Evaluation of a Vision-Related Utility Instrument: The German Vision and Quality of Life Index

Finger, Robert P.; Kortuem, Karsten; Fenwick, Eva; Livonius, Bettina von; Keeffe, Jill; Hirneiß, Christoph

doi:10.1167/iovs.12-10828

Cited by 11 publications

(12 citation statements)

References 11 publications

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“…44,45 In line with this observation, we found a four-to-five category revised rating scale structure to be adequate across all the items for the Indian VisQoL as compared to a three-to-four category structure reported to be optimal in the German VisQoL. 24 Our findings of category reorganization may be a function of the distinct study population and not the measure itself. The need for such post hoc category revision has been reported for other instruments that have been revalidated using Rasch analysis, for example, visual disability instruments, which have found that the participants are not always able to distinguish between finer increments (e.g., between ''more difficult'' and ''a lot more difficult'') in response options.…”

Section: Discussionsupporting

confidence: 62%

“…less, disordered thresholds of the Indian VisQoL categories have been reported for the German VisQoL too, 24 indicating that this finding is not a peculiarity of our study. Our participants found the distinction between ''a little'' and ''moderate,'' and ''more difficult'' and ''a lot more difficult'' ambiguous.…”

Section: Discussionsupporting

confidence: 52%

“…By comparison, however, the German VisQoL demonstrated suboptimal targeting of person ability to item difficulty, which possibly can be explained by the fact that the investigators included normally sighted (80%) and visually impaired patients (20%). 24 Given that targeting is sample dependent, it is important to consider differences in the participants when assessing the targeting of instruments.…”

Section: Discussionmentioning

confidence: 99%

“…23 Recently, the VisQoL was translated into German and was validated using Rasch analysis in the German population consisting of vision impaired and normally sighted patients. 24 However, the German VisQoL required revisions to achieve an optimal fit to the Rasch measurement model. 24 Rasch analysis, one of a number of psychometric techniques developed under IRT, is more useful because it provides greater insight into the measurement characteristics of an instrument (such as comprehensive understanding of the underlying latent structure) and is less sample dependent.…”

mentioning

confidence: 99%

“…24 However, the German VisQoL required revisions to achieve an optimal fit to the Rasch measurement model. 24 Rasch analysis, one of a number of psychometric techniques developed under IRT, is more useful because it provides greater insight into the measurement characteristics of an instrument (such as comprehensive understanding of the underlying latent structure) and is less sample dependent. 25,26 To our knowledge, an Indian version of the VisQoL has not been validated to date, and this is significant given that India is home to approximately one-fifth of the worlds' visually impaired population.…”

mentioning

confidence: 99%

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Vision and Quality of Life Index: Validation of the Indian Version Using Rasch Analysis

Gothwal¹,

Bagga²

2013

Invest. Ophthalmol. Vis. Sci.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Vision and Quality of Life Index: Validation of the Indian Version Using Rasch Analysis

Gothwal¹,

Bagga²

2013

Invest. Ophthalmol. Vis. Sci.

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A Systematic Review of the Literature on the Development of Condition-Specific Preference-Based Measures of Health

Goodwin

Green

2016

Appl Health Econ Health Policy

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Background. Health state utility values (HSUVs) are required to calculate quality-adjusted life-years (QALYs). They are frequently derived from generic preference-based measures of health. However, such generic measures may not capture health attributes of relevance to specific conditions. In such cases, a condition-specific preference-based measure (CSPBM) may be more appropriate.Objective. This systematic review aimed to identify all published accounts of developing CSPBMs, to describe and appraise the methods used. Results. Eighty-six publications were identified, describing 51 CSPBMs. Around two-thirds of these were QALY measures; the remainder were designed for clinical decision-making only. Classification systems for 33 CSPBMs were derived from existing instruments; 18 were developed de novo. HSUVs for 34 instruments were estimated using a 'composite' approach, involving statistical modelling; the remainder used a 'decomposed' approach based on multi-attribute utility theory. Half of the papers that described the estimation of HSUVs did not report validating their measures.Conclusion. Various methods have been used at all stages of CSPBM development. The choice between developing a classification system de novo or from an existing instrument may depend on the availability of a suitable existing measure, while the choice between a decomposed or composite approach appears to be determined primarily by the purpose for which the instrument is designed. The validation of CSPBMs remains an area for further development. 3 Key Points for Decision MakersThere are two main approaches to developing a classification system (derivation from an existing instrument or de novo) and two main approaches to estimating health state utility values (using statistical regression or multi-attribute utility theory) for a condition-specific preference based measure.There is more evidence available to support the validity of classification systems that were derived from existing measures of health-related quality of life than there is for classification systems developed de novo.

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The Role of Condition-Specific Preference-Based Measures in Health Technology Assessment

et al. 2017

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A condition-specific preference-based measure (CSPBM) is a measure of health-related quality of life (HRQOL) that is specific to a certain condition or disease and that can be used to obtain the quality adjustment weight of the quality-adjusted life-year (QALY) for use in economic models. This article provides an overview of the role and the development of CSPBMs, and presents a description of existing CSPBMs in the literature. The article also provides an overview of the psychometric properties of CSPBMs in comparison with generic preference-based measures (generic PBMs), and considers the advantages and disadvantages of CSPBMs in comparison with generic PBMs. CSPBMs typically include dimensions that are important for that condition but may not be important across all patient groups. There are a large number of CSPBMs across a wide range of conditions, and these vary from covering a wide range of dimensions to more symptomatic or uni-dimensional measures. Psychometric evidence is limited but suggests that CSPBMs offer an advantage in more accurate measurement of milder health states. The mean change and standard deviation can differ for CSPBMs and generic PBMs, and this may impact on incremental cost-effectiveness ratios. CSPBMs have a useful role in HTA where a generic PBM is not appropriate, sensitive or responsive. However, due to issues of comparability across different patient groups and interventions, their usage in health technology assessment is often limited to conditions where it is inappropriate to use a generic PBM or sensitivity analyses.

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Evaluation of a Vision-Related Utility Instrument: The German Vision and Quality of Life Index

Cited by 11 publications

References 11 publications

Vision and Quality of Life Index: Validation of the Indian Version Using Rasch Analysis

Vision and Quality of Life Index: Validation of the Indian Version Using Rasch Analysis

A Systematic Review of the Literature on the Development of Condition-Specific Preference-Based Measures of Health

The Role of Condition-Specific Preference-Based Measures in Health Technology Assessment

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