A critical look at Lean Thinking in healthcare.

BACKGROUND: With healthcare, Lean Thinking encounters a world, not devoid of value, but awash with sophisticated and mutually unconnected concepts of value. DESIGN: Given a shortage of systematic analysis in the literature, this paper provides a preliminary analysis of areas where the read-across from other sectors to healthcare is relatively well understood, based on a broad review of its impact on care delivery. It further proposes areas where conceptual development is needed. In particular, healthcare, with its many measures of value, presents an unusual challenge to the central Lean driver of value to the customer. CONCLUSION: We conclude that there is scope for methodological development, perhaps by defining three themes associated with value-the operational, the clinical and the experiential.

Markov chain modelling for geriatric patient care.

OBJECTIVES: To show that Markov chain modelling can be applied to data on geriatric patients and use these models to assess the effects of covariates. METHODS: Phase-type distributions were fitted by maximum likelihood to data on times spent by the patients in hospital and in community-based care. Data on the different events that ended the patients' periods of care were used to estimate the dependence of the probabilities of these events on the phase from which the time in care ended. The age of the patients at admission to care and the year of admission were also included as covariates. RESULTS: Differential effects of these covariates were shown on the various parameters of the fitted model, and interpretations of these effects made. CONCLUSIONS: Models based on phase-type distributions were appropriate for describing times spent in care, as the ordered phases had an interpretable structure corresponding to increasing amounts of care being given.

Evaluation of inherent performance of intelligent medical decision support systems: utilising neural networks as an example.

Researchers who design intelligent systems for medical decision support, are aware of the need for response to real clinical issues, in particular the need to address the specific ethical problems that the medical domain has in using black boxes. This means such intelligent systems have to be thoroughly evaluated, for acceptability. Attempts at compliance, however, are hampered by lack of guidelines. This paper addresses the issue of inherent performance evaluation, which researchers have addressed in part, but a Medline search, using neural networks as an example of intelligent systems, indicated that only about 12.5% evaluated inherent performance adequately. This paper aims to address this issue by concentrating on the possible evaluation methodology, giving a framework and specific suggestions for each type of classification problem. This should allow the developers of intelligent systems to produce evidence of a sufficiency of output performance evaluation.

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.

Implementation of intelligent decision support systems in health care.

The full implementation of any intelligent system in health care, which is designed for decision support, has several stages, from initial problem identification through development and, finally, cost-benefit analysis. Central to this is formal objectivist evaluation with its core component of inherent performance of the outputs from these systems. A Medline survey of one type of intelligent system is presented, which demonstrates that this issue is not being addressed adequately. Lack of criteria for dealing with the outputs from these "black box" systems to prescribe adequate levels of inherent performance may be preventing their being accepted by those in the health-care domain and, thus, their being applied widely in the field.

Performance evaluation of artificial intelligence classifiers for the medical domain.

The application of artificial intelligence systems is still not widespread in the medical field, however there is an increasing necessity for these to handle the surfeit of information available. One drawback to their implementation is the lack of criteria or guidelines for the evaluation of these systems. This is the primary issue in their acceptability to clinicians, who require them for decision support and therefore need evidence that these systems meet the special safety-critical requirements of the domain. This paper shows evidence that the most prevalent form of intelligent system, neural networks, is generally not being evaluated rigorously regarding classification precision. A taxonomy of the types of evaluation tests that can be carried out, to gauge inherent performance of the outputs of intelligent systems has been assembled, and the results of this presented in a clear and concise form, which should be applicable to all intelligent classifiers for medicine.

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.

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.

Do type as eat differently? A comparison of men and women.

Type A behaviour has been associated with coronary heart disease, but little is known about how Type A behaviour relates to diet. As part of a cross-sectional epidemiological study in Northern Ireland, Type A behaviour was assessed using a validated questionnaire and diet assessed using weighed records. Diet was described in terms of nutrient intake, food intake and dietary pattern. The study population comprised 245 men and 306 women aged 16 to 64 years. The relation between Type A behaviour and diet was examined by calculating partial correlation coefficients between A-type score and dietary variables, controlling for age and household socio-economic group. In men Type A score showed a weak but significant association with fat and protein intake, and intake of beef, cheese, yoghurt and chips. In women, Type A score showed a weak positive association with sugar and alcohol intake. In both men and women, Type A score was positively associated with the "convenience" dietary pattern. These relationships are discussed in the context of the dominant food ideology and coronary risk.

Attitudinal dimensions of food choice and nutrient intake.

A diet low in fat and rich in fibre has been recommended to optimize general health and in particular cardiovascular health. Health attitudes to fat and fibre were studied in relation to food and nutrient intake and sociocultural and lifestyle factors amongst the general population of Northern Ireland. The study population comprised 592 adults aged 16-64 years; health attitudes to fat and fibre were assessed by questionnaire (based on a social psychological model, which adjusted for taste and convenience factors). Dietary intake was estimated using the weighed inventory technique. Fat-phobic and fibre-philic attitudes were more prevalent in women than men. Fat-phobic attitudes in women were inversely related to intake of fat through a reduced intake of chips, butter and sausages. In contrast, men's fat-phobic attitudes were not strongly correlated with fat intake; consumption of chips and sausages was negatively associated with fat-phobic attitudes, but cake/biscuit, buns/pastries and milk consumption was positively associated with fat-phobic attitudes. Fibre-philic attitudes were positively associated with dietary fibre intake; intakes of potatoes, vegetables, wholemeal bread and breakfast cereal were positively associated with fibre-philic attitudes. There were clear sociocultural and lifestyle differences in relation to dietary attitude. These findings have implications for campaigns designed to effect population dietary change.

Dietary behaviour and health in Northern Ireland: an exploration of biochemical and haematological associations.

STUDY OBJECTIVE: The aim was to determine the relationships between dietary behaviour and biochemical and haematological measures. DESIGN: This was a cross sectional population study. SETTING: The study took place in the general community within Northern Ireland. SUBJECTS: 522 randomly selected adults aged 18-64 years took part (65% of the eligible sample). MEASUREMENTS AND MAIN RESULTS: Four dietary behaviours were identified using principal components analysis from 7 d weighed dietary records described in terms of mean intake of 41 food groups. Haematological and biochemical analyses were carried out on non-fasting blood samples. Social, personal, and lifestyle information was ascertained through interviewer administered questionnaires. Partial correlations controlled for age and smoking behaviour were calculated. There were significant negative associations between iron status measures and the "traditional" behaviour, while the "meat and two veg" behaviour showed positive associations. There were positive associations between the "cosmopolitan" and "convenience" behaviours and folate status in women. White cell count and platelet levels in women were negatively associated with the "traditional" and "cosmopolitan" behaviours. Total cholesterol levels showed significant negative associations with the "cosmopolitan" behaviour in women and HDL cholesterol levels were positively associated with the "cosmopolitan", "convenience" and "meat and two veg" behaviours. CONCLUSIONS: Through a multivariate approach to dietary assessment it is possible to identify food combinations that cluster and interact to influence biochemical and haematological indices of health status.

Dietary behaviours and sociocultural demographics in Northern Ireland.

Subjects aged 16-64 years (592; 258 men and 334 women), randomly selected from the population of Northern Ireland, kept a 7 d weighed record of all food and drink consumed. Social, personal and anthropometric data were also collected. From the weighed records food consumption was described in terms of forty-one food groups. Using principal components analysis, four distinct dietary patterns were generated which were identified as a traditional diet, a cosmopolitan diet, a convenience diet and a 'meat and two veg' diet. These dietary patterns were then correlated with sociocultural, lifestyle and anthropometric variables. It is clear that dietary behaviour is influenced by a number of inter-related sociocultural demographics and that identifiable population groups in Northern Ireland have different dietary behaviours.