Frequently, in order to improve population health or the delivery of services, decision-makers have to choose between two or more alternatives under conditions of uncertainty. As was proposed by Gray et al. (2011), such decisions require more than just data about effectiveness, decision-makers also have to consider the cost of their decisions. In health economics, the costs of any decision are the missed benefits if resources would have been used in the next best alternative – this is the economic notion of opportunity cost. Economic evaluation is a method of providing information to decision-makers about whether the benefits of a new intervention are worth achieving that is the benefits obtained from using resources to provide the new intervention outweigh the benefits that could have been provided had the resources been used in another way. Economic evaluation is defined by Drummond et al. (2005) as:
“The comparative analysis of alternative courses of action in terms of costs and consequences”.
It is important to highlight here that economic evaluations do not focus on identifying the cheapest alternative, their focus is on the most efficient alternative, even if that alternative is to ‘do-nothing’ (Guinness and Wiseman, 2011).
Depending on the unit that consequences are measured, economic evaluations can be divided into three main forms: cost-effectiveness analysis, cost-utility analysis, and cost-benefit analysis. These three forms are each briefly described below.
Cost-effectiveness analysis
This analysis compares two or more interventions using a single natural unit, such as the amount of caries or DMFT index, for example, as the measure of effectiveness. This type of analysis allows the comparison of health interventions that produce the same outcome (Gray et al. (2011), and can address questions of economic (productive) efficiency; i.e., how can a specific good or service be produced at the lowest cost?
Given that this type of economic evaluation is used in this thesis, a deeper description is given later in this chapter.
Cost-utility analysis
The concept of utility here is related to the preferences that an individual or society have for a particular set of health outcomes (Drummond et al., 2005). It uses a generic health index, typically reported as quality-adjusted life-years (QALY) as a measure of effectiveness. This allows the comparison of different health interventions with different clinical outcomes. This method is described as a variation of cost-effectiveness analysis. However, while generic health indices have been developed, there are concerns that these indices may not detect small variations in utility that might occur with treatments for oral diseases (Vernazza et al., 2012). Therefore, condition specific dental generic indices have been proposed. For example, the quality-adjusted tooth years, or QATY, was developed by Birch (1986), where one QATY represents a sound tooth over a 1-year period.
Cost-benefit analysis
Here, the effect of an intervention is translated into a unit of measurement that is commensurate with the unit of measurement of costs, typically a monetary measure of value (or benefit). The monetary valuation of benefits is compared with the cost used to estimate the cost-benefit of a treatment. Given that this analysis uses money as a common measure for costs and benefits, it allows the comparison of health interventions with interventions (or investment) of other areas of the economy. This methodology thus allows the consideration of how best to allocate resources within an economy, and so addresses allocative efficiency (i.e., how can we best use the resources we have available) as well as technical efficiency (i.e., how can we produce a given outcome at least cost or maximise outcomes for a set cost) (Guinness and Wiseman, 2011).
5.2.1 Economic evaluations in dentistry
In two different literature reviews about the use of economic evaluations in dentistry, Mariño et al. (2013) and Tonmukayakul et al. (2015) concluded that the use of economic evaluations in dentistry has increased in recent years. The systematic review done by Tonmukayakul et al. (2015), which included studies from 1973 to 2015, found that 53% (59 of 114) of economic evaluations were focused on caries prevention or its treatment and 30% of the studies were published between 2011-2013. The same authors, using the Drummond checklist as a way to evaluate the quality of the publications (see 5.9), concluded that most studies failed to satisfy some components of standard EE research methods, such a sensitivity analysis and discounting.
In the same line, the systematic review done by Mariño et al. (2013), which included only caries prevention programmes, established that economic evaluations in dentistry suffer from methodological problems related to how these studies deal with uncertainty (which is normally addressed within an economic evaluation using sensitivity analyses); see 5.8.
Several “dental” economic evaluations are discussed in the thesis, emphasising specific elements. A recently published economic evaluation of preventive interventions (Tickle et al., 2011;O'Neill et al., 2017;Tickle et al., 2017) is closely related to the objective of this thesis and will be discussed later on.
As was commented on earlier, regarding FV (Chapter 3), there are just one study about cost- effectiveness of FV on caries-free populations (NIC-PIP). Hence, this thesis should make an important contribution about the cost-effectiveness of fluoride varnish in caries-free populations.
5.2.2 Using randomised controlled trials as a framework to generate the data used in economic evaluations.
In order to compare health interventions, economic evaluations require data about both costs and consequences. A source of such data comes from randomized controlled trials (RCTs), which, as was commented by Richards (2009), are powerful research tools that allow the separation and measurement of the effect of an intervention, reducing the systematic differences between baseline characteristics of the groups that are compared.
RCTs have been used more and more as frameworks to generate such costs and consequences (Gray et al., 2011), because as well as the advantages of RCTs for comparative research, they allow prospective data collection about resources used concurrently and in the same people as data collection on outcomes. Therefore, they allow patient-specific data to be obtained, which are potentially useful for analysis of internal validity. Also, given that RCTs usually have a large fixed cost, adding an extra stage to collect economic data might only incur modest extra costs (Drummond et al., 2005).
Nevertheless, RCTs have limitations and cannot be used in all economic evaluations. For example, it is possible that an RCT for a given health intervention to be evaluated simply does not currently exist or could not be readily designed. Another limitation is that the time horizon of an available RCT is typically not sufficiently long enough to capture all relevant costs and
effects. This point is important in chronic pathologies that affect individuals during their entire lifetimes, as dental caries does.
In the author’s view, there are two more important limitations. First, RCTs might not provide evidence about a particular setting or group of patients (Gray et al., 2011) and, given the controlled nature of RCTs, they might not represent those patients or group of patients that an economic evaluation needs to analyse, i.e., those seen in clinical practice. The other prohibitive limitation is the cost of an RCT, which could be very large, especially for RCTs that need to study large populations over long periods of time.
These limitations have led researchers to employ other frameworks to gather costs and outcomes data to be used in economic evaluations.
5.2.3 Chilean guideline for economic evaluations
With the objective of establishing a standard methodological framework for the economic evaluations in Chile, the Chilean Ministry of Health MINSAL (2013c) published in 2013 a guideline titled “Methodological Guideline for Economic Evaluations of Health Intervention in Chile” (henceforth referred to as the Chilean guideline for economic evaluations). This guideline summarises basic aspects of economic evaluations and gives important recommendations related to the perspective to be considered including (in terms of target population) costs, outcomes, and time horizon.
This guideline was published with the objective of outlining a reference case; thus, it is considered mandatory for researchers that work on public health policies. Furthermore, it is requirement of work conducted for public institutions such as the Ministry of Health, National Health Fund, National Institute of Health, etc. (MINSAL, 2013c).
Given that this thesis analyses a national health programme and estimates the impact of Chilean public health policy, this research considers the Chilean guideline for economic evaluations in more detail.