| 1. |
- Ahmad Kiadaliri, Aliasghar, et al.
(författare)
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Assessing the external validity of algorithms to estimate EQ-5D-3L from the WOMAC
- 2016
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The use of mapping algorithms have been suggested as a solution to predict health utilities when no preference-based measure is included in the study. However, validity and predictive performance of these algorithms are highly variable and hence assessing the accuracy and validity of algorithms before use them in a new setting is of importance. The aim of the current study was to assess the predictive accuracy of three mapping algorithms to estimate the EQ-5D-3L from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) among Swedish people with knee disorders. Two of these algorithms developed using ordinary least squares (OLS) models and one developed using mixture model. Methods: The data from 1078 subjects mean (SD) age 69.4 (7.2) years with frequent knee pain and/or knee osteoarthritis from the Malmö Osteoarthritis study in Sweden were used. The algorithms' performance was assessed using mean error, mean absolute error, and root mean squared error. Two types of prediction were estimated for mixture model: weighted average (WA), and conditional on estimated component (CEC). Results: The overall mean was overpredicted by an OLS model and underpredicted by two other algorithms (P < 0.001). All predictions but the CEC predictions of mixture model had a narrower range than the observed scores (22 to 90 %). All algorithms suffered from overprediction for severe health states and underprediction for mild health states with lesser extent for mixture model. While the mixture model outperformed OLS models at the extremes of the EQ-5D-3D distribution, it underperformed around the center of the distribution. Conclusions: While algorithm based on mixture model reflected the distribution of EQ-5D-3L data more accurately compared with OLS models, all algorithms suffered from systematic bias. This calls for caution in applying these mapping algorithms in a new setting particularly in samples with milder knee problems than original sample. Assessing the impact of the choice of these algorithms on cost-effectiveness studies through sensitivity analysis is recommended.
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| 2. |
- Ahmad Kiadaliri, Aliasghar, et al.
(författare)
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Association of knee pain and different definitions of knee osteoarthritis with health-related quality of life : A population-based cohort study in southern Sweden
- 2016
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: While the impact of knee pain and knee osteoarthritis (OA) on health-related quality of life (HRQoL) has been investigated in the literature, there is a lack of knowledge on the impact of different definitions of OA on HRQoL. The main aim of this study was to measure and compare the impact of knee OA and its different definitions on HRQoL in the general population. Methods: A random sample of 1300 participants from Malmö, Sweden with pain in one or both knees in the past 12 months with duration ≥4 weeks and 650 participants without were invited to clinical and radiographic knee examination. A total of 1527 individuals with a mean (SD) age 69.4 (7.2) participated and responded to both generic (EQ-5D-3L) and disease-specific (the Knee injury and Osteoarthritis Outcome Score) questionnaires. Knee pain was defined as pain during the last month during most of the days. Knee OA was defined radiographically (equivalent to Kellgren and Lawrence grade ≥2) and clinically according to the American College of Rheumatology (ACR) criteria. Results: Of participants with either knee pain or knee OA or both, 7 % reported no problem for the EQ-5D-3L attributes. The corresponding proportion among references (neither knee pain nor OA) was 42 %. The participants with knee pain and OA had all HRQoL measures lower compared to those with knee pain but no OA. The ACR clinical definition of knee OA was associated with lower HRQoL than the definition based on radiographic knee OA (adjusted difference -0.08 in UK EQ-5D-3L index score). Conclusions: Applying different definitions of knee OA result in different levels of HRQoL and this is mainly explained by the knee pain experience. These differences may lead to discrepant conclusions from cost-utility analyses.
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| 3. |
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| 4. |
- Bejerholm, Ulrika, et al.
(författare)
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Rasch Analysis of the Profiles of Occupational Engagement in people with Severe mental illness (POES) instrument
- 2015
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The Profiles of Occupational Engagement in people with Severe mental illness (POES) instrument was developed to study time use profiles of occupations and measure the extent they are characterized by engagement. However, the dimensional factors are not known. The aim of the present study was to establish the internal construct validity of the POES using the Rasch measurement model. Methods: A sample of 192 outpatients in Sweden was administered the POES and data were subjected to Rasch analysis. Results: The POES showed good fit to the Rasch model after accommodation for local dependency. The nine items had high reliability as measured by person separation index, and no threshold disordering was present. Differential item functioning analysis showed no significant differences across groups of age, sex, diagnosis, or country of origin. Conclusion: The POES is a unidimensional scale that represents a continuum of occupational engagement. The transformed POES sum score can be used on an interval scale to measure status and changes in occupational engagement in mental health practice and research.
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| 5. |
- Berglund, Erik, et al.
(författare)
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Health and wellbeing in informal caregivers and non-caregivers : a comparative cross-sectional study of the Swedish a general population
- 2015
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525 .- 1477-7525. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Informal caregiving by relatives is a great resource for individuals as well as for society, but the caregiving role is associated with health problems for the caregiver. This study aimed to compare caregivers' self-rated health, number of recent days with poor health and psychological wellbeing with that of non-caregivers in a general Swedish population. Methods: From 2004 to 2013, 90,845 Swedish people completed a postal questionnaire about their health, number of recent days with poor health during last month, psychological wellbeing and if they were performing caregiving or not. Descriptive statistics, chi-square analysis, ANOVA, logistic regressions and negative binomial regression models were used to investigate associations between being a caregiver or not and health and wellbeing. Negative binomial regression was used to assess the relation between caregiver status and recent days with poor health or functioning. Results: Eleven percent reported having a caregiving role. Caregivers reported poorer self-rated health compered to non-caregivers, also in adjusted models; odds ratio (OR): 1.07 with a 95 % confidence interval (CI): 1.01-1.13. Caregivers also reported lower psychological wellbeing compared to non-caregivers; OR: 1.22, CI: 1.15-1.30. Caregiving status was associated with more recent days with poor physical health and more recent days with poor mental health. Conclusions: This study suggests that caregivers have worse perceptions in self-rated health and psychological wellbeing compared with non-caregivers, indicating that the role of caregiver is adversely associated with health. This association also appears in terms of reporting days of poor health in the last month. The underlying mechanism of these associations, including the potential detrimental health effects of being a caregiver, needs to be investigated in longitudinal studies.
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| 6. |
- Chaplin, John, 1955, et al.
(författare)
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The development of a health-related quality-of-life instrument for young people with narcolepsy: NARQoL-21
- 2017
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Narcolepsy is a lifelong sleep disorder with a prevalence of between 0.03% and 0.06% and onset at around puberty. It is associated with psychiatric comorbidities and cognitive difficulties. No valid and reliable condition-specific health-related quality-of-life (HrQoL) instrument has been developed for this population. METHODS: A questionnaire based on four mixed-gender age-defined focus group discussions and a patient panel analysis was administered to young people with narcolepsy and a control group. External reliability was measured by a test-retest procedure and internal reliability was measured using Cronbach's alpha. Convergent validity with the KIDSCREEN-10 index was assessed using with intraclass correlation coefficients (ICC) and receiver operating characteristic (ROC) curves. Factor analysis techniques were used to identify suitable items and confirm the factor structure. Baseline values were assessed for convergent validity, ceiling effects, agreement and sensitivity. Comparison with KIDSCREEN-10 was made on the basis of area under the curve (AUC). RESULTS: One hundred young people with narcolepsy and 95 control subjects returned questionnaires. The factor structure revealed two main factors with five domains and 21 questions, which was confirmed with confirmatory factor analysis. The domains of the NARQoL-21 showed good independence while the floor and ceiling effects were acceptable. The external reliability (0.928), convergent validity (rs = 0.769) and internal consistency (Cronbach's alpha = 0.886) were excellent. A Bland-Altman plot revealed some proportional bias. Good discriminant validity was detected for control/patient (Cohen's d = 2.114). ROC analysis showed significantly better AUC for NARQoL-21 (0.939) than KIDSCREEN (0.877). A cut-off score equivalent to KIDSCREEN-10 for suboptimal HrQoL which maximized sensitivity (84%) and specificity (92%) was found at NARQoL-21 score below 42. CONCLUSIONS: Establishing the validity of a disease-specific HrQoL instrument in a population of people with a rare condition poses significant challenges. The mixed-methods approach adopted here has resulted in a questionnaire of 21 items with good discrimination and convergent validity, and excellent internal and external reliability, allowing precise and stable measurements. The cut-off score can be useful to identify patients with very poor HrQoL and thus improve the design of treatment options. Further testing in a longitudinal cohort is recommended in order to establish responsiveness.
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| 7. |
- Dencker, Anna, 1956, et al.
(författare)
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Multidimensional fatigue inventory and post-polio syndrome - a Rasch analysis
- 2015
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 13:20
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Tidskriftsartikel (refereegranskat)abstract
- Background: Fatigue is a common symptom in post-polio syndrome (PPS) and can have a substantial impact on patients. There is a need for validated questionnaires to assess fatigue in PPS for use in clinical practice and research. The aim with this study was to assess the validity and reliability of the Swedish version of Multidimensional Fatigue Inventory (MFI-20) in patients with PPS using the Rasch model. Methods: A total of 231 patients diagnosed with PPS completed the Swedish MFI-20 questionnaire at post-polio out-patient clinics in Sweden. The mean age of participants was 62 years and 61% were females. Data were tested against assumptions of the Rasch measurement model (i.e. unidimensionality of the scale, good item fit, independency of items and absence of differential item functioning). Reliability was tested with the person separation index (PSI). A transformation of the ordinal total scale scores into an interval scale for use in parametric analysis was performed. Dummy cases with minimum and maximum scoring were used for the transformation table to achieve interval scores between 20 and 100, which are comprehensive limits for the MFI-20 scale. Results: An initial Rasch analysis of the full scale with 20 items showed misfit to the Rasch model (p < 0.001). Seven items showed slightly disordered thresholds and person estimates were not significantly improved by rescoring items. Analysis of MFI-20 scale with the 5 MFI-20 subscales as testlets showed good fit with a non-significant x(2) value (p = 0.089). PSI for the testlet solution was 0.86. Local dependency was present in all subscales and fit to the Rasch model was solved with testlets within each subscale. PSI ranged from 0.52 to 0.82 in the subscales. Conclusions: This study shows that the Swedish MFI-20 total scale and subscale scores yield valid and reliable measures of fatigue in persons with post-polio syndrome. The Rasch transformed total scores can be used for parametric statistical analyses in future clinical studies.
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| 8. |
- Djukanovic, Ingrid, et al.
(författare)
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Is the Hospital Anxiety and Depression Scale (HADS) a valid measure in a general population 65-80 years old? : A psychometric evaluation study
- 2017
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Ingår i: Health and Quality of Life Outcomes. - : BioMed Central. - 1477-7525 .- 1477-7525. ; 15, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Background: The HADS (Hospital Anxiety and Depression Scale) aims to measure symptoms of anxiety (HADS Anxiety) and depression (HADS Depression). The HADS is widely used but has shown ambiguous results both regarding the factor structure and sex differences in the prevalence of depressive symptoms. There is also a lack of psychometric evaluations of the HADS in non-clinical samples of older people. The aim of the study was to evaluate the factor structure of the HADS in a general population 65-80 years old and to exam possible presence of differential item functioning (DIF) with respect to sex. Methods: This study was based on data from a Swedish sample, randomized from the total population in the age group 65-80 years (n = 6659). Confirmatory factor analyses (CFA) were performed to examine the factor structure. Ordinal regression analyses were conducted to detect DIF for sex. Reliability was examined by both ordinal as well as traditional Cronbach's alpha. Results: The CFA showed a two-factor model with cross-loadings for two items (7 and 8) had excellent model fit. Internal consistency was good in both subscales, measured with ordinal and traditional alpha. Floor effects were presented for all items. No indication for meaningful DIF regarding sex was found for any of the subscales. Conclusions: HADS Anxiety and HADS Depression are unidimensional measures with acceptable internal consistency and are invariant with regard to sex. Despite pronounced ceiling effects and cross-loadings for item 7 and 8, the hypothesized two-factor model of HADS can be recommended to assess psychological distress among a general population 65-80 years old.
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| 9. |
- Dür, Mona, et al.
(författare)
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Do patient-reported outcome measures cover personal factors important to people with rheumatoid arthritis? : A mixed methods design using the International Classification of Functioning, Disability and Health as frame of reference
- 2015
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525 .- 1477-7525. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundPersonal factors (PFs) are internal factors that determine functioning and the individuals’ experience of disability. Their coverage by patient-reported outcome measures (PROMs) has not been examined in rheumatoid arthritis (RA) so far. The aims of this study were to identify PFs important in the life stories of people with RA and to determine their coverage by PROMs used in RA.MethodsThe qualitative data of people with RA was explored to identify PFs. Additionally a systematic literature search was conducted to find PROMs used in RA. PROMs items were linked to the components, domains and categories of the International Classification of Functioning, Disability and Health (ICF) to determine the coverage of important PFs by PROMs.ResultsTwelve PFs were found to be important in the life stories of people with RA. The PFs coping and reflecting about one’s life in an optimistic way were covered most frequently, each by 14 of the 42 explored PROMs, while job satisfaction was not covered at all. The London Coping with Rheumatoid Arthritis Questionnaire, General Self-Efficacy Scale, Arthritis Self-Efficacy Scale, Rheumatoid Arthritis Self-Efficacy Questionnaire and Revised Ways of Coping Inventory covered most PFs. Nineteen PROMs did not cover any of the PFs.ConclusionSeveral PFs were identified as important in the life stories of people with RA, but only 55% of the PROMS covered some of these PFs. When evaluating PFs important to people with RA, health professionals should be alert on which PROMs can be used to assess which PFs.
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| 10. |
- Geale, Kirk, et al.
(författare)
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How is disease severity associated with quality of life in psoriasis patients? : Evidence from a longitudinal population-based study in Sweden
- 2017
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Ingår i: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525 .- 1477-7525. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Assessing the impact of disease severity on generic quality of life (QOL) is a critical step in outcomes research and in the development of decision-analytic models structured around health states defined by clinical measures. While data from routine clinical practice found in healthcare registers are increasingly used for research, more attention should be paid to understanding the relationship between clinical measures of disease severity and QOL. The purpose of this work was therefore to investigate this relationship in psoriasis using a population-based dataset.METHODS: Severity was measured by the Psoriasis Area and Severity Index (PASI), which combines severity of erythema, induration, and desquamation into a single value ranging from 0 to 72. The generic EQ-5D-3L utility instrument, under the UK tariff, was used to measure QOL. The association between PASI and EQ-5D-3L was estimated using a population-based dataset of 2674 patients with moderate to severe psoriasis enrolled over ten years in the Swedish psoriasis register (PsoReg). Given the repeated measurement of patients in the register data, a longitudinal fixed-effects model was employed to control for unobserved patient-level heterogeneity.RESULTS: Marginal changes in PASI are associated with a non-linear response in EQ-5D-3L: Moving from PASI 10 to 9 (1 to 0) is associated with an increase of 0.0135 (0.0174) in EQ-5D-3L. Furthermore, unobserved patient-level heterogeneity appears to be an important source of confounding when estimating the relationship between QOL and PASI.CONCLUSIONS: Using register data to estimate the impact of disease severity on QOL while controlling for unobserved patient-level heterogeneity shows that PASI appears to have a larger impact on QOL than previously estimated. Routine collection of generic QOL data in registers should be encouraged to enable similar applications in other disease areas.
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