Effect of semaglutide 2.4 mg on physical functioning and weight- and health-related quality of life in adults with overweight or obesity: Patient-reported outcomes from the STEP 1-4 trials.

AIMS: To summarize the effects of semaglutide 2.4 mg on weight-related quality of life (WRQOL) and health-related quality of life (HRQOL), focusing on the confirmatory secondary endpoint of physical functioning. MATERIALS AND METHODS: The STEP 1-4 Phase 3a, 68-week, double-blind, randomized controlled trials assessed the efficacy and safety of semaglutide 2.4 mg versus placebo in individuals with overweight/obesity. WRQOL and HRQOL were assessed by change from baseline to Week 68 in two different but complementary measures, the Impact of Weight on Quality of Life-Lite Clinical Trials Version (IWQOL-Lite-CT; STEP 1 and 2) and the SF-36v2 Health Survey Acute (SF-36v2; STEP 1-4). RESULTS: Superiority for semaglutide 2.4 mg over placebo based on IWQOL-Lite-CT and SF-36v2 physical functioning scores was confirmed in STEP 1 and 2 and in STEP 1, 2 and 4, respectively. At Week 68, a greater proportion of participants treated with semaglutide 2.4 mg than with placebo reached meaningful within-person change (MWPC) thresholds for IWQOL-Lite-CT Physical Function scores in STEP 1 (51.8% vs. 28.3%; p < 0.0001) and STEP 2 (39.6% vs. 29.5%; p = 0.0083) and the MWPC threshold for SF-36v2 Physical Functioning in STEP 1 (39.8% vs. 24.1%; p < 0.0001), STEP 2 (41.0% vs. 27.3%; p = 0.0001) and STEP 4 (18.0% vs. 6.6%; p < 0.0001). All other IWQOL-Lite-CT and SF-36v2 scale scores in STEP 1-4 were numerically improved with semaglutide 2.4 mg versus placebo, except for SF-36v2 Role Emotional in STEP 2. CONCLUSIONS: Semaglutide 2.4 mg significantly improved physical functioning, with greater proportions of participants achieving MWPC compared with placebo, and showed beneficial effects on WRQOL and HRQOL beyond physical functioning.

Estimating anchor-based minimal important change using longitudinal confirmatory factor analysis.

PURPOSE: The minimal important change (MIC) is defined as the smallest within-individual change in a patient-reported outcome measure (PROM) that patients on average perceive as important. We describe a method to estimate this value based on longitudinal confirmatory factor analysis (LCFA). The method is evaluated and compared with a recently published method based on longitudinal item response theory (LIRT) in simulated and real data. We also examined the effect of sample size on bias and precision of the estimate. METHODS: We simulated 108 samples with various characteristics in which the true MIC was simulated as the mean of individual MICs, and estimated MICs based on LCFA and LIRT. Additionally, both MICs were estimated in existing PROMIS Pain Behavior data from 909 patients. In another set of 3888 simulated samples with sample sizes of 125, 250, 500, and 1000, we estimated LCFA-based MICs. RESULTS: The MIC was equally well recovered with the LCFA-method as using the LIRT-method, but the LCFA analyses were more than 50 times faster. In the Pain Behavior data (with higher scores indicating more pain behavior), an LCFA-based MIC for improvement was estimated to be 2.85 points (on a simple sum scale ranging 14-42), whereas the LIRT-based MIC was estimated to be 2.60. The sample size simulations showed that smaller sample sizes decreased the precision of the LCFA-based MIC and increased the risk of model non-convergence. CONCLUSION: The MIC can accurately be estimated using LCFA, but sample sizes need to be preferably greater than 125.

Health and quality of life of patients with haemophilia: A national study of 124 Danish men.

PURPOSE: In the past decades, haemophilia treatment has greatly improved the health of persons with haemophilia (PWH). This study compares PWH to the general population on social conditions and health. METHODS: In December 2021, all Danes with moderate or severe haemophilia A or B, or von Willebrands disease type 3 were invited to participate in an online self-report survey concerning sociodemographic factors, self-rated health, teeth status, chronic health conditions, symptoms and loneliness. This study compares responses from the 124 adult male PWH with responses from a male general population sample (N = 4849). Analyses used logistic regression, controlling for age and highest completed education. RESULTS: Fewer PWH were in the oldest age group (65-84 years). Controlling for age, no significant differences were found regarding cohabitation status or education. Fewer PWH were employed (OR = .48, [.33-.71])-particularly in the 45-64 age group. PWH were less likely to report good health (OR = .49, [.31-.77]). The odds of joint disease was much higher (OR = 13.00, [8.37-20.28]). Also, hypertension (OR = 2.25, [1.13-5.65]) and previous stroke (OR = 2.51, [1.44-3.50]) were more frequent. PWH were more likely to report pain in the arms/hands/legs/hips (OR = 2.94, [1.92-4.52]), but less likely to report pain in the head/neck/shoulder (OR = .66, [.45-.96]). CONCLUSION: The disease burden of haemophilia has improved so PWH resembles the general population in areas such as marriage and education. However, even for young PWH, the disease still imposes a significant burden from hemophilia arthropathy and pain in extremities and joints. Middle-aged PWH also have poorer levels of employment than same-aged peers.

The improved health utility of once-weekly subcutaneous semaglutide 2.4 mg compared with placebo in the STEP 1-4 obesity trials.

AIM: To assess health utility values in the Semaglutide Treatment Effect in People with obesity (STEP) 1-4 trials. MATERIALS AND METHODS: The STEP 1-4 phase 3a, 68-week, double-blind randomized controlled trials assessed the efficacy and safety of semaglutide 2.4 mg versus placebo in individuals with a body mass index (BMI) of 30 kg/m2 or higher or a BMI of 27 kg/m2 or higher and at least one comorbidity (STEP 1, 3 and 4), or a BMI of 27 kg/m2 or higher and type 2 diabetes (STEP 2). Patients received lifestyle intervention plus intensive behavioural therapy in STEP 3. Health-related quality of life was assessed using the Short Form 36-item Health Survey version 2 (SF-36v2) at baseline and week 68. Scores were converted into Short Form Six-Dimension version 2 (SF-6Dv2) utility scores or mapped onto the European Quality of Life Five-Dimension Three-Level (EQ-5D-3L) utility index using UK health utility weights. RESULTS: At week 68, semaglutide 2.4 mg was associated with minor health utility score improvements from baseline (all trials), while scores for placebo typically decreased. SF-6Dv2 treatment differences by week 68 for semaglutide 2.4 mg versus placebo were significant in STEP 1 and 4 (P ≤ .001), but not STEP 2 or 3. EQ-5D-3L treatment differences by week 68 for semaglutide 2.4 mg versus placebo were significant in STEP 1, 2 and 4 (P < .001 for all), but not STEP 3. CONCLUSIONS: Semaglutide 2.4 mg was associated with improvement in health utility scores compared with placebo, reaching statistical significance in STEP 1, 2 and 4.

Estimating meaningful thresholds for multi-item questionnaires using item response theory.

PURPOSE: Meaningful thresholds are needed to interpret patient-reported outcome measure (PROM) results. This paper introduces a new method, based on item response theory (IRT), to estimate such thresholds. The performance of the method is examined in simulated datasets and two real datasets, and compared with other methods. METHODS: The IRT method involves fitting an IRT model to the PROM items and an anchor item indicating the criterion state of interest. The difficulty parameter of the anchor item represents the meaningful threshold on the latent trait. The latent threshold is then linked to the corresponding expected PROM score. We simulated 4500 item response datasets to a 10-item PROM, and an anchor item. The datasets varied with respect to the mean and standard deviation of the latent trait, and the reliability of the anchor item. The real datasets consisted of a depression scale with a clinical depression diagnosis as anchor variable and a pain scale with a patient acceptable symptom state (PASS) question as anchor variable. RESULTS: The new IRT method recovered the true thresholds accurately across the simulated datasets. The other methods, except one, produced biased threshold estimates if the state prevalence was smaller or greater than 0.5. The adjusted predictive modeling method matched the new IRT method (also in the real datasets) but showed some residual bias if the prevalence was smaller than 0.3 or greater than 0.7. CONCLUSIONS: The new IRT method perfectly recovers meaningful (interpretational) thresholds for multi-item questionnaires, provided that the data satisfy the assumptions for IRT analysis.

Establishing thresholds for meaningful within-individual change using longitudinal item response theory.

PURPOSE: Thresholds for meaningful within-individual change (MWIC) are useful for interpreting patient-reported outcome measures (PROM). Transition ratings (TR) have been recommended as anchors to establish MWIC. Traditional statistical methods for analyzing MWIC such as mean change analysis, receiver operating characteristic (ROC) analysis, and predictive modeling ignore problems of floor/ceiling effects and measurement error in the PROM scores and the TR item. We present a novel approach to MWIC estimation for multi-item scales using longitudinal item response theory (LIRT). METHODS: A Graded Response LIRT model for baseline and follow-up PROM data was expanded to include a TR item measuring latent change. The LIRT threshold parameter for the TR established the MWIC threshold on the latent metric, from which the observed PROM score MWIC threshold was estimated. We compared the LIRT approach and traditional methods using an example data set with baseline and three follow-up assessments differing by magnitude of score improvement, variance of score improvement, and baseline-follow-up score correlation. RESULTS: The LIRT model provided good fit to the data. LIRT estimates of observed PROM MWIC varied between 3 and 4 points score improvement. In contrast, results from traditional methods varied from 2 to 10 points-strongly associated with proportion of self-rated improvement. Best agreement between methods was seen when approximately 50% rated their health as improved. CONCLUSION: Results from traditional analyses of anchor-based MWIC are impacted by study conditions. LIRT constitutes a promising and more robust analytic approach to identifying thresholds for MWIC.

Deciding Between SF-6Dv2 Health States: A Think-Aloud Study of Decision-Making Strategies Used in Discrete Choice Experiments.

OBJECTIVE: This study aimed to gain insight into decision-making strategies individuals used when evaluating pairs of SF-6Dv2 health states in discrete choice experiments (DCEs). METHODS: This qualitative, cross-sectional, noninterventional study asked participants to use a think-aloud approach to compare SF-6Dv2 health states in DCEs. Thematic analysis focused on comprehension and cognitive strategies used to compare health states and make decisions. RESULTS: Participants (N = 40) used 3 main strategies when completing DCEs: (1) trading, (2) reinterpretation, and (3) relying on previous experience. Trading was the most common strategy, used by everyone at least once, and involved prioritizing key attributes, such as preferring a health state with significant depression but no bodily pain. Reinterpretation was used by 17 participants and involved reconstructing health states by changing underlying assumptions (eg, rationalizing selecting a health state with significant pain because they could take pain medications). Finally, some (n = 13) relied on previous experience when making decisions on some choice tasks. Participants with experience dealing with pain, for instance, prioritized health states with the least impact in this dimension. CONCLUSIONS: Qualitatively evaluating the decision-making strategies used in DCEs allows researchers to evaluate whether the tasks and attributes are interpreted accurately. The findings from this study add to the understanding of the generation of SF-6Dv2 health utility weights and the validity of these weights (e.g., reinterpreting health states could undermine the validity of DCEs and utility weights), and the overall usefulness of the SF-6Dv2. The methodology described in this study can and should be carried forth in valuing other health utility measures, not just the SF-6Dv2.

Developing a New Generic Health and Wellbeing Measure: Psychometric Survey Results for the EQ-HWB.

OBJECTIVES: The development of measures such as the EQ-HWB (EQ Health and Wellbeing) requires selection of items. This study explored the psychometric performance of candidate items, testing their validity in patients, social carer users, and carers. METHODS: Article and online surveys that included candidate items (N = 64) were conducted in Argentina, Australia, China, Germany, United Kingdom, and the United States. Psychometric assessment on missing data, response distributions, and known group differences was undertaken. Dimensionality was explored using exploratory and confirmatory factor analysis. Poorly fitting items were identified using information functions, and the function of each response category was assessed using category characteristic curves from item response theory (IRT) models. Differential item functioning was tested across key subgroups. RESULTS: There were 4879 respondents (Argentina = 508, Australia = 514, China = 497, Germany = 502, United Kingdom = 1955, United States = 903). Where missing data were allowed, it was low (UK article survey 2.3%; US survey 0.6%). Most items had responses distributed across all levels. Most items could discriminate between groups with known health conditions with moderate to large effect sizes. Items were less able to discriminate across carers. Factor analysis found positive and negative measurement factors alongside the constructs of interest. For most of the countries apart from China, the confirmatory factor analysis model had good fit with some minor modifications. IRT indicated that most items had well-functioning response categories but there was some evidence of differential item functioning in many items. CONCLUSIONS: Items performed well in classical psychometric testing and IRT. This large 6-country collaboration provided evidence to inform item selection for the EQ-HWB measure.

Estimating a Preference-Based Index for Mental Health From the Recovering Quality of Life Measure: Valuation of Recovering Quality of Life Utility Index.

BACKGROUND: There are increasing concerns about the appropriateness of generic preference-based measures to capture health benefits in the area of mental health. OBJECTIVES: The aim of this study is to estimate preference weights for a new measure, Recovering Quality of Life (ReQoL-10), to better capture the benefits of mental healthcare. METHODS: Psychometric analyses of a larger sample of mental health service users (n = 4266) using confirmatory factor analyses and item response theory were used to derive a health state classification system and inform the selection of health states for utility assessment. A valuation survey with members of the UK public representative in terms of age, sex, and region was conducted using face-to-face interviewer administered time-trade-off with props. A series of regression models were fitted to the data and the best performing model selected for the scoring algorithm. RESULTS: The ReQoL-Utility Index (UI) classification system comprises 6 mental health items and 1 physical health item. Sixty-four health states were valued by 305 participants. The preferred model was a random effects model, with significant and consistent coefficients and best model fit. Estimated utilities modeled for all health states ranged from -0.195 (state worse than dead) to 1 (best possible state). CONCLUSIONS: The development of the ReQoL-UI is based on a novel application of item response theory methods for generating the classification system and selecting health states for valuation. Conventional time-trade-off was used to elicit utility values that are modeled to enable the generation of QALYs for use in cost-utility analysis of mental health interventions.

Associations between physical and psychosocial work environment factors and sickness absence incidence depend on the lengths of the sickness absence episodes: a prospective study of 27 678 Danish employees.

OBJECTIVES: This study examined if the association between work environment factors and sickness absence (SA) depended on the inclusion or exclusion of short-term SA episodes. METHODS: We linked the 'Work Environment and Health in Denmark' survey with the 'Danish Register of Work Absences' (n=27 678). Using covariate adjusted Cox regression, we examined the associations between work environment factors and SA by changing the cut-off points for the length of the SA episodes, for example, episodes ≥1 day, ≥6 days and ≥21 days. We examined three physical work environment factors: 'Back bend or twisted', 'Lifting or carrying', 'Wet hands' and three psychosocial work environment factors: 'Poor influence', 'Role conflicts' and 'Bullying'. RESULTS: 'Back bend or twisted' and 'Lifting or carrying' had small significant HRs for SA episodes ≥1 day and large and highly significant HRs for SA episodes ≥6 days and ≥21 days. 'Wet hands' had small significant HRs for SA episodes ≥1 day for both sexes and large and highly significant HR for ≥6 days for women. HRs of all three psychosocial factors were highly significant for SA episodes ≥1 day and ≥6 days for both sexes, and 'Poor influence' and 'Role conflicts' were significant for SA episodes ≥21 days for women. CONCLUSIONS: The physical work factors had higher associations with SA when SA episodes of 1-5 days were excluded and focus was on SA episodes ≥6 days. The psychosocial work factors were strongly associated with SA both with and without SA episodes of 1-5 days included in the analyses.

An item response theory analysis of an item pool for the recovering quality of life (ReQoL) measure.

PURPOSE: ReQoL-10 and ReQoL-20 have been developed for use as outcome measures with individuals aged 16 and over, experiencing mental health difficulties. This paper reports modelling results from the item response theory (IRT) analyses that were used for item reduction. METHODS: From several stages of preparatory work including focus groups and a previous psychometric survey, a pool of items was developed. After confirming that the ReQoL item pool was sufficiently unidimensional for scoring, IRT model parameters were estimated using Samejima's Graded Response Model (GRM). All 39 mental health items were evaluated with respect to item fit and differential item function regarding age, gender, ethnicity, and diagnosis. Scales were evaluated regarding overall measurement precision and known-groups validity (by care setting type and self-rating of overall mental health). RESULTS: The study recruited 4266 participants with a wide range of mental health diagnoses from multiple settings. The IRT parameters demonstrated excellent coverage of the latent construct with the centres of item information functions ranging from - 0.98 to 0.21 and with discrimination slope parameters from 1.4 to 3.6. We identified only two poorly fitting items and no evidence of differential item functioning of concern. Scales showed excellent measurement precision and known-groups validity. CONCLUSION: The results from the IRT analyses confirm the robust structure properties and internal construct validity of the ReQoL instruments. The strong psychometric evidence generated guided item selection for the final versions of the ReQoL measures.

Disability pension among persons with chronic disease: Differential impact of a Danish policy reform.

BACKGROUND: In 2013, Denmark implemented a reform that tightened the criteria for disability pension, expanded a subsidized job scheme ('flexi-job') and introduced a new vocational rehabilitation scheme. The overall aim of the reform was to keep more persons attached to the labour market. This study investigates the impact of the reform among persons with chronic disease and whether this impact differed across groups defined by labour market affiliation and chronic disease type. METHODS: The study was conducted as a register-based, nationwide cohort study. The study population included 480 809 persons between 40 and 64 years of age, who suffered from at least one of six chronic diseases. Hazard ratios (HR) and 95% confidence intervals (CI) of being awarded disability pension or flexi-job in the 5 years after vs. the 5 years prior to the reform were estimated. RESULTS: Overall, the probability of being awarded disability pension was halved after the reform (HR = 0.49, CI: 0.47-0.50). The impact was largest for persons receiving sickness absence benefits (HR = 0.31, CI: 0.24-0.39) and for persons with functional disorders (HR = 0.38, CI: 0.32-0.44). Also, the impact was larger for persons working in manual jobs than for persons working in non-manual jobs. The probability of being awarded a flexi-job was decreased by one-fourth (HR = 0.76, CI: 0.74-0.79) with the largest impact for high-skilled persons working in non-manual jobs. CONCLUSION: Access to disability pension and flexi-job decreased after the reform. This impact varied according to labour market affiliation and chronic disease type.

Developing a New Version of the SF-6D Health State Classification System From the SF-36v2: SF-6Dv2.

OBJECTIVE: The objective of this study was to develop the classification system for version of the SF-6D (SF-6Dv2) from the SF-36v2. SF-6Dv2 is an improved version of SF-6D, one of the most widely used generic measures of health for the calculation of quality-adjusted life years. STUDY DESIGN AND SETTING: A 3-step process was undertaken to generate a new classification system: (1) factor analysis to establish dimensionality; (2) Rasch analysis to understand item performance; and (3) tests of differential item function. To evaluate robustness, Rasch analyses were performed in multiple subsets of 2 large cross-sectional datasets from recently discharged hospital patients and online patient samples. RESULTS: On the basis of factor analysis, other psychometric evidence, cross-cultural considerations, and amenability to valuation, the 6-dimension classification used in SF-6D was maintained. SF-6Dv2 resulted in the following modifications to SF-6D: a simpler classification of physical function with clearer separation between levels; a more detailed 5-level description of role limitations; using negative wording to describe vitality; and using pain severity rather than pain interference. CONCLUSIONS: The SF-6Dv2 classification system describes more distinct levels of health than SF-6D, changes the descriptions used for a number of dimensions and provides clearer wording for health state valuation. The second stage of the study has developed a utility value set using discrete choice methods so that the measure can be used in health technology assessment. Further work should investigate the psychometric characteristics of the new instrument.

Effects of a participatory organisational, core work task focused workplace intervention on employees' primary healthcare consultations: secondary analysis of a cluster RCT.

OBJECTIVES: We aimed to examine whether a participatory organisational workplace intervention focusing on core tasks at work resulted in lower primary healthcare utilisation of employees. METHODS: The cluster randomised controlled trial included 78 preschools, 44 allocated to the intervention group (1745 employees) and 34 allocated to the control group (1267 employees). The intervention aimed to involve employees in improving the psychosocial work environment while focusing on core tasks at work. Using Poisson regression, we tested the rate ratios (RRs) of consultations in the intervention compared with the control group in terms of all consultations in primary healthcare and general practitioner (GP) consultations, respectively, per person-year during 31 months of follow-up. The fully adjusted model included adjustment for sex, age, job group, workplace type and size, and previous primary healthcare utilisation. RESULTS: During the follow-up, intervention group employees had 11.0 consultations/person-year, while control group employees had 11.6 consultations/person-year (RR 0.97, 95% CI 0.92 to 1.01). Employees in the intervention group had 7.5 GP consultations/person-year, while control group employees had 8.2 GP consultations/person-year (RR 0.95, 95% CI 0.90 to 0.99). Post hoc analyses indicated that the effect of the intervention was particularly strong in employees in preschools with a moderate or high level of implementation. CONCLUSIONS: The participatory organisational workplace intervention focusing on core tasks at work among preschool employees had a small, statistically non-significant effect on overall primary healthcare utilisation and a small, statistically significant effect on GP consultations. These results suggest a beneficial effect of the participatory organisational intervention on employees' health. TRIAL REGISTRATION NUMBER: ISRCTN16271504.

Determinants of voluntary early retirement for older workers with and without chronic diseases: A Danish prospective study.

Aims: This study explored differences in determinants (i.e. health-related, work-related and social factors) of voluntary early retirement between older workers with and without chronic diseases in Denmark. Methods: Workers aged 56-64 years who were members of a voluntary early retirement scheme were selected from the Danish National Working Environment Survey (2008-2009) and were followed in a public register for four years. Cox regression analyses were performed separately for older workers with and without chronic disease to identify the associations between determinants and voluntary early retirement. To explore the differences between groups, an interaction term between the determinant and having a chronic disease was included in the analyses for the total population. Results: Among 1861 eligible older workers, determinants associated with a higher risk of voluntary early retirement included poorer self-rated health, more depressive symptoms, a higher physical workload, lower job satisfaction and lower influence at work. For older workers with a chronic disease (n=1185), the presence of work-family conflict was also associated with a higher risk of voluntary early retirement, whereas for those with no chronic disease (n=676), a poorer relationship with colleagues was an additional determinant. Higher emotional demands, a higher work pace and higher quantitative demands were not significantly associated with voluntary early retirement for either group. None of the interaction terms was found to be statistically significant (p>0.05). Conclusions: Determinants associated with voluntary early retirement did not significantly differ between older workers with or without a chronic disease in Denmark. We conclude that several health-related, work-related and social factors are important for prolonged labour force participation of older workers (with and without a chronic disease).

Effort-reward imbalance at work and weight changes in a nationwide cohort of workers in Denmark.

OBJECTIVE: To investigate the relation between effort-reward imbalance (ERI) at work and subsequent weight changes. METHODS: We included participants from a population-based cohort of workers in Denmark (mean age = 47 years, 54% women) with two (n = 9005) or three repeated measurements (n = 5710). We investigated the association between (a) ERI (ie, the mismatch between high efforts spent and low rewards received at work) at baseline and weight changes after a 2-year follow-up (defined as ≥5% increase or decrease in body mass index (BMI) vs stable), and (b) onset and remission of ERI and subsequent changes in BMI. Using multinomial logistic regression we calculated risk ratios (RR) and 95% confidence intervals (CI), adjusted for sex, age, education, cohabitation, migration background, and follow-up time. RESULTS: After 2 years, 15% had an increase and 13% a decrease in BMI. Exposure to ERI at baseline yielded RRs of 1.09 (95% CI: 0.95-1.25) and 1.04 (95% CI: 0.90-1.20) for the increase and decrease in BMI, respectively. There were no differences between sex and baseline BMI in stratified analyses. The onset of ERI yielded RRs of 1.04 (95% CI: 0.82-1.31) and 1.15 (95% CI: 0.84-1.57) for subsequent increase and decrease in BMI. The RRs for the remission of ERI and subsequent increase and decrease in BMI were 0.92 (95% CI: 0.71-1.20) and 0.78 (95% CI: 0.53-1.13), respectively. Of the ERI components, high rewards were associated with a lower risk of BMI increase. CONCLUSION: ERI was not a risk factor for weight changes. Future studies may investigate whether this result is generalizable to other occupational cohorts and settings.

Applying PRO Reference Values to Communicate Clinically Relevant Information at the Point-of-care.

INTRODUCTION: The inclusion of reference values for common patient-reported outcomes (PROs) measures in clinical care settings provides a clinically relevant context for an individual patient's PRO scores. PRO reference values are currently not reported in clinical care settings. This is a missed opportunity, as clinicians are familiar with the presence and interpretation of reference values, commonly provided alongside laboratory test results. Incorporating PRO reference values into clinical PRO reporting requires: an understanding of the clinical purpose, the availability of an appropriate reference value, and graphical representation. METHODS FOR PRO SCORE INTERPRETATION: We present reference value terminology adapted for PROs and discuss important differences between using reference values in the PRO score interpretation compared to other types of clinical measures from clinical chemistry. We outline the basic methodological approaches in obtaining a PRO reference sample and calculating reference intervals. Lastly, we provide recommendations on how to present and use PRO reference values in clinical care settings. DISCUSSION: There is a strong, long-standing discipline behind reference value development and application in psychology and medicine, allowing for both providers and patients to understand comparisons and identify what is "out of range." PRO reference values can be communicated in a wide range of ways within clinical care settings and are adaptable as required to different patient populations or clinical care situations. However, a notable adoption barrier is the expense and methodological expertise needed to establish and apply PRO reference values effectively in clinical encounters.

Health-related quality of life predicted subsequent health care resource utilization in patients with active cancer.

PURPOSE: The objective of this study was to estimate the association between SF-12v2® Health Survey (SF-12v2) scores and subsequent health care resource utilization (HCRU) among patients with cancer. METHODS: We analyzed 18+ year participants in the Medical Expenditure Panel Survey, diagnosed with active cancer or malignancy (n = 647). HCRU was measured by total medical expenditures (MEs) and number of medical events (EVs) in the 6 months following the SF-12v2 assessment. The effect of SF-12v2 scores (physical (PCS) and mental (MCS) component summary scores and the SF-6D health-utility score) on HCRU was estimated using generalized linear models. Estimates were obtained for the entire sample and for the four cancer groups present in the sample: breast, prostate, skin, and lung. RESULTS: For PCS and MCS, a one-point better score was associated with 2% lower MEs (P < 0.001) and 2.5% lower MEs (P = 0.015), respectively. A 0.05-point better SF-6D score was associated with 7% lower MEs (P = 0.003). PCS and SF-6D were more strongly associated with MEs for prostate cancer patients (P = 0.009 and P = 0.003) and PCS was more strongly associated with MEs for skin cancer patients (P = 0.019), compared to other cancer groups. A 1-point better PCS predicted 1% lower EVs, while a 0.05 better SF-6D score predicted 4% lower EVs. CONCLUSIONS: The significant associations between SF-12v2 scores from oncology patients and subsequent HCRU can guide interpretations of SF-12v2 scores in evaluation of therapies and in health policy decisions.

Exploring the item sets of the Recovering Quality of Life (ReQoL) measures using factor analysis.

PURPOSE: This paper presents two studies exploring the latent structure of item sets used in the development of the Recovering Quality of Life mental health outcome measures: ReQoL-10 and ReQoL-20. METHOD: In study 1, 2262 participants completed an initial set of 61 items. In study 2, 4266 participants completed a reduced set of 40 items. Study 2 evaluated two formats of the questionnaires: one version where the items were intermingled and one where the positively worded and negatively worded items were presented as two separate blocks. Exploratory and confirmatory factor analyses were conducted on both datasets where models were specified using ordinal treatment of the item responses. Dimensionality based on the conceptual framework and methods effects reflecting the mixture of positively worded and negatively worded items were explored. Factor invariance was tested across the intermingled and block formats. RESULTS: In both studies, a bi-factor model (study 1: RMSEA = 0.061; CFI = 0.954; study 2: RMSEA = 0.066; CFI = 0.971) with one general factor and two local factors (positively worded questions and negatively worded questions) was preferred. The loadings on the general factor were higher than on the two local factors suggesting that the ReQoL scale scores can be understood in terms of a general factor. Insignificant differences were found between the intermingled and block formats. CONCLUSIONS: The analyses confirmed that the ReQoL item sets are sufficiently unidimensional to proceed to item response theory analysis. The model was robust across different ordering of positive and negative items.

Effect of tardive dyskinesia on quality of life in patients with bipolar disorder, major depressive disorder, and schizophrenia.

PURPOSE: Tardive dyskinesia (TD) is a common but serious hyperkinetic movement disorder and side effect of antipsychotic medications used to treat bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SZ). The purpose of this study was to evaluate health-related quality of life (HRQoL) in a population with diagnoses for BD, MDD, or SZ by comparing patients with TD (n = 197) with those without TD (n = 219). HRQoL in each group was also compared with HRQoL of the general population. METHODS: This study employed a cross-sectional web-based survey. HRQoL was assessed by four instruments: the SF-12 Health Survey, Version 2 (SF-12v2), the Quality of Life Enjoyment and Satisfaction Questionnaire, Short Form (Q-LES-Q-SF), the Social Withdrawal subscale of the Internalized Stigma of Mental Illness Scale (SW-ISMI); and two questions on movement disorders. RESULTS: Patients with TD had significantly worse HRQoL and social withdrawal than those without. The differences were more pronounced for physical HRQoL domains than for mental health domains. Patients with more-severe TD, assessed through either self-rating or clinician rating, experienced significantly worse HRQoL than did those with less-severe TD. The impact of TD was substantially greater in patients with SZ than in those with BD or MDD. Compared with the general population, patients with BD, MDD, or SZ experienced significantly worse HRQoL regardless of TD status, although this deficit in HRQoL was greater among those with TD. CONCLUSIONS: The presence of TD is associated with worse HRQoL and social withdrawal. The most severe impact of TD is on physical aspects of patients' HRQoL.