A Vision "Bolt-On" Item Could Increase the Discriminatory Power of the EQ-5D Index Score.

Recently, a vision "bolt-on" EuroQol five-dimensional questionnaire (EQ-5D) was developed and tentative utility values (i.e., a "value set") for this new descriptive system were estimated. To compare the discriminatory power of this bolt-on and standard utility-based EQ-5D health indices. Cross-sectional data on the (3-level) vision bolt-on EQ-5D were collected through face-to-face interviews with 500 and 336 individuals with and without visual impairment, respectively. To assess the discriminatory power of the vision bolt-on index relative to the standard EQ-5D index developed in the vision bolt-on valuation study, 16 pairs of mutually exclusive subgroups of individuals defined by the individuals' visual acuity and responses to the 14-item visual function questionnaire were compared pairwise. The absolute mean difference in the two index scores and the corresponding F statistic derived from the comparisons were used as measures of discriminatory power. The absolute mean difference in the bolt-on index score was larger than that in the standard EQ-5D index score in 14 of the 16 comparisons. The bolt-on index score exhibited a larger F-statistic value than did the standard EQ-5D index score in all known-group comparisons, with the F-statistic ratio ranging from 0.415 to 0.770. The vision bolt-on EQ-5D appears to be more discriminative than the standard EQ-5D in measurement of vision problems. Future studies should investigate the extent to which the vision bolt-on item can increase the sensitivity of the EQ-5D to vision change in interventional studies.

Luo N ，Wang X ，Ang M ，Finkelstein EA ，Aung T ，Wong TY ，Lamoureux E ... -  《-》

A vision 'bolt-on' increases the responsiveness of EQ-5D: preliminary evidence from a study of cataract surgery.

Gandhi M ，Ang M ，Teo K ，Wong CW ，Wei YC ，Tan RL ，Janssen MF ，Luo N ... -  《-》

Use of generic and condition-specific measures of health-related quality of life in NICE decision-making: a systematic review, statistical modelling and survey.

Longworth L ，Yang Y ，Young T ，Mulhern B ，Hernández Alava M ，Mukuria C ，Rowen D ，Tosh J ，Tsuchiya A ，Evans P ，Devianee Keetharuth A ，Brazier J ... -  《-》

An exploratory study to test the impact on three "bolt-on" items to the EQ-5D.

Generic preference-based measures were criticized for being inappropriate in some conditions. One solution is to include "bolt-on" dimensions describing additional specific health problems. This study aimed to develop bolt-on dimensions to the EuroQol five-dimensional questionnaire (EQ-5D) and assess their impact on health state values. Bolt-on dimensions were developed for vision problems, hearing problems, and tiredness. Each bolt-on dimension had three severity levels to match the EQ-5D. Three "core" EQ-5D states across a range of severity were selected, and each level of a bolt-on item was added, resulting in nine states in each condition. Health states with and without the bolt-on dimensions were valued by 300 members of the UK general public using time trade-off in face-to-face interviews, and mean health state values were compared using t tests. Regression analysis examined the impact of the bolt-on variants and the level of the bolt-on items after controlling for sociodemographic characteristics. Bolt-on dimensions had an impact on health state values of the EQ-5D; however, the size, direction, and significance of the impact depend on the severity of the core EQ-5D state and of the bolt-on dimension. Regression analysis demonstrated that after controlling for possible differences in sociodemographic characteristics between the groups, there were no significant differences in health state values between the three bolt-on dimensions but confirmed that the impact depended on the severity of the EQ-5D health state and the levels of bolt-on dimensions. The impact of a bolt-on dimension on the EQ-5D depends on the core health state and the level of the bolt-on dimension. Further research in this area is encouraged.

Yang Y ，Rowen D ，Brazier J ，Tsuchiya A ，Young T ，Longworth L ... -  《-》

A hearing bolt-on item increased the measurement properties of the EQ-5D-5L in a community-based hearing loss screening program.

To investigate the measurement properties of a hearing item ('bolt-on') added to the EQ-5D-5L descriptive system. Cross-sectional data on the EQ-5D-5L descriptive system with the addition of a hearing bolt-on item, namely, 'I have no/slight/moderate/severe/extreme problems hearing', was collected through face-to-face interviews with 418 participants of a community-based hearing loss screening program in Singapore. The distribution of responses to the EQ-5D and the hearing items were compared in terms of the proportion of 'no problems' and the Shannon index (H'). The measurement properties of the hearing item were assessed by testing its correlation with the hearing thresholds in dBHL; and with the standard EQ-5D items. The properties were also evaluated by comparing the proportion of 'full health' in participants with different hearing severities between standard and hearing bolt-on EQ-5D-5L; and the ability in identifying the participants between the standard EQ-5D-5L index score and the level sum score (LSS) of the hearing bolt-on system. Compared to the standard EQ-5D items, the hearing item has a lower proportion of 'no problems' (80.1% vs. 80.9-97.9%); more evenly-distributed responses (H' value: 0.92 vs. 0.18-0.87); and much stronger correlation with the hearing thresholds (|r|: 0.322 and 0.325 vs. 0.008-0.139). It generally has a weak correlation with EQ-5D items (|r|: 0.055-0.160); and reduces the proportion of 'full health' for the participants with different hearing functions with the percentage reduction varying from 6.6 to 22.7%. The LSS is more discriminative than the standard EQ-5D-5L index score as well (F-statistic: 12.71 and 13.93 vs.4.06 and 4.70). A hearing bolt-on to EQ-5D-5L can validly measure hearing severities and is likely to increase the sensitivity of the resultant preference-based EQ-5D index to hearing loss.

Wang P ，Chong SL ，Tan RL ，Luo N ... -  《-》