Critical Appraisal of Health Economic Evaluation Studies
Key areas for critical appraisal – 1. The question
We need to ask ourselves two questions about the question the economic evaluation study seeks to address:
a) Is the type of analysis used appropriate to the question?
b) What is the perspective of the analysis?
These questions are related as they determine the type of analysis which should have been performed and the type of costs and benefits which should be collected. Each question is broken down into several sub-questions, presented below.
Economic evaluation can be used to assess:
Is it worthwhile achieving a given goal?
The crucial point for appraisal is whether the correct methodology has been chosen for a specific question.
There are three basic types of economic evaluation methodology:
CEA relates costs to a single clinical or natural measure of effectiveness; i.e., a unidimensional outcome, e.g., pain reduction, activities of daily living.
CEA is best suited to measuring technical efficiency as it is difficult to compare treatments with different outcomes.
CEA can sometimes be used to provide limited information on allocative efficiency through a ratio of extra cost to extra benefit produced (incremental cost-efficiency analysis).
Cost-utility analysis relates costs to a multidimensional measure of effectiveness which takes into account the valuation of benefits; i.e., a measure of utility.
CUA can be used to measure technical efficiency.
CUA can be used for allocative efficiency but only within the health care sector where health care costs only are included.
CBA relates costs to a valuation of benefits in commensurate (having a common or equal unit of measure), usually monetary, terms.
CBA can be used to measure both technical and allocative efficiency questions. It can be measured either within the health care sector or across other sectors of the economy.
1b) What is the perspective of the analysis?
Perspective is important as it determines which costs and benefits are collected.
Possible perspectives that should be considered are:
- a specific provider or provider institution
- a patient or patient group
- a health care purchaser (or third party payer)
- society at large
As a general rule CEA and CUA require only health care costs to be collected.
CBA requires all costs and benefits to be collected, no matter on whom they fall.