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.

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.

Mediating role of multimorbidity in inequality in mortality: a register study on the Danish population.

BACKGROUND: The social inequality in mortality is due to differential incidence of several disorders and injury types, as well as differential survival. The resulting clustering and possible interaction in disadvantaged groups of several disorders make multimorbidity a potentially important component in the health divide. This study decomposes the effect of education on mortality into a direct effect, a pure indirect effect mediated by multimorbidity and a mediated interaction between education and multimorbidity. METHODS: The study uses the Danish population registers on the total Danish population aged 45-69 years. A multimorbidity index based on all somatic and psychiatric hospital contacts as well as prescribed medicines includes 22 diagnostic groups weighted together by their 5 years mortality risk as weight. The Aalen additive hazard model is used to estimate and decompose the 5 years risk difference in absolute numbers of deaths according to educational status. RESULTS: Most (69%-79%) of the effect is direct not involving multimorbidity, and the mediated effect is for low educated women 155 per 100 000 of which 87 is an effect of mediated interaction. For low educated men, the mediated effect is 250 per 100 000 of which 93 is mediated interaction. CONCLUSION: Multimorbidity plays an important role in the social inequality in mortality among middle aged in Denmark and mediated interaction represents 5%-17%. As multimorbidity is a growing challenge in specialised health systems, the mediated interaction might be a relevant indicator of inequities in care of multimorbid patients.

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.

Workplace Violence and Long-term Sickness Absence: Assessment of the Potential Buffering Effect of Social Support in Two Occupational Cohort Studies.

OBJECTIVES: We aimed to determine the effect of workplace violence on long-term sickness absence, and whether social support from supervisors and colleagues buffer this effect. METHODS: Information on workplace violence and social support were derived from the Danish Work Environment Cohort Study in 2000, 2005, and 2010 and the Swedish Longitudinal Occupational Survey of Health in 2006 and 2008. Individual- and joint-effects on register-based long-term sickness absence were determined using logistic regression models for repeated measurements. Cohort-specific estimates were combined in random effect meta-analyses. RESULTS: Workplace violence and low social support were independently associated with a higher risk of long-term sickness absence, and we did not find evidence of an interaction. CONCLUSION: Exposure to workplace violence is a risk factor for long-term sickness absence while social support is associated with a lower risk of long-term sickness absence.

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.

Work-unit social capital and long-term sickness absence: a prospective cohort study of 32 053 hospital employees.

OBJECTIVE: There is a lack of studies investigating social capital at the workplace level in small and relatively homogeneous work-units. The aim of the study was to investigate whether work-unit social capital predicts a lower risk of individual long-term sickness absence among Danish hospital employees followed prospectively for 1 year. METHODS: This study is based on the Well-being in HospitAL Employees cohort. The study sample consisted of 32 053 individuals nested within 2182 work-units in the Capital Region of Denmark. Work-unit social capital was measured with an eight-item scale covering elements of trust, justice and collaboration between employees and leaders. Social capital at the work-unit level was computed as the aggregated mean of individual-level social capital within each work-unit. Data on long-term sickness absence were retrieved from the employers' payroll system and were operationalised as ≥29 consecutive days of sickness absence. We used a 12-point difference in social capital as the metric in our analyses and conducted two-level hierarchical logistic regression analysis. Adjustments were made for sex, age, seniority, occupational group and part-time work at the individual level, and work-unit size, the proportion of female employees and the proportion of part-time work at the work-unit level. RESULTS: The OR for long-term sickness absence associated with a 12-point higher work-unit social capital was 0.73 (95% CI 0.68 to 0.78). Further, we found an association between higher work-unit social capital and lower long-term sickness absence across quartiles of social capital: compared with the lowest quartile, the OR for long-term sickness absence in the highest quartile was 0.51 (95% CI 0.44 to 0.60). CONCLUSION: Our study provides support for work-unit social capital being a protective factor for individual long-term sickness absence among hospital employees in the Capital Region of Denmark.

The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples.

Objective The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons' health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands with mixed clinical conditions and job types to evaluate the comparability of the scale structure. Methods Confirmatory factor and multi-group analyses were conducted in six cross-sectional working samples (total N = 2433) to evaluate and compare a five-factor model structure of the WRFQ (work scheduling demands, output demands, physical demands, mental and social demands, and flexibility demands). Model fit indices were calculated based on RMSEA ≤ 0.08 and CFI ≥ 0.95. After fitting the five-factor model, the multidimensional structure of the instrument was evaluated across samples using a second order factor model. Results The factor structure was robust across samples and a multi-group model had adequate fit (RMSEA = 0.63, CFI = 0.972). In sample specific analyses, minor modifications were necessary in three samples (final RMSEA 0.055-0.080, final CFI between 0.955 and 0.989). Applying the previous first order specifications, a second order factor model had adequate fit in all samples. Conclusion A five-factor model of the WRFQ showed consistent structural validity across samples. A second order factor model showed adequate fit, but the second order factor loadings varied across samples. Therefore subscale scores are recommended to compare across different clinical and working samples.

An Exploratory Study on Using Principal-Component Analysis and Confirmatory Factor Analysis to Identify Bolt-On Dimensions: The EQ-5D Case Study.

OBJECTIVE: Generic preference-based measures such as the EuroQol five-dimensional questionnaire (EQ-5D) are used in economic evaluation, but may not be appropriate for all conditions. When this happens, a possible solution is adding bolt-ons to expand their descriptive systems. Using review-based methods, studies published to date claimed the relevance of bolt-ons in the presence of poor psychometric results. This approach does not identify the specific dimensions missing from the Generic preference-based measure core descriptive system, and is inappropriate for identifying dimensions that might improve the measure generically. This study explores the use of principal-component analysis (PCA) and confirmatory factor analysis (CFA) for bolt-on identification in the EQ-5D. METHODS: Data were drawn from the international Multi-Instrument Comparison study, which is an online survey on health and well-being measures in five countries. Analysis was based on a pool of 92 items from nine instruments. Initial content analysis provided a theoretical framework for PCA results interpretation and CFA model development. PCA was used to investigate the underlining dimensional structure and whether EQ-5D items were represented in the identified constructs. CFA was used to confirm the structure. CFA was cross-validated in random halves of the sample. RESULTS: PCA suggested a nine-component solution, which was confirmed by CFA. This included psychological symptoms, physical functioning, and pain, which were covered by the EQ-5D, and satisfaction, speech/cognition,relationships, hearing, vision, and energy/sleep which were not. These latter factors may represent relevant candidate bolt-ons. CONCLUSIONS: PCA and CFA appear useful methods for identifying potential bolt-ons dimensions for an instrument such as the EQ-5D.

Work ability in rheumatoid arthritis patients: a register study on the prospective risk of exclusion and probability of returning to work.

Objectives: The aim was to study work ability in patients with RA compared with the general population by investigating the rates and risks of long-term sickness absence, unemployment and disability pension, and the chance of returning to work and the changes in these risks over time (1994-2011). Methods: This was a cohort study with up to 17 years of follow-up (mean 6.95 years/person) including 6677 RA patients of working age (identified in the nationwide DANBIO registry) and 56 955 matched controls from the general population. A multi-state model was used to analyse all shifts between the work-related states (long-term sickness absence, unemployment and disability pension, as well as the chance of returning to work) and calculate hazard rates (HRs). Analyses were stratified by disease duration and controlled for socio-demographic factors, physical job exposure and somatic and psychiatric co-morbidities. Results: RA patients had increased risk of long-term sickness absence (e.g. early RA: HR = 4.00, 95% CI: 3.64, 4.30) and disability pension (e.g. established RA: HR = 2.75, 95% CI: 2.54, 2.98) relative to controls. From 1994-99 to 2006-11, a decrease in the effect of established RA was observed [long-term sickness absence: from HR = 2.25 (95% CI: 1.99, 2.54) to 1.63 (95% CI: 1.51, 1.75); and disability pension: from HR = 3.49 (95% CI: 2.83, 4.32) to 2.40 (95% CI: 2.15, 2.69)]. RA patients had a lower chance of returning to work from long-term sickness absence or unemployment (HR = 0.60, HR=0.80), and this did not change over time. Conclusion: RA patients remain at high risk for long-term sickness absence and disability pension, despite a positive development between 1996-99 and 2006-11. Returning to work after sick leave or unemployment remains a challenge for RA patients.

Confirmatory factor analysis of the thyroid-related quality of life questionnaire ThyPRO.

BACKGROUND AND AIM: Thyroid diseases are prevalent and chronic. With treatment, quality of life is restored in most, but not all patients. Construct validity of the thyroid-related quality of life questionnaire, ThyPRO, has been established by multi-trait scaling, but not evaluated with more elaborate methods. The purpose of the present study was to evaluate dimensionality of the ThyPRO scales and to attempt to understand possible item misfit through structural equation modeling for categorical data. METHODS: The current 85-item version of ThyPRO consists of 13 scales, covering domains of physical (4 scales) and mental (2 scales) symptoms, function and well-being (3 scales) and participation/social function (4 scales). The data were collected from a cross-sectional sample of 907 thyroid patients. One-factor confirmatory models were fitted to each scale, and evaluated by model fit statistics (comparative fit index >0.95, root mean square error of approximation <0.08), magnitude of factor loadings, model residual correlations and modification indices (MI). Indications of multi-dimensionality were tested in bi-factor models. Possible item misfit was evaluated in a combined, investigational model. RESULTS: Each ThyPRO scale was adequately represented by a unidimensional model after minor revisions. Eleven items were identified in the unidimensional models as potentially misfitting and were investigated further by multidimensional modeling. CONCLUSION: Elaborate psychometric modeling supported the construct validity of the ThyPRO. However, 11 potentially misfitting items and 18 items with local dependence to other items are candidates for removal in future item reduction processes.

Prediction of future labour market outcome in a cohort of long-term sick-listed Danes.

BACKGROUND: Targeted interventions for the long-term sick-listed may prevent permanent exclusion from the labour force. We aimed to develop a prediction method for identifying high risk groups for continued or recurrent long-term sickness absence, unemployment, or disability among persons on long-term sick leave. METHODS: We obtained individual characteristics and follow-up data from the Danish Register of Sickness Absence Compensation Benefits and Social Transfer Payments (RSS) during 2004 to 2010 for 189,279 Danes who experienced a period of long-term sickness absence (4+ weeks). In a learning data set, statistical prediction methods were built using logistic regression and a discrete event simulation approach for a one year prediction horizon. Personalized risk profiles were obtained for five outcomes: employment, unemployment, recurrent sickness absence, continuous long-term sickness absence, and early retirement from the labour market. Predictor variables included gender, age, socio-economic position, job type, chronic disease status, history of sickness absence, and prior history of unemployment. Separate models were built for times of economic growth (2005-2007) and times of recession (2008-2010). The accuracy of the prediction models was assessed with analyses of Receiver Operating Characteristic (ROC) curves and the Brier score in an independent validation data set. RESULTS: In comparison with a null model which ignored the predictor variables, logistic regression achieved only moderate prediction accuracy for the five outcome states. Results obtained with discrete event simulation were comparable with logistic regression. CONCLUSIONS: Only moderate prediction accuracy could be achieved using the selected information from the Danish register RSS. Other variables need to be included in order to establish a prediction method which provides more accurate risk profiles for long-term sick-listed persons.

The Aggression Observation Short Form identified episodes not reported on the Staff Observation Aggression Scale--Revised.

The purpose of this study is to evaluate the underreporting of violence and aggression on the Staff Observation Aggression Scale-Revised (SOAS-R) when compared to a simpler assessment: the Aggression Observation Short Form (AOS). During a period of one year, two open and two closed wards gathered data on both the SOAS-R and the AOS for all of their patients. The 22-item SOAS-R is to be filled out after each violent episode. The 3-item AOS is to be filled out during each shift and should also record the absence of violence. The SOAS-R registered 703 incidents and the AOS registered 1,281 incidents. The agreement between the SOAS-R and the AOS was good (kappa = 0.65, 95% CI = 0.62-0.67). Among the 1,281 AOS episodes, 51% were also registered on the SOAS-R. For the 176 AOS episodes with harm, 42% were also registered on the SOAS-R. We found 44% missing registrations on the AOS, primarily for open wards and for patients with short admission lengths. Standard instruments such as the SOAS-R underreport aggressive episodes by 45% or more. Underreporting can be reduced by introducing shorter instruments, but it cannot be completely eliminated.

The predictive value of mental health for long-term sickness absence: the Major Depression Inventory (MDI) and the Mental Health Inventory (MHI-5) compared.

BACKGROUND: Questionnaires are valuable for population surveys of mental health. Different survey instruments may however give different results. The present study compares two mental health instruments, the Major Depression Inventory (MDI) and the Mental Health Inventory (MHI-5), in regard to their prediction of long-term sickness absence. METHOD: Questionnaire data was collected from N = 4153 Danish employees. The questionnaire included the MDI and the MHI-5. The information of long-term sickness absence was obtained from a register. We used Cox regression to calculate covariance adjusted hazard ratios for long-term sickness absence for both measures. RESULTS: Both the MDI and the MHI-5 had a highly significant prediction of long-term sickness absence. A one standard deviation change in score was associated with an increased risk of long-term sickness absence of 27% for the MDI and 37% for the MHI-5. When both measures were included in the same analysis, the MHI-5 performed best. CONCLUSION: In general population surveys, the MHI-5 is a better predictor of long-term sickness absence than the MDI.

A one-item workability measure mediates work demands, individual resources and health in the prediction of sickness absence.

OBJECTIVES: The study tested the hypothesis that a one-item workability measure represented an assessment of the fit between resources (the individuals' physical and mental health and functioning) and workplace demands and that this resource/demand fit was a mediator in the prediction of sickness absence. We also estimated the relative importance of health and work environment for workability and sickness absence. METHODS: Baseline data were collected within a Danish work and health survey (3,214 men and 3,529 women) and followed up in a register of sickness absence. Probit regression analysis with workability as mediator was performed for a binary outcome of sickness absence. The predictors in the analysis were as follows: age, social class, physical health, mental health, number of diagnoses, ergonomic exposures, occupational noise, exposure to risks, social support from supervisor, job control and quantitative demands. RESULTS: High age, poor health and ergonomic exposures were associated with low workability and mediated by workability to sickness absence for both genders. Low social class and low quantitative demands were associated with low workability and mediated to sickness absence among men. The mediated part was from 11 to 63 % of the total effect for the significant predictors. CONCLUSION: Workability mediated health, age, social class and ergonomic exposures in the prediction of sickness absence. The health predictors had the highest association with both workability and sickness absence; physical work environment was higher associated with the outcomes than psychosocial work environment. However, the explanatory value of the predictors for the variance in the model was low.

The Danish national return-to-work program--aims, content, and design of the process and effect evaluation.

The Danish national return-to-work (RTW) program aims to improve the management of municipal sickness benefit in Denmark. A study is currently ongoing to evaluate the RTW program. The purpose of this article is to describe the study protocol. The program includes 21 municipalities encompassing approximately 19 500 working-age adults on long-term sickness absence, regardless of reason for sickness absence or employment status. It consists of three core elements: (i) establishment of multidisciplinary RTW teams, (ii) introduction of standardized workability assessments and sickness absence management procedures, and (iii) a comprehensive training course for the RTW teams. The effect evaluation is based on a parallel group randomized trial and a stratified cluster controlled trial and focuses on register-based primary outcomes - duration of sickness absence and RTW - and questionnaire-based secondary outcomes such as health and workability. The process evaluation utilizes questionnaires, interviews, and municipal data. The effect evaluation tests whether participants in the intervention have a (i) shorter duration of full-time sickness absence, (ii) longer time until recurrent long-term sickness absence, (iii) faster full RTW, (iv) more positive development in health, workability, pain, and sleep; it also tests whether the program is cost-effective. The process evaluation investigates: (i) whether the expected target population is reached; (ii) if the program is implemented as intended; (iii) how the beneficiaries, the RTW teams, and the external stakeholders experience the program; and (iv) whether contextual factors influenced the implementation. The program has the potential to contribute markedly to lowering human and economic costs and increasing labor force supply. First results will be available in 2013. The trial registrations are ISRCTN43004323, and ISRCTN51445682.

Evaluating construct validity of the second version of the Copenhagen Psychosocial Questionnaire through analysis of differential item functioning and differential item effect.

AIMS: To evaluate the construct validity of the Copenhagen Psychosocial Questionnaire II (COPSOQ II) by means of tests for differential item functioning (DIF) and differential item effect (DIE). METHODS: We used a Danish general population postal survey (n = 4,732 with 3,517 wage earners) with a one-year register based follow up for long-term sickness absence. DIF was evaluated against age, gender, education, social class, public/private sector employment, and job type using ordinal logistic regression. DIE was evaluated against job satisfaction and self-rated health (using ordinal logistic regression), against depressive symptoms, burnout, and stress (using multiple linear regression), and against long-term sick leave (using a proportional hazards model). We used a cross-validation approach to counter the risk of significant results due to multiple testing. RESULTS: Out of 1,052 tests, we found 599 significant instances of DIF/DIE, 69 of which showed both practical and statistical significance across two independent samples. Most DIF occurred for job type (in 20 cases), while we found little DIF for age, gender, education, social class and sector. DIE seemed to pertain to particular items, which showed DIE in the same direction for several outcome variables. DISCUSSION: The results allowed a preliminary identification of items that have a positive impact on construct validity and items that have negative impact on construct validity. These results can be used to develop better shortform measures and to improve the conceptual framework, items and scales of the COPSOQ II. CONCLUSIONS: We conclude that tests of DIF and DIE are useful for evaluating construct validity.

Psychosocial work environment and its association with socioeconomic status. A comparison of Spain and Denmark.

AIMS: The purpose of this study was to describe psychosocial work environment inequalities among wage earners in Spain and Denmark. METHODS: Data came from the Spanish COPSOQ (ISTAS 21) and the Danish COPSOQ II surveys both performed in 2004-05 and based on national representative samples of employees with a 60% response rate. Study population was 3,359 Danish and 6,685 Spanish women and men. Only identical items from both surveys were included to construct 18 psychosocial scales. Socioeconomic status was categorized according to the European Socioeconomic Classification System. Analysis included ordinal logistic regression and multiple correspondence analysis after categorizing all scales. RESULTS: A relationship between socioeconomic status and psychosocial work environment in both Denmark and Spain was observed, with wider social inequalities in Spain for many scales, describing a strong interaction effect between socioeconomic status and country. CONCLUSIONS: Socioeconomic status is related to psychosocial work environment and some adverse psychosocial conditions tend to cluster in lower socioeconomic status groups in both Spain and Denmark. This effect could be modified by a country's characteristics, such as economic and labour market structures, normative regulations and industrial relations including work organization. Hence, preventive strategies to reduce social inequalities in working conditions should consider the combination of actions at the macro and micro levels.

Developing tailored instruments: item banking and computerized adaptive assessment.

Item banks and Computerized Adaptive Testing (CAT) have the potential to greatly improve the assessment of health outcomes. This review describes the unique features of item banks and CAT and discusses how to develop item banks. In CAT, a computer selects the items from an item bank that are most relevant for and informative about the particular respondent; thus optimizing test relevance and precision. Item response theory (IRT) provides the foundation for selecting the items that are most informative for the particular respondent and for scoring responses on a common metric. The development of an item bank is a multi-stage process that requires a clear definition of the construct to be measured, good items, a careful psychometric analysis of the items, and a clear specification of the final CAT. The psychometric analysis needs to evaluate the assumptions of the IRT model such as unidimensionality and local independence; that the items function the same way in different subgroups of the population; and that there is an adequate fit between the data and the chosen item response models. Also, interpretation guidelines need to be established to help the clinical application of the assessment. Although medical research can draw upon expertise from educational testing in the development of item banks and CAT, the medical field also encounters unique opportunities and challenges.