-Johnson diagrams to compare activity in acute specialties, but he did not commend their use in specialties with large numbers of beds and long lengths of stay. Performance comparison in geriatric medicine is difficult because factors such as the case mix and the discharge destination influence throughput. We used two mathematical models to compare the performance of five consultants in the same department. A Monte Carlo simulation based on historic-frequency tables indicated that the mean annual admissions to forty beds by the five consultants would vary between 592 and 748 admissions per year and a two-sample t-test indicated that only two of the consultants were the same, whereas the two-compartment flow model based on the average bed occupancy predicted the annual admissions to be between 650 and 856 and it indicated that the two consultants treated longer-stay patients differently. Thus the models identified differences in consultant performance which were not shown by simple statistics. The information required to decide if the variation in consultant performance is due to clinical or other differences is not yet routinely available. However, the benefit of modelling is that it identifies areas of variation and facilitates exploratory discussion.

A decision support system for bed-occupancy management and planning hospitals

The planning of services within a hospital is a complex task which relies on the availability of accurate data. Such data on patterns of bed occupancy enable us to develop tools which assess performance measures based on activity within a hospital and its beds, and hence they improve the efficiency of bed management and they facilitate the more effective use of resources. We report the development of a bed-occupancy-modelling package that uses a mathematical model to separate the pattern of bed occupancy in hospitals into acute, rehabilitative, and long-stay components. The bed-occupancy management and planning system analyses data downloaded from the patient administrative system. A query-by-example function is then used to separate the data into meaningful subgroups, such as age groups, or the various specialties. The underlying model is a mixed exponential where the number of terms in the mixture corresponds to the number of stages in the hospital spell, typically, acute, rehabilitative, and long stay. The software has been used to analyse data from a number of different specialties and services. A 'what-if' capability [correction of capacility] allows the planner to assess the effect of changes prior to their introduction.

Conflict of interest. Openness is not the only answer

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The St. George's dementia bed investigation study: a comparison of clinical and pathological diagnosis

Sixty-four elderly patients who had been admitted to the St. George's Hospital Alzheimer's disease evaluation project during 1981-1989 were followed up to postmortem examination. Comparison between clinical diagnoses and neuropathological diagnoses indicated positive predictive values for the antemortem diagnoses of 50-67%. Existing clinical criteria may not be accurate enough to permit firm antemortem diagnosis of older people for either research or clinical purposes.

Balancing acute and long-term care: the mathematics of throughput in departments of geriatric medicine

The empirical distribution of length of stay of patients in departments of geriatric medicine is fit extremely well by a sum of two exponentials. Most of the patients in a geriatric department are rehabilitated and discharged or they die within a few weeks of admission, but the few who become long-stay patients remain for months or even years. A model is presented for the flow of patients through a geriatric department, which has analogies to models of drug flow in pharmacokinetics. The theoretical model explains why the empirical pattern of length of stay in the occupied beds fits a sum of two exponentials; conversely, the empirical distribution, obtained from the midnight bed state report, can be used to study the effect of various policy decisions on both immediate and future admission rates for the department, and shows the benefits of policies which reduce long-stay patient numbers by improving long-stay rehabilitation.

Diagnosing dementia: do we get it right?

To find out whether the diagnosis of dementia agreed with findings at necropsy a detailed assessment of 27 elderly patients (mean age 82 (range 70-94] presenting with dementia was conducted at a combined department of geriatric medicine and psychiatry for the elderly. On the basis of the results the cause of the dementia was diagnosed clinically. Neuropathological examinations were performed after death. The clinical diagnosis made during life was not supported by the findings at necropsy in 11 cases. Alzheimer's disease was overdiagnosed in life (13 cases, of which only six were confirmed at necropsy). Although the clinical investigation was limited by availability of resources, neither cranial computed tomography nor the Hachinski score helped to distinguish between multi-infarct dementia and Alzheimer's disease in this age group. This study confirms the value of neuropathological studies in the precise diagnosis of dementia.

What is ageing?

The absolute numbers and proportion of elderly people within society is increasing and will continue to increase into the next century. An understanding of normal biology, physiology and anatomy of ageing are an essential prerequisite for the treatment of pathology in the elderly. Gerontology is a young scientific discipline where important developments are being made. Progress in increasing longevity has so far been limited, but continuing improvements in the quality of life for the elderly remain an attainable goal.