The HTA process Definitions

Various definitions o f ‘health technology’ and ‘health technology assessment’ have been stated and a number of interpretations and emphases are evident in the literature.

Goodman (1992) expressed concern over the equivocal nature of HTA, both in terms of definitions and its relationship to other processes such as quality assurance, health services research, effectiveness research and medical informatics. A detailed debate on the

subtleties of the definition and process of HTA is beyond the scope of this thesis. One interpretation of the HTA process is provided, with particular influence taken fi*om the current NHS strategy.

Health technology was described by the Advisory Group on Health Technology Assessment (1992) as:

The variety of methods used by health professionals to promote health, to prevent and treat disease, and to foster improved rehabilitation and long-term care.’

The US OTA describes health technology as:

The drugs, devices and medical and surgical procedures, used in medical care, and the organisational and supportive systems within which such care is provided’ (US Congress Office of Technology Assessment 1982).

The broad nature of these definitions reflects the wide variety of health technologies and also allows for a flexible interpretation. Emphasis is placed on the inclusion of ‘low-tech’ products such as syringes and dressings as well as ‘high-tech’ products such as imaging devices or lasers. The definitions also include health policies and the time and skills of health professionals. Littenberg (1992) stated that hospitals and the doctor-patient relationship should also be classified as health technologies. The broad nature of the

definitions contrast with a popular perception (by many health workers as well as the general public) that ‘health technology’ refers to the hard-ware used in health care.

An advisory panel to the Department of Health Central Research and Development Committee (Advisory Group on Health Technology Assessment 1992) stated that;

‘Rigorous assessment of new technologies is essential to evaluate their effectiveness and safety, their cost-effectiveness, and their social, ethical and organisational impacts’.

The US Institute of Medicine (1985) defines HTA as:

‘any process examining and reporting properties of a medical technology used in health care, such as safety, efficacy, feasibility, and indications for use, cost, cost- effectiveness, as well as social, economic, and ethical consequences, whether intended or unintended.’

The OTA defines HTA as:

‘a structured analysis of health care technology or related techniques, or

technology related issues, that is performed for the purpose o f providing input to a policy related decision’ (Irving 1995).

These definitions imply that a range of outcomes should be used in HTA, which may be used to assess clinical, economic, social, legal and ethical impact, depending on the technology. The philosophy is that the whole is greater than the sum of the parts. The measurement of a range of outcomes also implies a multidisciplinary approach to HTA. This does not necessarily mean that every assessment must be an examination of all outcomes possible; early assessments may provide information on the potential of a technology and offer guidance to the future development of the product and the methods used to evaluate it (Sculpher et al 1995). In this way, the HTA process can be regarded

as iterative, each step providing more information. It should also be stressed that HTA is a process which supports policy making.

The emphasis on the early work of the US OTA was to formulate policies to protect society from dangerous technologies. This still remains true for HTA, particularly as the introduction of many technologies remains outside of the control of any formal regulatory systems. The introduction of a new drug into the UK market requires years of carefully documented research and development and detailed submissions to the Medicines Control Agency. In contrast, there is no comprehensive regulation of medical devices (except a system for alerting health workers to dangerous or faulty technology), surgical techniques or computerised clinical support systems. For example, laparoscopic surgical techniques have been widely practised in the UK since the start of the decade despite there being little evidence to demonstrate safety or cost effectiveness. Assessment of this type of surgery has now been prioritised by the NHS (Spiby 1994).

Assessment of performance

The traditional assessment of health care includes measurement of both safety and performance. A range of qualitative and quantitative methods have been used to either measure these factors or obtain relevant opinion. These include randomised controlled trials (RCTs), performance analysis, case series, case studies, meta-analysis, consensus development conferences and opinion surveys (Hendee 1991). The RCT for assessing health technologies is considered to be the gold standard by many workers (for example, Laupacis et al 1992). While RCTs provide information concerning the potential for new

technologies, they are limited in that they are usually conducted under ideal conditions (and so provide a measure of efficacy); performance under normal conditions

(effectiveness) may be an equally usefiil measure to decision makers (Goodman 1992, Banta et a / 1981). A comprehensive HTA may therefore include an assessment of

al 1986). The medical audit processes should provide the final practice-based

measurements of effectiveness. Following widespread difiusion of a technology, epidemiological methods may provide information concerning the effectiveness of the technology on a macro level when set against a baseline, pre-intervention measurement (Tugwell et al 1986). Such techniques are also useful for prioritising the development

and assessment of new technologies, based on potential for reducing the incidence of treatable diseases or events.

Outcomes used to measure performance include survival rates, quality of life measures and other, intermediate or proxy outcomes such as reduction in blood pressure or tumour shrinkage. While the latter parameters are easier to measure in the short-term, they offer less meaning than true outcomes. Nevertheless intermediate outcomes have been deemed useful in early HTA research to assess the potential of a technology (Goodman 1992, Littenberg 1992, Sculpher et al 1995) and can eliminate the need for studies requiring

patient follow-up over long periods. Moreover intermediate outcomes such as reduction in blood pressure have been validated by studies which confirm associations with reduced morbidity and mortality. This approach, however carries the risk that other effects such as adverse drug reactions are not detected.

Economic factors

A feature of eveiy health care system in the world is the availability of limited resources with which to satisfy an unlimited demand. It is generally accepted that even if all harmful health technologies or those with no benefit were eliminated, there would still be an excess demand for resources (Buxton 1988). This fact makes rationing of health care inevitable. In the UK various forms of rationing, mostly implicit, have been operated

(Buxton 1993, Sheldon and Maynard 1993), for example waiting lists have been a consequence o f this. With the acceptance that some form of rationing is inevitable, it is desirable to prioritise the funding of (safe and effective) health technologies by objective means. Chris Ham (1993) emphasised the diflSculty in prioritising different types of health care by describing the process as being like ‘comparing apples, oranges and kiwi fruit’. A measure of the value for money provided by technologies may provide some direction.

Economic methods of assessing value for money are well established (Adang et al 1995,

Drummond et al 1987) and include cost-benefit analysis (CBA, where costs and benefits

are expressed in monetary terms), cost-effectiveness analysis (CEA, where treatments can be compared in terms of cost per unit of outcome) and cost-utility analysis (CUA, where, for example, treatments can be compared in terms of cost per quality-adjusted life year gained). CBA is useful for comparing technologies which have different impacts, though does rely on the ability to place a financial value on costs and outcomes, which is not always possible; willingness to pay is a commonly used approach. CEA is suitable for comparing technologies in the same clinical area, for example reduction in blood pressure or, less specifically, life years gained. CUA is useful for assessing technologies which have a multi-dimensional impact on both quality of life and survival.

W ider issues

Evaluation of efScacy, effectiveness and value for money may not provide a complete assessment of the technology in question. Wider issues should also be taken into account. The patient’s satisfaction with the health technology is increasingly being sought, for example Murphy et al (1996) carried out a RCT of GPs versus hospital doctors providing

Similarly the views of relatives and carers may be useful. Staff attitudes may play an important role, particularly in the evaluation of clinical support systems (Aydin 1994, Kaplan and Maxwell 1994). Qualitative and quantitative techniques may be useful to provide information on organisational changes and to assess the wider ‘knock-on’ effects of the technology. Some technologies may require an assessment of the ethical and legal implications.

Decision making

HTA research should provide answers to research questions. It is beyond the scope of an evaluative project to provide decision makers with definitive answers on whether a

technology should be adopted or not. In some instances, the decision will be easy; for example when a technology costs more than or the same as the established alternative and performs less well. For other scenarios the decision is more difficult, such as when an intervention costs more than the established technology but performs better, or when it costs less but performs worse. In these cases, the wider social and ethical issues may provide an important influence. Some workers have provided guidelines for decision making (Laupacis et al 1992) based on clinical and economic impacts, though other

workers have emphasised that decisions are often ultimately value-based (Deber 1992). Bos (1988) describes an explicit criteria based process for ranking technologies based on the nature of the target patient population. On a local level. Reiser (1992) describes a

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goal-orientated approach, considering civic, institutional, organisational and practice goals and other decision makers use a combination of criteria-based assessment and expert panel, GP and public preference (Watson et al 1996). Another approach has been to use

consensus development techniques, such as Delphi studies (Gallagher at al 1996) or consensus development conferences (Stocking et a ll9 9 \. Perry and Wilkinson 1992).