Applying multilevel item response theory to vision-related quality of life in Dutch visually impaired elderly

The Basic VRS-Effect Study: Clinical Trial Outcomes and Cost-Effectiveness of Low Vision Rehabilitation in Portugal

INTRODUCTION

The aim of this study was twofold: (1) to investigate the clinical impact of vision rehabilitation in patients with vision impairment and (2) to investigate the cost-effectiveness of a basic vision rehabilitation service in Portugal.

METHODS

The trial recruited patients diagnosed with age-related macular degeneration or diabetic retinopathy (DR) and visual acuity in the range 0.4-1.0logMAR in the better-seeing eye. Participants were randomised to one of the study arms consisting of immediate intervention and delayed intervention. The intervention included: new refractive correction, optical reading aids, in-office training and advice about modifications at home. Visual ability, health-related quality of life and costs were measured. Economic analysis was performed to evaluate whether the intervention was cost-effective. The trial compared the outcomes 12 weeks after the start in both arms.

RESULTS

Of the 46 participants, 34 (74%) were diagnosed with DR, 25 (54%) were female, and mean age was 70.08 years (SD = 8.74). In the immediate intervention arm visual ability increased a mean of 0.523 logits (SE = 0.11) (p < 0.001). Changes in the delayed intervention arm were not statistically significant (p = 0.95). Acuity in the better-seeing eye, near acuity and critical print size also improved during the study. The mean cost of the intervention was €118.79 (SD = 24.37). The incremental cost-effectiveness ratio using the EQ-5D-5L was 30,421€/QALY and 1186€/QALY when using near acuity.

CONCLUSION

The current study gives evidence of positive clinical impact of a basic vision rehabilitation intervention and shows that a basic vision rehabilitation service is cost-effective. These findings are important to clinical and rehabilitation practices and for planning vision rehabilitation services.

TRIAL REGISTRATION

Retrospectively registered, 21/01/2019. ISRCTN10894889, https://www.isrctn.com/ISRCTN10894889.

Low vision rehabilitation for better quality of life in visually impaired adults

BACKGROUND

Low vision rehabilitation aims to optimise the use of residual vision after severe vision loss, but also aims to teach skills in order to improve visual functioning in daily life. Other aims include helping people to adapt to permanent vision loss and improving psychosocial functioning. These skills promote independence and active participation in society. Low vision rehabilitation should ultimately improve quality of life (QOL) for people who have visual impairment.

OBJECTIVES

To assess the effectiveness of low vision rehabilitation interventions on health-related QOL (HRQOL), vision-related QOL (VRQOL) or visual functioning and other closely related patient-reported outcomes in visually impaired adults.

SEARCH METHODS

We searched relevant electronic databases and trials registers up to 18 September 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) investigating HRQOL, VRQOL and related outcomes of adults, with an irreversible visual impairment (World Health Organization criteria). We included studies that compared rehabilitation interventions with active or inactive control.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 44 studies (73 reports) conducted in North America, Australia, Europe and Asia. Considering the clinical diversity of low vision rehabilitation interventions, the studies were categorised into four groups of related intervention types (and by comparator): (1) psychological therapies and/or group programmes, (2) methods of enhancing vision, (3) multidisciplinary rehabilitation programmes, (4) other programmes. Comparators were no care or waiting list as an inactive control group, usual care or other active control group. Participants included in the reported studies were mainly older adults with visual impairment or blindness, often as a result of age-related macular degeneration (AMD). Study settings were often hospitals or low vision rehabilitation services. Effects were measured at the short-term (six months or less) in most studies. Not all studies reported on funding, but those who did were supported by public or non-profit funders (N = 31), except for two studies. Compared to inactive comparators, we found very low-certainty evidence of no beneficial effects on HRQOL that was imprecisely estimated for psychological therapies and/or group programmes (SMD 0.26, 95% CI -0.28 to 0.80; participants = 183; studies = 1) and an imprecise estimate suggesting little or no effect of multidisciplinary rehabilitation programmes (SMD -0.08, 95% CI -0.37 to 0.21; participants = 183; studies = 2; I2 = 0%); no data were available for methods of enhancing vision or other programmes. Regarding VRQOL, we found low- or very low-certainty evidence of imprecisely estimated benefit with psychological therapies and/or group programmes (SMD -0.23, 95% CI -0.53 to 0.08; studies = 2; I2 = 24%) and methods of enhancing vision (SMD -0.19, 95% CI -0.54 to 0.15; participants = 262; studies = 5; I2 = 34%). Two studies using multidisciplinary rehabilitation programmes showed beneficial but inconsistent results, of which one study, which was at low risk of bias and used intensive rehabilitation, recorded a very large and significant effect (SMD: -1.64, 95% CI -2.05 to -1.24), and the other a small and uncertain effect (SMD -0.42, 95%: -0.90 to 0.07). Compared to active comparators, we found very low-certainty evidence of small or no beneficial effects on HRQOL that were imprecisely estimated with psychological therapies and/or group programmes including no difference (SMD -0.09, 95% CI -0.39 to 0.20; participants = 600; studies = 4; I2 = 67%). We also found very low-certainty evidence of small or no beneficial effects with methods of enhancing vision, that were imprecisely estimated (SMD -0.09, 95% CI -0.28 to 0.09; participants = 443; studies = 2; I2 = 0%) and multidisciplinary rehabilitation programmes (SMD -0.10, 95% CI -0.31 to 0.12; participants = 375; studies = 2; I2 = 0%). Concerning VRQOL, low-certainty evidence of small or no beneficial effects that were imprecisely estimated, was found with psychological therapies and/or group programmes (SMD -0.11, 95% CI -0.24 to 0.01; participants = 1245; studies = 7; I2 = 19%) and moderate-certainty evidence of small effects with methods of enhancing vision (SMD -0.24, 95% CI -0.40 to -0.08; participants = 660; studies = 7; I2 = 16%). No additional benefit was found with multidisciplinary rehabilitation programmes (SMD 0.01, 95% CI -0.18 to 0.20; participants = 464; studies = 3; I2 = 0%; low-certainty evidence). Among secondary outcomes, very low-certainty evidence of a significant and large, but imprecisely estimated benefit on self-efficacy or self-esteem was found for psychological therapies and/or group programmes versus waiting list or no care (SMD -0.85, 95% CI -1.48 to -0.22; participants = 456; studies = 5; I2 = 91%). In addition, very low-certainty evidence of a significant and large estimated benefit on depression was found for psychological therapies and/or group programmes versus waiting list or no care (SMD -1.23, 95% CI -2.18 to -0.28; participants = 456; studies = 5; I2 = 94%), and moderate-certainty evidence of a small benefit versus usual care (SMD -0.14, 95% CI -0.25 to -0.04; participants = 1334; studies = 9; I2 = 0%). ln the few studies in which (serious) adverse events were reported, these seemed unrelated to low vision rehabilitation.

AUTHORS' CONCLUSIONS

In this Cochrane Review, no evidence of benefit was found of diverse types of low vision rehabilitation interventions on HRQOL. We found low- and moderate-certainty evidence, respectively, of a small benefit on VRQOL in studies comparing psychological therapies or methods for enhancing vision with active comparators. The type of rehabilitation varied among studies, even within intervention groups, but benefits were detected even if compared to active control groups. Studies were conducted on adults with visual impairment mainly of older age, living in high-income countries and often having AMD. Most of the included studies on low vision rehabilitation had a short follow-up, Despite these limitations, the consistent direction of the effects in this review towards benefit justifies further research activities of better methodological quality including longer maintenance effects and costs of several types of low vision rehabilitation. Research on the working mechanisms of components of rehabilitation interventions in different settings, including low-income countries, is also needed.

Low vision, visual impairments and metropolitan urban planning: example of a topographic enhancement, need and monitoring in an Italian city

Significance

The purpose of the study was to analyze all the steps needed to manage partially sighted or blind persons.

Purpose

The aim of the first research was to collect and analyze data and opinions regarding the mobility of visually disabled people in Turin. The aim of the second research was to assess issues, daily needs and expectations regarding the urban reclassification plan for Via Nizza (Turin).

Materials and methods

In the first study, we proposed a survey, partially structured and partially unstructured, of 100 patients enrolled in the Visual Rehabilitation Center of the Ophthalmic Hospital of Turin. In the second study, we collected data from a survey of eleven patients enrolled in the Turin section of the Italian Confederation of Blind.

Results

It was observed that the visually disabled population was not necessarily elderly (46% of the population was less than 60 years of age); it was observed that the visually disabled people were active frequently. Environmental aids considered more useful were sound traffic lights (30%) and gradient signaling (29%); the first was not widespread in urban areas and was the aid most requested by the patients enrolled (49%); 48% of enrolled patients did not use tactile maps. As regards the reclassification of the urban plan of the area in Turin, important needs and expectations were highlighted.

Conclusion

As regards urban planning in Turin as well as in other Italian cities, many changes in public facilities are to be done to ensure an increasing independence and safety of visually impaired people.

Why item response theory should be used for longitudinal questionnaire data analysis in medical research

BACKGROUND

Multi-item questionnaires are important instruments for monitoring health in epidemiological longitudinal studies. Mostly sum-scores are used as a summary measure for these multi-item questionnaires. The objective of this study was to show the negative impact of using sum-score based longitudinal data analysis instead of Item Response Theory (IRT)-based plausible values.

METHODS

In a simulation study (varying the number of items, sample size, and distribution of the outcomes) the parameter estimates resulting from both modeling techniques were compared to the true values. Next, the models were applied to an example dataset from the Amsterdam Growth and Health Longitudinal Study (AGHLS).

RESULTS

The results show that using sum-scores leads to overestimation of the within person (repeated measurement) variance and underestimation of the between person variance.

CONCLUSIONS

We recommend using IRT-based plausible value techniques for analyzing repeatedly measured multi-item questionnaire data.

Longitudinal observation, evaluation and interpretation of coping with mental (emotional) health in low vision rehabilitation using the Dutch ICF Activity Inventory

BACKGROUND

Since there is evidence that mental health aspects (such as depression) may inhibit an optimal rehabilitation outcome, there is growing interest in the psychosocial aspects of vision loss as part of rehabilitation. The purpose of this study is to provide more insight into the construct validity and (longitudinal) interpretation of goals related to 'Coping with mental (emotional) health aspects' which are part of the recently developed 'Dutch ICF Activity Inventory (D-AI). Moreover, the data allowed to provide some insight in the outcome in this domain in relation to rehabilitation programs followed in Dutch Multidisciplinary Rehabilitation Centers at baseline and follow-up.

METHODS

In a cohort of 241 visually impaired persons, the D-AI was assessed at baseline (enrollment), 4 and 12 months, The importance and difficulty of the D-AI goals 'Handle feelings', 'Acceptance', and 'Feeling fit' and difficulty scores of underlying tasks were further analyzed, together with similar or related standardized questionnaires. At baseline, Spearman correlations were determined between D-AI goals and task and additional questionnaires to investigate the construct validity. Corrected and uncorrected linear mixed models were used to determine longitudinal rehabilitation outcomes in relation to rehabilitation programs followed.

RESULTS

Baseline correlations indicated that the difficulty of tasks and the umbrella goal 'Acceptance' were not similar. Longitudinal analyses provided insight in some subtle differences in concepts measured at the goal and task level of the D-AI, as well as similar validated questionnaires. After correcting for confounding variables, none of the underlying task difficulty scales changed over time. For goal difficulty scores only 'Acceptance' was reported to be significantly less difficult at 4 and 12 months follow-up. Importance scores of goals were stable from baseline to follow-up.

CONCLUSION

With respect to the constructs measured, results support the formulation of the new goal question 'Emotional life' which replaces the goals 'Handle feelings' and 'Acceptance'. Results indicate that MRCs should pay more attention to problems related to mental health. They have started to use the D-AI as it seems a promising tool to investigate and evaluate rehabilitation needs (including those related to mental health) over time and to clearly define rehabilitation goals from the very start.

Evaluation of reading, writing, and watching TV using the Dutch ICF Activity Inventory

PURPOSE

To investigate the longitudinal outcomes of rehabilitation (from baseline to 4 and 12 months) at a multidisciplinary rehabilitation center. The three goals ("Reading," "Writing," and "Watching TV") were measured with the Dutch ICF Activity Inventory (D-AI). In addition, outcomes were compared with the Low Vision Quality-of-Life questionnaire (LVQOL) for better insight into the (longitudinal) interpretation.

METHODS

In a cohort of 241 visually impaired persons, corrected and uncorrected linear mixed models were used to determine longitudinal rehabilitation outcomes for the D-AI goals "Reading," "Writing," and "Watching TV," and difficulty and underlying tasks, as well as for the LVQOL scales "Basic aspects" and "Reading and fine work." At baseline, Spearman correlations were determined for similar scales of the D-AI and LVQOL.

RESULTS

Importance scores of goals were stable over time. Difficulty scores decreased over time, but the differences were not significant at each measurement moment. For reading, difficulty of underlying tasks seemed to reflect the (change in) difficulty at the goal level; however, change in writing tasks did not reflect the change in the umbrella goal. Each of the three subscales of underlying tasks of the goal "Watching TV" changed in a different way. Changes in similar LVQOL scales were comparable, although less pronounced and more influenced by depression. Prescription or advice of low-vision aids and training in visual devices was not related (p > 0.01) with any of the outcome measures.

CONCLUSIONS

It seems reasonable to conclude that the decrease in perceived difficulty was an effect of rehabilitation. The D-AI goal scores for difficulty were less influenced by depression and may be more sensitive to measure change over time compared with the LVQOL. Importance scores may not be useful for evaluation purposes.

Evaluation of an emotional support service for the visually impaired

PURPOSE

To evaluate the impact of a facilitated peer group emotional support service on visual quality of life (VQoL).

METHODS

Consecutive participants in an emotional support service delivered to groups of up to six and facilitated by trained counselors were recruited (n = 29). The VCM1 (Vision Quality-of-life Core Measure) instrument was administered to participants at the start of the service, at the end of the service, and 6 months after completion of the service.

RESULTS

For the group as a whole, VQoL significantly improved between the beginning of the service and the end (F(1,23) = 16.43, p = 0.000) but was no better than at the start 6 months later (F(1,23) = 3.60, p = 0.07). However, those with poorer initial VQoL showed significantly greater improvements after 6 months (1.74 ± 2.21 logits) than those with higher initial VQoL (-0.12 ± 0.71 logits) (t23 = 2.89, p = 0.008). The effect size of the intervention for those with poor initial VQoL was 1.10 at the end of service and 0.92 after 6 months. The items that became and remained easier were "feeling lonely or isolated due to eyesight," "feeling sad or low due to eyesight," and "feeling worried about general safety outside the home."

CONCLUSIONS

This facilitated peer group emotional support service significantly improves VQoL as assessed with the VCM1 over at least 6 months for those with poorer initial VQoL. Different interventions may be needed for those with initially good VQoL and to improve other aspects of QoL not influenced by the service.

Psychometric analyses to improve the Dutch ICF Activity Inventory

PURPOSE

In the past, rehabilitation centers for the visually impaired used unstructured or semistructured methods to assess rehabilitation needs of their patients. Recently, an extensive instrument, the Dutch ICF Activity Inventory (D-AI), was developed to systematically investigate rehabilitation needs of visually impaired adults and to evaluate rehabilitation outcomes. The purpose of this study was to investigate the underlying factor structure and other psychometric properties to shorten and improve the D-AI.

METHODS

The D-AI was administered to 241 visually impaired persons who recently enrolled in a multidisciplinary rehabilitation center. The D-AI uses graded scores to assess the importance and difficulty of 65 rehabilitation goals. For high-priority goals (e.g., daily meal preparation), the difficulty of underlying tasks (e.g., read recipes, cut vegetables) was assessed. To reduce underlying task items (>950), descriptive statistics were investigated and factor analyses were performed for several goals. The internal consistency reliability and test-retest reliability of the D-AI were investigated by calculating Cronbach α and Cohen (weighted) κ. Finally, consensus-based discussions were used to shorten and improve the D-AI.

RESULTS

Except for one goal, factor analysis model parameters were at least reasonable. Internal consistency reliability was satisfactory (range, 0.74 to 0.93). In total, 60% of the 65 goal importance items and 84.4% of the goal difficulty items showed moderate to almost perfect κ values (≥0.40). After consensus-based discussions, a new D-AI was produced, containing 48 goals and less than 500 tasks.

CONCLUSIONS

The analyses were an important step in the validation process of the D-AI and to develop a more feasible assessment tool to investigate rehabilitation needs of visually impaired persons in a systematic way. The D-AI is currently implemented in all Dutch rehabilitation centers serving all visually impaired adults with various rehabilitation needs.

Dual sensory loss: A major age-related increase of comorbid hearing loss and hearing aid ownership in visually impaired adults

AIM

Despite increasing interest in visual and hearing impairment in the older population, little attention has been paid to concurrent hearing and vision loss, also known as dual sensory loss. The aim of the present study was to investigate the prevalence of comorbid hearing disability and hearing aid ownership in visually impaired older adults.

METHODS

In a cross-sectional survey, a self-report hearing disability screener was administered to 1396 visually impaired patients (aged ≥ 50 years) of outpatient low vision rehabilitation centers in the Netherlands and Belgium.

RESULTS

Of all participants, 44.8% (95% CI 42.2-47.5) had insufficient or poor hearing; the prevalence increased quadratically with age. Of all dual sensory impaired participants, 31.2% in the Netherlands and 55.7% in Belgium did not own hearing aids.

CONCLUSIONS

The high prevalence of dual sensory loss calls for more awareness of related problems in these patients. Differences between the Netherlands and Belgium regarding hearing aid ownership might be due to different criteria used for hearing aid referral and insurance policies. For patients with dual sensory loss, specialized care implemented in low vision rehabilitation seems warranted.

Can we associate the hours of clinical services at the rehabilitation outcomes? The case of the visual impairment rehabilitation program

The purpose of this study was to determine the effects on the elderly of clinical interventions by professionals from a visual impairment rehabilitation program, more specifically, the effects on their daily life and the extent to which such interventions encourage social participation. In accordance with the conceptual framework of the Disability Creation Process, the clinical results of a population study group of 100 persons with various types of visual impairment enrolled in a rehabilitation program were analyzed as per the intensity of the clinical interventions (eg, hours of clinical services provided and dispensed by professionals). The results of the study tend to show that the hours of services accorded to a patient positively contribute to the progression of his or her Functional Global Profile as per the rehabilitation outcomes progression measures. In contrast, age and the spreading of services negatively contribute. The contributions of the study are innovative for assessing clinical effectiveness. For instance, the understanding of the relationship between the measurement of a patient's clinical results and the services that he or she has received should help us improve the practices and methods used in visual impairment rehabilitation.

VA LOVIT II: a protocol to compare low vision rehabilitation and basic low vision

PURPOSE

To compare the effectiveness of low vision rehabilitation (LVR) and basic low vision (LV) in a single masked multicentre randomised controlled trial (RCT).

METHODS

Three hundred and thirty patients eligible for US. Veterans Affairs (VA) healthcare services with primary eye diagnosis (better-seeing eye) of macular disease and best-corrected distance visual acuity of 0.40-1.00 logMAR (6/15 to 6/60 or 20/50 to 20/200 Snellen) are being enrolled at seven VA facilities. All participants receive an optometric LV examination; and they are eligible to receive the same LV devices that are provided without charge. In LVR, a LV therapist dispenses devices and provides 2 or 3 (1½ to 2½ h) therapy sessions with assigned homework to teach effective use of remaining vision and LV devices. Contact time with the therapist depends upon the devices prescribed and the patient's progress in learning the skills that are taught. In basic LV, devices are dispensed by the optometrist without LV therapy. Contact time for dispensing is one hour or less depending on LV devices prescribed. The primary outcome measure is a comparison of the changes in visual reading ability (estimated from patients' difficulty ratings of reading items on the VA LV VFQ-48 questionnaire) between the treatment and control arms from pre-intervention baseline to 4 months (2 months after completion of treatment). Secondary outcome measures are changes in overall visual ability, visual ability domain scores calculated from subsets of items (mobility, visual information processing and visual motor skills), Short Form-36, and Minnesota Low Vision Reading Test scores. Cost-effectiveness analysis will be conducted using VA LV VFQ-48 scores and QALYS computed from EuroQol scores.

RESULTS

A total of 137 patients representing 41.5% of the study target of 330 patients were randomised from October 2010 to March 2012. Among those 137 patients, mean age was 80.2 (S.D. ± 9.9) years at enrollment; 97.1% of the patients were males; 94.2% were white. Mean best corrected VA was 0.65 (S.D. ± 0.3) logMAR (approximately Snellen 6/27 or 20/90) at baseline.

CONCLUSIONS

LOVIT II is the first multicentre RCT comparing the effectiveness and cost-effectiveness of LVR and basic LV for patients with macular diseases and near normal or moderate levels of visual impairment.

The development & evaluation of two vision screening tools for correctable visual loss in older people

OBJECTIVES

In the UK, 20-50% of older people have undetected reduced vision and in most cases this results from correctable problems (refractive error and cataract). Many older people are not availing themselves of state-funded community optometric care. We assessed the efficacy of two vision screening instruments at detecting correctable visual problems and investigated the effect of optometric intervention on quality of life.

METHODS

A computerised vision screener (CVS) was developed and refined after a preliminary study of 180 older people to include tests of: monocular presenting distance high contrast and low contrast visual acuities (VAs), binocular near acuities, and monocular visual fields. The modified CVS and a flip-chart vision screener (FVS) were evaluated on a second sample of 200 people aged 65+ (mean age 77 years). All participants in both studies were given an optometric eye examination, including high and low contrast VAs, refraction, binocular vision tests, tonometry, automated perimetry, and dilated fundoscopy including cataract grading and ARM grading. The target conditions were significant gain in monocular distance VA or binocular near VA with new refractive correction, significant cataract, or macular degeneration at risk of rapid progression. The Low Vision Quality of Life Questionnaire (LVQoL) was administered before and up to 3 months after testing.

RESULTS

For the CVS, the best sensitivity (80.3%, 95% CI 72.4-86.4; specificity 66.7%, 95% CI 55.6-76.1) was obtained for a screener test combination of a fail on high contrast VA (>0.19 LogMAR) OR low contrast VA (>0.39 LogMAR) OR near VA (>N11.9). A screener test combination of high contrast VA OR near VA gave sensitivity of 79.5% (71.5-85.7) and specificity 67.9% (57-77.3). For the FVS, the best sensitivity was obtained for a test combination of a fail on high contrast VA OR low contrast VA OR near VA (sensitivity 82%, 95% CI 74.2-87.8; specificity 61.5%, 95% CI 50.4-71.6). A screener test combination of low contrast VA alone gave sensitivity of 75.4% (67.1-82.2) and specificity 76.9% (66.4-84.9). Significant improvements in LVQoL were found, with a significant correlation between gain in VA with new spectacles and improvement in LVQoL.

CONCLUSIONS

The vision screeners are effective tools for detecting those with reduced vision. Further work is required to determine their effectiveness as a tool for encouraging older people to engage in regular eyecare.

[Modern testing theory and its application in the field of health measurement]

This paper briefly introduces item response theory (IRT) as a typical representation of modern testing theory (MTT), and systematically reviews the processes and contents of the application of IRT in the area of health measurement, including, for example, item bank development, scale revision and computerized adaptive testing. The author presents the potential benefits and the notable problems during health measuring by IRT. Then, the author asserts the need for thorough assessment of feasibility when using the IRT in patient-reported outcome research. Further research based on IRT and computerized adaptive testing in health measurement will be carried out in the field of medical care including traditional Chinese medicine and integrative medicine.

Low vision rehabilitation plans comparing two intake methods

PURPOSE

This qualitative study investigates possible differences in identified rehabilitation needs indicated by the usual intake procedures at a Multidisciplinary Rehabilitation Center (MRC) for visually impaired persons compared with those indicated by the use of a structured Dutch version [based on the International Classification of the Disability, Functioning and Health (ICF)] of the Activity Inventory (D-AI).

METHODS

Twenty patients who enrolled at the MRC received a D-AI assessment by telephone, in addition to the usual intake. All patients received usual care, based on rehabilitation needs identified by the usual intake procedure at the MRC. Rehabilitation needs identified at the MRC were obtained from patient files retrospectively and were compared with rehabilitation needs identified by the D-AI.

RESULTS

The mean number of rehabilitation needs reported in the patient files was 6.9 (± 5.1) vs. 24.0 (± 11.2) using the D-AI. Only 22.6% (± 14.3) of the rehabilitation needs identified by the D-AI were present in the patient files; 79.3% (± 28.2) of the rehabilitation needs reported in the patient files were identified by the D-AI. Overall agreement corrected for chance between both intake methods revealed a fair Cohen kappa of 0.27.

CONCLUSIONS

At the MRC, more needs were revealed using the D-AI compared with the usual intake procedure. The systematic character of the D-AI prevents important topics being overlooked. In the usual intake, it was not clear whether needs were investigated from the patient's perspective. This may hamper (medical) communication and shared decision making about the rehabilitation program that needs to be followed. Moreover, using the unstructured information from the patient files makes it difficult to evaluate rehabilitation outcomes. With the D-AI, although an extensive overview of rehabilitation needs is produced, it remains difficult to focus on the most relevant needs. However, after assessment with the D-AI, all aspects of the ICF, Disability, and Health scheme can be discussed in a process of shared decision making, which leads to the final determination of rehabilitation goals.

Re-evaluating a vision-related quality of life questionnaire with item response theory (IRT) and differential item functioning (DIF) analyses

BACKGROUND

For the Low Vision Quality Of Life questionnaire (LVQOL) it is unknown whether the psychometric properties are satisfactory when an item response theory (IRT) perspective is considered. This study evaluates some essential psychometric properties of the LVQOL questionnaire in an IRT model, and investigates differential item functioning (DIF).

METHODS

Cross-sectional data were used from an observational study among visually-impaired patients (n = 296). Calibration was performed for every dimension of the LVQOL in the graded response model. Item goodness-of-fit was assessed with the S-X(2)-test. DIF was assessed on relevant background variables (i.e. age, gender, visual acuity, eye condition, rehabilitation type and administration type) with likelihood-ratio tests for DIF. The magnitude of DIF was interpreted by assessing the largest difference in expected scores between subgroups. Measurement precision was assessed by presenting test information curves; reliability with the index of subject separation.

RESULTS

All items of the LVQOL dimensions fitted the model. There was significant DIF on several items. For two items the maximum difference between expected scores exceeded one point, and DIF was found on multiple relevant background variables. Item 1 'Vision in general' from the "Adjustment" dimension and item 24 'Using tools' from the "Reading and fine work" dimension were removed. Test information was highest for the "Reading and fine work" dimension. Indices for subject separation ranged from 0.83 to 0.94.

CONCLUSIONS

The items of the LVQOL showed satisfactory item fit to the graded response model; however, two items were removed because of DIF. The adapted LVQOL with 21 items is DIF-free and therefore seems highly appropriate for use in heterogeneous populations of visually impaired patients.

Feasibility of the Dutch ICF Activity Inventory: a pilot study

Background

Demographic ageing will lead to increasing pressure on visual rehabilitation services, which need to be efficiently organised in the near future. The Dutch ICF Activity Inventory (D-AI) was developed to assess the rehabilitation needs of visually impaired persons. This pilot study tests the feasibility of the D-AI using a computer-assisted telephone interview.

Methods

In addition to the regular intake, the first version of the D-AI was assessed in 20 patients. Subsequently, patients and intake assessors were asked to fill in an evaluation form. Based on these evaluations, a new version of the D-AI was developed.

Results

Mean administration time of the D-AI was 88.8 (± 41.0) minutes. Overall, patients and assessors were positive about the D-AI assessment. However, professionals and 60% of the patients found the administration time to be too long. All included items were considered relevant and only minor adjustments were recommended.

Conclusion

The systematic character of the revised D-AI will prevent topics from being overlooked and indicate which needs have the highest priority from a patient-centred perspective. Moreover, ongoing assessment of the D-AI will enhance evaluation of the rehabilitation process. To decrease administration time, in the revised D-AI only the top priority goals will be fully assessed. Using the D-AI, a rehabilitation plan based on individual needs can be developed for each patient. Moreover, it enables better evaluation of the effects of rehabilitation. A larger validation study is planned.

A multilevel item response theory model was investigated for longitudinal vision-related quality-of-life data

OBJECTIVE

To investigate how a multilevel item response theory (IRT) model for longitudinal dependent data could provide average and individual quality-of-life outcomes of low-vision rehabilitation.

STUDY DESIGN AND SETTING

In a nonrandomized longitudinal design, visually impaired older patients (n=296) were referred to multidisciplinary rehabilitation or to an optometric service. The five-dimensional Low Vision Quality of Life Questionnaire was administered at four time points. The IRT model was characterized by the graded response model for rating scales. Covariates were added to the model, mainly to correct for missing data. The invariance assumption across time points was investigated.

RESULTS

Average and individual rehabilitation effects were estimated. For multidisciplinary rehabilitation, significant average deterioration was seen on three dimensions after 4.4 years. Many individuals in the optometric service group significantly improved on the "reading small print" dimension (18.5%); in both groups, many individuals significantly deteriorated on "visual (motor) skills" (22.2-30.0%). Invariance across time points could be assumed for all dimensions, except for "adjustment." Gender, education, visual acuity, and health status were significantly associated with the outcome.

CONCLUSION

We present how a multilevel IRT model can be applied to describe longitudinal dependent vision-related quality-of-life data, while focusing on average and individual effects.

Co-morbidity and visual acuity are risk factors for health-related quality of life decline: five-month follow-up EQ-5D data of visually impaired older patients

Background

Co-morbidity is a common phenomenon in the elderly and is considered to be a major threat to quality of life (QOL). Knowledge of co-existing conditions or patient characteristics that lead to an increased QOL decline is important for individual care, and for public health purposes. In visually impaired older adults, it remains unclear which co-existing conditions or other characteristics influence their health-related QOL. Our aim was to present a risk profile of characteristics and conditions which predict deterioration of QOL in visually impaired older patients.

Methods

Analyses were performed on data from an observational study among 296 visually impaired older patients from four Dutch hospitals. QOL was measured with the EuroQol-5D (EQ-5D) at baseline and at five-month follow-up. Nine co-existing condition categories (musculoskeletal; diabetes; heart; hypertension; chronic obstructive pulmonary disease (COPD) or asthma; hearing impairment; stroke; cancer; gastrointestinal conditions) and six patient characteristics (age; gender; visual acuity; social status; independent living; rehabilitation type) were tested in a linear regression model to determine the risk profile. The model was corrected for baseline EQ-5D scores. In addition, baseline EQ-5D scores were compared with reference scores from a younger visually impaired population and from elderly in the general population.

Results

From the 296 patients, 50 (16.9%) were lost to follow-up. Patients who reported diabetes, COPD or asthma, consequences of stroke, musculoskeletal conditions, cancer, gastrointestinal conditions or higher logMAR Visual Acuity values, experienced a lower QOL. After five months, visual acuity, musculoskeletal conditions, COPD/asthma and stroke predicted a decline in QOL (R² = 0.20). At baseline, the visually impaired older patients more often reported moderate or severe problems on most EQ-5D dimensions than the two reference groups.

Conclusion

In visually impaired older patients, visual acuity, musculoskeletal conditions, COPD/asthma and stroke predicted a relatively rapid decline in health-related QOL. With this risk profile, a specific referral by the ophthalmologist to another sub-specialty may have a beneficial effect on the patient's health-related QOL. A referral by the ophthalmologist or optometrist to a multidisciplinary rehabilitation service seems appropriate for some patients with co-morbidity. The current results need to be confirmed in studies using pre-structured questionnaires to assess co-morbidity.

Additional psychometric information and vision-specific questionnaires are available for age-related macular degeneration

PURPOSE

To present psychometric information and studies dealing with questionnaires for age-related macular degeneration (AMD) and visually impaired patients in addition to the study by Finger et al. "Quality of life in AMD: a review of available vision-specific psychometric tools". We propose that their literature search should not have focused solely on the specific eye disease AMD.

METHODS

The literature search was partly replicated (PubMed) by using "visual impairment" instead of "macular degeneration" as free text words. Psychometric information was obtained from the additional studies. Preliminary results from a differential item functioning (DIF) analysis used to examine the relationship between item responses on the Vision-related quality of life Core Measure (VCM1) of AMD patients versus patients with other eye conditions are discussed.

RESULTS

Eight studies of visually impaired patient populations, including AMD patients, are discussed, with psychometric information from six vision-specific questionnaires. The VCM1 items did not present DIF, which means that the items were equally interpreted by all patients.

CONCLUSIONS

The results on DIF and the additional studies presented here confirm that a specific eye disorder is of minor importance in the choice of a vision-specific questionnaire or, in this case, a literature search.