Developing an algorithm to convert routine measures of vision into utility values for glaucoma

Quality of Life of Patients with Glaucoma in Slovakia

Purpose: The aim of this study was to identify and analyse the quality of life of patients with primary open-angle glaucoma (POAG) based on their visus and peripheral vision. Methods: Our study was observational in nature; it was a cross-sectional study. In total, 119 patients with POAG were included in a causal-comparative character, ex post facto research design. The authors collected data using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) and World Health Organization Quality of Life abbreviated version questionnaire (WHOQOL-BREF) tools. Results: Only patients with POAG that were over 18 years of age and had no other ocular or chronic illnesses were included. The mean duration of glaucoma was 8.77 (SD ± 5.63) years. Binocular disability was observed in 68.0% of patients. Using WHOQOL-BREF, there were significant differences found in the better-eye-vision group in psychological (p < 0.001) and environment (p < 0.001) domains. In the worse-eye-vision group, significant differences were found in physical health (p < 0.001), environment (p < 0.001), and quality related to health (p < 0.001) domains. Using NEI VFQ-25, there were significant differences found (p = 0.000) in all domains except subscale driving. Conclusion: Quality of life of patients with visual impairment is significantly lower in comparison to that of patients without a visual impairment.

Visual function evaluation for low vision patients with advanced glaucoma

This study aimed to compare various visual function parameters for evaluating the quality of life (QOL) of patients with advanced glaucoma with low vision.In total, 44 eyes of advanced glaucoma patients with low vision were included in this cross-sectional study. A moving pattern edge band program was used to assess edge detection ability and the low vision quality-of-life (LVQOL) questionnaire was used for evaluating QOL scores of subjects. Correlation analyses between QOL scores and visual functional parameters including pattern edge band unit, visual acuity (VA), and Mean deviation (MD) of perimetry were performed. The areas under receiver operating characteristic curves (AUROCs) of diverse visual functional parameters were calculated.VA and pattern edge band unit were related to LVQOL score in all subjects. For patients with a decimal VA lower than 0.1, only the pattern edge band showed a significant correlation with the QOL associated with distant activities (P = .031). However, the MD of perimetry was not related to the QOL score. After sorting subjects into 2 groups according to the LVQOL score, VA and pattern edge band unit were significantly different (P < .01 and P = .029, respectively). The AUROC for edge detection ability using pattern edge band was higher than MD of perimetry.Assessment of edge detection ability using pattern edge band was meaningful for predicting QOL associated with visual performance in patients with far-advanced glaucoma. For these patients, edge detection could be used as an additional parameter for visual function with traditional VA and perimetry.

Time Trade-off Utility Values in Noninfectious Uveitis

PURPOSE

To investigate time trade-off (TTO) utility values in patients with noninfectious uveitis and determine whether patient demographics and clinical characteristics are associated with utility scores.

DESIGN

Time trade-off utility analysis.

METHODS

Setting: A tertiary care uveitis center in San Francisco, California, USA.

PATIENT POPULATION

One hundred and four consecutive adults with noninfectious uveitis, enrolled between November 2016 and February 2017.

MAIN OUTCOME MEASURES

TTO utility values, as collected by an interviewer-guided survey. Information regarding general health, ocular symptoms, and religion was also collected and medical record review was conducted to record anatomic location of uveitis, disease activity, visual acuity, and treatments. Multivariable regression analysis with backward selection was used to identify variables associated with TTO values.

RESULTS

Median TTO score was 0.975 (interquartile range [IQR]: 0.8-1.0), corresponding to trading a median 1.28 years of remaining life for healthy eyes (IQR: 0-6.29). Regression analysis revealed that worse eye visual acuity, >6 months of oral corticosteroid use, and current antidepressant use were associated with lower TTO scores (P = .008, P = .006, P = .008, respectively), controlling for age and sex. In particular, patients who had been taking oral corticosteroids for more than 6 months, regardless of dose, were 10.5 times more likely to trade 20% or more years of remaining life (TTO ≤0.8) than patients not taking oral corticosteroids (95% confidence interval: 2.3, 48.1; P = .002).

CONCLUSIONS

Patients with noninfectious uveitis had measurable, though modest, reductions in quality of life, as assessed by TTO, and these decreases were significantly associated with visual acuity in the worse eye and long-term oral corticosteroid use.

Multivariable Regression Model of the EuroQol 5-Dimension Questionnaire in Patients Seeking Outpatient Low Vision Rehabilitation

PURPOSE

To understand the source of between-person variance in baseline health utilities estimated from EuroQol 5-dimension questionnaire (EQ-5D) responses of a representative sample of the US low vision outpatient population prior to rehabilitation.

METHODS

A prospective, observational study of 779 new low vision patients at 28 clinic centers in the US. The EQ-5D, Activity Inventory (AI), Telephone Interview for Cognitive Status (TICS), Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) physical functioning component, and Geriatric Depression Scale (GDS) were administered by telephone interview prior to rehabilitation. EQ-5D responses were transformed into health utilities, which served as the dependent variable in all analyses. Data were then analyzed to determine how much overall visual ability, functional domains of visual ability, and comorbidities (e.g. physical functioning, depression, cognition) independently contribute to the EQ-5D-based health utility index.

RESULTS

Multivariable regression analyses showed that the GDS and SF-36 physical account for nearly 40% of the variance observed in health utilities estimated from EQ-5D responses of low vision patients. Age was also a significant predictor of health utilities, but accounted for very little variance. None of the other variables were significant predictors.

CONCLUSIONS

Health utilities of low vision patients estimated from the EQ-5D primarily are associated with comorbid factors that are not likely to be responsive to low vision rehabilitation, thereby rendering the EQ-5D an unsuitable outcome measure for this population. However, because the EQ-5D is responsive to comorbid states, it could be a useful tool for evaluating the impact of comorbidities on low vision patient quality of life.

Preference-based disease-specific health-related quality of life instrument for glaucoma: a mixed methods study protocol

INTRODUCTION

A primary objective of healthcare services is to improve patients' health and health-related quality of life (HRQoL). Glaucoma, which affects a substantial proportion of the world population, has a significant detrimental impact on HRQoL. Although there are a number of glaucoma-specific questionnaires to measure HRQoL, none is preference-based which prevent them from being used in health economic evaluation. The proposed study is aimed to develop a preference-based instrument that is capable of capturing important effects specific to glaucoma and treatments on HRQoL and is scored based on the patients' preferences.

METHODS

A sequential, exploratory mixed methods design will be used to guide the development and evaluation of the HRQoL instrument. The study consists of several stages to be implemented sequentially: item identification, item selection, validation and valuation. The instrument items will be identified and selected through a literature review and the conduct of a qualitative study. Validation will be conducted to establish psychometric properties of the instrument followed by a valuation exercise to derive utility scores for the health states described.

ETHICS AND DISSEMINATION

This study has been approved by the Trillium Health Partners Research Ethics Board (ID number 753). All personal information will be de-identified with the identification code kept in a secured location including the rest of the study data. Only qualified and study-related personnel will be allowed to access the data. The results of the study will be distributed widely through peer-reviewed journals, conferences and internal meetings.

Simulation contact lenses for AMD health state utility values in NICE appraisals: a different reality

BACKGROUND/AIMS

The National Institute for Health and Care Excellence (NICE) has recommended the use of ranibizumab for neovascular age-related macular degeneration (AMD) and for diabetic macular oedema (DMO) as part of its health technology appraisal process. In the economic evaluations of both interventions, utility values were derived from members of the general public wearing contact lenses with a central opacity that was meant to simulate the blind spot experienced by many patients with advanced retinal disease. This paper tests the validity of the contact lens simulation, and finding it to be invalid, explores the impact on prior economic evaluations.

METHODS

Visual acuity, contrast sensitivity and visual fields were assessed with and without simulation lenses in five healthy subjects with normal vision.

RESULTS

We identified important differences between the contact lens simulation and vision loss experienced by patients with AMD. The contact lens simulator did not cause the central scotoma which is characteristic of late-stage AMD and which leads to severe difficulty with everyday activities such as reading or recognising faces and objects. The contact lens instead caused a reduction in retinal illumination experienced by the subjects as a general dimming across the retina.

CONCLUSIONS

A contact lens with a central opacity does not simulate a central scotoma. The clinical differences between simulated and actual AMD suggest there has been an underestimation of the severity of AMD health states. This brings into question the validity of the economic evaluations of treatments for AMD and DMO used by NICE.

A comparison of the sensitivity of EQ-5D, SF-6D and TTO utility values to changes in vision and perceived visual function in patients with primary open-angle glaucoma

Background

Economic viability of treatments for primary open-angle glaucoma (POAG) should be assessed objectively to prioritise health care interventions. This study aims to identify the methods for eliciting utility values (UVs) most sensitive to differences in visual field and visual functioning in patients with POAG. As a secondary objective, the dimensions of generic health-related and vision-related quality of life most affected by progressive vision loss will be identified.

Methods

A total of 132 POAG patients were recruited. Three sets of utility values (EuroQoL EQ-5D, Short Form SF-6D, Time Trade Off) and a measure of perceived visual functioning from the National Eye Institute Visual Function Questionnaire (VFQ-25) were elicited during face-to-face interviews. The sensitivity of UVs to differences in the binocular visual field, visual acuity and visual functioning measures was analysed using non-parametric statistical methods.

Results

Median utilities were similar across Integrated Visual Field score quartiles for EQ-5D (P = 0.08) whereas SF-6D and Time-Trade-Off UVs significantly decreased (p = 0.01 and p = 0.001, respectively). The VFQ-25 score varied across Integrated Visual Field and binocular visual acuity groups and was associated with all three UVs (P ≤ 0.001); most of its vision-specific sub-scales were associated with the vision markers. The most affected dimension was driving. A relationship with vision markers was found for the physical component of SF-36 and not for any dimension of EQ-5D.

Conclusions

The Time-Trade-Off was more sensitive than EQ-5D and SF-6D to changes in vision and visual functioning associated with glaucoma progression but could not measure quality of life changes in the mildest disease stages.

Estimating quality-adjusted life years from patient-reported visual functioning

PURPOSE

Glaucoma is an important disease, the impacts of which on vision have been shown to have implications for patients' health-related quality of life (HRQoL). The primary aim of this study is to estimate a mapping algorithm to predict EQ-5D and SF-6D utility values based on the vision-specific measure, the 25-item Visual Functioning Questionnaire (VFQ-25), as well as the clinical measures of visual function, that is, integrated visual field, visual acuity, and contrast sensitivity.

METHODS

Ordinary least squares (OLS), Tobit, and censored least absolute deviations were compared using data taken from the Moorfields Eye Hospital in London, to assess mapping functions to predict the EQ-5D and SF-6D from the VFQ-25, and tests of visual function. These models were compared using root mean square error (RMSE), R(2), and mean absolute error (MAE).

RESULTS

OLS was the best-performing model of the three compared, as this produced the lowest RMSE and MAE, and the highest R(2).

CONCLUSIONS

The models provided initial algorithms to convert the VFQ-25 to the EQ-5D and SF-6D. Further analysis would be needed to validate the models or algorithms.