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Biomedical subjects

M J Buxton

Publications and source records attributed to M J Buxton.

15 recordsLinked to original sources

Screening for diabetic retinopathy: a relative cost-effectiveness analysis of alternative modalities and strategies.

Diabetic retinopathy is the most common cause of blindness among adults of working age in the UK. If the disease is detected early effective treatment can be provided and this has resulted in calls for a systematic national screening programme. Using data on the screening of 3423 diabetics collected as part of an experimental programme in three UK centres, the relative cost-effectiveness of various screening options is assessed. The paper utilises direct evidence on a number of single modality screening options, including ophthalmoscopy undertaken by general practitioners or ophthalmic opticians, and non-mydriatic photography. With the objective of increasing the sensitivity of screening and using data collected in the study, options based on two further potential screening strategies are modelled and evaluated: combined screening using both ophthalmoscopy and non-mydriatic photography; and selective screening where high-risk diabetics are directly referred to an ophthalmologist and low-risk cases are either left unscreened or are screened by one of the single or combined modality screening options. Given the objective of early detection, effectiveness is assessed in terms of the sensitivity and specificity of the referral decisions of screening options. Both health service and private resource costs of the various screening options are estimated, the latter in terms of travel and the opportunity cost of time. Cost effectiveness is evaluated in terms of the expected cost per true positive case of diabetic retinopathy referred by the screening options. To narrow the choice between the options, those subject to three-way domination with respect to the three choice variables of sensitivity, specificity and expected cost per true positive are excluded. Amongst the remaining options, the choice is dependent on the trade-off between the higher specifics of unselective single modality screening options and the higher sensitivities and lower expected costs per true positive case detected of combined modality and selective screening options.

Adult

Cost effectiveness of the implantable cardioverter defibrillator: a preliminary analysis.

BACKGROUND: An implantable cardioverter defibrillator (ICD) may be effective in reducing the risk of sudden cardiac death. The high cost of ICD treatment, however, compared with alternatives raises the question of whether this new technology is an efficient use of scarce health care resources. OBJECTIVE: To estimate the incremental cost effectiveness of the implantable cardioverter defibrillator compared with drug treatment with amiodarone in the management of patients at high risk of sudden cardiac death. DESIGN: A cost effectiveness model was constructed from data already published and other secondary sources. Differences in patient survival were calculated from life tables for comparable ICD and amiodarone patient series. Costs were based on typical patient management protocols derived from current United Kingdom practice and interviews with physicians. MAIN OUTCOME MEASURES: Cost effectiveness of ICD treatment was computed over 20 years; all future costs and effects were discounted at 6% per year. RESULTS: Estimated life expectancy was 11.1 and 6.7 years with ICD and amiodarone respectively; the discounted 20 year difference lies in the range 1.7 to 3.7 years. Discounted 20 year treatment costs were 28,400 pounds for the ICD and 2300 pounds for amiodarone. Cost effectiveness of ICD treatment lies in the range of 15,400 pounds to 8200 pounds per life-year gained. CONCLUSIONS: Cost effectiveness of ICD treatment is similar to some existing cardiac programmes funded under the NHS but uncertainty exists due to limitations of the data. Costs of ICD treatment may fall in the future as the life of the device increases and less invasive implantation methods are needed. The effectivess of ICD compared with amiodarone is currently being studied by a randomised controlled trial.

Amiodarone

Economic evaluation of ondansetron: preliminary analysis using clinical trial data prior to price setting.

This study combines secondary analysis of efficacy and side-effect data from a randomised controlled trial with estimates of resource use to evaluate the likely economic effects of the new antiemetic agent ondansetron. Costs, effects and cost-effectiveness of ondansetron in the prophylaxis of acute nausea and vomiting induced by chemotherapy are assessed relative to antiemetic therapy with metoclopramide. Superior efficacy of ondansetron is quantified both in terms of significant emesis avoided and emesis management costs avoided. A simple cost analysis, with the metoclopramide dosage priced at 10 pounds, indicates that therapy with ondansetron would give equivalent net treatment costs, at a price ratio (ondansetron/metoclopramide) of 2.3 to 1. If therapeutic success is defined as the avoidance of emesis and antiemetic side-effects, then the two therapies would be equally cost-effective at a drug price ratio of 5 to 1. We conclude that, (i) economic evaluation prior to price setting is feasible and informative; (ii) such models can indicate prospective data collection priorities.

Adult

Cost implications of alternative treatments for AIDS patients with cryptococcal meningitis. Comparison of fluconazole and amphotericin B-based therapies.

The extra demands placed upon health care resources by management of AIDS patients have increased the focus on cost implications of therapeutic alternatives. Cryptococcal meningitis is a common life-threatening infection in AIDS patients, usually treated with amphotericin B, often in combination with flucytosine. Administered intravenously, this therapy is associated with frequent and often severe side effects. Fluconazole is a new alternative which can be given orally once daily and has fewer such side effects. The purpose of this study was to examine the cost implications of these different therapies for both primary and maintenance treatment of cryptococcal meningitis. Comparison of these two therapies in recent clinical trials has indicated that fluconazole is at least as effective as amphotericin B, and therefore cost-minimisation analysis is an appropriate method to study the economic consequences of the alternative treatments. Patient management and resource-use information for both treatments was obtained using a modified Delphi technique with a panel of European physicians experienced in the treatment of this disease, and three models were developed to reflect the variability of practice evident among the panel members. U.K. health care costs were used to value these resources. The results indicated that, despite the higher cost of the drug itself, the costs associated with fluconazole were likely to be markedly less than those for amphotericin B for primary treatment, and similar or slightly cheaper for maintenance treatment. Over 1 year of treatment, the saving from the use of fluconazole would be in the range of 4000-14,000 pounds.

Acquired Immunodeficiency Syndrome

Economic evaluation studies in respiratory medicine.

The need for efficient use of resources in the provision of health care is now an accepted reality. Despite its economic significance, respiratory disease has been the subject of very few examples of the application of techniques of economic evaluation. There are a number of examples of cost-minimization studies, and these serve to emphasize that choices based on drug acquisition costs may be quite different from those based on the total costs of care. The difficulty of defining uni-dimensional measures of health outcome for respiratory disease has hampered the development of cost-effectiveness studies, and the future of these must lie with the efforts to develop measures of quality of life more appropriate to this area of medicine. But the multi-dimensional nature of relevant health outcomes suggests that cost-utility approaches are likely to play an important future role, as off attempts to directly establish patients' monetary valuations of the health benefits offered by new respiratory medicines.

Cost-Benefit Analysis

Screening for treatable diabetic retinopathy: a comparison of different methods.

The results of the screening of 3318 diabetic patients for sight-threatening diabetic retinopathy in three UK centres are reported. The aims of the study were to determine the extent of diabetic retinopathy in the screened population and to assess the relative effectiveness of different screening methods in appropriately referring cases from a diabetic population, in a context very close to a routine clinical service. Patients were assessed by ophthalmoscopic examination by an ophthalmological clinical assistant. The clinical assistants' referral grades formed the reference standard against which to assess the effectiveness of other screening methods including ophthalmoscopy by primary screeners who were general practitioners (GPs), ophthalmic opticians and hospital physicians, and the assessment by consultant ophthalmologists of non-mydriatic Polaroid fundus photography. The performance of primary screeners based on ophthalmoscopy ranged from a sensitivity of 0.41, with a specificity of 0.89, for one of the GP groups, to a sensitivity of 0.67, with a specificity of 0.96, for the hospital physician group. The performance of the non-mydriatic camera ranged from a sensitivity of 0.35, with a specificity of 0.95, to a sensitivity of 0.67, with a specificity of 0.98.

Aged

An economic evaluation of transdermal glyceryl trinitrate in the prevention of intravenous infusion failure.

A common cause of peripheral intravenous infusion failure is due to the patient developing phlebitis or extravasation. Recent clinical trials indicate that the use of transdermal glyceryl trinitrate (GTN patches) can reduce the incidence of infusion failure and hence the costs of re-infusion. In this study we conduct an economic evaluation of this new pharmaceutical application to determine whether the use of such patches results in hospital resource cost savings. Time-to-first infusion failure probabilities from a placebo-controlled trial are used to model the sequential failure problem as a Markov process. Using estimated staff and materials costs for first and subsequent infusions, we calculate the expected cost per infused patient to time t for treatment and control groups. Using this simple comparative cost method, results indicate that the net impact on hospital resources from patch usage is dependent upon the total required length of infusion time. Analysis of infusion time thresholds indicates that for patients requiring long-term (t greater than 50 hours) periods of infusion the use of patches is likely to generate resource savings. We conclude that to realize such resource savings clinical decisions to infuse with GTN patches should incorporate the prior probability that the total required length of infusion time exceeds 50 hours.

Administration, Cutaneous

Population characteristics and the distribution of general medical practitioners.

By applying the logic of the Resource Allocation Working Party to the analysis of the distribution of general medical practitioners, the relevant Family Practitioner Committee (FPC) populations were weighted according to known patterns of use related to specific characteristics--namely, age, sex, marital state, and socioeconomic group. Comparative weightings were also calculated using standardised mortality ratios. Adjusting the populations to take account of differential use has relatively little impact on national variations in list sizes but an appreciable effect on particular FPCs, notably East and West Sussex, Dorset, and the Isle of Wight. Inequalities in the distribution of general practitioners are increased considerably, however, if figures taking account of the inflation of list sizes and cross-boundary flows are used. To formulate and monitor policy about the distribution of general practitioners more sensitive measures of population and its likely demand for services must be developed.

Adolescent

Variations in GP night visiting rates: medical organisation and consumer demand.

Specially obtained data for night visiting fees show a considerable increase in the number of claims made per general practitioner and per 1000 patients. There were also considerable variations between the 116 executive councils: in 1973-4 the range was from 3-8 to 17-0 per 1000 patients. To explain these variations, their relations with the local characteristics of family practice and of the population was explored using regression analysis. The factors most strongly associated with variations in implied visiting rates were found to be deputising services and the proportion of social class V in the population.

Adolescent

Cost-benefit analysis of long-term haemodialysis for chronic renal failure.

A cost-benefit analysis of long-term maintenance haemodialysis indicates that there is a large gulf between the cost of the service and "economic" benefit. The difference may be considered to represent one estimate of the price society is prepared to pay to maintain life. Using "best estimates" from available data we found the implicit social value of maintaining a patient on haemodialysis to be approximately pounds 4720 per annum in hospital or pounds 2600 at home. The analysis would suggest that society must look carefully at alternative uses for health expenditure before extending indiscriminately to large sections of the population these treatment programmes or other similarly expensive.

Costs and Cost Analysis

Distribution of hospital provision: policy themes and resource variations.

There has been much discussion in the past about the inequitable distribution of N.H.S. resources between different regions. This paper examines the distribution of hospital resources in terms of current revenue and beds in different specialties in eight regions (49 area health authorities). Variations between A.H.A.s are far more important than those between regions, and indeed they are so large (even in the acute specialties) that it is doubtful whether some A.H.A.s can be considered to be offering a comprehensive service. In the light of these findings the paper explores policy problems involved in trying to secure a more equitable distribution of N.H.S. resources at a time of financial stringency.

Beds

A relative cost-effectiveness analysis of different methods of screening for diabetic retinopathy.

The relative cost and cost-effectiveness of different methods of screening diabetic patients for sight-threatening retinopathy are assessed. The resource costs per screening visit, both to the health service and to patients, of ophthalmoscopic examination by primary screeners including general practitioners, hospital physicians, and ophthalmic opticians are estimated together with those of a similar screening test by ophthalmological clinical assistants. The total resource cost per screen of screening using non-mydriatic photography is also estimated. Using estimates of sensitivity, specificity, and prevalence generated in the screening of 3318 diabetic patients in three UK centres, the relative cost-effectiveness of screening methods is estimated in terms of their cost per true positive case detected. On the assumption that a patient makes a special trip for eye screening, the cost per true positive case detected for primary screeners ranges from 633 pounds for a GP-screened group in one centre to 1079 pounds for another GP-screened group in a second centre; the cost per true positive case detected of photography ranges from 497 pounds for a camera that is taken to general practices in one centre to 1546 pounds for a hospital-based camera. Relative cost-effectiveness changes if, in some contexts, the screening can take place without requiring an additional patient visit, and is strongly related to the relative sensitivity of the screening methods and to the prior probability (prevalence or incidence) of retinopathy in the diabetic population.

Cost-Benefit Analysis