Page 75 - Htain Manual

E
conomic Evaluation (EE) is one of the important aspects of a health

technology assessment. Classically, an EE is defined as a comparative

assessment of two or more interventions, in terms of their costs and
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consequences . As the definition suggests, any EE would comprise of two measurements –
costs and consequences, which has to be done for both the intervention and the comparators.

The key question is that how should we measure the costs and consequences, such that our

methodology is comprehensive viz. it measures all the important costs and consequences
which accrue as a result of a given intervention. Such an assessment can be done alongside

any epidemiological study which is being used to measure the effectiveness or efficacy, if we

also piggy-back measurement of costs. However, an epidemiological study may not be able

to measure all costs and consequences comprehensively, in a manner which may be

considered appropriate for an EE. This leads to the need for decision modelling.

Section 1 of this chapter describes the limitations of undertaking EE alongside a clinical

trial which necessitates use of a decision model. Subsequently, in section 2 we describe how

a decision model is able to bridge the limitations of an epidemiological study in undertaking

EE. We also introduce the 2 types of decision models which are used for EE, i.e. decision tree
and Markov model. Section 3 uses an illustration of each of the two types of decision models

for explanation. A hypothetical example of implementation of special newborn care units at

district hospitals to treat sick newborns is used to explain a decision tree. Similarly, a
published cost-effectiveness analysis of use of sorafenib – drug used for treatment of

hepatocellular carcinoma is used to explain use of Markov model. Finally, we conclude on

what cautions should be exercised by the researchers undertaking economic evaluation for

health technology assessment (HTA).

Can RCT alone be used to do an Economic Evaluation?

As introduced above, the measurement of costs and consequences in an EE can be

undertaken alongside an epidemiological study. Classically, a randomized controlled trial
(RCT) is considered the epidemiological study with highest degree of rigour for internal

validity; hence the word RCT will be used as a proxy for an epidemiological study.

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