The effect of adding a vision dimension to the EQ-5D-5L in patients with visual impairment: a bolt-on exploratory study.

BACKGROUND

One approach to address the limitations of the EQ-5D-5L questionnaire is to add additional dimensions. This study investigated the effect of adding a vision dimension to the EQ-5D-5L questionnaire on health state valuations in people with visual impairments.

METHODS

This cross-sectional study was conducted using both the standard EQ-5D-5L and an expanded version (EQ-5D-5L + V, including a vision dimension) through face-to-face interviews with 300 individuals with visual impairments. Twenty health states, with and without the vision dimension, were assessed using the Time Trade-Off (TTO) method according to the EQ-VT protocol. Data were analyzed using Chi-square and Fisher's exact tests, independent t-tests, and multivariate regression.

RESULTS

The addition of the vision dimension significantly increased the differences in health state valuations, particularly for severe health states (P < 0.001). The largest differences in TTO scores were observed for severe health states 555555, 555553, 532441, and 351431.

CONCLUSION

Adding a vision dimension to the EQ-5D-5L instrument significantly affects health state valuations, especially for severe levels (4 and 5) and severe health states. Future studies should further explore the impact of adding vision and other bolt-on dimensions, focusing on the levels of the added dimensions.