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

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

Selenium supplementation for patients with Graves' hyperthyroidism (the GRASS trial):Study protocol for a randomized controlled trial

BACKGROUND: Graves’ hyperthyroidism is an autoimmune disease causing hyperfunction of the thyroid gland. The concentration of selenium is high in the thyroid gland and two important groups of enzymes within the thyroid are selenoproteins, that is, they depend on selenium. Selenium may have beneficial effects on autoimmune hypothyroidism and on Graves' orbitopathy, but the effects of selenium on Graves' hyperthyroidism is unknown. We hypothesize that adjuvant selenium may be beneficial in the treatment of Graves' hyperthyroidism. The objective is to investigate if selenium supplementation plus standard treatment with anti-thyroid drugs versus standard treatment with anti-thyroid drugs will lead to a decrease in anti-thyroid drug treatment failure (that is, failure to remain euthyroid, without further treatment, one year after cessation of anti-thyroid drug treatment), faster and longer lasting remission (that is, anti-thyroid drug treatment success), and improved quality of life in patients with Graves’ hyperthyroidism. METHODS AND DESIGN: The trial is an investigator-initiated, randomised, blinded, multicentre clinical trial. Inclusion criteria are: age 18 years or older; diagnosis of active Graves' hyperthyroidism within the last two months; and informed consent. Exclusion criteria are major co-morbidity; previous radioactive iodine treatment; ongoing anti-thyroid drug treatment for more than two months; treatment with immunomodulatory drugs; known allergy towards the components in the selenium and placebo pills; pregnancy or breast-feeding; and intake of selenium supplementation above 70 μg per day. We plan to include 492 participants, randomised (1:1) to two tablets of 100 μg selenium once daily for the 24 to 30 months intervention period versus two identical placebo tablets once daily. The primary outcome is the proportion of participants with anti-thyroid drug treatment failure (see above) at the end of the intervention period (24 to 30 months). Secondary outcomes are: thyroid-specific quality of life during the first year after randomisation; level of thyroid stimulating hormone-receptor antibodies at 18 months after randomisation and at the end of the intervention period (24 to 30 months); hyperthyroid symptoms during the first year after randomisation; eye symptoms during the first year after randomisation, and at the end of the intervention period (24 to 30 months); adverse reactions during the intervention period; and serious adverse events during the intervention period. DISCUSSION: It was of great importance to the initiators of this trial, that the results would be directly applicable to daily clinical practice. Therefore, it was designed as a pragmatic trial: the patients follow their usual treatment at their usual hospitals. In order to still collect high quality data on the clinical course and quality of life, an elaborate trial management system was designed to keep track of patient input, need for trial personnel input and action, and to collect data from medical chart systems. Meticulous follow-up on missing responses to the QoL measurements has been incorporated into the system, to minimise missing quality of life data. Monitoring of adverse reactions and events is achieved by thorough instruction of the participants, surveillance of patient-reported outcomes, and integration with national databases regarding hospitalizations. A very long intervention period was necessary, since patients are not considered in remission until one year after stopping anti-thyroid drugs. Usually, patients are treated for 12 to 18 months with anti-thyroid drugs, yielding a total intervention period of 24 to 30 months. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01611896

Recovering Quality of Life (ReQoL): a new generic self-reported outcome measure for use with people experiencing mental health difficulties†

Outcome measures for mental health services need to adopt a service-user recovery focus. To develop and validate a 10- and 20-item self-report recovery-focused quality of life outcome measure named Recovering Quality of Life (ReQoL). Qualitative methods for item development and initial testing, and quantitative methods for item reduction and scale construction were used. Data from >6500 service users were factor analysed and item response theory models employed to inform item selection. The measures were tested for reliability, validity and responsiveness. ReQoL-10 and ReQoL-20 contain positively and negatively worded items covering seven themes: activity, hope, belonging and relationships, self-perception, well-being, autonomy, and physical health. Both versions achieved acceptable internal consistency, test–retest reliability (>0.85), known-group differences, convergence with related measures, and were responsive over time (standardised response mean (SRM) > 0.4). They performed marginally better than the Short Warwick-Edinburgh Mental Well-being Scale and markedly better than the EQ-5D. Both versions are appropriate for measuring service-user recovery-focused quality of life outcomes. M.B. and J.Co. were members of the research group that developed the Clinical Outcomes in Routine Evaluation (CORE) outcome measures

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