Development, use and psychometric properties of vision and hearing bolt-ons for EQ-5D-3L and EQ-5D-5L : a systematic review

Abstract

Objectives We aimed to systematically review studies that had developed, used, or assessed the psychometric properties of vision or hearing bolt-ons for EQ-5D-3L and EQ-5D-5L. Methods A systematic review was conducted up to 17 March 2025, in Embase, PubMed, and Web of Science following the PRISMA 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, four vision and 13 hearing bolt-ons for EQ5D-5L originated from two 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 (e.g. HUI-3, Cat-PROM5). However, convergent validity was weaker for some clinical measures, including visual acuity and hearing thresholds. Knowngroup validity based on relevant clinical characteristics (e.g. 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 favourable, the evidence base remains partial and heterogeneous. This review informs future development of bolt-ons that should prioritise identifying the most appropriate item wordings, and exploring psychometric properties using both qualitative and quantitative approaches in relevant patient populations.