Methods to measure quality of life in health economic evaluation

Some diseases are more detrimental than others, sometimes it’s possible to recover, whereas other times only the quality of life can be improved. How can one compare different health outcomes across different disease areas and treatments? How “bad” is having hip problems compared to having vision problems? How much could one’s health improve by using different measures? Various methods are being used to measure this.

A few examples are:

1. Visual Analogue Scale - indicates how good one’s health is on a scale from 0 to 1, also called VAS scale
2. Standard Gamble (SG) – measures the disutility of a health state by observing the willingness to accept a certain risk of death to avoid the state
3. Time trade-off (TTO) – involves remaining life expectancy that a person may be willing to trade-off in order to avoid remaining in a sub-perfect health state.
4. Person trade-off – includes estimation of social values, changes to one’s wellbeing, of different interventions. How many outcomes of one kind does one consider equivalent in social value to X outcomes of another kind?
5. Various generic instruments (EQ-5D, 15-D, SF36 (SF6D), HUI etc.) - which measures utility in QALYs.

The methods VAS, SG and TTO are time-consuming, therefore generic forms are often used instead to measure the health-related quality of life (HRQoL) which in turn can be converted into QALYs.