Biomedical subjects

Alastair Fischer

Publications and source records attributed to Alastair Fischer.

4 recordsLinked to original sources

PubMed2006

Cholinesterase inhibitors for Alzheimer's disease: variations in clinical practice in the north-west of England.

BACKGROUND: In the UK, the National Institute for Health and Clinical Excellence (NICE) is currently reviewing cost-effectiveness of cholinesterase inhibitors (ChEIs) for Alzheimer's disease (AD) in the NHS. The implementation of the original NICE (2001) guidance that made these drugs available in the UK was not examined in this review process, and was the objective of this study. METHOD: Ten hospitals in and around Manchester participated in the audit. Case records of all patients who were started on ChEIs between January 2002 and the date of the audit (November 2003 to December 2004) were examined to assess adherence to the NICE (2001) guidance. Information about available resources was gathered from lead clinicians of each hospital. RESULTS: A total of 1,092 case records were examined. The treatment of AD with ChEIs varied considerably with regard to pre-treatment investigations, waiting period for treatment, scales used to assess efficacy, adherence to the NICE (2001) guidance, and available resources. The actual number of patients with mild to moderate AD receiving ChEIs was much lower than that expected from known prevalence rates. Non-uniformity of clinical practice and missing data were the main limitations of the audit. CONCLUSION: There is a need to harmonise the use and monitoring of ChEIs for AD in the NHS so that the data from routine clinical practice could feed into future clinical and cost-effectiveness analyses.

Aged↗

PubMed2006

Non-linearity in the cost-effectiveness frontier.

Conventional cost-effectiveness decision rules rely on the assumptions that all health care programmes are divisible and exhibit constant returns to scale for a homogeneous population; hence, the path between adjacent programmes on a cost-effectiveness frontier must be linear. In this paper we build a framework to analyse non-linear 'expansion' paths. We model the impact of two key sources of non-linearity: economies of scale or scope in the production of health care; and prioritisation of patients who are most likely to benefit from more expensive and more effective treatments. We conclude that the expansion path might be linear, convex or concave, depending on the situation. The path might also exhibit vertical discontinuity due to fixed costs or horizontal discontinuity due to indivisibility. The efficiency of resource allocation might be improved by empirical estimation of expansion paths. We discuss the advantages and disadvantages of this approach compared with a standard stratified analysis.

Cost-Benefit Analysis↗

PubMed2006

The economics of diagnosis.

Any population can be divided into two groups, one with the presence of a given disease or condition, and the other without. Diagnosis consists of using tests to sort the population into these groups. Diagnostic tests use a threshold value of a diagnostic variable to distinguish between disease-positive and disease-negative individuals. The analysis of error in diagnostic tests has typically been undertaken using receiver-operator characteristic (ROC) curves. More recently, economic value of information (VOI) methods have characterised the costs and consequences of testing. This paper develops a new method for economic test evaluation, which we call ROTS analysis. The ROTS curve plots the costs and effects of changing test thresholds, in cost-effectiveness space. We illustrate the use of our method with a worked example, and show how it can answer three key questions: (1) Is there any test that is worth doing? (2) What is a test's optimum operating point in terms of sensitivity and specificity? (3) If two tests are available, which is best? We contrast the merits of our method with those of established ROC and VOI analysis. We argue that ROTS analysis more clearly reveals the link between changing test thresholds and the cost-effectiveness of different treatments.

Cost-Benefit Analysis↗

PubMed2004

Health care resource allocation: is the threshold rule good enough?

We review the foundations of resource allocation rules based on cost-effectiveness information. Comprehensive approaches, where a total budget is allocated in one go, require estimation of the costs and effects of all available health care programmes, which is unlikely to be practical. A common alternative is to assess individual programmes against a cost-effectiveness threshold. This has been shown to be efficient if the threshold is well calibrated and all programmes can be wholly or partially implemented with constant returns to scale. We discuss the feasibility of these assumptions, and the effects of relaxing them, concluding that programme indivisibility is unlikely to be a serious problem at a national level, but that miscalibration of the threshold and non-constant returns to scale might be. A rule that avoids these difficulties has been proposed previously: a new programme should only be implemented if it can be funded by cancelling another less effective programme. This could never reduce efficiency, unlike the threshold rule, though we show that it might sometimes fail to recommend an efficiency-improving change. We suggest a refinement of this reallocation rule based on explicit estimation of the costs and effects of partial implementation of the programmes under review. Research is required to assess the practicality of this option.

Cost-Benefit Analysis↗