Development, Use, and Psychometric Properties of Vision and Hearing Bolt-Ons for EQ-5D-3L and EQ-5D-5L: A Systematic Review.

OBJECTIVES

We aimed to systematically review studies that had developed, used, or assessed the psychometric properties of vision or hearing bolt-ons for EuroQol 5-Dimension 3-Level instrument (EQ-5D-3L) and EuroQol 5-Dimension 5-Level instrument (EQ-5D-5L).

METHODS

A systematic review was conducted up to 17 March 2025, in Embase, PubMed, and Web of Science following the Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 guideline. Findings for EQ-5D-3L and EQ-5D-5L with vision and hearing bolt-ons, including the number of different bolt-on wordings and psychometric performance, were summarized narratively.

RESULTS

The review included 21 and eight publications for vision and hearing bolt-ons, respectively. More differentiated bolt-ons were developed for the EQ-5D-5L than for the EQ-5D-3L (vision: 9 vs 1; hearing: 20 vs 1). Among them, 4 vision and 13 hearing bolt-ons for EQ-5D-5L originated from 2 separate qualitative development studies. Six studies (vision: 3; hearing: 3) used qualitative research during item development. Across general-population and patient-population studies, both vision and hearing bolt-ons reduced the ceiling effects (vision: 4.3%-38.1%; hearing: 1.65%-18.8%) and showed good convergent validity with relevant external measures (eg, HUI-3, Cat-PROM5). However, convergent validity was weaker for some clinical measures, including visual acuity and hearing thresholds. Known-group validity based on relevant clinical characteristics (eg, visual acuity, unilateral vs bilateral hearing loss) was reported. Responsiveness, test-retest reliability and patient-proxy agreement evidence was limited.

CONCLUSION

Although psychometric properties were generally favorable, the evidence base remains partial and heterogeneous. This review informs future development of bolt-ons that should prioritize identifying the most appropriate item wordings and exploring psychometric properties using both qualitative and quantitative approaches in relevant patient populations.