Group-level Comparisons Research Articles

Evaluation of traffic signal control system using a system-wide performance measure under two-fluid model theory

This study compared the performance of an adaptive traffic control system and a semi-actuated coordinated control system using trip time and stop time relation under the two-fluid model theory. Using the test vehicle data collected for the evaluation of SCATS in Cobb County, Georgia, the parameters were estimated and interpreted. At the initial interpretation, potentially conflicting recommendations could be drawn from the individual route-period group level comparisons and the two-fluid model results. Therefore, a new interpretation combining the two approaches was presented. The new approach resulted in curves representing restricted ranges of the trip time versus stop time relationship. Using the curves and a two-fluid model assumption, the fraction of moving vehicles in the network can be obtained. Unlike the measures adopted in the previous traffic signal system evaluation studies, such as mean travel time and speed, this measure is defined by all time periods and routes data, allowing for a system-wide performance measure. Application of this measure showed that under SCATS approximately 10% more vehicles were moving on end-to-end type routes when the network was most congested and 15% to 20% less vehicles were moving on side-street to side-street type routes over different traffic concentration levels.

A random-effects model for group-level analysis of diffuse optical brain imaging

Diffuse optical imaging is a non-invasive technique for measuring changes in blood oxygenation in the brain. This technique is based on the temporally and spatially resolved recording of optical absorption in tissue within the near-infrared range of light. Optical imaging can be used to study functional brain activity similar to functional MRI. However, group level comparisons of brain activity from diffuse optical data are difficult due to registration of optical sensors between subjects. In addition, optical signals are sensitive to inter-subject differences in cranial anatomy and the specific arrangement of optical sensors relative to the underlying functional region. These factors can give rise to partial volume errors and loss of sensitivity and therefore must be accounted for in combining data from multiple subjects. In this work, we describe an image reconstruction approach using a parametric Bayesian model that simultaneously reconstructs group-level images of brain activity in the context of a random-effects analysis. Using this model, we demonstrate that localization accuracy and the statistical effects size of group-level reconstructions can be improved when compared to individualized reconstructions. In this model, we use the Restricted Maximum Likelihood (ReML) method to optimize a Bayesian random-effects model.

Measuring Quality of Life in Oncologic Breast Surgery: A Systematic Review of Patient-Reported Outcome Measures

Multiple randomized trials demonstrate equivalent survival between BCT and mastectomy, but clinical outcomes research must also evaluate patient satisfaction and quality of life. This review analyzes existing patient-reported outcome (PRO) measures in oncologic breast surgery to assess utility and make recommendations for future research. We performed a systematic literature review to identify PRO measures used in oncologic breast surgery patients. After applying inclusion and exclusion criteria, qualifying instruments were assessed for adherence to international guidelines for health outcomes instrument development and validation. Ten measures underwent development and psychometric evaluation in an oncologic breast surgery population. Five of ten measures (EORTC QLQ BR-23, FACT-B, HBIS, BIBCQ, and BREAST-Q) reported an adequate development and validation process. Three of these 5 measures (EORTC QLQ BR-23, FACT-B, HBIS) focused on non-surgical treatment issues. A fourth instrument (BIBCQ) did not address aesthetic concerns after breast reconstruction. The fifth instrument (BREAST-Q) was developed for use in patients undergoing mastectomy ± reconstruction, but did not address breast-conserving therapy. Overall, two key limitations were noted: 1) surgery-specific issues of breast-conserving surgery patients were not well represented and 2) measures were largely developed without the aid of newer psychometric methods that may improve their clinical utility. Reliable and valid PRO measures in breast cancer patients exist, but even the best instruments do not address all important surgery-specific and psychometric issues of oncologic breast surgery patients. Newer psychometric methods would facilitate development of scales for use in individual patient care as well as group level comparisons.

The Promise and Challenge of Including Multimedia Items in Medical Licensure Examinations: Some Insights From an Empirical Trial

The Comprehensive Osteopathic Medical Licensing Examination conducted a trial of multimedia items in the 2008-2009 Level 3 testing cycle to determine (1) if multimedia items were able to test additional elements of medical knowledge and skills and (2) how to develop effective multimedia items. Forty-four content-matched multimedia and text multiple-choice items were randomly delivered to Level 3 candidates. Logistic regression and paired-samples t tests were used for pairwise and group-level comparisons, respectively. Nine pairs showed significant differences in either difficulty or/and discrimination. Content analysis found that, if text narrations were less direct, multimedia materials could make items easier. When textbook terminologies were replaced by multimedia presentations, multimedia items could become more difficult. Moreover, a multimedia item was found not uniformly difficult for candidates at different ability levels, possibly because multimedia and text items tested different elements of a same concept. Multimedia items may be capable of measuring some constructs different from what text items can measure. Effective multimedia items with reasonable psychometric properties can be intentionally developed.

Retired Status and Older Adults’ 10-Year Drinking Trajectories

Little research has examined the role of retirement in shaping late-life drinking careers, and it has generally been limited to cross-sectional designs or short-term follow-ups that emphasize group-level comparisons of retirees and nonretirees. The purpose of this study was to determine the following: (a) the effect of retired status on older adults' 10-year within-person drinking trajectories and (b) whether age, gender, income, health, and problem-drinker status account for or moderate this effect. We first estimated older adults' (baseline M= 62 years; n = 595) 10-year within-person drinking trajectories using three successively predictive multilevel regression models: unconditional growth, retired status alone, and retired status controlling for covariates. Next, we determined whether inclusion of Retired Status x Covariate interactions would improve prediction of the trajectories. Participants' drinking frequency declined moderately over the 10-year interval, and retired status hastened the decline. However, this effect disappeared once covariates were added to the model: Baseline poorer health, lower income, and current problem-drinker status predicted steeper decline in drinking frequency, whereas former problem-drinker status predicted slower decline. Lower income and current drinking problems also predicted steeper declines in amount of alcohol consumed. There were no statistically significant or uniquely contributive interactions between retired status and age, gender, health, income, or drinking problems for predicting late-life drinking trajectories. Baseline health, income, and problem-drinking history are more important than retired status for predicting older adults' long-term within-person drinking trajectories. These factors-and recency of drinking problems-should be considered in future studies of retirement and late-life drinking patterns.

Comparative analysis of two FFQ

To examine the utility of a shorter FFQ compared with a longer FFQ, both of which are commonly used in Australia. Comparative study. Community setting. One hundred and fifty-nine men (mean 55 (sem 7) years) screened for participation in an intervention study completed both the Commonwealth Scientific and Industrial Research Organisation FFQ and the Cancer Council of Victoria FFQ. Agreement between both questionnaires was assessed according to Bland-Altman plots and limits of agreement (LOA) and ordinary least products regression to test for the presence of fixed and proportional bias. There was good relative agreement between the methods for energy and macronutrients (Pearson's correlation coefficients: energy r = 0.7, protein r = 0.6, fat r = 0.8, carbohydrate r = 0.7, alcohol r = 0.8; P < 0.01). Mean group-level agreement for the majority of nutrients (70 %) fell between 80 % and 110 %. According to the criteria used (maximum LOA was 50-200 % and no significant proportional bias), there was acceptable agreement between the FFQ for energy and total saturated and monounsaturated fat, but not for protein, carbohydrate and fibre. Micronutrients that did not meet the agreement criteria including calcium, iron, thiamin, niacin, riboflavin and folate. When the data were analysed according to quintiles, the majority of subjects were either in exactly the same quintile or within one quintile for most nutrients, and 1-2 % were grossly misclassified by three or four quintiles. We conclude that there is sufficient agreement between the instruments for group-level comparisons in men, but they are not interchangeable for estimation of individual intakes.

Individual differences in cortisol responses to fear and frustration during middle childhood

The purpose of this study was to examine individual differences in the activation and regulation of the hypothalamic–pituitary–adrenal (HPA) axis in prepubertal children after exposure to two different stress modalities and to evaluate the utility of an individual differences approach to the examination of HPA axis functioning. After a 30-min controlled baseline period, 73 7-year-olds (40 boys and 33 girls) were randomly assigned to a validity check condition or one of two experimental tasks designed to elicit fear or frustration. This was followed by a 60-min controlled regulation phase. A total of 17 saliva samples were collected, including 12 poststress samples at 5-min intervals. There was a significant stress modality effect, with children exposed to the fear condition reaching peak cortisol levels at 25 min poststress and those exposed to the frustration condition reaching peak levels at 45 min poststress. There was no difference in peak cortisol levels between the stress modalities. Individual variability across conditions was significant, with participants reaching peak levels as early as 10 min poststress and as late as 60 min poststress. Our data suggest that analysis of individual curves prior to making group-level comparisons may improve the explanatory power of HPA axis behavior models.

A review of participation instruments based on the International Classification of Functioning, Disability and Health

Purpose. To identify and review instruments which assess participation as defined by the International Classification of Functioning, Disability and Health (ICF).Methods. A systematic search of the literature was conducted. Data related to the content, administration, scoring, reliability, validity and responsiveness was abstracted.Results. Eleven instruments met the inclusion criteria. Seven instruments include questions with content from Chapters 4 to 9 in the ICF activities and participation component. Four instruments exclude Chapter 5 (self-care). Most of the instruments assess subjective aspects of participation. Evidence on reliability was available for 10 instruments and the majority met the criteria for group level comparisons for internal consistency and reproducibility in the health conditions assessed. In terms of validity, dimensionality was assessed in eight instruments, with six using modern measurement methods. Participation instruments have been compared with various generic and/or disease-specific instruments, but they have not been compared with each other. Evidence on responsiveness was only available for four instruments.Conclusions. There has been considerable interest in developing instruments to measure participation. To date, the World Health Organisation Disability Assessment Schedule II has undergone the most psychometric testing. Future research must continue to assess these instruments in persons with various health conditions to advance the conceptualisation and measurement of participation.

Study of observed and self-reported HRQL in older frail adults found group-level congruence and individual-level differences

Objective To evaluate the consistency of self-reported health-related quality of life (HRQL) using the Health Utilities Index Mark 2 (HUI2) with observer rated HRQL using the Minimum Data Set Health-Status Index (MDS-HSI). Study Design and Setting Frail older home care clients in Calgary Alberta and Wayne County, Michigan responded to HUI2 questionnaires and were assessed using the Minimum Data Set Home Care tool ( n = 514). HRQL scores were calculated and compared for the HUI2 and the MDS-HSI. The intraclass correlation coefficient (ICC) was used to assess individual level agreement. Results The MDS-HSI provided HRQL scores that consistently averaged 0.10 points higher than HUI2 self-reported HRQL scores overall and within client characteristics. The ICC was 0.46 in the full population but increased to 0.63 when 10% of the sample with the largest discrepant scores was removed. Pain and emotion health attributes showed the lowest level of agreement. Conclusion The MDS-HSI and HUI2 provide analogous group-level results but only moderate individual-level agreement. When HUI2 survey data are not available, the MDS-HSI can be used to substitute for the HUI2 in group-level comparisons but not for individual clinical evaluation comparisons.

Validation of a self-completion measure of breakfast foods, snacks and fruits and vegetables consumed by 9- to 11-year-old schoolchildren

To evaluate the validity and reliability of a dietary recall questionnaire, designed for group-level comparisons of foods eaten at breakfast and intake of fruits, vegetables, sweet items and crisps. Validity was assessed relative to 24-h dietary recall interviews, and reliability by comparing the baseline data with 4-month follow-up data. Fifty-eight schools took part in the validity assessments, with 374 children completing both measures. Reliability was assessed using 29 schools, with 1233 children at baseline and 1033 at follow-up. Children were aged 9-11 years and schools were located in socio-economically deprived areas of Wales. Results indicated moderate to substantial agreements for most foods eaten at breakfast on the day of reporting and fair to moderate agreements for breakfast foods the previous day. For items throughout the rest of the previous day, agreement was fair to substantial during school hours, but slight after school. Correlations were moderate in terms of 'healthy' items and 'unhealthy' items consumed at breakfast on the day of reporting, but weaker for the previous breakfast. Correlations between measures in terms of fruits, vegetables, sweet items and crisps throughout the rest of the previous day were fair to moderate. The measure demonstrated fair to substantial group-level reliability. The questionnaire, while subject to a number of limitations, gives an adequately valid and reliable overview of selected aspects of children's diet. It is likely to be of value at group-level in randomized controlled trials of school-based interventions.

Investigating Diagnostic Substitution and Autism Prevalence Trends

In this issue of Pediatrics , Dr Shattuck presents findings from his intensive statistical analysis of diagnostic substitution in US special education data.1 Diagnostic substitution is one factor potentially contributing to the large observed increase in autism prevalence and, unlike many other possible factors, empirical evaluation of this factor can actually be approached by using existing administrative data. However, analyses of this sort are not without their challenges and complexities. When considering diagnostic substitution in US special education data, we are limited to group-level comparisons. We do not know whether individual children have switched classifications, and of course we can never know whether a given child in a particular birth cohort would have been classified differently had they been born either earlier or later. At best, analyses of this type are merely trying to determine if trends in one classification have the potential to offset those in another. Although Shattuck's models incorporate a number of advantageous features, they essentially distill the assessment of this … Address correspondence to Craig J. Newschaffer, PhD, Department of Epidemiology, Center for Autism and Developmental Disabilities Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Room E6030, Baltimore, MD 21205. E-mail: cnewscha{at}jhsph.edu

Short forms of the Child Perceptions Questionnaire for 11–14-year-old children (CPQ11–14): Development and initial evaluation

BackgroundThe Child Perceptions Questionnaire for children aged 11 to 14 years (CPQ11–14) is a 37-item measure of oral-health-related quality of life (OHRQoL) encompassing four domains: oral symptoms, functional limitations, emotional and social well-being. To facilitate its use in clinical settings and population-based health surveys, it was shortened to 16 and 8 items. Item impact and stepwise regression methods were used to produce each version. This paper describes the developmental process, compares the discriminative properties of the resulting four short-forms and evaluates their precision relative to the original CPQ11–14.MethodsThe item impact method used data from the CPQ11–14 item reduction study to select the questions with the highest impact scores in each domain. The regression method, where the dependent variable was the overall CPQ11–14 score and the independent variables its individual questions, was applied to the data collected in the validity study for the CPQ11–14. The measurement properties (i.e. criterion validity, construct validity, internal consistency reliability and test-retest reliability) of all 4 short-forms were evaluated using the data from the validity and reliability studies for the CPQ11–14.ResultsAll short forms detected substantial variability in children's OHRQoL. The mean scores on the two 16-item questionnaires were almost identical, while on the two 8-item questionnaires they differed by only one score point. The mean scores standardized to 0–100 were higher on the short forms than the original CPQ11–14 (p < 0.001). There were strong significant correlations between all short-form scores and CPQ11–14 scores (0.87–0.98; p < 0.001). Hypotheses concerning construct validity were confirmed: the short-forms' scores were highest in the oro-facial, lower in the orthodontic and lowest in the paediatric dentistry group; all short-form questionnaires were positively correlated with the ratings of oral health and overall well-being, with the correlation coefficient being higher for the latter. The relative validity coefficients were 0.85 to 1.18. Cronbach's alpha and intraclass correlation coefficients ranged 0.71–0.83 and 0.71–0.77, respectively.ConclusionAll short forms demonstrated excellent criterion validity and good construct validity. The reliability coefficients exceeded standards for group-level comparisons. However, these are preliminary findings based on the convenience sampling and further testing in replicated studies involving clinical and general samples of children in various settings is necessary to establish measurement sensitivity and discriminative properties of these questionnaires.

Psychometric properties of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), Japanese version

BackgroundThe importance of evaluating the outcomes of health care from the standpoint of the patient is now widely recognized. The purpose of this study is to develop and test a Japanese version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25).MethodsA Japanese version was developed with a previously standardized method. The questionnaire and optional items were completed by 245 patients with cataracts, glaucoma, or age-related macular degeneration, by 110 others before and after cataract surgery, and by a reference group (n = 31). We computed rates of missing data, measured reproducibility and internal consistency reliability, and tested for convergent and discriminant validity, concurrent validity, known-groups validity, factor structure, and responsiveness to change.ResultsBased on information from the participants, some items were changed to 2-step items (asking if an activity was done, and if it was done, then asking how difficult it was). The near-vision and distance-vision subscales each had 1 item that was endorsed by very few participants, so these items were replaced with items that were optional in the English version. For example, more than 60% of participants did not drive, so the driving question was excluded. Reliability and validity were adequate for all subscales except driving, ocular pain, color vision, and peripheral vision. With cataract surgery, most scores improved by at least 20 points.ConclusionWith minor modifications from the English version, the Japanese NEI VFQ-25 can give reliable, valid, responsive data on vision-related quality of life, for group-level comparisons or for tracking therapeutic outcomes.

Test–retest reliability of health utilities index scores: Evidence from hip fracture

There is relatively little evidence on the test-retest reliability of utility scores derived from multiattribute measures. The objective was to estimate test-retest reliability for Health Utilities Index Mark 2 (HUI2) and Mark 3 (HUI3) utility scores in patients recovering from hip fracture. We enrolled an inception cohort of hip fracture patients within 3 to 5 days of surgery. Baseline assessments included the Functional Independence Measure (FIM), Folstein Mini-Mental State Examinations, and the HUI2 and HUI3 questionnaire. Follow-up assessments at 1, 3, and 6 months also included a global change question. Test-retest reliability was assessed as agreement between 3- and 6-month scores using the intraclass correlation coefficient (ICC). Two approaches were used to classify patients as stable; a third approach based on the generalizability theory was also used. Patients were classified as stable if their FIM overall scores changed by 10 points or fewer and if they classified themselves as having experienced no or only a little change according to their global change question. Complete data at both the 3- and 6-month assessments based on self-report were available for 196 patients; 141 patients with complete data were classified as stable. The ICCs for HUI2 and HUI3 for stable patients were 0.71 and 0.72; the ICCs derived from the generalizability theory were 0.76 and 0.77. Test-retest reliability for HUI in this cohort was similar to reliability estimates for other preference-based multiattribute and generic health-profile measures--in the acceptable range for making valid group-level comparisons.

The PedsQL???

We sought to assess the reliability and validity of the PedsQL 4.0 SF15, a shortened version of the 23-item PedsQL 4.0 Generic Core Scales, which is a pediatric health-related quality of life (HRQoL) instrument, and the PedsQL 3.0 SF22 Asthma Module, a short-form of the PedsQL 3.0 Asthma Module. The PedsQL 4.0 SF15 and the PedsQL 3.0 SF22 Asthma Module were administered by telephone to 125 adolescents (aged 12-18) and 338 parents of children with asthma (aged 2-11). Healthy (n = 451) and chronically ill (n = 422) children, matched by age, respondent status, and ethnicity to the asthma sample, provided data for selected validity tests. The Total Score from the PedsQL 4.0 SF15 and the Asthma Symptoms scale and Treatment Problems scale from the PedsQL 3.0 SF22 Asthma Module were sufficiently reliable for group comparisons (alpha > or = 0.70 across all age groups) in the asthma sample. The PedsQL 4.0 SF15 and the PedsQL 3.0 SF22 Asthma Module were able to distinguish between children of different clinical status and correlated as expected with measures of productivity and family functioning in the asthma sample. The psychometric properties of the PedsQL 4.0 SF15 were generally comparable to those of the original instrument. The Total Score of the PedsQL 4.0 SF15 and the Asthma Symptoms scale of the PedsQL 3.0 SF22 Asthma Module demonstrated the best reliability and validity and should be suitable for group-level comparisons of generic and asthma-specific HRQoL in clinical research studies of children with asthma.

Longitudinal and cross-sectional studies of HIV-1 RNA and DNA loads in blood and the female genital tract

Objective: To examine if correlates of HIV-1 genital shedding in cross-sectional studies can be used to determine the risk of shedding in individual HIV-1-positive women. Study design: Longitudinal samples from blood and cervix were obtained from 18 HIV-1 infected women, and HIV-1 RNA and cell-associated DNA virus, and beta-chemokine levels, were measured. Associations between variables were analyzed at both individual and group level. Results: The variation over time was 2.9-, 2.1-, and 2.3-fold in plasma RNA, PBMC DNA and cervical RNA load, respectively, and reached 6.2-fold in cervical DNA load. Differences were observed between associations in individual- and group-level comparisons, suggesting that a separate reservoir of HIV replication may exist in the genital tract of some women, which is influenced by local environmental factors. Conclusions: Our study underscores the importance of caution during contact with genital fluids at all stages of infection and disease regardless of treatment and HIV-1 blood loads.

Validation and Application of the Dutch Fatigue Scale and the Dutch Exertion Fatigue Scale

PURPOSE To develop and validate self-assessment and proxy assessment versions of two measurement instruments for fatigue, the Dutch Fatigue Scale (DUFS), based on NANDA characteristics and the Dutch Exertion Fatigue Scale (DEFS). METHODS Cross-sectional designs were employed to test content, construct, and criterion-related validity; internal consistency; sensitivity; specificity; and usefulness of both scales among patients with heart disease, postpartum women, and patients living in a home for the elderly. FINDINGS AND CONCLUSIONS ▪ Both scales showed sufficient reliability and validity. ▪ The DUFS (scale coefficient H= .48; KR-20 = .79) is suitable as a measurement instrument for the assessment of patients' fatigue. The DUFS may be used reliably and validly for group-level comparisons. ▪ The DEFS (scale coefficient H= .61; Cronbach's alpha = .91) is suitable as a measurement instrument for the assessment of patients' exertion fatigue. The DEFS may be used reliably and validly in clinical practice at individual level. ▪ Scale items are considered weak if H < .40, medium if H < .50, and strong when H≥.50. Using these criteria, the DUFS may be classified as a high medium scale and the DEFS as a strong scale. ▪ Comparisons of the average DUFS sum scores between nonfatigued and fatigued subjects, as well as between patients with chronic heart failure and post-natal women, and correlation coefficients performed with sociodemographic factors (age, gender, education) show that the DUFS may be used as a reliable and valid measurement tool for the accurate assessment of patients' fatigue. Comparison of the assessments of nonfatigued and fatigued domiciliary heart patients (self-assessment) and their significant others (proxy assessment) also show evidence of the reliability and validity of the DUFS as a measurement tool for the accurate assessment of patients' fatigue. ▪ Comparison of the assessments of nonexertion fatigue and exertion fatigue between domiciliary heart patients (self-assessment) and their significant others (proxy assessment) show that the DEFS is a reliable and valid measurement tool for the accurate assessment of patients' exertion fatigue.

Comparison of analytic approaches for the economic evaluation of new technologies alongside multicenter clinical trials

Background In reporting economic evaluations of clinical trials, results are often stated without a description of the methodology used to derive the cost estimates. We compared methods for measuring costs from multicenter clinical trials to determine the extent to which the methodology affects results. Methods Patient-level data (n = 1849) from 3 multicenter clinical trials of percutaneous coronary revascularization were used to compare 4 methods of estimating costs: 1) hospital charges; 2) hospital charges converted to costs by use of hospital-level cost-to-charge ratios; 3) hospital charges converted to costs by use of department-level cost-to-charge ratios; 4) itemized catheterization laboratory costs with nonprocedural hospital costs generated from department-level cost-to-charge ratios. Results The method used to approximate costs did not affect the main results of the economic comparisons for any of the trials. The magnitude of the cost estimates and the cost differences between treatment groups varied considerably by method, however. Charges were approximately twice as high as hospital cost estimates. At the patient level, costs generated by use of method 1 were within 10% of those generated by use of method 4 for only 5% of patients, compared with 34% and 22% of patients with methods 2 and 3, respectively. Only method 3 produced estimates of between-group cost differences that were consistently within $500 of the reference standard. Conclusion Cost estimates derived from clinical trials in the cardiovascular arena vary substantially according to accounting methodology. Thus, in reporting the results of economic analyses, a detailed description of cost derivation is necessary, particularly when the absolute magnitude of the cost estimates is important to clinical decision-making or policy-level recommendations. For the purposes of group-level comparisons, conversion of hospital charges to costs on the basis of department-level cost-to-charge ratios appears to represent a reasonable compromise between accuracy and ease of implementation. (Am Heart J 2003;145:452-8.)

Psychometric properties of the National Eye Institute Visual Function Questionnaire (NEI-VFQ). NEI-VFQ Field Test Investigators.

To test the reliability and validity of the 51-item Field Test Version of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) across 5 common chronic eye conditions. Prospective observational cohort study of persons with 1 of 5 chronic eye diseases who were scheduled for nonurgent visits in ophthalmology practices or had low vision from any cause, and a reference sample of persons without eye disease. Six university-based ophthalmology practices and the National Eye Institute Clinical Center, Bethesda, Md. Eligible participants had to have 1 of the following eye conditions: age-related cataracts, age-related macular degeneration, diabetic retinopathy, primary open-angle glaucoma, cytomegalovirus retinitis, or low vision from any cause. Each of the 7 sites also enrolled persons in a reference sample. Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error. All eligible persons had to be aged 21 years or older, English speaking, and cognitively able to give informed consent and participate in a health status interview. To provide the data needed to assess the reliability and validity of the 51-item NEI-VFQ, all subjects completed an interview that consisted of the 51-item NEI-VFQ, the Medical Outcomes Study 36-Item Short-Form Health Survey, and at least 1 measure of vision-targeted functional status. Estimates of internal consistency and test-retest reproducibility indicate that the 51-item NEI-VFQ is reliable. Tests of association with other scales and clinical variables support the construct validity of the survey. In this cross-sectional study, the 51-item NEI-VFQ seems to be reliable and valid and should be a useful tool for group-level comparisons of vision-targeted, health-related quality of life in clinical research. Additionally, the psychometric properties of the NEI-VFQ were not influenced by the type or severity of the underlying eye disease, suggesting that the measure will provide reproducible and valid data when used across multiple eye conditions.

ASSESSMENT OF HEALTH-RELATED QUALITY OF LIFE IN KIDNEY TRANSPLANT PATIENTS RECEIVING TACROLIMUS (FK506)-BASED VERSUS CYCLOSPORINE-BASED IMMUNOSUPPRESSION1,2

We evaluated health-related quality of life (HQL) in kidney transplant patients participating in a multicenter, prospective, randomized, phase III trial comparing tacrolimus to cyclosporine. HQL data were available for 303 of 412 patients and assessed with the SF-36 Health Survey and six multi-item scales: Current Health, Health Outlook, Health Distress, Fleming Self-Esteem, Bergner Physical Appearance, and Sexual Functioning. Patients completed surveys at baseline, week 6, and months 3, 6, and 12. The mean change in HQL was evaluated by rejection occurrence and number of hospitalizations. Analysis of covariance was used to model endpoint HQL scores as a function of treatment group and baseline HQL. All scales but two met psychometric standards for group-level comparisons. Baseline demographics and HQL scores were not different by treatment. The mean HQL change was lower for patients with rejection compared with no rejection in seven of eight SF-36 scales and three of four remaining supplemental scales. One year after transplantation, study patients were functioning at least as well as half of the general population in Vitality and Role-Emotional Functioning, moving from the 18th percentile of the U.S. population scores to the 50th percentile for Vitality and 54th percentile for Role-Emotional Functioning. Patients improved their percentile ranking by at least 20 points in five of eight SF-36 scales. Patients with kidney disease demonstrate substantial HQL burden before transplantation, and transplantation is associated with substantial HQL improvements. Rejection is associated with less HQL improvement. Endpoint HQL values were significantly different (P<0.05) by treatment, favoring tacrolimus, in the Bergner Physical Appearance scale, which was designed to measure the HQL impact of side effects such as gingival hyperplasia and facial hirsutism on physical appearance.