Differential item functioning in the Danish translation of the SF-36

Health-related quality of life and cognitive function after out-of-hospital cardiac arrest; a comparison of prehospital return-of-spontaneous circulation and refractory arrest managed with extracorporeal cardiopulmonary resuscitation

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) for selected refractory out-of-hospital cardiac arrest (OHCA) is increasingly used. Detailed knowledge of health-related quality of life (HRQoL) and long-term cognitive function is limited. HRQoL and cognitive function were assessed in ECPR-survivors and OHCA-survivors with prehospital return of spontaneous circulation after standard advanced cardiac life support (sACLS).

METHODS

Fifteen ECPR-survivors and 22 age-matched sACLS-survivors agreed to participate in this follow-up study. Participants were examined with echocardiography, 6-minute walk test, and neuropsychological testing, and answered HRQoL (EQ-5D-5L and Short Form 36 (SF-36)), and mental health questionnaires.

RESULTS

Most patients were male (73 % and 82 %) and median age at follow-up was similar between groups (55 years and 60 years). Low flow time was significantly longer for ECPR-survivors (86 min vs. 15 min) and lactate levels were significantly higher (14.1 mmol/l vs. 3.9 mmol/l). No between-group difference was found in physical function nor in cognitive function with scores corresponding to the 23rd worst percentile of the general population. SACLS-survivors had HRQoL on level with the Danish general population while ECPR-survivors scored lower in both EQ-5D-5L (index score 0.73 vs. 0.86, p = 0.03, visual analog scale: 70 vs. 84, p = 0.04) and in multiple SF-36 health domains (role physical, bodily pain, general health, and mental health).

CONCLUSIONS

Despite substantially longer low flow times with thrice as high lactate levels, ECPR-survivors were similar in cognitive and physical function compared to sACLS-survivors. Nonetheless, ECPR-survivors reported lower HRQoL overall and related to mental health, pain management, and the perception of limitations in physical role.

Unsupervised item response theory models for assessing sample heterogeneity in patient-reported outcomes measures

PURPOSE

Unsupervised item-response theory (IRT) models such as polytomous IRT based on recursive partitioning (IRTrees) and mixture IRT (MixIRT) models can be used to assess differential item functioning (DIF) in patient-reported outcome measures (PROMs) when the covariates associated with DIF are unknown a priori. This study examines the consistency of results for IRTrees and MixIRT models.

METHODS

Data were from 4478 individuals in the Alberta Provincial Project on Outcome Assessment in Coronary Heart Disease registry who received cardiac angiography in Alberta, Canada, and completed the Hospital Anxiety and Depression Scale (HADS) depression subscale items. The partial credit model (PCM) based on recursive partitioning (PCTree) and mixture PCM (MixPCM) were used to identify covariates associated with differential response patterns to HADS depression subscale items. Model covariates included demographic and clinical characteristics.

RESULTS

The median (interquartile range) age was 64.5(15.7) years, and 3522(78.5%) patients were male. The PCTree identified 4 terminal nodes (subgroups) defined by smoking status, age, and body mass index. A 3-class PCM fits the data well. The MixPCM latent classes were defined by age, disease indication, smoking status, comorbid diabetes, congestive heart failure, and chronic obstructive pulmonary disease.

CONCLUSION

PCTree and MixPCM were not consistent in detecting covariates associated with differential interpretations of PROM items. Future research will use computer simulations to assess these models' Type I error and statistical power for identifying covariates associated with DIF.

Assessment of the Psychometric Properties of the Danish VISA-P

Purpose

The objective of the current study was to conduct a rigorous assessment of the psychometric properties of the Victorian Institute of Sports Assessment-patellar tendinopathy (VISA-P).

Methods

Rasch analysis, confirmatory factor analysis (CFA), and multivariable linear regression were used to assess the psychometric properties of the VISA-P questionnaire in 184 Danish patients with patellar tendinopathy who had symptoms ranging from under 3 months to over 1 year. A group of 100 healthy Danish persons was included as a reference for known-group validation.

Results

The analyses revealed that the 8-item VISA-P did not fit a unidimensional model, yielded at best a 3-factor model, and exhibited differential item functioning (DIF) across healthy subjects versus people with patellar tendinopathy.

Conclusion

VISA-P in its present form does not satisfy a measurement model and is not a robust scale for measuring patellar tendinopathy. A new PROM for patellar tendinopathy should be developed and appropriately validated, and meanwhile, simple pain scoring (e.g., numeric rating scales) and functional tests are suggested as more appropriate outcome measures for studies of patellar tendinopathy.

A New Stopping Criterion for Rasch Trees Based on the Mantel-Haenszel Effect Size Measure for Differential Item Functioning

To detect differential item functioning (DIF), Rasch trees search for optimal splitpoints in covariates and identify subgroups of respondents in a data-driven way. To determine whether and in which covariate a split should be performed, Rasch trees use statistical significance tests. Consequently, Rasch trees are more likely to label small DIF effects as significant in larger samples. This leads to larger trees, which split the sample into more subgroups. What would be more desirable is an approach that is driven more by effect size rather than sample size. In order to achieve this, we suggest to implement an additional stopping criterion: the popular Educational Testing Service (ETS) classification scheme based on the Mantel-Haenszel odds ratio. This criterion helps us to evaluate whether a split in a Rasch tree is based on a substantial or an ignorable difference in item parameters, and it allows the Rasch tree to stop growing when DIF between the identified subgroups is small. Furthermore, it supports identifying DIF items and quantifying DIF effect sizes in each split. Based on simulation results, we conclude that the Mantel-Haenszel effect size further reduces unnecessary splits in Rasch trees under the null hypothesis, or when the sample size is large but DIF effects are negligible. To make the stopping criterion easy-to-use for applied researchers, we have implemented the procedure in the statistical software R. Finally, we discuss how DIF effects between different nodes in a Rasch tree can be interpreted and emphasize the importance of purification strategies for the Mantel-Haenszel procedure on tree stopping and DIF item classification.

Internal Structure of the Work-Family Conflict Questionnaire (WFCQ) in Teacher Teleworking

The interference between family and work roles has led to the development of scales for their measurement. However, instrumental studies of work-family conflict have not been conducted in the context of teacher teleworking during the COVID-19 pandemic. For this reason, the objectives of this study were set to obtain evidence of the internal structure and fairness of the Blanch and Aluja Work-Family Conflict Questionnaire, as well as its association with job satisfaction and other sociodemographic variables. A total of 235 Peruvian school teachers between the ages of 24 and 72 years (M = 43.79 and SD = 9.67) responded to the scale using the online form. The analysis employed the non-parametric item response theory modeling (Mokken scaling analysis). The structure of two correlated factors was confirmed: work conflict in the family (WCF) and family conflict in the work (FCW). Both dimensions were invariant with respect to sex group and educational level. The association of both dimensions with job satisfaction was theoretically convergent, and the gender of the teachers slightly moderated this relationship. The reliability was adequate for group research. Finally, the instrument can be useful in the organizational context of teachers who telework.

Developing a short standard questionnaire for assessing work organization hazards: the Healthy Work Survey (HWS)

Background

At present, no short standard questionnaire exists for assessing and comparing major work organization hazards in the workplaces of the United States.

Methods

We conducted a series of psychometric tests (content validity, factor analysis, differential-item functioning analysis, reliability, and concurrent validity) to validate and identify core items and scales for major work organization hazards using the data from the 2002-2014 General Social Surveys (GSSs), including the Quality of Worklife (QWL) questionnaire. In addition, an extensive literature review was undertaken to find other major work organization hazards which were not addressed in the GSS.

Results

Although the overall validity of the GSS-QWL questionnaire was satisfactory in the psychometric tests, some GSS-QWL items of work-family conflict, psychological job demands, job insecurity, use of skills on the job, and safety climate scales appeared to be weak. In the end, 33 questions (31 GSS-QWL and 2 GSS) were chosen as the least, but best validated core questions and included in a new short standard questionnaire (called the Healthy Work Survey [HWS]). And their national norms were established for comparisons. Furthermore, based on the literature review, fifteen more questions for assessing other significant work organization hazards (e.g., lack of scheduling control, emotional demands, electronic surveillance, wage theft) were included in the new questionnaire. Thus, the HWS includes 48 questions in total for assessing traditional and emerging work organization hazards, which covers seven theoretical domains: work schedule/arrangement, control, support, reward, demands, safety, and justice.

Conclusions

The HWS is a short standard questionnaire for assessing work organization hazards which can be used as a first step toward the risk management of major work organization hazards in the workplaces of the US.

Quality of life in mothers and fathers of children treated for acute lymphoblastic leukaemia in Sweden, Finland and Denmark

Acute lymphoblastic leukaemia (ALL) has a high survival rate, but treatment is lengthy with risk of severe side‐effects, which may also impact parents' health‐related quality of life (HRQOL). We present data on 526 parents of 310 children treated for ALL according to the NOPHO ALL2008‐protocol, in Sweden, Finland and Denmark. Parents were asked to complete the 36‐Item Short Form Survey (SF‐36) at least 6 months after end of treatment and data were compared with Norwegian reference data. Parental background factors were collected via a study‐specific questionnaire. Participating parents scored significantly lower than the reference population on both physical and mental summary indexes, but only surpassed a minimal clinically important difference for the mental summary index (Mental Component Summary [MCS]). Mothers scored lower than fathers in the MCS and stopped working and took care of the affected child more often than the fathers. Higher mental HRQOL was associated with male gender and living in Finland or Denmark (compared to Sweden). Correlations within spouses in physical and mental scores were weak to moderate. In conclusion, ALL negatively affects parental HRQOL, especially the mental domains, even after treatment. Findings suggest that mothers are more affected than fathers and may require extra support.

The Functional Rating Index: Twenty Years of Invalid Measurement

STUDY DESIGN

The 2001 Functional Rating Index (FRI) was not developed under today's standard psychometric analysis. The original data of 108 cases were re-analyzed using Rasch item response theory. In 2015, 2 alternative forms were administered to an additional 140 patients for establishing and perhaps improving its psychometric characteristics.

OBJECTIVE

To evaluate the FRI with item response theory.

SUMMARY OF BACKGROUND DATA

The 2001 FRI data showed internal agreement among items and weak item-total correlation items. The FRI's true reliability and validity were never established.

METHODS

The original 2001 FRI 108 and two new versions with 140 respondents with back pain were compared by Rasch analysis for unidimensionality, local independence, monotonicity, and differential item functioning.

RESULTS

All three versions exhibited more than the requisite single latent construct. The original Form 2001 had two items that were non-monotonic, four with differential item functioning (DIF), five with poor infit, and four with poor outfit. Form B had five nonmonotonic items, five had DIF, three had poor infit, and three had poor outfit. Form C had only monotonic items, one item with DIF, three items with poor infit, and two with poor outfit.

CONCLUSION

The original FRI and alternative forms all fail failed crucial psychometric tests and fail to accurately measure more than one latent construct. It is thus unfit as a pain, function, and disability assessment. Only reducing the number of Likert choices improved the test. Other back pain assessments should be used instead, and all surveys would benefit from periodic item responses to adjust to shifts in grammar and meaning.Level of Evidence: 3.

Web-Based Skin Cancer Assessment and Classification Using Machine Learning and Mobile Computerized Adaptive Testing in a Rasch Model: Development Study

Background

Web-based computerized adaptive testing (CAT) implementation of the skin cancer (SC) risk scale could substantially reduce participant burden without compromising measurement precision. However, the CAT of SC classification has not been reported in academics thus far.

Objective

We aim to build a CAT-based model using machine learning to develop an app for automatic classification of SC to help patients assess the risk at an early stage.

Methods

We extracted data from a population-based Australian cohort study of SC risk (N=43,794) using the Rasch simulation scheme. All 30 feature items were calibrated using the Rasch partial credit model. A total of 1000 cases following a normal distribution (mean 0, SD 1) based on the item and threshold difficulties were simulated using three techniques of machine learning—naïve Bayes, k-nearest neighbors, and logistic regression—to compare the model accuracy in training and testing data sets with a proportion of 70:30, where the former was used to predict the latter. We calculated the sensitivity, specificity, receiver operating characteristic curve (area under the curve [AUC]), and CIs along with the accuracy and precision across the proposed models for comparison. An app that classifies the SC risk of the respondent was developed.

Results

We observed that the 30-item k-nearest neighbors model yielded higher AUC values of 99% and 91% for the 700 training and 300 testing cases, respectively, than its 2 counterparts using the hold-out validation but had lower AUC values of 85% (95% CI 83%-87%) in the k-fold cross-validation and that an app that predicts SC classification for patients was successfully developed and demonstrated in this study.

Conclusions

The 30-item SC prediction model, combined with the Rasch web-based CAT, is recommended for classifying SC in patients. An app we developed to help patients self-assess SC risk at an early stage is required for application in the future.

Patients Decision-Making Characteristics Affects Gynecomastia Treatment Satisfaction: A Multicenter Study Using the BODY-Q Chest Module

BACKGROUND

Patient satisfaction is the most critical outcome in gynecomastia treatment. However, patient satisfaction may be affected by the patient's decision-making trait, such as exhaustively searching for the best outcome or being content with an outcome that satisfies a preconceived requirement.

OBJECTIVE

To assess whether patient's decision-making characteristic affect their satisfaction with gynecomastia treatment.

METHODS

This was a cross-sectional study including patients treated for gynecomastia between January 2009 and December 2019 at two tertiary hospitals in Denmark. Alive patients were sent the BODY-Q: Chest module, the SF-36 questionnaire, and the Maximizer/Satisficer decision-making survey. Patients were classified as Maximizers if they scored more than 40 points on the Maximizer/Satisficer survey. Percentage score differences (PDs) in quality of life scales were calculated between Maximizers and Satisficers.

RESULTS

In total, 192 gynecomastia patients were included in this study and classified as Maximizers (n = 152) or Satisficers (n = 40). Maximizers were younger and more had gynecomastia following abuse of anabolic steroids than Satisficers (p < 0.05). With respect to bodily satisfaction, Maximizers showed significantly worse satisfaction with nipples (PDs: - 12.98%), psychological function (PDs: - 13.68%) and social function (PDs: - 8.77%, p < 0.05). In addition, Maximizers had significantly worse emotional role functioning (- 11.03%), vitality (PDs: - 11.72%) and mental health (PDs: - 10.00%, p < 0.05).

CONCLUSION

Patients exhibiting maximizing-type decision-making characteristics have worse satisfaction with gynecomastia treatment and poorer psychosocial health. This information may facilitate patient counseling and alignment of treatment expectations.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Patient-reported outcome measures for clinical decision-making in outpatient follow-up: validity and reliability of a renal disease questionnaire

BACKGROUND

Patient-reported outcome measures are increasingly used by clinicians to support communication in telephone- or face-to-face consultations with patients. A renal disease questionnaire has been developed, but not sufficiently evaluated through clinimetrics in clinical setting. Hence, we aimed to evaluate the content validity, construct validity and the test-retest reliability of a renal disease questionnaire to be used for clinical decision-making.

METHODS

A content, construct validity and test-retest reliability study was conducted in 3 nephrology outpatient clinics in Central Denmark Region, Denmark. Content validity (face validity, comprehensibility and relevance) was assessed among 8 patients and 6 clinicians. Reliability was assessed by asking outpatients with chronic kidney disease to complete the questionnaire twice. Reliability was assessed by kappa statistics and agreement by percentage. Construct validity was determined using 4 a priori defined hypotheses and comparing 2 known groups.

RESULTS

Five new domains emerged, 6 items were rephrased and 3 items were removed following the content validity test. A total of 160 patients completed the questionnaire with median 8 days (IQR 2 days) between assessments. The test-retest reliability parameters of the single items in the questionnaire were substantial to almost perfect as all the observed weighted kappa values ranged from 0.61 to 0.91, 95% CI (0.34 to 0.95). In total, 61% of the single items showed almost perfect agreement. In total, 3 of the 4 hypotheses were accepted and 44% of the items showed satisfying known-group discriminative validity.

CONCLUSION

A renal disease questionnaire used for clinical decision-making in outpatient follow-up showed acceptable content validity and substantial to almost perfect reliability. Sufficient construct validity was not established. Incorporating the questionnaire into routine clinical practice may improve the evaluation of disease burden in patients with chronic kidney disease. We ask patients with chronic kidney disease (CKD) in Central Region Denmark to complete a questionnaire before each outpatient visit. The answers they provide are used to support communication with their health care provider. A questionnaire requires testing to ensure it can accurately capture important information about patient's symptoms and quality of life. When questionnaires are used to support communication between patients and health care professionals, they need to have good measurement properties. This means they need to be: (1) trustworthy, (2) relevant to a patient's health condition, (3) consistent and produce stable results every time. We explored the measurement properties of a questionnaire designed to be used in the face-to face outpatient visits for patients with CKD. We found that the questionnaire captured consistent and stable results. Using this questionnaire may help health care professionals to assess the patients´ burden of symptoms with a more patient-centered approach. Potentially, the use of the questionnaire will increase the patients´ ability to cope with their symptoms and strengthen patients´ involvement in the clinical decisions concerning their treatment.

The impact of lymphedema on health-related quality of life up to 10 years after breast cancer treatment

The impact of breast cancer-related lymphedema (BCRL) on long-term quality of life is unknown. The aim of this study was to investigate the impact of BCRL on health-related quality of life (HRQoL) up to 10 years after breast cancer treatment. This regional population-based study enrolled patients treated for breast cancer with axillary lymph node dissection between January 1st 2007 and December 31th 2017. Follow up and assessments of the included patients were conducted between January 2019 and May 2020. The study outcome was HRQoL, evaluated with the Lymphedema Functioning, Disability and Health Questionnaire, the Disabilities of the Arm, Shoulder and Hand Questionnaire and the Short Form (36) Health Survey Questionnaire. Multivariate linear logistic regression models adjusted for confounders provided mean score differences (MDs) with 95% confidence intervals in each HRQoL scale and item. This study enrolled 244 patients with BCRL and 823 patients without BCRL. Patients with BCRL had significantly poorer HRQoL than patients without BCRL in 16 out of 18 HRQoL subscales, for example, in physical function (MDs 27, 95%CI: 24; 30), mental health (MDs 24, 95%CI: 21; 27) and social role functioning (MDs 20, 95%CI: 17; 23). Age, BMI, BCRL severity, hand and dominant arm affection had only minor impact on HRQoL (MDs < 5), suggesting a high degree of inter-individual variation in coping with lymphedema. This study showed that BCRL is associated with long-term impairments in HRQoL, especially affecting the physical and psychosocial domains. Surprisingly, BCRL diagnosis rather than clinical severity drove the largest impairments in HRQoL.

Assessment of content validity and psychometric properties of VISA-A for Achilles tendinopathy

A recent COSMIN review found that the Victorian Institute of Sports Assessment-Achilles tendinopathy questionnaire (VISA-A) has flawed construct validity. The objective of the current study was to assess specifically the process of how VISA-A was constructed and validated, and whether the Danish version of VISA-A is a valid patient-reported outcome measure (PROM) for measuring the perceived impact of Achilles tendinopathy. The original item generation strategy for content validity and the process for confirming the scaling properties (construct validity) were examined. In addition, construct validity was evaluated directly using several psychometric methods (Rasch analysis, confirmatory factor analysis (CFA), and multivariable linear regression) in a cohort of 318 persons with Achilles tendinopathy with symptom duration groups ranging from less than 3 months to more than 1 year of chronicity, and a group of 120 healthy persons. We found that the item generation and item reduction in the original construction of VISA-A was based on literature review and clinician consensus with little or no patient involvement. We determined that 1) VISA-A consists of ambiguous conceptual item themes and thus lacks content validity, 2) there was no thorough investigation of the psychometric properties of the original version of VISA-A, which thus lacks construct validity, and 3) rigorous direct assessment of the psychometric properties of the Danish VISA-A revealed inadequate psychometric properties. In agreement with the COSMIN study, we conclude that when used as a single score, VISA-A is not an adequate scale for measuring self-reported impact of Achilles tendinopathy.

Challenges in Measuring Applied Cognition: Measurement Properties and Equivalence of the Functional Assessment in Acute Care Multidimensional Computerized Adaptive Test (FAMCAT) Applied Cognition Item Bank

OBJECTIVE

To present challenges in assessment of applied cognition and the results of differential item functioning (DIF) analyses used to inform the development of a computerized adaptive test (CAT).

DESIGN

Measurement evaluation cohort study. DIF analyses of 107 items were conducted across educational, age, and sex groups. DIF hypotheses informed the evaluation of the results.

SETTING

Hospital-based rehabilitation from a single hospital system.

PARTICIPANTS

A total of 2216 hospitalized patients (N=2216).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Applied cognition item pool from multiple sources.

RESULTS

Many items were hypothesized to show DIF, particularly for age. Information was moderately high in the lower (cognitive disability) tail of the distribution, but some items were not informative. Reliability estimates were high (>0.89) across all studied groups, regardless of estimation method. There were 35 items with DIF of high magnitude and 19 with accompanying supportive hypotheses.

CONCLUSIONS

A key clinical tool in inpatient rehabilitation medicine is assessment of applied functional cognitive ability to inform patient-centered rehabilitation strategies to improve function. This was the first study to evaluate measurement equivalence of the applied cognition item pool across large samples of hospitalized patients. Although about one-third of the item pool evidenced DIF or low discrimination, results supported placement of most items into the bank and its use across groups differing in education, age, and sex. Six items were classified with salient DIF, defined as consistent DIF of high magnitude and or impact, with confirmatory directional DIF hypotheses, generated by content experts. These were recommended for adjustment or removal from the bank; 4 were deleted from the bank and 2 had lowered CAT exposure (administration frequency) rates. Many items hypothesized to show DIF contained content measuring constructs other than applied cognition such as physical frailty, perceptual difficulties, or skills reflective of greater educational attainment. Challenges in measurement of this construct are discussed.

Psychometric Validation of the Danish Version of the Oswestry Disability Index in Patients With Chronic Low Back Pain

STUDY DESIGN

Registry-based repeated-measures psychometric validation of the Danish Oswestry Disability Index (ODI).

OBJECTIVE

The goal was to use classical and modern psychometric validation methods to assess the measurement properties and the minimally clinical important difference (MCID) of the ODI in a Danish cohort of patients with chronic low back pain being treated with spinal surgery.

SUMMARY OF BACKGROUND DATA

Scores for the ODI, EQ-5D, SF-36, leg pain, back pain, and a general rating of pain item from 800 patients with chronic low back pain were extracted from the National Danish Spine Registry (DaneSpine) at baseline and 1-year postspine surgery.

METHODS

Confirmatory factor analysis and item response theory (IRT) models were used to assess the psychometric properties of the ODI. MCID was also calculated based on generic legacy PROMs (EQ-5D and SF-36) and follow-up pain scores.

RESULTS

While ODI did not fit a Rasch model, adequate fit to a confirmatory factor analysis and a two-parameter item response theory model was found when accounting for differential item functioning across diagnostic subgroups (degenerative spondylolisthesis, spondylosis, spinal stenosis, and herniated intervertebral disc). In addition, each group exhibited substantially different MCID values.

CONCLUSION

The Danish version of the ODI is valid and responsive, but only within each of the four major diagnosis subgroups: degenerative spondylolisthesis, spondylosis, spinal stenosis, and herniated intervertebral disc.

LEVEL OF EVIDENCE

4.

Developing a Job Exposure Matrix of Work Organization Hazards in the United States: A Review on Methodological Issues and Research Protocol

Background

Most job exposure matrices (JEMs) have been developed for chemical and physical hazards in the United States (US). In addition, the overall validity of most JEMs of work organization hazards using self-reported data in the literature remains to be further tested due to several methodological weaknesses.

Methods

This paper aims to review important methodological issues with regard to a JEM of work organization hazards using self-report data and to present a research protocol for developing a four-axis (job titles, hazards, sex, and time) JEM of major work organization hazards using the US General Social Survey-Quality of Work-Life (GSS-QWL) data (2002–2018; N = 7,100 workers).

Results

Five methodological weaknesses in existing JEMs of work organization hazards using self-report data were identified: having only two axes (hazard and occupation), using psychometrically weak items and scales, including scales having little interoccupational variability, unresolved optimal minimum numbers of subjects per occupation, and low accessibility. The methodological weaknesses were successfully addressed in the proposed research protocol.

Conclusion

The work organization JEM to be developed will significantly facilitate and strengthen occupational epidemiological studies on work organization hazards and major health outcomes, improve national and occupational surveillance of work organization hazards, and promote interventions for a healthy work environment in the US.

Translation and Cross-cultural Validation of the English Young Adult Burn Outcome Questionnaire (YABOQ) in Spanish

The Young Adult Burn Outcome Questionnaire (YABOQ) is a validated, English-language patient-reported outcome assessment of young adults' recovery from burn injury across 15 scale domains. We evaluated the cross-cultural validity of a newly developed Spanish version of the YABOQ. Secondary data from English- and Spanish-speaking burn survivors (17 to 30 years of age) were obtained from the Multicenter Benchmarking Study. We conducted classic psychometric analyses and evaluated the measurement equivalence of the English and Spanish YABOQs in logistic and ordinal logistic regression differential item functioning analyses. All multi-item scales in the Spanish YABOQ demonstrated adequate reliability except the Pain and Itch scales. One item in the Perceived Appearance scale showed differential item functioning across English- and Spanish-speaking burn survivors, but the observed differential item functioning had no clinically significant impact on scale-level Perceived Appearance scores. Our findings support the cross-cultural validity of the YABOQ Physical Function, Perceived Appearance, Sexual Function, Emotion, Family Function, Family Concern, Satisfaction with Symptom Relief, Satisfaction with Role, Work Reintegration and Religion scales among English- and Spanish-speaking young adult burn survivors. This work supports the use of these English and Spanish YABOQ scales to assess the effect of therapeutic interventions on young adults' burn outcomes in pooled analyses and to assess disparities in young adults' burn outcomes across language groups.

Evaluating the cross-cultural validity of three family quality of life sub-scales

BACKGROUND

Families of children with disabilities often face unique challenges. Developed in a U.S. context, the Beach Center Family Quality of Life measure assesses the effectiveness of supports and services that families receive. This study examines whether items from three sub-scales of the Beach Center instrument perform similarly for two samples, one from Lusaka, Zambia, and the second from a Midwestern U.S. state.

METHODS

This cross-sectional research used secondary data and completed hierarchical ordinal regression analyses on item-level performance within the sub-scales.

RESULTS

Only one item flagged for potential item bias with remaining items performing similarly when controlling for overall sub-scale scores.

CONCLUSIONS

This study extends existing research on the cultural and linguistic appropriateness of the Beach Center measure, providing additional validity evidence about the internal structure of the scales. Findings indicate that these items are acceptable outcome measures for policy and programme evaluations in Zambia.

Translation and Cultural Adaptation of the German Mastocytosis Quality of Life Questionnaire (MC-QoL) into Spanish

BACKGROUND

Mastocytosis encompasses a spectrum of disorders in which different organs and tissues are affected by the clonal expansion of mast cells. The skin is one of the most frequently affected organs. The clinical manifestations of mastocytosis are linked to the release of proinflammatory mediators, and the impact of this disorder on patient quality of life has been described in various studies. The Mastocytosis Quality of Life Questionnaire (MC-QoL), which was recently developed in Germany and now also exists in English, is an important tool for evaluating the psychosocial impact of this disease.

OBJECTIVE

To create a Spanish version of the MC-QoL that was culturally equivalent to the original German questionnaire.

MATERIAL AND METHODS

The adaptation process, which involved forward translation, cognitive interviews, and back translation, was conducted in accordance with the principles of good practice for the translation and cultural adaptation of patient-reported measures of the International Society for Pharmacoeconomics and Outcomes Research. The MC-QoL contains 27 items in 4 domains: symptoms, emotions, social life/functioning, and skin.

RESULTS

The first version of the Spanish questionnaire, obtained by forward translation from German, was tested in cognitive interviews, after which 3 items were modified to make them easier to understand. The German back translation of the Spanish questionnaire was analyzed by the authors of the original MC-QoL, who modified 1 item they considered to have lost specificity in the adaptation process. The definitive Spanish MC-QoL was then produced following minor modifications agreed on with the German authors.

CONCLUSION

We have produced a cultural adaptation of the MC-QoL in Spanish that can be used in routine clinical practice to obtain a more complete picture of the impact of mastocytosis on patient quality of life.

The impact of sex and disease classification on patient-reported outcome measures in axial spondyloarthritis: a descriptive prospective cross-sectional study

Background

The aim of this study was to explore the impact of sex and disease classification on outcomes in axial spondyloarthritis (axSpA) patients, including both radiographic (r-) axSpA and non-radiographic (nr-) axSpA, in males and females, respectively.

Methods

AxSpA patients were consecutively recruited from two rheumatology outpatient university clinics. We explored how sex and axSpA disease classification affected patient-reported outcome measures (PROMs). General linear models were used to investigate if there was an association between the continuous variables and each of the main effects of interest (sex and axSpA classification), as well as the possible interaction between them. Categorical outcome measures were analyzed with the use of logistic regression with the same fixed effects. We analyzed the relationship between tender point count (TPC) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The prevalence of extra-articular manifestations (EAMs) and the Charlson Comorbidity Index (CCI) were determined.

Results

According to the protocol, a total of 100 outpatients with axSpA were enrolled (r-axSpA males 30, r-axSpA females 10, nr-axSpA males 25, nr-axSpA females 35). The BASDAI scores appeared higher among nr-axSpA females (median [Q₁; Q₃], 47 [21; 60]) compared with the combined median for the 3 other subgroups 25 [12; 25]. Female sex was associated with a higher number of tender point count (TPC, P < 0.001). TPC and BASDAI were correlated for female nr-axSpA patients (r = 0.44, P = 0.008) and male nr-axSpA patients (r = 0.56, P = 0.003). Being classified as nr-axSpA was associated with a lower SF-36 Mental Component Summary (median for the 4 subgroups: nr-axSpa females 46.7, nr-axSpA males 52.3 vs. r-axSpA males 56.9 and r-axSpA females 50.4). EAMs were frequent (up to 50%). The CCI was low in all 4 subgroups, and no difference in the CCI between the subgroups was observed (P = 0.14). However, male sex had a significant impact on the CCI (P = 0.03).

Conclusions

In summary, patients with r-axSpA, regardless of sex, appeared less affected on most PROMs compared with nr-axSpA patients. However, female sex was associated with a higher number of TPC. TPC could possibly confound disease activity outcomes such as BASDAI, and one can consider different thresholds for defining high disease activity depending on the patient’s sex.

Trial registration

The trial is registered and approved by the Region of Southern Denmark’s Ethics Committee (S-20150219). Registered 19 February 2015.

Treatment of chronic post-herpetic neuralgia with autologous fat grafts: a first-in-the-world case report

A 60-year-old woman suffering from severe chronic post-herpetic neuralgia (PHN) was treated with simple autologous fat grafting to the affected area of skin. Post-operatively, she reported a great improvement in her symptoms. The effect was stable throughout the 3-month follow-up period. This case report presents a first-in-the-world case of using fat grafting to treat chronic post-herpetic neuralgia and discusses the future potential of this as a primary treatment of this syndrome. This report presents partial data of a pilot study registered at clinicaltrials.org (ClinicalTrials.gov Identifier: NCT03584061).

Differential item functioning of the SF-12 in a population-based regional joint replacement registry

Background

Joint replacement, an increasingly common procedure amongst older adults, can substantially improve health-related quality of life (HRQoL). However, differential item functioning (DIF) may affect the accurate interpretation of differences in HRQoL amongst patients with different demographic and health status characteristics but the same underlying (i.e., latent) level of the investigated construct. This study tested for DIF in pre-operative SF-12 physical health (PH) and mental health (MH) sub-scale items amongst patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods

Data were from a population-based joint replacement registry from the Canadian province of Manitoba. TKA and THA patients who had surgery between 2009 and 2015 and completed a pre-operative assessment were included. DIF was tested using the multiple indicators multiple causes (MIMIC) method with sex, age group, body weight status, and presence of multiple comorbid conditions (i.e., multimorbidity) as covariates. Analyses were stratified by joint type.

Results

The study cohort included 8820 patients; 42.1% underwent THA, 57.3% were female, 32.7% were 70+ years, and 52.8% were obese. For each sub-scale, four of the six items exhibited DIF in both THA and TKA groups. Differences in the covariate effect estimates for DIF and No-DIF models on the MH latent variable were largest for age and body weight status for the THA group, and for sex and multimorbidity for the TKA group. All of the differences were small for PH. Multimorbidity had the strongest association with PH and age and sex had the strongest association with MH in the DIF models.

Conclusions

Demographic and health status characteristics influenced SF-12 PH and MH item responses in joint replacement populations, although the size of the effects were not large for PH. We recommend testing and adjusting for DIF effects to ensure comparability of HRQoL measures in joint replacement populations.

Electronic supplementary material

The online version of this article (10.1186/s12955-019-1166-1) contains supplementary material, which is available to authorized users.

Are Insomnia Type Sleep Problems Associated With a Less Physically Active Lifestyle? A Cross-Sectional Study Among 7,700 Adults From the General Working Population

Background: Sleep problems are common in the general population and negatively affect both private and work life. A vicious circle may exist between poor sleep and an unhealthy lifestyle. For example, poor sleep may drain the energy to do health-promoting physical activity during leisure-time after work. The aim of the present study was to investigate the association between sleep problems and the duration of low- and high-intensity leisure-time physical activity in sedentary and physical workers. Methods: This cross-sectional study employ data from the Danish Work Environment Cohort Study in 2010, where currently employed wage-earners in Denmark on daytime schedule (N = 7,706) replied to questions about sleep quality (cf. the Bergen Insomnia Scale) and participation in low- and high-intensity leisure-time physical activity. Associations were modeled using general linear models controlling for various confounders. Results: Workers with high levels of sleep problems reported less high-intensity leisure-time physical activity. Specifically, the weekly duration of high-intensity leisure-time physical activity was 139 (95%CI 111-168), 129 (95%CI 101-158), and 122 (95%CI 92-151) min in sedentary workers with sleep problems < 1, 1-3, and ≥3 days per week, respectively. The same pattern was observed among physical workers. In sedentary workers ≥50 years, the fully adjusted model showed a weekly duration in high-intensity physical activity during leisure of 122 (95%CI 83-161), 102 (95%CI 64-141), and 90 (95%CI 51-130) among those with sleep problems < 1, 1-3, and ≥3 days per week, respectively. Conclusions: Workers, particularly sedentary older workers, having sleep problems report less high-intensity leisure-time physical activity. These data suggest that a vicious circle may indeed exist between poor sleep and reduced leisure-time physical activity.

Measurement invariance of the SF-12 among different demographic groups: The HELIUS study

AIM

To investigate whether items of the SF-12, widely used to assess health outcome in clinical practice and public health research, provide unbiased measurements of underlying constructs in different demographic groups regarding gender, age, educational level and ethnicity.

METHODS

We included 23,146 men and women aged 18-70 of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish, or Moroccan origin from the HELIUS study. Both multiple group confirmatory factor analyses (MGCFA), with increasingly stringent model constraints (i.e. assessing Configural, Metric, Strong and Strict measurement invariance (MI)), and regression analysis were conducted to establish comparability of SF-12 items across demographic groups.

RESULTS

MI regarding gender, age and education was tested in the ethnic Dutch group (N = 4,615). In each subsequent step of testing MI, change in goodness-of-fit measures did not exceed 0.010 (RMSEA) or 0.004 (CFI). Moreover, goodness-of-fit indices showed good fit for strict invariance models: RMSEA<0.055; CFI>0.97. Regarding ethnicity, RMSEA values of metric and subsequent models fell above 0.055, indicating violation of measurement invariance in factor loadings, thresholds and residual variances. Regression analysis revealed possible age-, education- and ethnicity-related DIF. Adjustment for this DIF had little impact on the magnitude of age and educational differences in physical and mental health, but ethnic inequalities in physical health-and to a lesser extent mental health-were reduced after DIF adjustment.

CONCLUSIONS

We found no evidence of violation of measurement invariance of the SF-12 regarding gender, age and educational level. If minor DIF would remain undetected in our MGCFA analyses, we showed that this would have negligible effect on the magnitude of demographic health inequalities. Regarding ethnicity, the SF-12 was not measurement invariant. After accounting for DIF, we observed a reduction of ethnic inequalities in health, in particular in physical health. Caution is warranted when comparing SF-12 scores across population groups with various ethnic backgrounds.

Fear Avoidance Beliefs and Risk of Long-Term Sickness Absence: Prospective Cohort Study among Workers with Musculoskeletal Pain

Background and Objective

Musculoskeletal pain is common in the population. Negative beliefs about musculoskeletal pain and physical activity may lead to avoidance behavior resulting in absence from work. The present study investigates the influence of fear avoidance beliefs on long-term sickness absence.

Methods

Workers of the general working population with musculoskeletal pain (low back, neck/shoulder, and/or arm/hand pain; n = 8319) from the Danish Work Environment Cohort Study were included. Long-term sickness absence data were obtained from the Danish Register for Evaluation and Marginalization (DREAM). Time-to-event analyses (cox regression) controlled for various confounders estimated the association between fear avoidance beliefs (very low, low, moderate [reference category], high, and very high) at baseline and long-term sickness absence (LTSA; ≥6 consecutive weeks) during a 2-year follow-up.

Results

During the 2-year follow-up, 10.2% of the workers experienced long-term sickness absence. In the fully adjusted model, very high-level fear avoidance increased the risk of LTSA with hazard ratio (HR) of 1.48 (95% CI 1.15-1.90). Similar results were seen analyses stratified for occupational physical activity, i.e., sedentary workers (HR 1.72 (95% CI 1.04-2.83)) and physically active workers (HR 1.48 (95% CI 1.10-2.01)).

Conclusion

A very high level of fear avoidance is a risk factor for long-term sickness absence among workers with musculoskeletal pain regardless of the level of occupational physical activity. Future interventions should target fear avoidance beliefs through information and campaigns about the benefits of staying active when having musculoskeletal pain.

Conceptualizing patient-reported outcome measures for use within two Danish psychiatric clinical registries: description of an iterative co-creation process between patients and healthcare professionals

BACKGROUND

Denmark has national clinical indicator programs for adult patients diagnosed with depression and schizophrenia, respectively. Within each program, the responsible steering group (SG) decided to add some indicators based upon patient-reported outcome measures (PROMs).

AIMS

The primary aim was to describe the process of selecting PROMs and defining a national measurement concept for use in clinical practice and for indicator monitoring and the secondary aim s to collect patient recommendations for implementation.

METHODS

An interdisciplinary SG of healthcare professionals and a Patient Peer Board (PPB) representing both patient groups co-created the output in an iterative process. The work included literature search, PPB workshops, SG meetings, ratings of PROM topics and items, and a pilot. The PPB discussed the following: item relevance, mode of data collection, graphical format of the online PROMs, and display of results. Finally, requirements for PROM patient information were identified. Based upon input from the PPB, the SG selected the items and specified the measurement concept.

RESULTS

The PPB prioritized 20 of 53 suitable items and suggested alternative wording and answer categories. A pilot was performed and 19 items covering well-being, lack of well-being, impairment of functioning, and overall health were selected for clinical testing. The patients recommended concrete, unambiguous, easily understandable information and procedures for data collection and display of results.

CONCLUSIONS

The iterative co-creation process based upon a high degree of patient involvement resulted in a set of PROMs, a national measurement concept, and patient recommendations for implementation. The cooperation between patients and professionals was successful.

Self-rated health, quality of life and appetite as predictors of initiation of dialysis and mortality in patients with chronic kidney disease stages 4-5: a prospective cohort study

Objective

Patient-reported health status, including symptom burden, functional status and quality of life, are important measures of health in patients with chronic kidney disease. We aimed to investigate patient-reported outcomes (PRO) on self-rated health, appetite, quality of life and their associations with clinical outcomes. We conducted a prospective observational cohort study. Data was collected at baseline using a PRO questionnaire. The primary outcomes were initiation of dialysis, transplantation and mortality. Kaplan–Meier curves and multivariable Cox proportional hazards regression analyses were used.

Results

A total of 126 patients with chronic kidney disease with an eGFR of ≤ 25 mL/min/1.73 m² were followed for a median of 321 (range 10–523) days. Poor appetite was associated with mortality (hazard ratio 20.9, 95% CI 3.7–129.8). Initiation of dialysis was associated with low self-rated health (hazard ratio 5.2, 95% CI 1.2–24.0). Mean decline in estimated glomerular filtration rate was − 0.9 mL/min/1.73 m² (95% CI − 1.6 to − 0.2). Decline in self-rated health (p = 0.001) and appetite (p = 0.002) were correlated with reduction in renal function.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3472-9) contains supplementary material, which is available to authorized users.

Health-related quality of life in patients with nonsurgical hypoparathyroidism and pseudohypoparathyroidism

OBJECTIVE

Nonsurgical hypoparathyroidism (NS-HypoPT) and pseudohypoparathyroidism (PHP) are rare diseases, with a prevalence of 2/100.000 and 1/100.000, respectively. Only few studies on Quality of Life (QoL) among patients with Ns-HypoPT and PHP are available. We aimed to investigate the QoL among patients with Ns-HypoPT and PHP including information about education.

DESIGN

A cohort study with patients identified from a previously epidemiological study.

PATIENTS

Fifty seven patients with Ns-HypoPT and 30 patients with PHP.

MEASUREMENTS

The well-validated questionnaires SF-36v2 and WHO-5 Well Being Index. Results compared to norm-based material, disease-specific norm-based material and patients with postsurgical HypoPT RESULTS: SF36v2 showed a significantly reduced score in all eight subdomains in patients with NS-HypoPT compared with a norm-based population. PHP patients scored lower in five subdomains. Females were more affected than males. Compared with postsurgical HypoPT, Ns-HypoPT and PHP are compatible at most domains. At the domains Physical Function, Social Function and Mental Health, Ns-HypoPT and PHP patients scored significantly lower (P_all  < .05). At the Mental Component Score, patients with Ns-HypoPT had a lower score compared with postsurgical HypoPT (P < .01). The overall WHO-5 Well Being Index score was comparable between groups (P = .45). No differences were seen comparing patients with postsurgical HypoPT and Ns-HypoPT (P = .68) or postsurgical HypoPT and PHP (P = .67). A WHO-5 score below 28 indicates depression (NS-HypoPT=7; PHP=3, P = .71), whereas a score between 28-50 suggesting poor emotional well-being (NS-HypoPT=19; PHP=5, P = .13). The remaining patients scored above 50 suggesting well-being.

CONCLUSION

QoL is impaired equally among patients with Ns-HypoPT and PHP.

Measurement Properties of the SEAM Questionnaire Using Rasch Analysis on Data From a Representative Danish Sample of 0- to 6-Year-Olds

In the current study, the strength-based questionnaire Social-Emotional Assessment/Evaluation Measure (SEAM)–Research Edition was for the first time applied in a nationally representative sample of 0- to 6-year-old children. The focus of this study was the measurement properties of a Danish adaptation of SEAM. Rasch analysis was used to examine the criterion-related construct validity as well as accuracy and reliability of the measurement. The primary goal was to determine whether the 10 SEAM benchmarks could be combined into one total score or into a limited number of subscores. Data were collected by child-care providers in nonparental child-care facilities, and the response rate was high (95%; N = 9,827). The 10 benchmarks were successfully combined into two overall indexes: Empathy and Self-regulation & Cooperation. The reliability coefficients ranged from adequate (0.79) to excellent (0.94). However, standard errors of measurements were relatively large for the two indexes.

Psychometric evaluation of an item bank for computerized adaptive testing of the EORTC QLQ-C30 cognitive functioning dimension in cancer patients

BACKGROUND

The European Organisation of Research and Treatment of Cancer (EORTC) Quality of Life Group is developing computerized adaptive testing (CAT) versions of all EORTC Quality of Life Questionnaire (QLQ-C30) scales with the aim to enhance measurement precision. Here we present the results on the field-testing and psychometric evaluation of the item bank for cognitive functioning (CF).

METHODS

In previous phases (I-III), 44 candidate items were developed measuring CF in cancer patients. In phase IV, these items were psychometrically evaluated in a large sample of international cancer patients. This evaluation included an assessment of dimensionality, fit to the item response theory (IRT) model, differential item functioning (DIF), and measurement properties.

RESULTS

A total of 1030 cancer patients completed the 44 candidate items on CF. Of these, 34 items could be included in a unidimensional IRT model, showing an acceptable fit. Although several items showed DIF, these had a negligible impact on CF estimation. Measurement precision of the item bank was much higher than the two original QLQ-C30 CF items alone, across the whole continuum. Moreover, CAT measurement may on average reduce study sample sizes with about 35-40% compared to the original QLQ-C30 CF scale, without loss of power.

CONCLUSION

A CF item bank for CAT measurement consisting of 34 items was established, applicable to various cancer patients across countries. This CAT measurement system will facilitate precise and efficient assessment of HRQOL of cancer patients, without loss of comparability of results.

E pluribus unum: Harmonization of physical functioning across intervention studies of middle-aged and older adults

Common scales for physical functioning are not directly comparable without harmonization techniques, complicating attempts to pool data across studies. Our aim was to provide a standardized metric for physical functioning in adults based on basic and instrumental activities of daily living scaled to NIH PROMIS norms. We provide an item bank to compare the difficulty of various physical functioning activities. We used item response theory methods to place 232 basic and instrumental activities of daily living questions, administered across eight intervention studies of middle-aged and older adults (N = 2,556), on a common metric. We compared the scale’s precision to an average z-score of items and evaluated criterion validity based on objective measures of physical functioning and Fried’s frailty criteria. Model-estimated item thresholds were widely distributed across the range of physical functioning. From test information plots, the lowest precision in each dataset was 0.80. Using power calculations, the sample size needed to detect 25% physical functional decline with 80% power based on the physical functioning factor was less than half of what would be needed using an average z-score. The physical functioning factor correlated in expected directions with objective measurements from the Timed Up and Go task, tandem balance, gait speed, chair stands, grip strength, and frailty status. Item-level harmonization enables direct comparison of physical functioning measures across existing and potentially future studies and across levels of function using a nationally representative metric. We identified key thresholds of physical functioning items in an item bank to facilitate clinical and epidemiologic decision-making.

Latent variable mixture models to test for differential item functioning: a population-based analysis

BACKGROUND

Comparisons of population health status using self-report measures such as the SF-36 rest on the assumption that the measured items have a common interpretation across sub-groups. However, self-report measures may be sensitive to differential item functioning (DIF), which occurs when sub-groups with the same underlying health status have a different probability of item response. This study tested for DIF on the SF-36 physical functioning (PF) and mental health (MH) sub-scales in population-based data using latent variable mixture models (LVMMs).

METHODS

Data were from the Canadian Multicentre Osteoporosis Study (CaMos), a prospective national cohort study. LVMMs were applied to the ten PF and five MH SF-36 items. A standard two-parameter graded response model with one latent class was compared to multi-class LVMMs. Multivariable logistic regression models with pseudo-class random draws characterized the latent classes on demographic and health variables.

RESULTS

The CaMos cohort consisted of 9423 respondents. A three-class LVMM fit the PF sub-scale, with class proportions of 0.59, 0.24, and 0.17. For the MH sub-scale, a two-class model fit the data, with class proportions of 0.69 and 0.31. For PF items, the probabilities of reporting greater limitations were consistently higher in classes 2 and 3 than class 1. For MH items, respondents in class 2 reported more health problems than in class 1. Differences in item thresholds and factor loadings between one-class and multi-class models were observed for both sub-scales. Demographic and health variables were associated with class membership.

CONCLUSIONS

This study revealed DIF in population-based SF-36 data; the results suggest that PF and MH sub-scale scores may not be comparable across sub-groups defined by demographic and health status variables, although effects were frequently small to moderate in size. Evaluation of DIF should be a routine step when analysing population-based self-report data to ensure valid comparisons amongst sub-groups.

Development and validation of a condition-specific diary to measure severity, bothersomeness and impact on daily activities for patients with acute urinary tract infection in primary care

BACKGROUND

Urinary tract infection (UTI) is a common condition in primary care. Patient-reported outcome measures (PROMs) are crucial in the evaluation of interventions to improve diagnosis, treatment and prognosis of UTI. The aim of this study was to identify an existing condition-specific PROM to measure symptom severity, bothersomeness and impact on daily activities for adult patients with suspected urinary tract infection in primary care; or, in the absence of such a PROM, to test items identified from existing PROMs for coverage and relevance in single and group interviews and to psychometrically validate the resulting PROM.

METHODS

The literature was searched for existing PROMs covering the three domains. Items from the identified PROMs were tested in single and group interviews. The resulting symptom diary was psychometrically validated using the partial credit Rasch model for polytomous items in a cohort of 451 women participating in two studies regarding UTI.

RESULTS

No existing PROM fulfilled the inclusion criteria. Content validation resulted in one domain concerning symptom severity (18 items), one concerning bothersomeness (18 items), and one concerning impact on daily activities (7 items). Psychometrical validation resulted in four dimensions in each of the first two domains and one dimension in the third domain.

CONCLUSIONS

Domains were not unidimensional, which meant that we identified dimensions of patient-experienced UTI that differed substantially from those previously found. We recommend that future studies on UTI, in which PROMs are to be used, should ensure high content validity of their outcome measures and unidimensionality of the included dimensions.

Hard Physical Work Intensifies the Occupational Consequence of Physician-Diagnosed Back Disorder: Prospective Cohort Study with Register Follow-Up among 10,000 Workers

While musculoskeletal pain is common in the population, less is known about its labor market consequences in relation to physical activity at work. This study investigates whether hard physical work aggravates the consequences of back disorder. Using Cox regression analyses, we estimated the joint association of physical activity at work and physician-diagnosed back disorder in 2010 with the risk of register-based long-term sickness absence (LTSA) of at least 6 consecutive weeks during 2011-2012 among 9,544 employees from the general working population (Danish Work Environment Cohort Study). Control variables were age, gender, psychosocial work environment, smoking, leisure physical activity, BMI, depression, and mental health. At baseline, 19.4% experienced high low-back pain intensity (≥5, 0–9 scale) and 15.2% had diagnosed back disorder. While high pain intensity was a general predictor for LTSA, physician-diagnosed back disorder was a stronger predictor among those with hard physical work (HR 2.23; 95% CI 1.68–2.96) compared with light work (HR 1.40; 95% CI 1.09–1.80). Similarly, physician-diagnosed back disorder with simultaneous high pain intensity predicted LTSA to a greater extent among those with hard physical work. In conclusion, the occupational consequence of physician-diagnosed back disorder on LTSA is greater among employees with hard physical work.

Testing whether patients with diabetes and healthy people perceive the meaning of the items in the Persian version of the SF-36 questionnaire similarly: a differential item functioning analysis

PURPOSE

It has been rarely studied whether observed disparity in health-related quality-of-life (HRQoL) scores between patients with diabetes and healthy individuals is due to differential item functioning (DIF) or a true difference in the underlying construct. This study aimed to examine DIF in the SF-36 questionnaire and its effect on comparing HRQoL scores between patients with diabetes and healthy people.

METHODS

The sample consisted of 230 patients with type 2 diabetes and 642 healthy individuals who filled out the Persian version of the SF-36 questionnaire. To detect DIF across patients with diabetes and healthy individuals, multiple-group multiple-indicator multiple-causes model was used. In addition, item calibration strategy was used to determine whether the effect of item-level DIF was transferred to the scale level.

RESULTS

Nine out of thirty-six (25 %) items were detected as DIF, of which one item (11 %) was flagged as uniform and eight items (89 %) as non-uniform DIF. Most of the DIF items were detected in the mental health component which includes vitality, perceived mental health and social functioning subscales rather than in physical health component. Moreover, nonsignificant latent mean differences for general health perception and social functioning subscales became significant after DIF calibration.

CONCLUSION

The findings of the present study show that patients with diabetes and healthy individuals perceived some items in the SF-36 questionnaire differently. More importantly, in some subscales, the effect of item-level DIF was transferred to the scale level. Consequently, considerable caution should be taken in comparing HRQoL scores between patients with diabetes and healthy individuals.

The importance of considering differential item functioning in investigating the impact of chronic conditions on health-related quality of life in a multi-ethnic Asian population

PURPOSE

The present study aims to examine the impact of chronic conditions after adjusting for differential item functioning (DIF) on the various aspects of health-related quality of life (HRQoL) in a multi-ethnic Asian population in Singapore.

METHOD

Data on 3006 participants from a nation-wide cross-sectional survey of mental health literacy conducted in Singapore were used. Multiple Indicators Multiple Causes model was used to investigate the effects of chronic medical conditions on various HRQoL dimensions assessed with the 36-item Medical Outcomes Study Short Form Health Survey (SF-36) after adjusting for DIF.

RESULTS

Twenty out of 36 items were detected with DIF for chronic conditions including high blood pressure, cardiovascular disorders, diabetes, cancer, neurological disorders and ulcer as well as for a few demographic factors such age, gender and marital status. Twenty significant associations between chronic conditions and SF-36 domains were observed. After controlling for all chronic conditions, socio-demographic and DIF items, a significant association emerged between cardiovascular disorders and physical functioning, while the association between diabetes and ulcer and general health became nonsignificant. All other associations remained statistically significant.

CONCLUSION

Our findings provide useful information and important implications of DIF on the impact of chronic conditions on HRQoL. We found the impact of DIF with respect to the impact of chronic conditions on HRQoL to be minimal after accounting for measurement bias in this multiracial Asian population.

Mental health and school dropout across educational levels and genders: a 4.8-year follow-up study

Background

Education is a key determinant of future employment and income prospects of young people. Poor mental health is common among young people and is related to risk of dropping out of school (dropout). Educational level and gender might play a role in the association, which remains to be studied.

Methods

Mental health was measured in 3146 Danish inhabitants aged 16–29 years using the 12-Item Short-Form Health Survey and examined across genders and educational levels. For students, educational level at baseline was used; for young people who were not enrolled in school at baseline (non-students), the highest achieved educational level was used. The risk of dropout in students was investigated in administrative registers over a 4.8–year period (1^st March 2010–31^th December 2014). Odds ratios (OR) and 95 % confidence intervals (CI) were calculated for mental health and in relation to dropout in logistic regression models, adjusting for age, gender, educational level, parental education, parental income and ethnicity.

Results

Poor mental health was present in 24 % (n = 753) of the participants, 29 % (n = 468) in females and 19 % (n = 285) in males (p < 0.0001). The prevalence differed from 19 to 39 % across educational levels (p < 0.0001). Females had a statistically significantly higher adjusted risk of poor mental health than males (OR = 1.8, CI = 1.5–2.2). Among the students the lowest risk was found at the elementary level (OR = 1.3, CI = 0.8–2.3), while students in higher education had a statistically significantly higher risk (OR = 1.9, CI = 1.2–2.9). The lowest-educated non-students had the highest OR of poor mental health (OR = 3.3, CI = 2.1–5.4). Dropout occurred in 8 % (n = 124) of the students. Poor mental health was associated to dropout in vocational (OR = 1.8, CI = 1.0–3.2) and higher education (OR = 2.0, CI = 1.0–4.2). For males in higher education, poor mental health was a predictor of dropout (OR = 5.2, CI = 1.6–17.3), which was not seen females in higher education (OR = 1.2, CI = 0.5–3.1).

Conclusions

Poor mental health was significantly associated to dropout among students in vocational and higher education. Males in higher education had five times the risk of dropout when reporting poor mental health, while no such association was found for females.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3622-8) contains supplementary material, which is available to authorized users.

Regular use of medication for musculoskeletal pain and risk of long-term sickness absence: A prospective cohort study among the general working population

BACKGROUND

The aim was to determine the prospective association between use of pain medication - due to musculoskeletal pain in the low back, neck/shoulder and hand/wrist - and long-term sickness absence.

METHODS

Cox-regression analysis was performed to estimate the prospective association between regular use of pain medication and long-term sickness absence (LTSA; at least 6 consecutive weeks) among 9,544 employees from the general working population (Danish Work Environment Cohort Study 2010) and free from LTSA during 2009-2010. The fully adjusted model was controlled for age, gender, body mass index, smoking, leisure physical activity, job group, physical activity at work, psychosocial work environment, pain intensity, mental health and chronic disease.

RESULTS

In 2010, the proportion of regular pain medication users due to musculoskeletal disorders was 20.8%: 13.4% as over-the-counter (i.e. non-prescription) and 7.4% as doctor prescribed. In the fully adjusted model, regular use of over-the-counter [HR 1.44 (95% CI 1.13-1.83)] and doctor prescribed (HR 2.18 (95% CI 1.67-2.86)) pain medication were prospectively associated with LTSA.

CONCLUSIONS

Regular use of pain medication due to musculoskeletal pain is prospectively associated with LTSA even when adjusted for pain intensity. This study suggests that use of pain medication can be an important factor to be aware of in the prevention of sickness absence. Thus, regular use of pain medication - and not solely the intensity of pain - can be an early indicator that musculoskeletal pain can lead to serious consequences such as long-term sickness absence.

SIGNIFICANCE

Use of medication due to musculoskeletal pain is prospectively associated with long-term sickness absence even when adjusted for pain intensity. Use of pain medication can be a red flag to be aware of in the prevention of sickness absence.

Multi-Item Scales for Measuring Global Self-Rated Health

The authors used multigroup confirmatory factor analysis and structural equations models to examine the construct validity and item functioning of the five-item General Health (GH) scale from the SF-36 in Danes over 16 years of age ( n = 4,084). They included four criteria variables for physical and mental health. Items GH2-GH5 had low response rates among the elderly, probably due to the compact layout of these items in the questionnaire. The authors found differential item functioning for several items, indicating some degree of multidimensionality in the GH scale. Thus, GH1 had stronger associations with age, physical functioning, and chronic diseases than predicted by the one-factor model. However, psychometrical problems were mostly found in the youngest age group. If the problem of missing values is solved by layout changes or interview administration, the GH scale appears to be a valid measure of self-rated health in elderly populations.

Cross-Cultural Evaluation of Health Status Using Item Response Theory

To make meaningful cross-cultural comparisons of health-related quality of life (HRQOL) or to pool international research data, it is essential to create culturally unbiased measures that detect clinically important differences between patients. We evaluated the measurement properties of the Functional Assessment of Cancer Therapy-Breast (FACT-B) in 111 Austrian and 144 U.S. patients with breast cancer using item response theory (IRT) methods. A small number of items were identified as displaying statistically significant differential item functioning (DIF), suggesting possible measurement bias. The majority of the items functioned similarly between the two cultural groups. U.S. patients reported lower (worse) physical function and well-being compared with Austrian patients, higher (better) social/family well-being and similar emotional well-being, before and after adjustment for DIF. IRT and related measurement models provide useful methods for assessing cross-cultural equivalence and determining which items can be pooled across languages before analyzing HRQOL data. Determination of clinically significant cross-cultural differences will require additional investigation.

International SF-36 reference values in patients with ischemic heart disease

PURPOSE

International reference data for the SF-36 health survey (version 1) are presented based on a sample of 5508 adult patients with ischemic heart disease.

METHODS

Patients with angina, myocardial infarction and ischemic heart failure completed the SF-36. Data were analyzed by diagnosis, gender, age, region and country within region and presented as mean ± standard deviation (SD), minimum, maximum, 25th, 50th and 75th percentile of the physical (PCS) and mental component summary (MCS) measures.

RESULTS

Mean PCS scores were reported as being more than one SD below the normal range (standardized mean of 50 ± 10) by more than half of the patient subgroups (59 %) with all of the mean MCS scores falling within the normal range. Patients with angina and patients with ischemic heart failure reported the poorest mean PCS scores with both diagnoses reporting scores more than one SD below the standardized mean. Females, older patients (especially >70 years) and patients from Eastern Europe reported significantly worse mean PCS scores than male, younger and non-Eastern European patients. The cardiac diagnosis had no effect on the mean MCS scores; however, females, younger patients (especially <51 years) and patients from Eastern Europe reported significantly worse mean MCS scores than male, older and non-Eastern European patients.

CONCLUSIONS

These international reference SF-36 values for patients with IHD are useful for clinicians, researchers and health-policy makers when developing improved health services.

Cost-effectiveness of chiropractic care versus self-management in patients with musculoskeletal chest pain

Aims

To assess whether primary sector healthcare in the form of chiropractic care is cost-effective compared with self-management in patients with musculoskeletal chest pain, that is, a subgroup of patients with non-specific chest pain.

Methods and results

115 adults aged 18–75 years with acute, non-specific chest pain of musculoskeletal origin were recruited from a cardiology department in Denmark. After ruling out acute coronary syndrome and receiving usual care, patients with musculoskeletal chest pain were randomised to 4 weeks of community-based chiropractic care (n=59) or to a single information session aimed at encouraging self-management as complementary to usual care (n=56). Data on resource use were obtained from Danish national registries and valued from a societal perspective. Patient cost and health-related quality-adjusted life years (QALYs; based on EuroQol five-dimension questionnaire (EQ-5D) and Short Form 36-item Health Survey (SF-36)) were compared in cost-effectiveness analyses over 12 months from baseline. Mean costs were €2183 lower for the group with chiropractic care, but not statistically significant (95% CI −4410.5 to 43.0). The incremental cost-effectiveness ratio suggested that chiropractic care was cost-effective with a probability of 97%, given a threshold value of €30 000 per QALY gained. In both groups, there was an increase in the health-related quality of life, and the mean increases were similar over the 12-month evaluation period. The mean differences in QALYs between the groups were negligible.

Conclusions

Chiropractic care was more cost-effective than self-management. Therefore, chiropractic care can be seen as a good example of a targeted primary care approach for a subgroup of patients with non-specific chest pain.

Trial registration number

NCT00462241.

Differential Item Functioning in the SF-36 Physical Functioning and Mental Health Sub-Scales: A Population-Based Investigation in the Canadian Multicentre Osteoporosis Study

Background

Self-reported health status measures, like the Short Form 36-item Health Survey (SF-36), can provide rich information about the overall health of a population and its components, such as physical, mental, and social health. However, differential item functioning (DIF), which arises when population sub-groups with the same underlying (i.e., latent) level of health have different measured item response probabilities, may compromise the comparability of these measures. The purpose of this study was to test for DIF on the SF-36 physical functioning (PF) and mental health (MH) sub-scale items in a Canadian population-based sample.

Methods

Study data were from the prospective Canadian Multicentre Osteoporosis Study (CaMos), which collected baseline data in 1996–1997. DIF was tested using a multiple indicators multiple causes (MIMIC) method. Confirmatory factor analysis defined the latent variable measurement model for the item responses and latent variable regression with demographic and health status covariates (i.e., sex, age group, body weight, self-perceived general health) produced estimates of the magnitude of DIF effects.

Results

The CaMos cohort consisted of 9423 respondents; 69.4% were female and 51.7% were less than 65 years. Eight of 10 items on the PF sub-scale and four of five items on the MH sub-scale exhibited DIF. Large DIF effects were observed on PF sub-scale items about vigorous and moderate activities, lifting and carrying groceries, walking one block, and bathing or dressing. On the MH sub-scale items, all DIF effects were small or moderate in size.

Conclusions

SF-36 PF and MH sub-scale scores were not comparable across population sub-groups defined by demographic and health status variables due to the effects of DIF, although the magnitude of this bias was not large for most items. We recommend testing and adjusting for DIF to ensure comparability of the SF-36 in population-based investigations.

Estimating Skin Cancer Risk: Evaluating Mobile Computer-Adaptive Testing

Background

Response burden is a major detriment to questionnaire completion rates. Computer adaptive testing may offer advantages over non-adaptive testing, including reduction of numbers of items required for precise measurement.

Objective

Our aim was to compare the efficiency of non-adaptive (NAT) and computer adaptive testing (CAT) facilitated by Partial Credit Model (PCM)-derived calibration to estimate skin cancer risk.

Methods

We used a random sample from a population-based Australian cohort study of skin cancer risk (N=43,794). All 30 items of the skin cancer risk scale were calibrated with the Rasch PCM. A total of 1000 cases generated following a normal distribution (mean [SD] 0 [1]) were simulated using three Rasch models with three fixed-item (dichotomous, rating scale, and partial credit) scenarios, respectively. We calculated the comparative efficiency and precision of CAT and NAT (shortening of questionnaire length and the count difference number ratio less than 5% using independent t tests).

Results

We found that use of CAT led to smaller person standard error of the estimated measure than NAT, with substantially higher efficiency but no loss of precision, reducing response burden by 48%, 66%, and 66% for dichotomous, Rating Scale Model, and PCM models, respectively.

Conclusions

CAT-based administrations of the skin cancer risk scale could substantially reduce participant burden without compromising measurement precision. A mobile computer adaptive test was developed to help people efficiently assess their skin cancer risk.

Physical workload and risk of long-term sickness absence in the general working population and among blue-collar workers: prospective cohort study with register follow-up

OBJECTIVE

To determine the prospective association between physical workload--in terms of specific physical exposures and the number of exposures--and long-term sickness absence (LTSA).

METHODS

Using cox-regression analyses, we estimated the risk of register-based incident LTSA (at least 3 consecutive weeks) from self-reported exposure to different physical workloads among 11,908 wage earners from the general working population (Danish Work Environment Cohort Study year 2000 and 2005).

RESULTS

The incidence of LTSA was 8.9% during two-year follow-up. Spending 25% or more of the total work time with a bent or twisted back (HR 1.59 (95% CI 1.39 to 1.83)), arms above shoulder height (HR 1.35 (95% CI 1.14 to 1.59)), squatting or kneeling (HR 1.30 (95% CI 1.09 to 1.54)), pushing/pulling or lifting/carrying (HR 1.40 (95% CI 1.22 to 1.62)) and standing in the same place for 50% or more of total work time (HR 1.19 (95% CI 1.00 to 1.42), were risk factors for LTSA when adjusted for baseline age, gender, psychosocial work environment, lifestyle, musculoskeletal and mental disorders, and socioeconomic status. HR increased from 1.25 (95% CI 1.04 to 1.51) for one to 1.94 (95% CI 1.56 to 2.41) for four combined physical workloads. Results largely remained stable in subgroup analyses including only blue-collar workers (n=5055). Population attributable risks for LTSA from one or more physical workloads were 26% and 40% in the general working population and among blue-collar workers, respectively.

CONCLUSIONS

Several of the investigated types of physical workload were risk factors for LTSA when exceeding 25% of the work time. A higher number of combined physical workloads was associated with progressively increased risk. Our study underscores the importance of physical workload as risk factors for LTSA in the general working population as well as among blue-collar workers.

Differential item functioning (DIF) of SF-12 and Q-LES-Q-SF items among french substance users

Background

Differential Item Functioning (DIF) is investigated to ensure that each item displays a consistent pattern of responses irrespective of the characteristics of the respondents. Assessing DIF helps to understand the nature of instruments, to assess the quality of a measure and to interpret results. This study aimed to examine whether the items of the Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF) and Short-Form 12 (SF-12) exhibit DIF.

Method

A total of 124 outpatients diagnosed with substance dependence participated in a cross-sectional, multicenter study. In addition to the Q-LES-Q-SF and SF-12 results, demographic data such as age, sex, type of substance dependence and education level were collected. Rasch analysis was conducted (using RUMM2020 software) to assess DIF of the Q-LES-Q-SF and SF-12 items.

Results

For SF-12, significant age-related uniform DIF was found in two of the 12 items, and sex-related DIF was found in one of the 12 items. All of the observed DIF effects in SF-12 were found among the mental health items. Three items showed DIF on the Q-LES-Q-SF; however, the impact of DIF item on the delta score calculation for the comparisons of self-reported health status between the groups was minimal in the SF-12 and small in the Q-LES-Q-SF.

Conclusion

These results indicated that no major measurement bias affects the validity of the self-reported health status assessed using the Q-LES-Q-SF or SF-12. Thus, these questionnaires are largely robust measures of self-reported health status among substance users.