Rasch Analysis Reveals Problems with Multiplicative Scoring in the Macular Disease Quality of Life Questionnaire

Measuring Quality of Life in Diabetic Retinal Disease: A Narrative Review of Available Patient-Reported Outcome Measures

Topic

Several patient-reported outcome measures (PROMs) are available to measure health-related quality of life (HRQoL) in patients with late-stage clinical diabetic retinal diseases (DRDs). However, an understanding of the psychometric properties of PROMs is needed to assess how they could relate to severity levels of a revised DRD grading system. This narrative review assessed the available generic-, vision-, and DRD-related PROMs used in DRD research and highlights areas for improvement.

Clinical Relevance

Diabetic retinal disease is a common complication of diabetes and can lead to sight-threatening complications with a devastating effect on HRQoL.

Methods

The Quality of Life working group is one of 6 working groups organized for the DRD Staging System Update Effort, a project of the Juvenile Diabetes Research Foundation Mary Tyler Moore Vision Initiative. PubMed, Cochrane Library, Embase, and Google Scholar databases were searched using core keywords to retrieve ophthalmology-related review articles, randomized clinical trials, and prospective, observational, and cross-sectional studies in the English language. A detailed review of 12 PROMs (4 QoL questionnaires and 8 utilities) that met a minimum level of evidence (LOE) was conducted. The relevance of each PROM to DRD disease stage and Biomarker Qualification guidelines (Biomarkers, EndpointS, and other Tools) categories was also defined.

Results

The National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25), Impact of vision impairment-computerized adaptive testing, and Diabetic Retinopathy and Macular Edema Computerized Adaptive Testing System had a LOE of II in detecting change due to late-stage DRD (diabetic macular edema), although several areas for improvement (e.g., psychometrics and generalizability) were identified. Other PROMs, particularly the utilities, had a LOE of III due to cross-sectional evidence in late-stage clinical DRD. Although the NEI VFQ-25 has been the most widely used PROM in late-stage DRD, more work is required to improve its multidimensional structure and other psychometric limitations. No PROM was deemed relevant for subclinical or early/mid-DRD.

Conclusion

This narrative review found that the most commonly used PROM is NEI VFQ-25, but none meets the ideal psychometric, responsiveness, and clinical setting digital administration requirements that could be included in an updated DRD staging system for diagnosis and monitoring of DRD progression.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The General Mattering Scale, the Anti-Mattering Scale, and the Fear of Not Mattering Inventory: Psychometric Properties and Links with Distress and Hope Among Chinese University Students

Purpose

Mattering is essential to university students' mental health. Feeling valued by others or unimportant can affect their overall well-being. However, most measures for assessing mattering have been developed and tested in Western countries, with limited evaluation of the measures when administered to university students in other regions. This study evaluated the reliability and validity of three mattering-related instruments - the General Mattering Scale (GMS), Anti-Mattering Scale (AMS), and Fear of Not Mattering Inventory (FNMI) among Chinese university students using classical test theory and Rasch analysis.

Methods

The study comprised 3594 university students from 19 universities across 13 provinces in mainland China, with a balanced gender distribution of 47.2% females and 52.8% males. Participants' ages ranged from 18 to 37, averaging 20.02 years. Most (78.4%) were in four-year programs, with the rest in three-year programs. The majority were freshmen (54.2%), and 86.3% had siblings. The predominant major was engineering (43.4%), followed by roughly equal representations in science, social science, and literature/art.

Results

The three scales showed high reliability and factorial validity, with Rasch analysis confirming their unidimensionality and monotonicity, although 2 of 15 items (one GMS item and one FNMI item) had lower fit. There were no substantial differences in item functioning between male and female respondents. Further analyses indicated that mattering, anti-mattering, and fear of not mattering all explained significant unique variance in levels of hope and distress.

Conclusion

All three mattering-related instruments are suitable for assessing Chinese students' mattering, anti-mattering, and fear of not mattering and changes in levels of these mattering dimensions. Moreover, each measure represents a unique element of the mattering construct in terms of associations with levels of hope and distress assessed in during the COVID-19 pandemic.

Development and Validation of the Life for Low Vision Questionnaire (LIFE4LVQ) Using Rasch Analysis: A Questionnaire Evaluating Ability and Independence

Low vision (LV) has a substantial impact on an individual’s daily functionality and patient-reported outcome measures (PROMs) are increasingly incorporated into the evaluation of this problem. The objective of this study was to describe the design of the new “Life for Low Vision Questionnaire (LIFE4LVQ)”, as a measure of daily functionality in LV and to explore its psychometric properties. A total of 294 participants completed the LIFE4LVQ and the data were subjected to Rasch analysis to determine the psychometric properties of the questionnaire, including response category ordering, item fit statistics, principal component analysis, precision, differential item functioning, and targeting. Test–retest reliability was evaluated with an interval of three weeks and intraclass correlation coefficients (ICC) were used. The correlation between the questionnaire score and Best Corrected Visual Acuity (BCVA) was examined using Spearman’s correlation coefficient. Rasch analysis revealed that for most items the infit and outfit mean square fit values were close to 1, both for the whole scale and its subscales (ability and independence). The separation index for person measures was 5.18 with a reliability of 0.96, indicating good discriminant ability and adequate model fit. Five response categories were found for all items. The ICC was 0.96 (p < 0.001; 95% CI, 0.93–0.98), suggesting excellent repeatability of the measure. Poorer BCVA was significantly associated with worse scores (rho = 0.559, p < 0.001), indicating excellent convergent validity. The functional, 40-item LIFE4LVQ proved to be a reliable and valid tool that effectively measures the impact of LV on ability and independence.

The management of neovascular age-related macular degeneration: A systematic literature review of patient-reported outcomes, patient mental health and caregiver burden

PURPOSE

The aim of this systematic literature review was to describe patient-reported outcomes, mental health and caregiver burden in patients with neovascular age-related macular degeneration (nAMD) treated with anti-vascular endothelial growth factor (VEGF) agents in routine clinical practice.

METHODS

Electronic searches were conducted in Embase and MEDLINE according to pre-defined criteria.

RESULTS

Of 856 records identified, 63 met inclusion criteria. Depression or depressive symptoms were reported in up to 42% of patients with nAMD. Of 25/63 (40%) studies evaluating quality of life (QoL) and using various tools, eight studies reported composite National Eye Institute Visual Functioning Questionnaire scores following anti-VEGF treatment. Of these, seven reported a statistically significant improvement at the earliest time point measured (Month 3-12) and approximately 50% reported sustained QoL benefits at 12 months. In studies comparing the attributed or different regimens, the most important factor from the patient's perspective was the likelihood that a particular regimen would maintain vision. There was a preference towards treat and extend, which was associated with a perceived reduction in patient and caregiver burden, compared to fixed dosing.

CONCLUSIONS

A coordinated holistic approach to patient care is key to optimizing patient well-being as well as visual outcomes. Further research regarding the patient-reported impact of nAMD management outside the trial setting (particularly international longitudinal studies) is warranted. Standardization of QoL studies would assist in establishing whether sustained QoL improvement, rather than prevention of QoL decline, should be a realistic expectation of treatment of nAMD in the longer term.

HLS19-NAV-Validation of a New Instrument Measuring Navigational Health Literacy in Eight European Countries

To manoeuvre a complex and fragmented health care system, people need sufficient navigational health literacy (NAV-HL). The objective of this study was to validate the HLS19-NAV measurement scale applied in the European Health Literacy Population Survey 2019-2021 (HLS19). From December 2019 to January 2021, data on NAV-HL was collected in eight European countries. The HLS19-NAV was translated into seven languages and successfully applied in and validated for eight countries, where language and survey method differed. The psychometric properties of the scale were assessed using confirmatory factor analysis (CFA) and Rasch modelling. The tested CFA models sufficiently well described the observed correlation structures. In most countries, the NAV-HL data displayed acceptable fit to the unidimensional Rasch partial credit model (PCM). For some countries, some items showed poor data-model fit when tested against the PCM, and some items displayed differential item functioning for selected person factors. The HLS19-NAV demonstrated high internal consistency. To ensure content validity, the HLS19-NAV was developed based on a conceptual framework. As an estimate of discriminant validity, the Pearson correlations between the NAV-HL and general health literacy (GEN-HL) scales were computed. Concurrent predictive validity was estimated by testing whether the HLS19-NAV, like general HL measures, follows a social gradient and whether it forms a predictor of general health status as a health-related outcome of general HL. In some countries, adjustments at the item level may be beneficial.

Identifying the content for an item bank and computerized adaptive testing system to measure the impact of age-related macular degeneration on health-related quality of life

PURPOSE

We are developing an age-related macular degeneration (AMD) health-related quality of life (HRQoL) item bank, applicable to Western and Asian populations. We report primarily on content generation and refinement, but also compare the HRQoL issues reported in our study with Western studies and current AMD-HRQoL questionnaires.

METHODS

In this cross-sectional, qualitative study of AMD patients attending the Singapore National Eye Centre (May-December 2019), items/domains were generated from: (1) AMD-specific questionnaires; (2) published articles; (3) focus groups/semi-structured interviews with AMD patients (n = 27); and (4) written feedback from retinal experts. Following thematic analysis, items were systematically refined to a minimally representative set and pre-tested using cognitive interviews with 16 AMD patients.

RESULTS

Of the 27 patients (mean ± standard deviation age 67.9 ± 7.0; 59.2% male), 18 (66.7%), two (7.4%), and seven (25.9%) had no, early-intermediate, and late/advanced AMD (better eye), respectively. Whilst some HRQoL issues, e.g. activity limitation, mobility, lighting, and concerns were similarly reported by Western patients and covered by other questionnaires, others like anxiety about intravitreal injections, work tasks, and financial dependency were novel. Overall, 462 items within seven independent HRQoL domains were identified: Activity limitation, Lighting, Mobility, Emotional, Concerns, AMD management, and Work. Following item refinement, items were reduced to 219, with 31 items undergoing amendment.

CONCLUSION

Our 7-domain, 219-item AMD-specific HRQoL instrument will undergo psychometric testing and calibration for computerized adaptive testing. The future instrument will enable users to precisely, rapidly, and comprehensively quantify the HRQoL impact of AMD and associated treatments, with item coverage relevant across several populations.

Impact of incident age-related macular degeneration and associated vision loss on vision-related quality of life

BACKGROUND

We examined the associations between the 6-year incidence of age-related macular degeneration (AMD) and vision-related quality of life (VRQoL), and the contribution of presenting visual acuity (VA), in an Asian population.

METHODS

Fundus images from the Singapore Chinese Eye Study, a population-based cohort study (baseline: 2009-2011; follow-up: 2015-2017), were graded using a modified Wisconsin age-related maculopathy grading system. Incident AMD was defined as no baseline AMD in both eyes and early/late AMD in the worse eye at follow-up. Presenting VA was assessed using the logarithm of the minimum angle of resolution chart at 4 m under standard lighting conditions with habitual correction. Multiple linear regression models determined the associations between AMD incidence with changes in the Rasch-transformed scores of the Reading, Mobility and Emotional VRQoL domains of the 32-item Impact of Visual Impairment (IVI-32) questionnaire, adjusted for traditional confounders. The contribution of presenting VA to changes in VRQoL was also estimated.

RESULTS

Of the 2251 participants without AMD at baseline (mean age (SD): 57.7 (9) years, 51.4% women), 101 (4.5%) and 11 (0.5%) developed incident early and late AMD at follow-up, respectively. Incident late AMD was associated with significant 30.3%, 32.5% and 30.9% decrements in Reading, Mobility and Emotional IVI scores, respectively. The contribution of presenting VA ranged between 1.62% and 4.35% of the observed decrements. No significant associations were noted with incident early AMD.

CONCLUSION

Incident late AMD had a substantial impact on all aspects of VRQoL, with presenting VA contributing only minimally to this longitudinal relationship.

Investigating Pre-Service Biology Teachers’ Diagnostic Competences: Relationships between Professional Knowledge, Diagnostic Activities, and Diagnostic Accuracy

Teachers’ diagnostic competences are essential with respect to student achievement, classroom assessment, and instructional quality. Important components of diagnostic competences are teachers’ professional knowledge including content knowledge (CK), pedagogical knowledge (PK), and pedagogical content knowledge (PCK), their diagnostic activities as a specification of situation-specific skills, and diagnostic accuracy. Accuracy is determined by comparing a teacher’s observation of classroom incidents with subject-specific challenges to be identified from scripted instructional situations. To approximate diagnostic situations close to real-life, the assessment of science teachers’ diagnostic competences requires a situated context that was provided through videotaped classroom situations in this study. We investigated the relationship between professional knowledge (PCK, CK, PK) of 186 pre-service biology teachers, their diagnostic activities, and diagnostic accuracy measured with the video-based assessment tool DiKoBi Assess. Results of path analyses utilizing Rasch measures showed that both PCK and PK were statistically significantly related to pre-service teachers’ diagnostic activities. Additionally, biology teachers’ PCK was positively related to diagnostic accuracy. Considering higher effect sizes of PCK compared to PK, the findings support previous findings indicating the importance of PCK, thus demonstrating its importance in the context of subject-specific diagnosis as well.

Development of the School Mental Health Self-Efficacy Teacher Survey Using Rasch Analysis

Given the important role that teachers play in supporting student mental health, it is critical teachers feel confident in their ability to fill such roles. To inform strategies intended to improve teacher confidence in supporting student mental health, a psychometrically sound tool assessing teacher school mental health self-efficacy is needed. The current article details the initial development and psychometric functioning of the school mental health self-efficacy teacher survey (SMH-SETS). A component of the development included Rasch analysis of pilot data to provide a psychometric appraisal of the SMH-SETS functioning and initial psychometric evidence. Results suggest the SMH-SETS exhibits strong psychometric properties and can be used to measure school mental health self-efficacy, track self-efficacy over time, and inform training and professional development.

Development of the Biological Variation In Experimental Design And Analysis (BioVEDA) assessment

Variation is an important concept that underlies experimental design and data analysis. Incomplete understanding of variation can preclude students from designing experiments that adequately manage organismal and experimental variation, and from accurately conducting and interpreting statistical analyses of data. Because of the lack of assessment instruments that measure students' ideas about variation in the context of biological investigations, we developed the Biological Variation in Experimental Design and Analysis (BioVEDA) assessment. Psychometric analyses indicate that BioVEDA assessment scores are reliable/precise. We provide evidence that the BioVEDA instrument can be used to evaluate students' understanding of biological variation in the context of experimental design and analysis relative to other students and to their prior scores.

An alternative application of Rasch analysis to assess data from ophthalmic patient-reported outcome instruments

Purpose

To highlight the potential shortcomings associated with the current use Rasch analysis for validation of ophthalmic questionnaires, and to present an alternative application of Rasch analysis to derive insights specific to the cohort of patients under investigation.

Methods

An alternative application of Rasch analysis was used to investigate the quality of vision (QoV) for a cohort of 481 patients. Patients received multifocal intraocular lenses and completed a QoV questionnaire one and twelve months post-operatively. The rating scale variant of the polytomous Rasch model was utilized. The parameters of the model were estimated using the joint maximum likelihood estimation. Analysis was performed on data at both post-operative assessments, and the outcomes were compared.

Results

The distribution of the location of symptoms altered between assessments with the most annoyed patients completely differing. One month post-operatively, the most prevalent symptom was starbursts compared to glare at twelve months. The visual discomfort from the most annoyed patients is substantially higher at twelve months. The current most advocated approach for validating questionnaires using Rasch analysis found that the questionnaire was “Rasch-valid” one month post-operatively and “Rasch-invalid” twelve months post-operatively.

Conclusion

The proposed alternative application of Rasch analysis to questionnaires can be used as an effective decision support tool at population and individual level. At population level, this new approach enables one to investigate the prevalence of symptoms across different cohorts of patients. At individual level, the new approach enables one to identify patients with poor QoV over time. This study highlights some of the potential shortcomings associated with the current use of Rasch analysis to validate questionnaires.

Development and Validation of the Vision-Related Dizziness Questionnaire

Purpose

To develop and validate the first patient-reported outcome measure (PROM) to quantify vision-related dizziness. Dizziness is a common, multifactorial syndrome that causes reductions in quality of life and is a major risk factor for falls, but the role of vision is not well understood.

Methods

Potential domains and items were identified by literature review and discussions with experts and patients to form a pilot PROM, which was completed by 335 patients with dizziness. Rasch analysis was used to determine the items with good psychometric properties to include in a final PROM, to check undimensionality, differential item functioning, and to convert ordinal questionnaire data into continuous interval data. Validation of the final 25-item instrument was determined by its convergent validity, patient, and item-separation reliability and unidimensionality using data from 223 patients plus test–retest repeatability from 79 patients.

Results

120 items were originally identified, then subsequently reduced to 46 to form a pilot PROM. Rasch analysis was used to reduce the number of items to 25 to produce the vision-related dizziness or VRD-25. Two subscales of VRD-12-frequency and VRD-13-severity were shown to be unidimensional, with good psychometric properties. Convergent validity was shown by moderately good correlations with the Dizziness Handicap Inventory (r = 0.75) and good test–retest repeatability with intra-class correlation coefficients of 0.88.

Conclusion

VRD-25 is the only PROM developed to date to assess vision-related dizziness. It has been developed using Rasch analysis and provides a PROM for this under-researched area and for clinical trials of interventions to reduce vision-related dizziness.

Domains of health-related quality of life in age-related macular degeneration: a qualitative study in the Chinese cultural context

OBJECTIVE

To explore which areas of health-related quality of life were affected in Chinese patients, and to identify whether the areas are well covered by validated questionnaires.

DESIGN

A qualitative study based on semistructured interviews was conducted. A qualitative thematic analysis following the approach of Colaizzi was used to analyse the interview data for significant statements and phrases. The themes and subthemes organised from the analysis were then compared by using the following current instruments: National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), Macular Disease Quality of life Questionnaire (MacDQoL) and Low-Luminance Questionnaire (LLD).

PARTICIPANTS AND SETTING

Twenty-one patients with age-related macular degeneration were recruited from the eye clinic of Southwest Eye Hospital in Chongqing, mainland China.

RESULTS

The mean age of the participants was 69.8 years (range 57-82 years) and the duration of the disease ranged from 3 months to 6 years. The qualitative analysis revealed nine important domains including symptoms, difficulties with daily activities, depending on others, depression and uncertainty, optimism and hope, social isolation, role change, family support and financial burden. However, all the three questionnaires were insufficient to capture the full extent of quality of life issues of Chinese patients with AMD, and MacDQoL covered more domains when compared with NEI-VFQ-25 and LLD.

CONCLUSION

The domains of concepts important to people with AMD in the Chinese culture are not fully represented in the three widely used questionnaires. Nine important domains were identified for the assessment of quality of life and should be considered when assessing the impact of AMD on Chinese individuals. Further studies are needed to develop an AMD quality of life questionnaire, better tailored to the needs and culture of Chinese patients.

Methods to Develop the Eye-tem Bank to Measure Ophthalmic Quality of Life

PURPOSE

There is an increasing demand for high-standard, comprehensive, and reliable patient-reported outcome (PRO) instruments in all the disciplines of health care including in ophthalmology and optometry. Over the past two decades, a plethora of PRO instruments have been developed to assess the impact of eye diseases and their treatments. Despite this large number of instruments, significant shortcomings exist for the measurement of ophthalmic quality of life (QoL). Most PRO instruments are short-form instruments designed for clinical use, but this limits their content coverage often poorly targeting any study population other than that which they were developed for. Also, existing instruments are static paper and pencil based and unable to be updated easily leading to outdated and irrelevant item content. Scores obtained from different PRO instruments may not be directly comparable. These shortcomings can be addressed using item banking implemented with computer-adaptive testing (CAT). Therefore, we designed a multicenter project (The Eye-tem Bank project) to develop and validate such PROs to enable comprehensive measurement of ophthalmic QoL in eye diseases.

METHODS

Development of the Eye-tem Bank follows four phases: Phase I, Content Development; Phase II, Pilot Testing and Item Calibration; Phase III, Validation; and Phase IV, Evaluation.

CONCLUSIONS/DISCUSSION

This project will deliver technologically advanced comprehensive QoL PROs in the form of item banking implemented via a CAT system in eye diseases. Here, we present a detailed methodological framework of this project.

The Norwegian version of the QOLIBRI - a study of metric properties based on a 12 month follow-up of persons with traumatic brain injury

BACKGROUND

Consequences after Traumatic brain injury (TBI) affect the injured person's self-image and quality of life. The purpose was to assess the health related quality of life (HRQoL) at 12 months after a TBI in patients admitted to regional trauma centres, and to evaluate the metric properties of the Norwegian version of the Quality of Life After Brain Injury (QOLIBRI) questionnaire.

METHODS

Two hundred four patients with TBI of all severities were included. HRQoL at 12 months post-injury was measured by the QOLIBRI. It has a total scale and 6 subscales (satisfied with Cognition, Self, Daily Life and Autonomy and Social Relationships, and bothered by Emotions and Physical Problems). Demographic and injury related data were registered. Disability was registered by Glasgow Outcome Scale Extended (GOSE) and Rivermead Post-Concussion Questionnaire, and mental health by Hospital Anxiety and Depression Scale. Descriptive statistics, internal consistency by Cronbach's alpha and Corrected Item-Total Correlations were calculated. Rasch analysis, Principal Component Analysis (PCA) and Structural Equation Modelling (SEM) were applied.

RESULTS

Mean age was 37.6 (SD 15.4) years; 72% were men, and 41% had higher education. Over 60% were severely injured. Mean Glasgow Coma Scale score was 9.3 (SD 4.5). According to the GOSE 5.9% had severe disability, 45.5% had moderate disability, and 48.5% had good recovery at 12 months post-injury. The QOLIBRI scales had a high internal consistency (α = 0.75-0.96), and only Physical Problems had an α < 0.85. In the Rasch analysis all subscales and their items fit the Rasch model, except for the depression item in the Emotion subscale. PCA and SEM analyses supported a six-factor structure in a second-order latent model. The QOLIBRI supports an underlying unidimensional HRQoL model. The SEM model fit statistics of the second-order model indicated a moderate fit to the observed data (CFI = 0.86, TLI = 0.85, RMSEA = 0.076, SRMR = 0.061, χ2 = 1315.76, df = 623, p-value < 0.001).

CONCLUSION

The Norwegian QOLIBRI has favourable psychometric properties, but there were some weaknesses related to its measurement properties of the total score when tested on a TBI population where many had severe TBI, and many had good recovery.

Reliability, validity and responsiveness of the Greek MacDQoL individualized measure of the impact of macular degeneration on quality of life

PURPOSE

To assess the psychometric properties of the Greek Macular Disease-Dependent Quality of Life Questionnaire (MacDQoL).

METHODS

The MacDQoL was translated in Greek and administered to 191 patients with neovascular age-related macular degeneration (AMD). To assess validity, all patients completed the Greek SF-12 health survey and underwent vision measurements. For test-retest reliability, a subset of twenty participants completed the MacDQoL twice, 2 weeks apart. Responsiveness was assessed on 102 patients who completed the MacDQoL at a follow-up visit, 1 year later. Rasch analysis was used to assess the Greek MacDQoL's response category functioning, precision, unidimensionality, targeting and differential item functioning.

RESULTS

Internal and test-retest reliability of the average weighted impact (AWI) was 0.952 and 0.97, respectively. Test-retest reliability of MacDQoL items ranged from 0.78 to 0.99. Principal component analysis revealed three subscales (activities, embarrassment and family life), which were also confirmed by confirmatory factor analysis. Rasch analysis revealed poor functionality of response categories and that was resolved by collapsing response categories and using the impairment scores only. In terms of convergent validity, the AWI and revised MacDQoL scales showed significant correlations with SF-12 summary scales (ρ = 0.21-0.30) and vision assessments (ρ = 0.31-0.46). Poorer AMD-related QoL at 1-year follow-up was associated with deterioration in distance visual acuity and worse eye near visual acuity.

CONCLUSIONS

The Greek MacDQoL is a reliable, valid and sensitive to change in vision instrument for assessing AMD patients' perceptions of QoL. However, Rasch analysis revealed that its multiplicative rating scale is flawed. Scientific measurement was restored with a number of revisions to the questionnaire.

Colombian Rasch validation of KIDSCREEN-27 quality of life questionnaire

BACKGROUND

The family of KIDSCREEN instruments is the only one with trans-cultural adaptation and validation in Colombia. These validations have been performed from the classical test theory approach, which has evidenced satisfactory psychometric properties. The aim of this study was to evaluate psychometric properties of KIDSCREEN-27 children and parent-proxy versions, through Rasch analysis.

METHODS

The participants in the present study were two different sets of populations, 321 kids with a mean age of 12.3 (SD 2.6), 41 % 8 to 11 years old and 59 % 12 to 18 years old; and 1150 parent-proxy with an average age of 45.5 (SD 18.9). Psychometric properties were assessed using the partial credits model in the Rasch approach. Unidimensionality, fitting of person and item, response form, and differential item functioning (DIF) were measured.

RESULTS

The Infit MNSQ in child self-reported version that ranges between 0.71-1.76, and 0.69-1.31 in the parent-proxy version. Scores gathered on Likert forms of 5-response options, person separation was 2.08 for child self-reported version and 2.40 for parent-proxy; reliability was 0.81 and 0.85, respectively. Items reliability was 0.99 on both versions, with separations of 11.92 for child self-reported and 10.83 for parent-proxy. There was not DIF according to the variables sex and age but was present according to socioeconomic status.

CONCLUSION

There was a good fit for items and individuals to the Rasch model. Item separation was adecuate, and person separation improved when the response form was re-codified to four options. The presence of DIF according to socioeconomic status implies a scale's bias in the measure of HRQoL of Colombian children.

Quality of Life with Macular Degeneration Is Not as Dark as It May Seem: Patients' Perceptions of the MacDQoL Questionnaire

To determine the perceived relevance and value of an individualized measure of the impact of macular degeneration on quality of life (QoL) for elderly people with Age-Related Macular Degeneration (AMD) in the USA, through the assessment of the suitability of the measure’s domains and by gaining a deeper insight into the impact of AMD on patients’ QoL vis-á-vis these domains, community-dwelling older adults in the metropolitan Salt Lake City, Utah area were interviewed using the macular degeneration on quality of life (MacDQoL) instrument. Participants felt that the MacDQoL was a relevant instrument for use in this US study population, though it could be improved by adding items pertaining to transportation, and independent driving, in particular, as an important QoL indicator. The emerging theme from analysis of the respondent’s commentary was that, in spite of AMD, these respondents were committed to engage in, and enjoy life. This is an important concept for clinicians and those who offer support programs to integrate into their care planning and reinforce in messaging to patients with the condition.

Traditional and Rasch psychometric analyses of the Quality of Life in Adult Cancer Survivors (QLACS) questionnaire in shorter-term cancer survivors 15 months post-diagnosis

OBJECTIVE

The aim of this paper is to provide new insights into the psychometrics of the Quality of Life in Adult Cancer Survivors (QLACS) questionnaire, originally developed for longer-term survivors 5+years post-diagnosis. Specifically, to examine the classic psychometric properties of QLACS in a sample of shorter-term survivors, and to undertake Rasch analysis to explore the extent to which the Generic and Cancer-Specific summary scales (and separately-analysed Benefits of cancer domain) are unidimensional, with linear measurement properties and no differential item functioning (DIF).

METHODS

Patients with potentially curable breast, colorectal or prostate cancer completed QLACS 15 months post-diagnosis (N=407). Score distributions, floor and ceiling effects, internal reliability, and feasibility (completion time and missing data) were examined. Rasch analysis included examination of item fit, DIF and unidimensionality.

RESULTS

The QLACS domains and summary scales had very similar score distributions and classic psychometric properties (no ceiling effects, majority no floor effects, acceptable reliability) to those found in development work with longer-term survivors. Median completion time was 10 min and total missing data 2.3%. The Generic summary scale contained several misfitting items and exhibited multidimensionality. The Cancer-Specific summary scale and Benefits domain showed fit to the Rasch model and demonstrated unidimensionality and no DIF, with just one or no item modifications respectively.

CONCLUSION

QLACS demonstrates similarly good classic psychometric properties among shorter-term as among longer-term survivors, and has good feasibility. The Cancer-Specific summary scale and Benefits domain showed an impressive degree of fit to the Rasch model, although the validity of computing the Generic summary score was not supported.

Quality assessment of ophthalmic questionnaires: review and recommendations

PURPOSE

The aim of this article was to systematically review all the available ophthalmic patient-reported outcome (PRO) instruments (questionnaires) that demonstrated interval measurement properties to identify the instruments with the highest psychometric quality for use in different eye diseases and conditions.

METHODS

An extensive literature review was carried out to identify all existing ophthalmic PRO instruments. Instruments were then excluded if they did not have demonstrable interval measurement properties; the remaining instruments were reviewed. The quality of the following psychometric properties was assessed: content development (initial item development process), performance of the response scale, dimensionality (whether the instrument measures a single construct), measurement precision, validity (convergent, concurrent, discriminant, and known groups), reliability (test-retest), targeting (whether the items are appropriate [e.g., difficulty level] for the population), differential item functioning (whether subgroups of people respond differently to an item), and responsiveness.

RESULTS

The search identified 48 PRO instruments that demonstrated interval measurement properties, and these were relevant to nine applications: glaucoma, dry eye, refractive errors, cataract, amblyopia and strabismus, macular diseases, adult low vision, children low vision, and others. These instruments were evaluated against the psychometric property quality criteria and were rated for quality based on the number of criteria met.

CONCLUSIONS

This review provides a descriptive catalog of ophthalmic PRO instruments to inform researchers and clinicians on the choice of the highest-quality PRO instrument suitable for their purpose.

The impact of anti-vascular endothelial growth factor treatment on quality of life in neovascular age-related macular degeneration

PURPOSE

To assess the impact of anti-vascular endothelial growth factor (VEGF) treatment in routine medical practice on vision-related quality of life (VRQoL) in neovascular age-related macular degeneration (AMD).

DESIGN

Prospective case series.

PARTICIPANTS

A total of 169 patients with neovascular AMD undergoing anti-VEGF treatment.

METHODS

The VRQoL interviews at baseline (n = 169), 6 months (n = 138), and 12 months (n = 120), routine anti-VEGF treatment with up to monthly follow-ups, and re-treatment as indicated. The Impact of Vision Impairment (IVI) questionnaire was subjected to Rasch analysis to assess its measurement performance and generate interval-level estimates of VRQoL at all time points, anchoring the instrument to its baseline measurement characteristics. Factors associated with a change in reported VRQoL were assessed using generalized linear regression models.

MAIN OUTCOME MEASURES

The VRQoL as measured by the IVI using its 3 subscales: Accessing Information, Mobility, and Emotional Well-being.

FINDINGS

The mean age was 70 years (±6 years standard deviation [SD]); 56% were female. Visual acuity (VA) improved by a mean of 8 letters (±17 SD), and mean retinal thickness decreased by 87 (±89.7) μm with an average of 6.5 (±2.6) injections over 12 months. Those who lost >2 lines (n = 13, 11%) reported worse VRQoL at 12 months on the Accessing Information and Mobility subscales (P = 0.007 and P = 0.050, respectively). Conversely, those who gained >2 lines (n = 29, 24%) reported better VRQoL on the Accessing Information and Emotional Well-being subscales (P = 0.009 and P = 0.008, respectively). Patients who did not experience a change in VA reported no change in their VRQoL. In multivariate analyses, only a change in VA but not whether the better or worse eye was treated predicted a change in VRQoL on the Accessing Information (P = 0.004) and the Emotional Well-being (P = 0.008) subscales.

CONCLUSIONS

We confirmed that anti-VEGF treatment for neovascular AMD improves patients' VRQoL in those who gain vision and maintains VRQoL in those who maintain VA in their treated eye, irrespective of whether the worse or better eye is treated. Against this background, the best possible outcomes should be aimed for even if the worse eye is treated because a loss of VA in the worse eye will adversely affect patients' VRQoL.

[Cost of illness of age-related macular degeneration. Systematic review on the development of a costs diary]

Due to demographic changes in the German population a significant rise in incident cases of age-related macular degeneration (AMD) is to be expected in the coming years. Also the corresponding increase in costs of the illness requires appropriate survey instruments to allow accurate estimations of costs. The cost diary for patients with AMD developed in this study is based on a previously established systematic review. The seven studies that were included were evaluated regarding their quality in order to then extract the listed cost items. The result is a prospective survey instrument with six different cost sectors of AMD.

Evaluation of item candidates for a diabetic retinopathy quality of life item bank

PURPOSE

We are developing an item bank assessing the impact of diabetic retinopathy (DR) on quality of life (QoL) using a rigorous multi-staged process combining qualitative and quantitative methods. We describe here the first two qualitative phases: content development and item evaluation.

METHODS

After a comprehensive literature review, items were generated from four sources: (1) 34 previously validated patient-reported outcome measures; (2) five published qualitative articles; (3) eight focus groups and 18 semi-structured interviews with 57 DR patients; and (4) seven semi-structured interviews with diabetes or ophthalmic experts. Items were then evaluated during 3 stages, namely binning (grouping) and winnowing (reduction) based on key criteria and panel consensus; development of item stems and response options; and pre-testing of items via cognitive interviews with patients.

RESULTS

The content development phase yielded 1,165 unique items across 7 QoL domains. After 3 sessions of binning and winnowing, items were reduced to a minimally representative set (n = 312) across 9 domains of QoL: visual symptoms; ocular surface symptoms; activity limitation; mobility; emotional; health concerns; social; convenience; and economic. After 8 cognitive interviews, 42 items were amended resulting in a final set of 314 items.

CONCLUSIONS

We have employed a systematic approach to develop items for a DR-specific QoL item bank. The psychometric properties of the nine QoL subscales will be assessed using Rasch analysis. The resulting validated item bank will allow clinicians and researchers to better understand the QoL impact of DR and DR therapies from the patient's perspective.