Comparison of Rasch and summated rating scales constructed from SF-36 physical functioning items in seven countries: results from the IQOLA Project. International Quality of Life Assessment

Self-reported limitations in physical function are common 6 months after out-of-hospital cardiac arrest

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Limitations in physical function are common in cardiac arrest survivors.

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Age and gender are associated with limitations in physical function.

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Cognitive impairment is a predictive variable for physical limitations.

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Anxiety and depression symptoms are associated with physical limitations.

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Physical function should be addressed at follow-up after cardiac arrest.

Title

Self-reported limitations in physical function are common 6 months after out-of-hospital cardiac arrest.

Background

Out-of-hospital cardiac arrest (OHCA) survivors generally report good health-related quality of life, but physical aspects of health seem more affected than other domains. Limitations in physical function after surviving OHCA have received little attention.

Aims

To describe physical function 6 months after OHCA and compare it with a group of ST elevation myocardial infarction (STEMI) controls, matched for country, age, sex and time of the cardiac event. A second aim was to explore variables potentially associated with self-reported limitations in physical function in OHCA survivors.

Methods

A cross-sectional sub-study of the Targeted Temperature Management at 33 °C versus 36 °C (TTM) trial with a follow-up 6 months post-event. Physical function was the main outcome assessed with the self-reported Physical Functioning-10 items scale (PF-10). PF-10 is presented as T-scores (0–100), where 50 represents the norm mean. Scores <47 at a group level, or <45 at an individual level indicate limitations in physical function.

Results

287 OHCA survivors and 119 STEMI controls participated. Self-reported physical function by PF-10 was significantly lower for OHCA survivors compared to STEMI controls (mean 46.0, SD 11.2 vs. 48.8, SD 9.0, p = 0.025). 38% of OHCA survivors compared to 26% of STEMI controls reported limitations in physical function at an individual level (p = 0.022). The most predictive variables for self-reported limitations in physical function in OHCA survivors were older age, female sex, cognitive impairment, and symptoms of anxiety and depression after 6 months.

Conclusion

Self-reported limitations in physical function are more common in OHCA survivors compared to STEMI controls.

Trial registration

ClinicalTrials.gov Identifier: NCT01946932.

Cross-cultural validity of the WHO-5 Well-Being Index and Euthymia Scale: A clinimetric analysis

BACKGROUND

The assessment of psychological well-being and euthymia represents an emerging issue in clinical psychology and psychiatry. Rating scales and indices such as the 5-item version of the World Health Organization Well-Being Index (WHO-5) and the Euthymia Scale (ES) were developed but insufficient attention has been devoted to the evaluation of their cross-cultural validity. This is the first study using Clinimetric Patient-Reported Outcome Measures (CLIPROM) criteria to assess cross-cultural validity and sensitivity of five different versions of the WHO-5 and ES.

METHODS

A multicenter cross-sectional study involving a total of 3762 adult participants from different European (i.e., Italy, Poland, Denmark) and non-European (i.e., China, Japan) countries was conducted. Item Response Theory models (Mokken and Rasch analyses) were applied.

RESULTS

Mokken coefficients of scalability were found to range from 0.42 to 0.84. The majority of the versions of the WHO-5 fitted the Rasch model expectations. Paired t-tests revealed that the Italian and Danish WHO-5 versions were unidimensional. Person Separation Reliability indices showed that the Polish, Danish, and Japanese ES versions could reliably discriminate between subjects with different levels of euthymia.

LIMITATIONS

A convenience sampling was used, thus limiting the generalizability of study findings. In addition, no measures of negative mental health were administered.

CONCLUSIONS

WHO-5 can be used in international studies for cross-cultural comparisons since it covers transcultural components of subjective well-being. Findings also suggest that the ES can be used as a cross-cultural screening tool since it entailed the clinimetric property of sensitivity.

Rasch-Validated Italian Scale for Diagnosing Digital Eye Strain: The Computer Vision Syndrome Questionnaire IT©

The use of digital devices affects eye health; this can influence the performance of workers. To assess this impact, validated patient-reported outcome questionnaires are needed. The purpose of this study was to validate the psychometric properties of the Italian version of the Computer Vision Syndrome Questionnaire (CVS-Q©) using Rasch analysis. Two hundred and forty-one Italian workers completed an ad hoc questionnaire on anamnesis and exposure to digital devices, and the Italian version of the CVS-Q©. Subsequently, a battery involving three clinical ocular surface and tear tests was performed. The reliability and validity of the scale was assessed using the Andrich Rating Scale Model, and the prevalence of computer vision syndrome (CVS) was calculated. A good fit of both items and persons to the predictions of the Rasch model was observed, with acceptable reliability, unidimensionality, and no or minimal severe differences as a function of gender or age; moreover, good test–retest repeatability, adequate values of sensitivity, reliability, and area under the curve, and adequate construct validity based on clinical tests were obtained. Workers with a questionnaire score ≥ 7 were found to present with CVS. The prevalence of CVS was 76.6%. The CVS-Q IT© is a valid and reliable scale to assess CVS in Italian workers who use digital devices.

Quality of life in Italian patients with Multiple endocrine neoplasia type 1 (MEN 1): results of an extensive survey

Background

MEN1 is a complex, rare, syndrome inherited in an autosomal dominant tract and characterized by the development of multiple neuroendocrine tumors, requiring lifelong surveillance and multiple medical and surgical therapies throughout the patient’s life. For all these reasons, a diagnosis of MEN1 can be a psychological shock for the patient, as well as his/her relatives, more so than the diagnosis of a single tumor. In the last two decades, clinicians have started to consider the emotional, psychological, relational, and social aspects of their patients’ lives. The data collected in the present analyses highlight the unique features of MEN1 syndrome, and aim to evaluate the Quality of Life in the patients and their relatives. In this study, a comprehensive survey of various aspects of Health-Related Quality of Life was performed in a large series of Italian MEN1 patients, by administering five of the most common targeted questionnaires.

Results

The results of the study showed that our patients, despite having a complex multi-tumor syndrome, were moderately optimistic (50%), and this corresponds with a normal Quality of Life. This positive response is strictly correlated with the fact that the patients are cared for at a dedicated Referral Center, receiving personalized care and constant follow-up, which gives them reassurance regarding the high quality of management of the disorder.

Conclusions

The possibility of having access to a clinical Referral Center for their complex rare disease, together with the support of a dedicated patient association, has been demonstrated to be the ideal model for the management of post-diagnosis shock, and contributes to the preservation of a good Health-Related Quality of Life for MEN1 patients.

Mediterranean diet and physical functioning trajectories in Eastern Europe: Findings from the HAPIEE study

Background

Unhealthy diet may increase the risk of impaired physical functioning in older age. Although poor diet and limited physical functioning both seem to be particularly common in Eastern Europe, no previous study has assessed the relationship between these two factors in this region. The current analysis examined the association between overall diet quality and physical functioning in Eastern European populations.

Methods

We used data on 25,504 persons (aged 45–69 years at baseline) who participated in the Health Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) study. Dietary assessment at baseline used food frequency questionnaire, and the overall diet quality was evaluated by the Mediterranean diet score (MDS). Physical functioning (PF) was measured by the physical functioning subscale (PF-10) of the 36-item Short-Form Health Survey at baseline and three subsequent occasions over a 10-year period. The cross-sectional and longitudinal relationships between the MDS and PF were examined simultaneously using growth curve models.

Results

Men and women with higher adherence to the Mediterranean diet had significantly better PF at baseline; after multivariable adjustment, the regression coefficient per 1-unit increase in the MDS was 0.39 (95% CI: 0.25, 0.52) in men and 0.50 (0.36, 0.64) in women. However, we found no statistically significant link between baseline MDS and the subsequent slope of PF decline in neither gender; the coefficients were -0.02 (-0.04, 0.00) in men and -0.01 (-0.03, 0.02) in women.

Discussion

Our results do not support the hypothesis that the Mediterranean diet has a substantial impact on the trajectories of physical functioning, although the differences existing at baseline may be related to dietary habits in earlier life.

The Graded and Redefined Assessment of Strength, Sensibility, and Prehension Version 2 Provides Interval Measure Properties

The Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) is a valid, reliable, and responsive outcome measure to evaluate upper limb function in individuals with tetraplegia. GRASSP generates ordinal total scores; therefore, applicability as an interval level measurement requires testing of its measurement properties. This study examined the metric characteristics with Rasch Analysis to derive interval level scales of the respective GRASSP subtests. The GRASSP was recorded within 10 days, and at 1, 3, 6, and 12 months after cervical spinal cord injury (SCI). Rasch analysis was performed for each GRASSP subscale to assess the following metric assumptions: absence of local item dependency (LID), unidimensionality, monotonicity, item and model fit, reliability, and absence of differential item functioning (DIF) for side (left and right) and examination stage. If these assumptions could not be met, adjustments were undertaken to achieve a good fit to the Rasch model. Seventy-seven individuals with cervical SCI were included (n = 154 arms). Stacking the data for the side (left and right) resulted in a total of 614 observations, which were based on the repeated measurements. With minor adjustments, the GRASSP subscales showed good reliability, item fit, and ordered response options. Local item dependencies were found in the strength and sensibility subscales. Redundancies among some measurement items allowed shortening of the subscales without reasonable loss of reliability. Absence of DIF for the examination stage supported robustness of the subscales over time. The modified GRASSP, now Version 2, subtest scores can be applied as interval level measurements, and the reduction of items within subscales allows for shorter assessment times in clinical studies without degrading metric properties.

ISYQOL: a Rasch-consistent questionnaire for measuring health-related quality of life in adolescents with spinal deformities

BACKGROUND CONTEXT

Spinal deformities are commonly associated with poor health-related quality of life (HRQOL). Several questionnaires (eg, Scoliosis Research Society-24 [SRS-24] and Scoliosis Research Society-22 [SRS-22]) have been developed to evaluate HRQOL in these conditions. In adults as well as during growth, the HRQOL is considered one of the most relevant outcomes of both conservative and surgical treatments. Rasch analysis is a powerful statistical technique for developing high-quality and valid questionnaires. The SRS-24 and SRS-22 have been evaluated using the Rasch analysis but showed poor measurement properties. Thus, a proper measure of HRQOL in people with a spine condition is still missing.

PURPOSE

This study aimed to develop a new questionnaire that is totally Rasch consistent for measuring the HRQOL in young people with a spine condition.

STUDY DESIGN

This is a cross-sectional study for developing a new HRQOL measure.

PATIENT SAMPLE

A total of 402 participants with adolescent idiopathic scoliosis or Scheuermann juvenile kyphosis were included in the study.

OUTCOME MEASURE

The outcome measure used was the Italian Spine Youth Quality of Life (ISYQOL) questionnaire.

MATERIALS AND METHODS

The study consisted of different stages: a conventional approach content analysis, an opinion poll among clinicians trained in spine deformities, and the Rasch analysis (partial credit model).

RESULTS

The Rasch analysis showed that all items of the ISYQOL questionnaire had ordered thresholds and a good fit to the model. Differential item functioning was present for Item 1, with bracing only, and was solved with a conventional items splitting procedure. The ISYQOL item map spans an adequate range of HRQOL. The principal component analysis for Rasch residuals showed, in practical terms, the ISYQOL unidimensionality. The reliability of ISYQOL was high enough so that approximately three significantly different levels of HRQOL could be discerned. Two questionnaire versions were provided for patients with and without the brace, respectively.

CONCLUSIONS

ISYQOL is the first HRQOL questionnaire developed according to the Rasch analysis. It was developed in a conservative treatment setting for all types of spinal deformities, including also patients with surgical curves. Validation in many languages is already under way.

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.

The Relationship between Body Mass Index and 10-Year Trajectories of Physical Functioning in Middle-Aged and Older Russians: Prospective Results of the Russian HAPIEE Study

OBJECTIVE

To investigate the associations of overweight and obesity with longitudinal decline in physical functioning (PF) among middle-aged and older Russians.

DESIGN

Prospective cohort study.

SETTING

Four rounds of data collection in the Russian Health, Alcohol and Psychosocial factors In Eastern Europe study with up to 10 years of follow-up.

PARTICIPANTS

9,222 men and women aged 45-69 years randomly selected from the population of two districts of Novosibirsk, Russia.

MEASUREMENTS

PF score (range 0-100) was measured by the Physical Functioning Subscale (PF-10) of the 36-item Short Form Health Survey (SF-36) at baseline and three subsequent occasions. Body mass index (BMI), derived from objectively measured body height and weight at baseline, was classified into normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), obesity class I (BMI 30.0-34.9), and obesity class II+ (BMI≥35.0).

RESULTS

The mean annual decline in the PF score during the follow-up was -1.92 (95% confidence interval -2.17; -1.68) in men and -1.91 (-2.13; -1.68) in women. At baseline, compared with normal weight, obesity classes I and II+ (but not overweight) were associated with significantly lower PF in both sexes. In prospective analyses, the decline in PF was faster in overweight men (difference from normal weight subjects -0.38 [-0.63; -0.14]), class I obese men and women (-0.49 [-0.82; -0.17] and -0.44 [-0.73; -0.15] respectively) and class II+ obese men and women (-1.13 [-1.73; -0.53] and -0.43 [-0.77; -0.09] respectively). Adjustment for physical activity and other covariates did not materially change the results.

CONCLUSIONS

PF decreased more rapidly in obese men and women than among those with normal weight. The adverse effect of high BMI on PF trajectories appeared to be more pronounced in men than in women, making more extremely obese Russian men an important target population to prevent/slow down the process of decline in PF.

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.

Education, material condition and physical functioning trajectories in middle-aged and older adults in Central and Eastern Europe: a cross-country comparison

Background

Two competing hypotheses, cumulative advantage/disadvantage and age-as-leveller, have been proposed to explain the contradictory findings on socioeconomic differences in health over the lifespan. To test these hypotheses, this investigation examined the influence of educational attainment and material condition on individual trajectories of physical functioning (PF) in unexplored ageing populations in Central and Eastern Europe.

Methods

28 783 men and women aged 45–69 years selected from populations in seven Czech towns, Krakow (Poland) and Novosibirsk (Russia). PF was measured by the Physical Functioning Subscale (PF-10) of the Short-Form-36 questionnaire (SF-36) at baseline and three subsequent occasions. The highest educational attainment was self-reported at baseline, and material condition was captured by the sum score of 12 household amenities and assets.

Results

In all cohorts, participants with a university degree had the highest PF-10 score at baseline and slowest rate of decline in the score during follow-up, while the lowest baseline scores and fastest decline rate were found in participants with less than secondary education in all cohorts and in Russians with secondary education. Similar disparities in the baseline PF-10 score and decline rate were observed across tertiles of material condition, but differences in decline rates across the three tertiles among Czechs or between the lower two tertiles among Russians were not statistically significant.

Conclusions

Disparities in PF by educational attainment and material condition among middle-aged and older adults in Central and Eastern Europe existed at baseline and widened during ∼10 years of follow-up, supporting the cumulative advantage/disadvantage hypothesis.

Patients' expectations about total knee arthroplasty outcomes

OBJECTIVE

The aim of this study was to ascertain Patients' pre-operative expectations of total knee arthroplasty (TKA) recovery.

METHODS

Two hundred and thirty-six patients with knee osteoarthritis (OA) who underwent TKA completed self-administered questionnaires before their surgery. Patients' expectations of time to functional recovery were measured using an ordinal time-response scale to indicate expected time to recovery for each of 10 functional activities. Expected time to recovery was dichotomized into short- and long-term expectations for recovery of each activity using median responses. Knee pain and function were ascertained using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Other measures included the SF-36, the Depression, Anxiety and Stress Scale (DASS) and the Medical Outcomes Study Social Support Survey (MOS-SSS). Multivariate logistic regression was used to identify pre-operative characteristics associated with short- vs. long-term expectations.

RESULTS

Sixty-five percent of the patients were females and 70% Whites; mean age was 65 years. Patients were optimistic about their time to functional recovery: over 65% of patients expected functional recovery within 3 months. Over 80% of the patients expected to perform 8 of the 10 activities within 3 months. Patients who expected to be able to perform the functional activities in <6 weeks were more likely to be younger, male, and have lower self-reported pain and better general health before surgery compared to those who expected to be able to perform the activities 3 months post-surgery or later.

CONCLUSION

Pre-operative patient characteristics may be important to evaluate when considering individual Patients' expectations of post-operative outcomes.

Alcohol Consumption and Longitudinal Trajectories of Physical Functioning in Central and Eastern Europe: A 10-Year Follow-up of HAPIEE Study

Background:

Physical functioning (PF) is an essential domain of older persons’ health and quality of life. Health behaviors are the main modifiable determinants of PF. Cross-sectionally, alcohol consumption appears to be linked to better PF, but longitudinal evidence is mixed and very little is known about alcohol consumption and longitudinal PF trajectories.

Methods:

We conducted longitudinal analyses of 28,783 men and women aged 45–69 years from Novosibirsk (Russia), Krakow (Poland), and seven towns of the Czech Republic. At baseline, alcohol consumption was measured by a graduated frequency questionnaire and problem drinking was evaluated using the CAGE questionnaire. PF was assessed using the Physical Functioning Subscale of the SF-36 instrument at baseline and three subsequent occasions. Growth curve modeling was used to estimate the associations between alcohol consumption and PF trajectories over 10-year follow-up.

Results:

PF scores declined during follow-up in all three cohorts. Faster decline in PF over time was found in Russian female frequent drinkers, Polish female moderate drinkers, and Polish male regular heavy drinkers, in comparison with regular and/or light-to-moderate drinkers. Nondrinking was associated with a faster decline compared with light drinking only in Russian men. Problem drinking and past drinking were not related to the decline rate of PF.

Conclusions:

This large longitudinal study in Central and Eastern European populations with relatively high alcohol intake does not strongly support the existence of a protective effect of alcohol on PF trajectories; if anything, it suggests that alcohol consumption is associated with greater deterioration in PF over time.

HEALTH-RELATED QUALITY OF LIFE AFTER PERCUTANEOUS RADIOFREQUENCY ABLATION OF COLD, SOLID, BENIGN THYROID NODULES: A 2-YEAR FOLLOW-UP STUDY IN 40 PATIENTS

OBJECTIVE

We studied the impact of radiofrequency ablation (RFA) on health-related quality of life (HRQL) in patients with benign thyroid nodules (TN) in a 2-year follow-up.

METHODS

Forty patients (35 women and 5 men; age, 54.9 ± 14.3 years) with cold thyroid solitary nodules or a dominant nodule within a normofunctioning multi-nodular goiter (volume range, 6.5 to 90.0 mL) underwent RFA of thyroid nodular tissue under ultrasound real-time assistance.

RESULTS

Data are mean and standard deviation. Energy delivered was 37,154 ± 18,092 joules, with an output power of 37.4 ± 8.8 watts. Two years after RFA, nodule volume decreased from 30.0 ± 18.2 mL to 7.9 ± 9.8 mL (-80.1 ± 16.1% of initial volume; P<.0001). Thyroid-stimulating hormone, free triiodothyronine, and free thyroxine levels remained stable. Symptom score measured on a 0- to 10-cm visual analogue scale (VAS) declined from 5.6 ± 3.1 cm to 1.9 ± 1.3 cm (P<.0001). Cosmetic score (VAS 0-10 cm) declined from 5.7 ± 3.2 cm to 1.9 ± 1.5 cm (P<.0001). Two patients became anti-thyroglobulin antibody-positive. Physical Component Summary (PCS)-12 improved from 50.4 ± 8.9 to 54.5 ± 5.3, and the Mental Component Summary (MCS)-12 improved from 36.0 ± 13.3 to 50.3 ± 6.3 (P<.0001 for both score changes).

CONCLUSION

Our 2-year follow-up study confirms that RFA of benign TNs is effective in reducing nodular volume and compressive and cosmetic symptoms, without causing thyroid dysfunction or life-threatening complications. Our data indicate that the achievement of these secondary endpoints is associated with HRQL improvement, measured both as PCS and MCS.

Development and validation of the activity significance personal evaluation (ASPEn) scale

BACKGROUND/AIM

Engagement in desired occupations can promote health and wellbeing in older adults. Assessments of engagement often measure frequency, amount or importance of specific activities. This study aimed to develop a scale to measure older adults' evaluation of the extent to which their everyday activities are contributing to their health and wellness.

METHODS

Eighteen items, each scored with a seven-point rating scale, were initially developed by content experts, covering perceptions of how daily activities contribute to physical and mental health, as well as satisfaction and activity participation in the last six months. Rasch analysis methods were used to refine the scale using the pencil and paper responses of 460 community-living older adults.

RESULTS

Initial Rasch analysis indicated three unlabelled rating scale categories were seldom used, reducing measurement precision. Five items were conceptually different by misfit statistics and principal component analysis. Subsequently, those items were removed and the number of rating scale steps reduced to 4. The remaining 13-item, 4-step scale, termed the Activity Significance Personal Evaluation (ASPEn), formed a unidimensional hierarchy with good fit statistics and targeting. Person separation reliability (2.7) and internal consistency (.91) indicated the tool is appropriate for individual person measurement. Relative validity indicated equivalence between Rasch measures and total raw scores.

CONCLUSIONS

ASPEn is a brief, easily administered assessment of older adults' perception of the contribution of everyday activities to personal health and wellness. ASPEn may facilitate occupational therapy practice by enabling clinicians to assess change in meaning of an older adult's activity over time.

Laparoscopic vs. open surgery for treating benign liver lesions: assessing quality of life in the first year after surgery

Laparoscopic liver surgery has not yet gained widespread acceptance among liver surgeons. Some questions remain regarding indications to surgery and health related quality of life (HRQOL) after surgery, especially for the treatment of benign lesions, has so far not yet been investigated. The aim of this study is to evaluate HRQOL at 1 month, 6 months and 1 year after surgery in two groups of patients undergoing liver resections for benign liver lesions either by laparoscopic or open surgery. From January 2004 to September 2010 75 patients underwent surgery (29 laparoscopic, 46 open) for benign liver lesions.We retrospectively compared surgical results of the two groups and evaluated HRQOL with the SF-36 test. A personal or telephonic interview was administrated for the assessment of HRQOL before surgical treatment and at1 month, 6 months and 1 year after surgery. Sixty six patients (88%) were available for the study. The length of stay (4.7 vs. 8.2 days, p = 0.0002), the reprisal of oral intake (II post-op vs. III post-op, p = 0.02) the number of transfused patients (2 vs. 8, p = 0.1) and the overall rate of morbidity (p = 0.06) were lower in the laparoscopic group.HRQOL was significantly better in the laparoscopic group in the first year after surgery. Surgical treatment for benign liver lesions, when indicated, should be laparoscopic. This approach shows a lower rate of surgical complications with a better quality of life after surgery and a faster reprisal of social and job activities.

Development of an Expanded Measure of Physical Functioning for Older Persons in Epidemiologic Research

We scaled a measure of physical functioning to a population-based normative sample by extending self-reported basic and instrumental activities of daily living with items from the Medical Outcomes Study 12-Item Short Form Survey. We used item response theory to place items administered to a sample of older elective surgery patients on a common metric linked to the Patient Reported Outcomes Measurement Information System (PROMIS) normative sample using published data. The summary measure for physical functioning was internally consistent (Cronbach's α = .83), reliable across a broad range of functioning, and was moderately correlated with walking speed (r = .52) and energy expenditure (r = .40). Demonstrating predictive criterion validity, less impaired scores were associated with lower risk of discharge to a rehabilitation facility (odds ratio = .38, 95% confidence interval [CI] [0.22, 0.66]) and shorter hospital stays (incidence rate ratio [IRR] = 0.87, 95% CI [0.79, 0.97]). Our approach may facilitate direct comparison of physical functioning measures across existing and future studies using a common, population-based metric, when overlapping items with the National Institutes of Health (NIH) PROMIS item bank are present.

Baseline health-related quality of life and 10-year all-cause mortality among 1739 Chinese adults

BACKGROUND AND PURPOSE

Health-related quality of life (HRQOL) may be associated with the longevity of patients; yet it is not clear whether this association holds in a general population, especially in low- and middle-income countries. The objective of this study was to determine whether baseline HRQOL was associated with 10-year all-cause mortality in a Chinese general population.

METHODS

A prospective cohort study was conducted from 2002 to 2012 on 1739 participants in 11 villages of Beijing. Baseline data on six domains of HRQOL, chronic diseases and cardiovascular risk factors were collected in either 2002 (n = 1290) or 2005 (n = 449). Subjects were followed through the end of the study period, or until they were censored due to death or loss to follow-up, whichever came first.

RESULTS

A multivariable Cox model estimated that Total HRQOL score (bottom 50% versus top 50%) was associated with a 44% increase in all-cause mortality (Hazard Ratio [HR] = 1.44; 95% confidence interval [CI]: 1.00-2.06), after adjusting for sex, age, education levels, occupation, marital status, smoking status, fruit intake, vegetable intake, physical exercise, hypertension, history of a stroke, myocardial infarction, chronic respiratory disease, and kidney disease. Among the six HRQOL domains, the Independence domain had the largest fully adjusted HR (HR = 1.66; 95% CI: 1.13-2.42), followed by Psychological (HR = 1.47; 95% CI: 1.03-2.09), Environmental (HR = 1.43, 95% CI: 1.003-2.03), Physical (HR = 1.38; 95% CI: 0.97-1.95), General (HR = 1.37; 95% CI: 0.97-1.94), and the Social domain (HR = 1.15; 95% CI: 0.81-1.65).

CONCLUSION

Lower HRQOL, especially the inability to live independently, was associated with a significantly increased risk of 10-year all-cause mortality. The inclusion of HRQOL measures in clinical assessment may improve diagnostic accuracy to improve clinical outcomes and better target public health promotions.

The PROMIS Physical Function item bank was calibrated to a standardized metric and shown to improve measurement efficiency

OBJECTIVE

To document the development and psychometric evaluation of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) item bank and static instruments.

STUDY DESIGN AND SETTING

The items were evaluated using qualitative and quantitative methods. A total of 16,065 adults answered item subsets (n>2,200/item) on the Internet, with oversampling of the chronically ill. Classical test and item response theory methods were used to evaluate 149 PROMIS PF items plus 10 Short Form-36 and 20 Health Assessment Questionnaire-Disability Index items. A graded response model was used to estimate item parameters, which were normed to a mean of 50 (standard deviation [SD]=10) in a US general population sample.

RESULTS

The final bank consists of 124 PROMIS items covering upper, central, and lower extremity functions and instrumental activities of daily living. In simulations, a 10-item computerized adaptive test (CAT) eliminated floor and decreased ceiling effects, achieving higher measurement precision than any comparable length static tool across four SDs of the measurement range. Improved psychometric properties were transferred to the CAT's superior ability to identify differences between age and disease groups.

CONCLUSION

The item bank provides a common metric and can improve the measurement of PF by facilitating the standardization of patient-reported outcome measures and implementation of CATs for more efficient PF assessments over a larger range.

Exploring the aggregation of four functional measures in a population of older adults with joint pain and comorbidity

BACKGROUND

In clinical settings, it is important for health care providers to measure different aspects of functioning in older adults with joint pain and comorbidity. Besides the use of distinct measures, it could also be attractive to have one general measure of functioning that incorporates several distinct measures, but provides one summary score to quantify overall level of functioning, for example for the identification of older adults at risk of poor functional outcome. Therefore, we selected four measures of functioning: Physical Functioning (PF), Activities of Daily Living (ADL), Instrumental Activities of Daily Living (IADL) and participation, and tested the possibility to aggregate these measures into one general measure of functioning.

METHODS

A prospective cohort study of older adults (≥65 years) with joint pain and comorbidity provided baseline data (n = 407) consisting of PF (PF subscale, RAND-36; 10 items), ADL (KATZ index; 6 items), IADL (Lawton index; 7 items) and participation (KAP; 6 items). We tested two models with confirmatory factor analysis: first, a bifactor model with all four measures and second, a bifactor model with PF, ADL and IADL and a correlated but distinct subgroup factor for participation. Several model fit indexes and reliability coefficients, such as explained common variance (ECV) and omegas were computed for both models.

RESULTS

The first model fitted the data well, but the reliability analysis indicated multidimensionality and unique information in the subgroup factor participation. The second model showed similar model fits, but better reliability; ECV = 0.67, omega-t = 0.94, low omega-s = 0.18-0.22 on the subgroup factors and high omega of 0.82 on participation, which all were in favour of the second model.

CONCLUSIONS

The results indicate that PF, ADL and IADL could be aggregated into one general measure of functioning, whereas participation should be considered as a distinct measure.

Using the bootstrap to establish statistical significance for relative validity comparisons among patient-reported outcome measures

Background

Relative validity (RV), a ratio of ANOVA F-statistics, is often used to compare the validity of patient-reported outcome (PRO) measures. We used the bootstrap to establish the statistical significance of the RV and to identify key factors affecting its significance.

Methods

Based on responses from 453 chronic kidney disease (CKD) patients to 16 CKD-specific and generic PRO measures, RVs were computed to determine how well each measure discriminated across clinically-defined groups of patients compared to the most discriminating (reference) measure. Statistical significance of RV was quantified by the 95% bootstrap confidence interval. Simulations examined the effects of sample size, denominator F-statistic, correlation between comparator and reference measures, and number of bootstrap replicates.

Results

The statistical significance of the RV increased as the magnitude of denominator F-statistic increased or as the correlation between comparator and reference measures increased. A denominator F-statistic of 57 conveyed sufficient power (80%) to detect an RV of 0.6 for two measures correlated at r = 0.7. Larger denominator F-statistics or higher correlations provided greater power. Larger sample size with a fixed denominator F-statistic or more bootstrap replicates (beyond 500) had minimal impact.

Conclusions

The bootstrap is valuable for establishing the statistical significance of RV estimates. A reasonably large denominator F-statistic (F > 57) is required for adequate power when using the RV to compare the validity of measures with small or moderate correlations (r < 0.7). Substantially greater power can be achieved when comparing measures of a very high correlation (r > 0.9).

Self-rated health: analysis of distances and transitions between response options

PURPOSE

We explored health differences between population groups who describe their health as excellent, very good, good, fair, or poor.

METHODS

We used data from a population-based survey which included self-rated health (SRH) and three global measures of health: the SF36 general health score (computed from the 4 items other than SRH), the EQ-5D health utility, and a visual analogue health thermometer. We compared health characteristics of respondents across the five health ratings.

RESULTS

Survey respondents (N = 1.844, 49.2 % response) rated their health as excellent (12.2 %), very good (39.1 %), good (41.9 %), fair (6.0 %), or poor (0.9 %). The means of global health assessments were not equidistant across these five groups, for example, means of the health thermometer were 95.8 (SRH excellent), 88.8 (SRH very good), 76.6 (SRH good), 49.7 (SRH fair), and 33.5 (SRH poor, p < 0.001). Recoding the SRH to reflect these mean values substantially improved the variance explained by the SRH, for example, the linear r (2) increased from 0.50 to 0.56 for the health thermometer if the SRH was coded as poor = 1, fair = 2, good = 3.7, very good = 4.5, and excellent = 5. Furthermore, transitions between response options were not explained by the same health-related characteristics of the respondents.

CONCLUSIONS

The adjectival SRH is not an evenly spaced interval scale. However, it can be turned into an interval variable if the ratings are recoded in proportion to the underlying construct of health. Possible improvements include the addition of a rating option between good and fair or the use of a numerical scale instead of the classic adjectival scale.

Rasch-based scoring offered more precision in differentiating patient groups in measuring upper limb function

OBJECTIVE

To compare the discriminatory ability of Rasch-based and summative scoring in the context of assessing upper limb function of patients with stroke.

STUDY DESIGN AND SETTING

Data were from a cohort study of 497 adults with stroke undergoing physiotherapy. Upper limb function was assessed at admission and discharge using the upper limb subscale of the Motor Assessment Scale (UL-MAS). Rasch analysis was used to transform raw UL-MAS scores into interval measures. A relative precision (RP) index was used to differentiate patients by discharge destination.

RESULTS

The analysis confirmed the unidimensional structure of UL-MAS at both admission and discharge and demonstrated the adequate fit of the items. The RP index favored the Rasch-based scoring over the summative scoring in differentiating between the two patient groups, with significant gains in precision at admission (15%) and discharge (11%). When examining patients in the upper or lower quartile of UL-MAS, the gains in precision were statistically significant in favor of the Rasch-based scoring, with 20% precision at admission and 19% precision at discharge.

CONCLUSION

Rasch-based scoring was more precise in differentiating patient groups by discharge destination than the summative scoring used to measure upper limb function, especially at the extreme range of the scale.

Spatio-temporal Rasch analysis of quality of life outcomes in the French general population: measurement invariance and group comparisons

BACKGROUND

This study aims at analyzing Health related quality of life (HRQoL) data on the French general population between 1995 and 2003 using an Item Response Theory (IRT) model.

METHODS

Data concerned 26388 individuals having responded to the SF36 questionnaire in 1995 or in 2003. General Health, Mental Health and Physical Functioning dimensions have been analyzed using a latent regression mixed Partial Credit Model. Differential Item Functioning (DIF) have been searched on each item between age categories, genders, regions of residency, and years of study. Mean and variance of the latent traits have been explained by the same variables, in order to quantify their impact.

RESULTS

Few DIF have been detected between age categories or genders. The analysis shows already known evolutions for HRQoL data: the decrease with age and the differences between genders with worst values for women. We note differences between regions, with better mean value in Paris, in the West or in the South of France, and worst values in the North and in the East. Last, a decrease of the three studied dimensions is noted between 1995 and 2003.

CONCLUSIONS

This study using IRT model offers several advantages compared to a classical approach based on scores. First, DIF can be taken into account. More, handling of missing data is easy, because IRT models do not required imputation of missing data. Last, analysis using IRT model is more powerful than analysis based on scores, and allow highlighting a most important number of effects.

Validation of the individualised neuromuscular quality of life for the USA with comparison of the impact of muscle disease on those living in USA versus UK

Background

The Individualised Neuromuscular Quality of Life (INQoL) questionnaire is a published muscle disease specific measure of QoL that has been validated using both qualitative and quantitative methods in a United Kingdom population of adults with muscle disease. If INQoL is to be used in other countries it needs to be linguistically and culturally validated for those countries. It may be important to understand any cultural differences in how patients rate their QoL when applying QoL measures in multi-national clinical trials.

Methods

We conducted a postal survey of QoL issues in US adults with muscle disease using an agreed translation, from UK to US English, of the same questionnaire as was used in the original construction of INQoL. This questionnaire included an opportunity for free text comments on any aspects of QoL that might not have been covered by the questionnaire. We examined the responses using both quantitative and qualitative approaches. The frequency of the responses in US versus UK populations was compared using appropriate correlation tests and Rasch analysis. A phenomenological approach was used to guide the qualitative analysis and facilitate the exploration of patients' perceptions and experiences.

Results

The US survey received 333 responses which were compared with 251 UK survey responses.

We found that INQoL domains covered all the issues raised by US subjects with no additional domains required. The experiences of those with muscle disease were remarkably similar in the US and UK but there were differences related to the impact of muscle disease on relationships and on employment which was greater for those living in the United States. The greater impact on employment was associated with a higher importance rating given to employment in the US. This may reflect the lower level of financial support for those who are unemployed, and the loss of employment related health benefits.

Conclusions

INQoL is appropriate for use in US population but there may be differences in the importance that US subject attach to certain aspects of QoL that could be the basis for further study.

If these differences are confirmed then this may have implications for the interpretation of QoL outcomes in multi-national trials.

Dietary fat intake and quality of life: the SUN project

Background

Few studies have related nutritional factors with quality of life in healthy populations. The purpose of the study was to assess whether dietary fat intake is associated to mental and physical quality of life.

Methods

This analysis included 8,430 participants from the SUN (Seguimiento Universidad de Navarra) Project. The intake of saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA), trans unsaturated fatty acids (TFA), and monounsaturated fatty acids (MUFA) was assessed through a 136-item food frequency questionnaire at baseline. Quality of life was measured with the SF-36 Health Survey after 4 years of follow-up. Generalized Linear Models were fitted to assess the regression coefficients (b) and their 95% confidence intervals (95% CI) for the 8 domains of the SF-36 according to successive quintiles of each kind of fatty acids intake.

Results

The multivariate-adjusted models revealed a significant inverse association for SFA intake (in quintiles) and two of the physical domains (physical functioning and general health). E.g. for general health domain: (highest quintile of intake (Q5) vs. lowest quintile (Q1), b = -1.6; 95% CI = -3.1, -0.1. General health also showed a dose-response relationship (p for trend < 0.05). For TFA intake (in quintiles), a significant inverse association was found for most of the mental domains (vitality, social functioning and role emotional). E.g. for vitality domain (Q5) vs. (Q1), b = -2.0, 95% CI = -3.4 to -0.6. We also found an inverse association between TFA intake and the bodily pain domain: (Q5 vs. Q1), b = -2.6; 95% CI = -4.4 to -0.8, with a statistically significant dose-response relationship (p for trend < 0.05). Except for TFA intake and the mental domains, the rest of the associations were attenuated when we repeated the analysis adjusting for adherence to the Mediterranean diet.

Conclusions

A detrimental relationship between TFA intake at baseline and most of the SF-36 mental domains measured 4 years later were found, whereas weak inverse associations were found for SFA intake and some physical domains.

Maternal psychosocial factors around delivery, and the behavior of 2-year-old children

BACKGROUND

The objectives of the present study were to explore whether maternal psychosocial factors, mental health and work stress around delivery, are related to the behavior of 2-year-old children.

METHODS

In a prospective cohort study design, pregnant women attending the National Taiwan University Hospital for delivery and post-partum care from April 2004 to January 2005 were recruited and their children were observed at 24 months. A total of 186 mother-term-born child dyads completed the measurement. The five-item Mental Health Index (MHI-5) self-report data of maternal psychosocial factors were selected from the Taiwanese version of the short form 36 (SF-36). The Child Behavior Checklist for age 1½-5 (CBCL/1½-5) was completed by the parents when the child was 2 years old.

RESULTS

The mean score of mental health around delivery was 68.11. The proportion of mothers with work stress seldom and always was 61.8% and 24.7%, respectively. The mean of the total CBCL score, and internalizing, externalizing behavior and sleep problems scores was 45.95, 11.89, 15.59 and 4.23, respectively. After adjusting for the potential confounders, maternal work stress around delivery was found to have a significant effect on the total CBCL and externalizing, attention and aggressive, behavioral problems of 2-year old children. Maternal mental health around delivery, however, did not show significant effects on child behavior.

CONCLUSIONS

Work stress around delivery seems to aggravate children's externalizing behavior problems at 2 years old. It is therefore important to improve the psychosocial health and reduce the stress of pregnant women.

Can we rely on the Dermatology Life Quality Index as a measure of the impact of psoriasis or atopic dermatitis?

The Dermatology Life Quality Index (DLQI) is a widely used health-related quality of life measure. However, little research has been conducted on its dimensionality. The objectives of the current study were to apply Rasch analysis to DLQI data to determine whether the scale is unidimensional, to assess its measurement properties, test the response format, and determine whether the measure exhibits differential item functioning (DIF) by disease (atopic dermatitis versus psoriasis), gender, or age group. The results show that there were several problems with the scale, including misfitting items, DIF by disease, age, and gender, disordered response thresholds, and inadequate measurement of patients with mild illness. As the DLQI did not benefit from the application of Rasch analysis in its development, it is argued that a new measure of disability related to dermatological disease is required. Such a measure should use a coherent measurement model and ensure that items are relevant to all potential respondents. The current use of the DLQI as a guide to treatment selection is of concern, given its inadequate measurement properties.

Self-perceived quality of life predicts mortality risk better than a multi-biomarker panel, but the combination of both does best

Background

Associations between measures of subjective health and mortality risk have previously been shown. We assessed the impact and comparative predictive performance of a multi-biomarker panel on this association.

Methods

Data from 4,261 individuals aged 20-79 years recruited for the population-based Study of Health in Pomerania was used. During an average 9.7 year follow-up, 456 deaths (10.7%) occurred. Subjective health was assessed by SF-12 derived physical (PCS-12) and mental component summaries (MCS-12), and a single-item self-rated health (SRH) question. We implemented Cox proportional-hazards regression models to investigate the association of subjective health with mortality and to assess the impact of a combination of 10 biomarkers on this association. Variable selection procedures were used to identify a parsimonious set of subjective health measures and biomarkers, whose predictive ability was compared using receiver operating characteristic (ROC) curves, C-statistics, and reclassification methods.

Results

In age- and gender-adjusted Cox models, poor SRH (hazard ratio (HR), 2.07; 95% CI, 1.34-3.20) and low PCS-12 scores (lowest vs. highest quartile: HR, 1.75; 95% CI, 1.31-2.33) were significantly associated with increased risk of all-cause mortality; an association independent of various covariates and biomarkers. Furthermore, selected subjective health measures yielded a significantly higher C-statistic (0.883) compared to the selected biomarker panel (0.872), whereas a combined assessment showed the highest C-statistic (0.887) with a highly significant integrated discrimination improvement of 1.5% (p < 0.01).

Conclusion

Adding biomarker information did not affect the association of subjective health measures with mortality, but significantly improved risk stratification. Thus, a combined assessment of self-reported subjective health and measured biomarkers may be useful to identify high-risk individuals for intensified monitoring.

Physical activity and mammographic parenchymal patterns among Greek postmenopausal women

OBJECTIVE

To examine whether physical activity during the last five years is related to later breast mammographic density in postmenopausal Greek women.

METHODS

We designed a cross-sectional study in 724 women, of ages 45-67 years. An interview-administered questionnaire was used to obtain information on duration and intensity of recreational physical activity during five years preceding study recruitment. Mammograms were evaluated according to BIRADS classification and BIRADS score was also estimated. Multivariate ordinal logistic regression analysis was used to assess associations between physical activity index and breast density according to the BIRADS classification methods.

RESULTS

We observed a statistically significant inverse association of mammographic breast density measured by the BIRADS classification method and recreational exercise (OR=-0.10; 95% CI -0.018, -0.001; p=0.022). For one unit increase in physical activity as expressed by the MET-h/week score, the odds of lower versus higher breast density categories are 1.105 greater, given that all of the other variables in the model are held constant. A modifying effect by age at recruitment was evident among participants, with a stronger inverse association between recreational activity and mammographic breast density among older women (OR=-0.036; 95% CI -0.063, -0.009; p=0.009). An inverse association between physical activity and BIRADS score was evident, not reaching statistical significance (OR=0.00; 95% CI -0.009, 0.008; p=0.887).

CONCLUSIONS

Mammographic breast area was lower in postmenopausal women who participated in sports/recreational physical activity compared to inactive controls. Increasing physical activity levels among postmenopausal women might be a reasonable approach to reduce mammographic density. However, until more physical activity and mammographic breast density studies are conducted that confirm our findings, they have to be interpreted with caution, due to the retrospective nature of our data and the possibility of memory bias.

Maternal psychosocial factors around delivery on development of 2-year-old children: A prospective cohort study

AIM

To explore whether maternal psychosocial factors around delivery are related to development of 2-year-old children.

METHODS

Pregnant women going to the hospital for delivery were recruited, and their children were observed at 24 months. A total of 186 mother-child dyads completed the measurement. Self-report data of maternal psychosocial factors around delivery were selected from the Taiwanese version of the short-form 36. The Comprehensive Developmental Inventory for Infants and Toddlers was completed by interviewers and the main care givers for the child at 2 years old.

RESULTS

Using the multiple linear regression analysis and adjusting for potential confounders, maternal vitality around delivery was found to have a significantly positive relationship with the whole Comprehensive Developmental Inventory for Infants and Toddlers (P = 0.005) and self-help development (P = 0.001), but work stress had a significantly negative relationship with motor development (seldom, P = 0.050; always, P = 0.048).

CONCLUSIONS

Maternal vitality around delivery was beneficial to a child's self-help development, while work stress seemed to be an adverse effect on child's motor development in later life. It is important to improve the psychosocial health of pregnant women.

Psychometric properties of visual functioning index using Rasch analysis

PURPOSE

The visual functioning index (VFI) was one of the first questionnaires developed using classical test theory to assess outcomes of cataract surgery. However, it was not Rasch-validated. The objective of this study was to examine the psychometric properties of the VFI using Rasch analysis in patients with cataract.

METHODS

The 11-item VFI was self-administered to 243 patients (mean age 73.9 years) drawn from a cataract surgery waiting list. We examined the response category thresholds, item fit statistics, differential item functioning and unidimensionality for the VFI and its three subscales.

RESULTS

Category thresholds were ordered. The person separation and reliability were low, indicating the poor discriminatory ability of the VFI. No items misfit but there was suboptimal targeting of item difficulty to patient ability. On the whole the items in the VFI were too easy for the sample. Only one item showed moderate differential item functioning.

CONCLUSION

The VFI does not meet the stringent requirements of the Rasch model. However adding more items to suit the more able patients with cataract as well as those awaiting second-eye cataract surgery could optimize the VFI.

A comparison of Rasch item-fit and Cronbach's alpha item reduction analysis for the development of a Quality of Life scale for children and adolescents

OBJECTIVE

This study compares item reduction analysis based on classical test theory (maximizing Cronbach's alpha - approach A), with analysis based on the Rasch Partial Credit Model item-fit (approach B), as applied to children and adolescents' health-related quality of life (HRQoL) items. The reliability and structural, cross-cultural and known-group validity of the measures were examined.

METHODS

Within the European KIDSCREEN project, 3019 children and adolescents (8-18 years) from seven European countries answered 19 HRQoL items of the Physical Well-being dimension of a preliminary KIDSCREEN instrument. The Cronbach's alpha and corrected item total correlation (approach A) were compared with infit mean squares and the Q-index item-fit derived according to a partial credit model (approach B). Cross-cultural differential item functioning (DIF ordinal logistic regression approach), structural validity (confirmatory factor analysis and residual correlation) and relative validity (RV) for socio-demographic and health-related factors were calculated for approaches (A) and (B).

RESULTS

Approach (A) led to the retention of 13 items, compared with 11 items with approach (B). The item overlap was 69% for (A) and 78% for (B). The correlation coefficient of the summated ratings was 0.93. The Cronbach's alpha was similar for both versions [0.86 (A); 0.85 (B)]. Both approaches selected some items that are not strictly unidimensional and items displaying DIF. RV ratios favoured (A) with regard to socio-demographic aspects. Approach (B) was superior in RV with regard to health-related aspects.

CONCLUSION

Both types of item reduction analysis should be accompanied by additional analyses. Neither of the two approaches was universally superior with regard to cultural, structural and known-group validity. However, the results support the usability of the Rasch method for developing new HRQoL measures for children and adolescents.

Work stress of primary care physicians in the US, UK and German health care systems

Work-related stress among physicians has been an issue of growing concern in recent years. How and why this may vary between different health care systems remains poorly understood. Using an established theoretical model (effort-reward imbalance), this study analyses levels of work stress among primary care physicians (PCPs) in three different health care systems, the United States, the United Kingdom and Germany. Whether professional autonomy and specific features of the work environment are associated with work stress and account for possible country differences are examined. Data are derived from self-administered questionnaires obtained from 640 randomly sampled physicians recruited for an international comparative study of medical decision making conducted from 2005 to 2007. Results demonstrate country-specific differences in work stress with the highest level in Germany, intermediate level in the US and lowest level among UK physicians. A negative correlation between professional autonomy and work stress is observed in all three countries, but neither this association nor features of the work environment account for the observed country differences. Whether there will be adequate numbers of PCPs, or even a field of primary care in the future, is of increasing concern in several countries. To the extent that work-related stress contributes to this, identification of its organizational correlates in different health care systems may offer opportunities for remedial interventions.

Derivation and testing of an interval-level score for measuring locomotor disability in epidemiological studies of middle and old age

PURPOSE

Locomotor disability is prevalent in middle and old age and although interval-level measurement instruments have been developed that relate to locomotor disability, there is currently no brief, interval-level score developed specifically to measure the severity of locomotor disability in the general population. We aimed to create such a score from five items of the SF-36 Physical Functioning subscale (PF-10): three walking- and two stair-climbing-related, and assess the scoring mechanism's measurement properties.

METHODS

Data were collected from postal surveys of adults aged 50 years and over. The walking and stair-climbing items were formed into two super-items to remove response dependency. The Rasch measurement model was used to form an interval-level score and fit to this model was assessed. The scoring mechanism was applied to three external data sets and fit to the Rasch model was assessed. Repeatability, construct validity, and responsiveness of the new interval scale were examined.

RESULTS

Overall, the fit of the super-items to the Rasch model was good, with little evidence of misfit. Our analyses broadly support the generalisability, repeatability, construct validity, and responsiveness of this new interval-level score.

CONCLUSIONS

An interval-level score for locomotor disability was created from five items of the PF-10 completed in a general population of adults aged 50 years and over. Further work is needed to assess the generalisability of this Rasch score to other populations and to determine a clinically meaningful change score.

Evaluation of the German translation of the Stroke Impact Scale using Rasch analysis

To assess the complex and heterogeneous consequences of stroke, currently comprehensive patient-centered measures, like the Stroke Impact Scale (SIS), are increasingly being developed. The purpose of this study was to evaluate the psychometric properties of the German translation of the SIS using Rasch analyses. A total of 196 patients with stroke from 16 study centers participated in the study. In tests for item fit, 7 of the 64 items displayed model misfit. Response categories of 25 items showed threshold disordering. Person separation reliability lay above.80 in six domains. No differential item functioning was detected with respect to age, gender, disability severity, and setting. The results provide support for validity and reliability of the SIS, and also point out issues for further improvement and adaptation of the SIS.

Function and disability in late life: comparison of the Late-Life Function and Disability Instrument to the Short-Form-36 and the London Handicap Scale

PURPOSE

We evaluated the Late-Life Function and Disability Instrument's (LLFDI) concurrent validity, comprehensiveness and precision by comparing it with the Short-Form-36 physical functioning (PF-10) and the London Handicap Scale (LHS).

METHODS

We administered the LLFDI, PF-10 and LHS to 75 community-dwelling adults (> 60 years of age). We used Pearson correlation coefficients to examine concurrent validity and Rasch analysis to compare the item hierarchies, content ranges and precision of the PF-10 and LLFDI function domains, and the LHS and the LLFDI disability domains.

RESULTS

LLFDI Function (lower extremity scales) and PF-10 scores were highly correlated (r = 0.74 - 0.86, p > 0.001); moderate correlations were found between the LHS and the LLFDI Disability limitation (r = 0.66, p < 0.0001) and Disability frequency (r = 0.47, p < 0.001) scores. The LLFDI had a wider range of content coverage, less ceiling effects and better relative precision across the spectrum of function and disability than the PF-10 and the LHS. The LHS had slightly more content range and precision in the lower end of the disability scale than the LLFDI.

CONCLUSIONS

The LLFDI is a more comprehensive and precise instrument compared to the PF-10 and LHS for assessing function and disability in community-dwelling older adults.

The natural history of disability and its determinants in adults with lower limb musculoskeletal pain

OBJECTIVE

To investigate determinants of deterioration or improvement in disability in people with chronic hip and knee pain.

METHODS

We analyzed data from the Somerset and Avon Survey of Health, a longitudinal, community-based cohort study containing data collected in 1994-95 and again in 2002-03. The Medical Outcomes Study Short-Form 36 was completed by subjects at both timepoints, and used to categorize people as disabled or not. Baseline data were used to explore possible determinants of change in functional status over the 8-year time period. Adjusted odds ratios (OR) were derived from a multivariate, multinomial logistic model.

RESULTS

Data were available on 1072 subjects, all of whom reported chronic hip and/or knee pain at baseline. At baseline, 56.8% of women and 42.0% of men were disabled. Of 545 people with disabilities at baseline, 107 (19.6%) reported no disability at followup; of 527 with no disability at baseline, 177 (33.6%) became disabled. The development of disability was significantly associated with older age (OR 2.1), living in the most deprived areas (2.4), the presence of 3 or more comorbidities (3.6), more problems with physical function at baseline (2.0), and more severe pain (2.4). The determinants of improvement mirrored those of deterioration. The data suggest a "threshold effect" at which recovery becomes unlikely.

CONCLUSION

Of people presenting with hip or knee pain, healthcare professionals should be most concerned about those who are older, of lower socioeconomic status, with comorbidities, and who have more severe pain. Much longstanding disability might be preventable.

MRI bone oedema scores are higher in the arthritis mutilans form of psoriatic arthritis and correlate with high radiographic scores for joint damage

Introduction

The aim of this study was to investigate the magnetic resonance imaging (MRI) features of bone disease in the arthritis mutilans (AM) form of psoriatic arthritis (PsA).

Methods

Twenty-eight patients with erosive PsA were enrolled (median disease duration of 14 years). Using x-rays of both hands and feet, 11 patients were classified as AM and 17 as non-AM (erosive psoriatic arthritis without bone lysis)by two observers. MRI scans (1.5T) of the dominant hand (wrist and fingers scanned separately) were obtained using standard contrast-enhanced T1-weighted and fat-saturated T2-weighted sequences. Scans were scored separately by two readers for bone erosion, oedema and proliferation using a PsA MRI scoring system. X-rays were scored for erosions and joint space narrowing.

Results

On MRI, 1013 bones were scored by both readers. Reliability for scoring erosions and bone oedema was high (intraclass correlation coefficients = 0.80 and 0.77 respectively) but only fair for bone proliferation (intraclass correlation coefficient = 0.42). MRI erosion scores were higher in AM patients (53.0 versus 15.0, p = 0.004) as were bone oedema and proliferation scores (14.7 versus 10.0, p = 0.056 and 3.6 versus 0.7, p = 0.003 respectively). MRI bone oedema scores correlated with MRI erosion scores and X-ray erosion and joint space narrowing scores (r = 0.65, p = 0.0002 for all) but not the disease activity score 28-C reactive protein (DAS_28CRP) or pain scores.

Conclusions

In this patient group with PsA, MRI bone oedema, erosion and proliferation were all more severe in the AM-form. Bone oedema scores did not correlate with disease activity measures but were closely associated with X-ray joint damage scores. These results suggest that MRI bone oedema may be a pre-erosive feature and that bone damage may not be coupled with joint inflammation in PsA.

Application of item response theory to achieve cross-cultural comparability of occupational stress measurement

Our objective was to examine cross-cultural comparability of standard scales of the Effort-Reward Imbalance occupational stress scales by item response theory (IRT) analyses. Data were from 20,256 Japanese employees, 1464 Dutch nurses and nurses' aides, 2128 representative employees from post-communist countries, 963 Swedish representative employees, 421 Chinese female employees, 10,175 employees of the French national gas and electric company and 734 Spanish railroad employees, sanitary personnel and telephone operators. The IRT likelihood ratio model was used for differential item functioning (DIF) and differential test functioning (DTF) analyses. Despite the existence of DIF, most comparisons did not show discernible differences in the relations between Effort-Reward total score and level of the underlying trait across cultural groups. In the case that DTF was suspected, excluding an item with significant DIF improved the comparability. The full cross-cultural comparability of Effort-Reward Imbalance scores can be achieved with the help of IRT analysis.