Health-related quality of life in Welsh adults: psychometric properties of the SF-36v2 and normative data.

OBJECTIVES: The use of normative data has become well-accepted and a common strategy to interpret individual's health outcome scores, which can help in making decisions. The objectives of this study were to obtain population normative data for the domains and component summaries of the 36-item SF-36® Health Survey (SF-36), and to evaluate its reliability and construct validity. METHODS: This study was conducted using population-based data from the Welsh Health Survey (WHS; 2011-2015). This study used version 2 of the SF-36 (SF-36v2® Health Survey). The descriptive statistics and normative data for the eight domains and two summaries, physical component summary (PCS) and mental component summary (MCS), were calculated. Reliability assessment used internal consistency methods and construct validity assessment used known group comparisons and item-scale correlations. STUDY DESIGN AND SAMPLE: We performed a secondary analyses of data from the Welsh Health Survey (WHS). RESULTS: This study included 74,578 participants aged 16 years or older (53.6% were women). Participants aged 16-24 years scored higher on SF-36 scale than older groups on all domains. The SF-36 profiles by age group demonstrated lower scores for older age groups, with the most pronounced differences shown on the physical-related scales. Across the age groups, men had higher PCS and MCS scores than women. All SF-36 domains and PCS and MCS achieved a good to excellent internal consistency reliability exceeding 0.7. The scales demonstrated construct validity by showing associations with a range of factors known to be related to health. CONCLUSIONS: This study provides SF-36 normative data for Wales based on a representative data and confirms the construct validity and reliability of the SF-36.

Increased risk of long-term sickness absence, lower rate of return to work and higher risk of disability pension among people with type 1 and type 2 diabetes mellitus: a Danish retrospective cohort study with up to 17 years' follow-up.

AIM: To evaluate labour market outcomes in type 1 or type 2 diabetes. METHODS: Individuals with type 1 (n = 431) and type 2 diabetes (n = 4047) were identified in Danish national registers from 1994 to 2011 and compared with individuals without diabetes (n = 101 295). Multi-state Cox proportional hazards analyses estimated hazard ratios (HR) with 95% confidence intervals (CI) for transitions between work, sickness absence, unemployment and disability pension. RESULTS: We observed significantly higher HR of sickness absence in type 1 diabetes (women: 1.34, 95% CI 1.12-1.62; men: 1.43, 1.01-2.03) and type 2 diabetes (women: 1.46, 95% CI 1.35-1.58; men: 1.64, 1.46-1.85) compared with people without diabetes. HR of unemployment was higher for men with type 1 diabetes (1.25, 95% CI 1.01-1.53) and women with type 2 diabetes (1.09, 95% CI 1.03-1.16) and men with type 2 diabetes (1.17, 95% CI 1.08-1.27). HR of disability pension was higher in type 1 diabetes (women: 1.90, 95% CI 1.46-2.46; men: 2.09, 1.38-3.18) and type 2 diabetes (women: 1.78, 95% CI 1.62-1.96; men: 2.11, 1.86-2.40). Only women with type 2 diabetes were less likely to return to work from sickness absence (HR 0.91, 95% CI 0.86-0.98) or unemployment (0.89, 95% CI 0.85-0.94). We found no significant difference between the two types of diabetes. Hazard ratios for diabetes regarding unemployment, sickness absence while unemployed and disability pension were significantly higher for men than for women. CONCLUSIONS: Both type 1 and type 2 diabetes affect labour market outcomes, but future studies should also consider comorbidity and social gradient.

THE ROMANIAN VERSION OF THE THYROID-RELATED PATIENT-REPORTED OUTCOMES THYPRO AND THYPRO-39. TRANSLATION AND ASSESSMENT OF RELIABILITY AND CROSS-CULTURAL VALIDITY.

BACKGROUND: ThyPRO is a recently developed thyroid-specific quality of life (QoL) questionnaire applicable to patients with benign thyroid disorders(BTD). The aim of the present study was to translate ThyPRO and ThyPRO-39 into Romanian, and to evaluate reliability and cross-cultural validity. METHODS: Standard methodology for translation and linguistic validation of patient-reported outcomes (PRO) was applied. The questionnaire was completed by 130 patients with benign thyroid diseases seen at Department of Endocrinology in the Emergency County Hospital, Tîrgu Mures, Romania, between October 2015 and March 2016. Internal reliability of the Romanian version of the ThyPRO (ThyPROro) scales was assessed for multi-item scales using Cronbach's alpha coefficient. An efficient method for testing cross-cultural validity is analysis of differential item functioning (DIF). Uniform DIF between the Romanian and the original Danish sample was investigated using ordinal logistic regression. The translation process proceeded without difficulties, and any disagreements were revised by one of the developers and the language coordinator. RESULTS: Internal reliability for ThyPRO was satisfactory. Cronbach`s alpha coefficients for the 13 scales ranged from 0.78 to 0.93 for the ThyPROro and 0.78 to 0.87 for the ThyPROro-39. In the 85-item ThyPRO, nine instances of DIF were found. Most were minor, explaining <3% of the variation in scale score, but DIF in positively worded items were larger, with explained variance (R2's) around 10-15%. CONCLUSION: The ThyPROro questionnaire is ready for assessment of health-related quality of life in Romanian patients with benign thyroid diseases.

Job strain as a risk factor for clinical depression: systematic review and meta-analysis with additional individual participant data.

BACKGROUND: Adverse psychosocial working environments characterized by job strain (the combination of high demands and low control at work) are associated with an increased risk of depressive symptoms among employees, but evidence on clinically diagnosed depression is scarce. We examined job strain as a risk factor for clinical depression. METHOD: We identified published cohort studies from a systematic literature search in PubMed and PsycNET and obtained 14 cohort studies with unpublished individual-level data from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium. Summary estimates of the association were obtained using random-effects models. Individual-level data analyses were based on a pre-published study protocol. RESULTS: We included six published studies with a total of 27 461 individuals and 914 incident cases of clinical depression. From unpublished datasets we included 120 221 individuals and 982 first episodes of hospital-treated clinical depression. Job strain was associated with an increased risk of clinical depression in both published [relative risk (RR) = 1.77, 95% confidence interval (CI) 1.47-2.13] and unpublished datasets (RR = 1.27, 95% CI 1.04-1.55). Further individual participant analyses showed a similar association across sociodemographic subgroups and after excluding individuals with baseline somatic disease. The association was unchanged when excluding individuals with baseline depressive symptoms (RR = 1.25, 95% CI 0.94-1.65), but attenuated on adjustment for a continuous depressive symptoms score (RR = 1.03, 95% CI 0.81-1.32). CONCLUSIONS: Job strain may precipitate clinical depression among employees. Future intervention studies should test whether job strain is a modifiable risk factor for depression.

Improvements in health-related quality of life with liraglutide 3.0 mg compared with placebo in weight management.

Obesity has a negative impact on health-related quality of life (HRQoL). The SCALE Obesity and Prediabetes study investigated the effect of liraglutide 3.0 mg, as adjunct to diet and exercise, on HRQoL in patients with obesity [body mass index (BMI) ≥ 30 kg m(-2) ] or overweight (BMI ≥ 27 kg m(-2) ) with comorbidity. Participants were advised on a 500 kcal d(-1) deficit diet and a 150-min week(-1) exercise programme and were randomised 2:1 to once-daily subcutaneous liraglutide 3.0 mg or placebo. HRQoL was assessed using the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) and Short-Form 36 (SF-36) v2 health questionnaires. Individuals on liraglutide 3.0 mg (n = 2046) had significantly greater improvements in IWQOL-Lite total score (10.6 ± 13.3) vs. placebo (n = 1020) (7.7 ± 12.8) and SF-36 physical (PCS) and mental (MCS) component summary scores (PCS, 3.6 ± 6.8; MCS, 0.2 ± 8.1) vs. placebo (PCS, 2.2 ± 7.7; MCS, -0.9 ± 9.1). The estimated treatment differences were IWQOL-Lite total score 3.1 (95% CI: 2.2; 4.0), P < 0.0001; SF-36 PCS 1.7 (95% CI: 1.2; 2.2), P < 0.0001 and MCS 0.9 (95% CI: 0.3; 1.5), P = 0.003. All subscales of the IWQOL-Lite and SF-36 were significantly improved with liraglutide 3.0 mg vs. placebo. More patients on liraglutide 3.0 mg experienced meaningful improvement on the IWQOL-Lite total (P < 0.0001) and the SF-36 PCS (P < 0.0001) scores.

Increased risk of long-term sickness absence, lower rate of return to work, and higher risk of unemployment and disability pensioning for thyroid patients: a Danish register-based cohort study.

CONTEXT: Little is known about how thyroid diseases affect work ability. OBJECTIVE: The objective of this study was to evaluate the risk of work disability for patients with thyroid disease compared with the general population. DESIGN, SETTING, AND PARTICIPANTS: In a longitudinal register study, outpatients (n = 862) with nontoxic goiter, hyperthyroidism, Graves' orbitopathy (GO), autoimmune hypothyroidism, or other thyroid diseases and their matched controls (n = 7043) were observed in the years 1994-2011 in Danish national registers of social benefits, health, and work characteristics. Cox regression analyses estimated adjusted hazard ratios (HRs) for the first year after diagnosis and subsequent years. MAIN OUTCOME MEASURES: Transitions between work, long-term sickness absence, unemployment, and disability pension were measured. RESULTS: Patients differed significantly from the general population with regard to sickness absence, disability pension, return from sickness absence, and unemployment. In the first year after diagnosis, higher risks of sickness absence was seen for GO (HR 6.94) and other hyperthyroid patients (HR 2.08), who also had lower probability of returning from sickness absence (HR 0.62) and higher risk of disability pension (HR 4.15). Patients with autoimmune hypothyroidism showed a lower probability of returning from sickness absence (HR 0.62). In subsequent years, GO patients had significantly higher risk of sickness absence (HR 2.08), lower probability of return from sickness absence (HR 0.51), and unemployment (HR 0.52) and a higher risk of disability pension (HR 4.40). Hyperthyroid patients also had difficulties returning from sickness absence (HR 0.71). CONCLUSIONS: Thyroid patients' risk of work disability is most pronounced in the first year after diagnosis and attenuates in subsequent years. GO patients have the highest risk of work disability.

Job strain and the risk of severe asthma exacerbations: a meta-analysis of individual-participant data from 100 000 European men and women.

BACKGROUND: Many patients and healthcare professionals believe that work-related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations in working-age European men and women. METHODS: We analysed individual-level data, collected between 1985 and 2010, from 102 175 working-age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self-reported at baseline. Incident severe asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study-specific findings combined using random-effects meta-analyses. RESULTS: During a median follow-up of 10 years, 1 109 individuals experienced a severe asthma exacerbation (430 with asthma as the primary diagnostic code). In the age- and sex-adjusted analyses, job strain was associated with an increased risk of severe asthma exacerbations defined using the primary diagnostic code (hazard ratio, HR: 1.27, 95% confidence interval, CI: 1.00, 1.61). This association attenuated towards the null after adjustment for potential confounders (HR: 1.22, 95% CI: 0.96, 1.55). No association was observed in the analyses with asthma defined using any diagnostic code (HR: 1.01, 95% CI: 0.86, 1.19). CONCLUSIONS: Our findings suggest that job strain is probably not an important risk factor for severe asthma exacerbations leading to hospitalization or death.

A comparison of health-related quality of life (health utility) between insulin degludec and insulin glargine: a meta-analysis of phase 3 trials.

AIM: To evaluate health-related quality of life (health utility) scores in patients with diabetes receiving insulin degludec (IDeg) or insulin glargine (IGlar). METHODS: Patient-level data from six, randomized, controlled, open-label, multicentre, confirmatory, treat-to-target trials of 26- or 52 weeks' duration were pooled in this analysis. The Short Form 36 (SF-36) version-2 health questionnaire was completed by patients at baseline and end-of-trial. SF-36 scores for 4001 individual patients were then mapped onto the EuroQol-5D health utility scale, which has a range from -0.59 (a state worse than death) to 1.00 (perfect health). RESULTS: IDeg treatment exhibited a significant improvement in health status of 0.005 (CI: 0.0006; 0.009) points compared with IGlar (p < 0.024). Gender, region, trial and age also had a significant influence on estimated utility scores as did baseline utility scores, p < 0.05. Prior to the removal of interaction variables a difference of 0.008 points was observed, p < 0.045. Previous insulin treatment did not have an impact on the final outcome. CONCLUSION: This study shows that IDeg is associated with a modest, but statistically significant, improvement in health utility compared with IGlar in patients with diabetes.

Evaluation of a role functioning computer adaptive test (RF-CAT).

OBJECTIVES: To evaluate the validity and participants' acceptance of an online assessment of role function using computer adaptive test (RF-CAT). METHODS: The RF-CAT and a set of established quality of life instruments were administered in a cross-sectional study in a panel sample (n = 444) recruited from the general population with over-selection of participants with selected self-report chronic conditions (n = 225). The efficiency, score accuracy, validity, and acceptability of the RF-CAT were evaluated and compared to existing measures. RESULTS: The RF-CAT with a stopping rule of six items with content balancing used 25 of the available bank items and was completed on average in 66 s. RF-CAT and the legacy tools scores were highly correlated (.64-.84) and successfully discriminated across known groups. The RF-CAT produced a more precise assessment over a wider range than the SF-36 Role Physical scale. Patients' evaluations of the RF-CAT system were positive overall, with no differences in ratings observed between the CAT and static assessments. CONCLUSIONS: The RF-CAT was feasible, more precise than the static SF-36 RP and equally acceptable to participants as legacy measures. In empirical tests of validity, the better performance of the CAT was not uniformly statistically significant. Further research exploring the relationship between gained precision and discriminant power of the CAT assessment is needed.

Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies.

BACKGROUND: Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses. OBJECTIVES: To examine the association between job strain and body mass index (BMI) in a large adult population. METHODS: We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222). RESULTS: A total of 86 429 participants were of normal weight (BMI 18.5-24.9 kg m(-2) ), 2149 were underweight (BMI < 18.5 kg m(-2) ), 56 572 overweight (BMI 25.0-29.9 kg m(-2) ) and 13 523 class I (BMI 30-34.9 kg m(-2) ) and 3073 classes II/III (BMI ≥ 35 kg m(-2) ) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.00-1.25], obese class I (odds ratio 1.07, 95% CI 1.02-1.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.01-1.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up. CONCLUSIONS: In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a 'U'-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.

Evaluation of a preliminary physical function item bank supported the expected advantages of the Patient-Reported Outcomes Measurement Information System (PROMIS).

OBJECTIVE: The Patient-Reported Outcomes Measurement Information System (PROMIS) was initiated to improve precision, reduce respondent burden, and enhance the comparability of health outcomes measures. We used item response theory (IRT) to construct and evaluate a preliminary item bank for physical function assuming four subdomains. STUDY DESIGN AND SETTING: Data from seven samples (N=17,726) using 136 items from nine questionnaires were evaluated. A generalized partial credit model was used to estimate item parameters, which were normed to a mean of 50 (SD=10) in the US population. Item bank properties were evaluated through Computerized Adaptive Test (CAT) simulations. RESULTS: IRT requirements were fulfilled by 70 items covering activities of daily living, lower extremity, and central body functions. The original item context partly affected parameter stability. Items on upper body function, and need for aid or devices did not fit the IRT model. In simulations, a 10-item CAT eliminated floor and decreased ceiling effects, achieving a small standard error (< 2.2) across scores from 20 to 50 (reliability >0.95 for a representative US sample). This precision was not achieved over a similar range by any comparable fixed length item sets. CONCLUSION: The methods of the PROMIS project are likely to substantially improve measures of physical function and to increase the efficiency of their administration using CAT.

Diabetic patients treated with dialysis: complications and quality of life.

AIMS/HYPOTHESIS: The aim of this study was to describe the prevalence of complications, health-related quality of life (HRQOL) and the influence of beliefs about control over health in diabetic dialysis patients. METHODS: Of 53 eligible diabetic patients on chronic dialysis during January 2004 in our clinic, 38 (76%) completed a kidney-specific (Kidney Disease Quality of Life) and a generic (SF-36) questionnaire and were characterised in terms of cardiovascular diseases and diabetic complications. Matched groups of non-diabetic dialysis patients (n = 40) and diabetic patients with a long duration of diabetes and normal kidney function (n = 38) served as controls. Generic HRQOL was compared with matched data from a survey on the Danish general population (n = 2248). RESULTS: Micro- and macrovascular complications were significantly more frequent in diabetic dialysis patients than in diabetic patients without renal disease. Self-rated physical health was significantly worse (p < 0.01) in diabetic dialysis patients (35 +/- 9 [mean +/- SD]) compared with non-diabetic dialysis patients (41 +/- 10), diabetic patients with normal kidney function (45 +/- 12) and the matched general population (47 +/- 19). The diabetic dialysis patients had similar levels of kidney-specific quality of life and mental health compared with the control groups. Reduced physical health was predicted by the presence of end-stage renal disease, diabetes and short time spent in education. Among the diabetic patients, those who believed more on their own ability to control their diabetes and less on chance reported better mental health and were less likely to be on dialysis. CONCLUSIONS/INTERPRETATIONS: Diabetic dialysis patients are characterised by a high prevalence of diabetic complications, reduced self-rated physical health but relatively good mental health.

Health-related quality of life one month after thrombolysis or primary PCI in patients with ST-elevation infarction. A DANAMI-2 sub-study.

OBJECTIVES: To evaluate the health-related quality of life (HRQoL) following Primary percutaneous coronary intervention (PCI) or thrombolytic treatment for ST-elevation myocardial infarction (STEMI). DESIGN: A questionnaire based study on patients randomised in the DANAMI-2 study to Primary PCI or thrombolysis for STEMI. A total of 1 351 patients (93.2% response rate) randomised in the DANAMI-2 study completed the HRQoL questionnaire one month after the infarction. RESULTS: With respect to the primary end-points (SF-36 physical component score, angina pectoris, and dyspnoea), patients randomised to primary PCI scored better on the SF-36 physical component score (PCS) (p=0.007), and reported significantly less angina pectoris (p=0.010) and dyspnoea (p=0.010). Higher scores among PCI patients were also found on the SF-36 scales physical functioning (p=0.015), role-physical (p=0.017), and general health (p=0.009). CONCLUSION: The results in this study support the hypothesis that primary PCI is superior to thrombolysis in treating STEMI, not only in clinical outcome, but also in quality of life outcome.

Quality of life in the Danish general population--normative data and validity of WHOQOL-BREF using Rasch and item response theory models.

BACKGROUND: The main objective of this study was to investigate the construct validity of the WHOQOL-BREF by use of Rasch and Item Response Theory models and to examine the stability of the model across high/low scoring individuals, gender, education, and depressive illness. Furthermore, the objective of the study was to estimate the reference data for the quality of life questionnaire WHOQOL-BREF in the general Danish population and in subgroups defined by age, gender, and education. METHODS: Mail-out-mail-back questionnaires were sent to a randomly selected sample of the Danish general population. The response rate was 68.5%, and the sample reported here contained 1101 respondents: 578 women and 519 men (four respondents did not indicate their genders). RESULTS: Each of the four domains of the WHOQOL-BREF scale fitted a two-parameter IRT model, but did not fit the Rasch model. Due to multidimensionality, the total score of 26 items fitted neither model. Regression analysis was carried out, showing a level of explained variance of between 10 and 14%. The mean scores of the WHOQOL-BREF are reported as normative data for the general Danish population. CONCLUSION: The profile of the four WHOQOL-BREF domains is a more adequate expression of quality of life than the total score of all 26 items. Although none of the subscales are statistically sufficient measures of their domains, the profile scores seem to be adequate approximations to the optimal score.

Use of item response theory to develop a shortened version of the EORTC QLQ-C30 emotional functioning scale.

BACKGROUND: As part of a larger study whose objective is to develop an abbreviated version of the EORTC QLQ-C30 suitable for research in palliative care, analyses were conducted to determine the feasibility of generating a shorter version of the 4-item emotional functioning (EF) scale that could be scored in the original metric. METHODS: We used data from 24 European cancer studies conducted in 10 different languages (n = 8242). Item selection was based on analyses by item response theory (IRT). Based on the IRT results, a simple scoring algorithm was developed to predict the original 4-item EF sum scale score from a reduced number of items. RESULTS: Both a 3-item and a 2-item version (item 21 'Did you feel tense?' and item 24 'Did you feel depressed?') predicted the total score with excellent agreement and very little bias. In group comparisons, the 2-item scale led to the same conclusions as those based on the original 4-item scale with little or no loss of measurement efficiency. CONCLUSION: Although these results are promising, confirmatory studies are needed based on independent samples. If such additional studies yield comparable results, incorporation of the 2-item EF scale in an abbreviated version of the QLQ-C30 for use in palliative care research settings would be justified. The analyses reported here demonstrate the usefulness of the IRT-based methodology for shortening questionnaire scales.

The responsiveness of headache impact scales scored using 'classical' and 'modern' psychometric methods: a re-analysis of three clinical trials.

BACKGROUND: While item response theory (IRT) offers many theoretical advantages over classical test theory in the construction and scoring of patient based measures of health few studies compare scales constructed from both methodologies head to head. OBJECTIVE: Compare the responsiveness to treatment of migraine specific scales scored using summated rating scale methods vs. IRT methods. METHODS: The data came from three clinical studies of migraine treatment that used the Migraine Specific Quality of Life Questionnaire (MSQ). Five methods of quantifying responsiveness were used to evaluate and compare changes from pre- to post-treatment in MSQ scales scored using Likert and IRT scaling methods. RESULTS: Changes in all MSQ scale scores from pre- to post-treatment were highly significant in all three studies. A single index scored from the MSQ using IRT methods was determined to be more responsive than any one of the MSQ subscales across the five methods used to quantify responsiveness. Across 13 of the 15 tests (5 responsiveness methods * 3 studies) conducted, the single index scored from the MSQ using IRT methods was the most responsive measure. CONCLUSIONS: IRT methods increased the responsiveness of the MSQ to the treatment of migraine. The results agree with the psychometric evidence that suggest that it is feasible to score a single index from the MSQ using IRT methods. This approach warrants further testing with other measures of migraine impact.

A six-item short-form survey for measuring headache impact: the HIT-6.

BACKGROUND: Migraine and other severe headaches can cause suffering and reduce functioning and productivity. Patients are the best source of information about such impact. OBJECTIVE: To develop a new short form (HIT-6) for assessing the impact of headaches that has broad content coverage but is brief as well as reliable and valid enough to use in screening and monitoring patients in clinical research and practice. METHODS: HIT-6 items were selected from an existing item pool of 54 items and from 35 items suggested by clinicians. Items were selected and modified based on content validity, item response theory (IRT) information functions, item internal consistency, distributions of scores, clinical validity, and linguistic analyses. The HIT-6 was evaluated in an Internet-based survey of headache sufferers (n = 1103) who were members of America Online (AOL). After 14 days, 540 participated in a follow-up survey. RESULTS: HIT-6 covers six content categories represented in widely used surveys of headache impact. Internal consistency, alternate forms, and test-retest reliability estimates of HIT-6 were 0.89, 0.90, and 0.80, respectively. Individual patient score confidence intervals (95%) of app. +/-5 were observed for 88% of all respondents. In tests of validity in discriminating across diagnostic and headache severity groups, relative validity (RV) coefficients of 0.82 and 1.00 were observed for HIT-6, in comparison with the Total Score. Patient-level classifications based in HIT-6 were accurate 88.7% of the time at the recommended cut-off score for a probability of migraine diagnosis. HIT-6 was responsive to self-reported changes in headache impact. CONCLUSIONS: The IRT model estimated for a 'pool' of items from widely used measures of headache impact was useful in constructing an efficient, reliable, and valid 'static' short form (HIT-6) for use in screening and monitoring patient outcomes.

Fatigue in the Danish general population. Influence of sociodemographic factors and disease.

OBJECTIVE: To measure the levels of fatigue in the general population, and to examine how disease and sociodemographic factors influence fatigue. DESIGN: Cross sectional questionnaire study in the Danish general population. SUBJECTS: A random, age stratified sample of 1608 people aged 20-77 with an equal gender distribution (response rate 67%). MAIN OUTCOME MEASURES: Five fatigue scales from the questionnaire Multidimensional Fatigue Inventory: General Fatigue, Physical Fatigue, Reduced Activity, Reduced Motivation and Mental Fatigue. RESULTS: Fatigue scores were skewed towards absence of fatigue. The General Fatigue and Physical Fatigue scales showed the highest fatigue levels while the Reduced Motivation scale showed lowest levels. Gender differences in fatigue scores were small, but the variability among women was higher-that is, more women had high scores. A multiple linear regression analysis showed that respondents of low social status and respondents with a depression had high fatigue scores on all scales, independent of other factors. Chronic somatic disease had an independent direct effect on Mental Fatigue, but for the rest of the scales, the effect of somatic disease depended on age, gender and/or whether the person was living alone. For example, General and Physical Fatigue decreased with age among healthy people, whereas scores on these scales increased with age among those with a somatic disease. CONCLUSIONS: Physical and mental diseases play essential parts for the level of fatigue and as modulators of the associations between sociodemographic factors and fatigue. These interactions should be taken into account in future research on fatigue and sociodemographic factors and when data from clinical studies are compared with normative data from the general population.

Anxiety and depression in breast cancer patients at low risk of recurrence compared with the general population: a valid comparison?

Breast cancer and its treatment have been associated with psychological morbidity. In this study our aim was to quantify the excess anxiety and depression resulting from breast cancer. We compared 538 newly diagnosed breast cancer patients at low risk of recurrence (87.0% responded) to 872 women randomly selected from the Danish general population (69.7% responded) using the Hospital Anxiety and Depression Scale (HADS). Contrary to expectations, the proportions classified as "cases" of anxiety and depression were not significantly different in the two groups. The breast cancer patients' mean HADS scores were significantly lower than those in the general population sample (anxiety, P = 0.021; depression, P < 0.001), indicating less anxiety and depression. However, we question the validity of this comparison. The HADS may not be suitable for use in the general population and there may be methodological problems in comparisons of groups whose life situations are very different.