Comparing multi-attribute utility instruments: CP-6D, a Cerebral palsy specific instrument, vs AQoL-4D

Area of Science:

• Health Economics
• Quality of Life Research
• Rehabilitation Medicine

Background:

• Economic evaluations for Cerebral Palsy (CP) traditionally rely on generic health-related quality of life (HRQoL) utility estimates.
• Generic multi-attribute utility instruments (MAUIs) have limitations in capturing the specific aspects of living with CP.
• The Cerebral palsy 6 Dimension (CP-6D) was developed as a disease-specific MAUI for CP.

Purpose of the Study:

• To compare the performance of the disease-specific CP-6D with the generic AQoL-4D.
• To test the criterion validity of the CP-6D in the general Australian population.
• To evaluate how both instruments capture socio-demographic variations.

Main Methods:

• An online survey administered to 2002 individuals in the Australian general population.
• Participants completed both the AQoL-4D and CP-6D MAUIs.
• Validity was assessed through correlations between domains, items, and instruments; ANOVA and t-tests analyzed discrimination across socio-demographic categories.

Main Results:

• A moderate correlation (0.64) was found between the CP-6D and AQoL-4D instruments.
• Both instruments demonstrated similar responses to socio-demographic differences, with medium effect sizes (p < 0.001).
• The CP-6D showed greater sensitivity to variations in income and education.

Conclusions:

• The CP-6D and AQoL-4D appear to measure a similar underlying construct of HRQoL.
• Both instruments exhibit comparable responsiveness to socio-demographic factors.
• The CP-6D offers a valuable, disease-specific alternative for assessing HRQoL in CP populations.