Pharmacoeconomics: NICE's approach to decision-making

Abstract

The National Institute for Health and Clinical Excellence (NICE) is a decision-maker. Where NICE reaches a positive conclusion about the use of a particular health technology (such as a pharmaceutical product) in the National Health Service (NHS), there is a legal requirement for the service to make it available if a patient's physician considers it clinically appropriate [1]. Although this legal obligation does not apply to technologies recommended in NICE's clinical guidelines, there is still a reasonable expectation by the Care Quality Commission for NHS healthcare professionals to use NICE's clinical guidelines as the basis, where appropriate, for their clinical practice. NICE's independent advisory bodies (the Appraisal Committees, the Public Health Advisory Committee and Guideline Development Groups) are required to take account of both clinical and cost-effectiveness in reaching their conclusions about the use of health technologies generally and of pharmaceuticals in particular [2–4]. These advisory bodies must fully assess the available evidence on benefits and costs in order to come to a decision as to whether the use of a technology is considered a cost-effective use of resources. However, the scientific evidence underpinning any decision about the use of a particular health technology is never perfect. Nor is it all-embracing. Advisory bodies therefore need to use their experience to make judgements beyond the existing evidence. These judgements are of two types [5]: Scientific value judgements are ones about what can be inferred from the available evidence base; and the extent to which imperfections in the evidence base should influence decisions. Social value judgements are concerned with what is appropriate and acceptable for society in delivering healthcare across the NHS. Health technologies, including pharmaceuticals, can be considered to be clinically effective if, in normal clinical practice, they confer an overall health benefit (taking account of any harmful effects) when compared with relevant alternative treatments [6]. This is the central concern of patients for whom the treatment might be indicated. Technologies can be considered to be cost-effective if their health benefits are greater than the opportunity costs of services, in the NHS, that may be displaced were they to be adopted [3]. This is the central concern of all other NHS patients whose treatments might be displaced by prioritized spending on the new technology. The evidence for clinical effectiveness may be derived from experimental or observational studies [7]. These are usually pooled in a systematic review that often includes one or more meta-analyses. NICE as a decision-maker, however, needs to consider: The strengths and limitations of the systematic evidence review. Although systematic reviewing is based on well-accepted principles, judgment is required in deciding which studies should be included as well as in the interpretation of the results. Thus different inclusion and exclusion criteria used for the review, as well as for the meta-analyses, will yield different results. The absence of direct comparisons. Many randomized controlled trials for new pharmaceutical products are compared with placebo rather than with the active comparators used in current clinical care. The use of indirect or mixed treatment comparisons adds an additional layer of complexity to the analysis [8]. The end-points used in the relevant studies. Only a minority of trials measure health-related quality of life together with reliable estimates of the period for which it is 'enjoyed'. Frequently the data for effectiveness rely heavily (or exclusively) on surrogate outcomes or other biomarkers. The time scale of the studies. Randomized controlled trials rarely last more than 6–12 months, but chronic diseases and their treatments often persist throughout life. External validity (generalizability) of the available data. Despite the advantages of randomized controlled trials, in respect of their internal validity, their small scale and often homogeneous patient populations can render the real impact of treatment uncertain [4]. Observational evidence, which could assist generalizability, is likely to be limited for new products. All of these considerations, and more, demand judgements on the part of the particular advisory body. These judgements are informed by the science, but are nevertheless judgements. NICE's preferred measure of cost-effectiveness is the incremental cost-effectiveness ratio (ICER) [6]. This relates the increased marginal gain in health, expressed as the quality-adjusted life year (QALY), to the increased (or decreased) marginal costs less the savings attributable to the use of the product. This almost invariably requires the use of an economic model that has normally been developed specifically for the particular decision problem. Economic modelling requires judgements to be made by both modellers and decision-makers. The i