Dataset Information

Performance of the Dutch SF-36 version 2 as a measure of health-related quality of life in patients with rheumatoid arthritis.

ABSTRACT:

Background

The aim of this study was to examine the measurement properties of the Dutch SF-36 version 2 (SF-36v2) health survey in patients with rheumatoid arthritis (RA).

Methods

Scaling assumptions, internal reliability, and internal construct validity were examined using available data from 1884 RA patients included in the Dutch Rheumatoid Arthritis Monitoring (DREAM) registry. External construct validity and responsiveness to change were examined using baseline and 6-month follow-up data from a subset of 387 early RA patients participating in the DREAM remission induction cohort.

Results

The individual items of the SF-36v2 adequately met scaling assumptions, although four items correlated too highly with items from different scales. Internal consistency was high for all eight scales and the physical and mental health components underlying the scales were replicated, supporting the use of the standard scoring algorithms. The SF-36v2 scales demonstrated minimal floor effects and ceiling effects were noteworthy only for the role-physical, social functioning, and role-emotional scales. Correlations with other core measures were as expected and the SF-36v2 showed excellent known-groups validity in distinguishing between patients with low or moderate-high disease activity. All scales related to physical health showed moderate to large responsiveness to change in patients that achieved low disease activity at six months.

Conclusion

The SF-36v2 appears to be a psychometrically sound tool for the assessment of health-related quality of life of Dutch patients with RA.

SUBMITTER: ten Klooster PM

PROVIDER: S-EPMC3656790 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

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Publications

Performance of the Dutch SF-36 version 2 as a measure of health-related quality of life in patients with rheumatoid arthritis.

ten Klooster Peter M PM Vonkeman Harald E HE Taal Erik E Siemons Liseth L Hendriks Lidy L de Jong Alphons J L AJ Dutmer Ellen A J EA van Riel Piet L C M PL van de Laar Mart A F J MA

Health and quality of life outcomes 20130508

<h4>Background</h4>The aim of this study was to examine the measurement properties of the Dutch SF-36 version 2 (SF-36v2) health survey in patients with rheumatoid arthritis (RA).<h4>Methods</h4>Scaling assumptions, internal reliability, and internal construct validity were examined using available data from 1884 RA patients included in the Dutch Rheumatoid Arthritis Monitoring (DREAM) registry. External construct validity and responsiveness to change were examined using baseline and 6-month fol ...[more]

PMID: 23651685

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Project description:Health-Related Quality of Life (HRQoL) measures are becoming increasingly used in clinical trials as primary outcome measures. Investigators are now asking statisticians for advice on how to analyse studies that have used HRQoL outcomes.HRQoL outcomes, like the SF-36, are usually measured on an ordinal scale. However, most investigators assume that there exists an underlying continuous latent variable that measures HRQoL, and that the actual measured outcomes (the ordered categories), reflect contiguous intervals along this continuum. The ordinal scaling of HRQoL measures means they tend to generate data that have discrete, bounded and skewed distributions. Thus, standard methods of analysis such as the t-test and linear regression that assume Normality and constant variance may not be appropriate. For this reason, conventional statistical advice would suggest that non-parametric methods be used to analyse HRQoL data. The bootstrap is one such computer intensive non-parametric method for analysing data. We used the bootstrap for hypothesis testing and the estimation of standard errors and confidence intervals for parameters, in four datasets (which illustrate the different aspects of study design). We then compared and contrasted the bootstrap with standard methods of analysing HRQoL outcomes. The standard methods included t-tests, linear regression, summary measures and General Linear Models.Overall, in the datasets we studied, using the SF-36 outcome, bootstrap methods produce results similar to conventional statistical methods. This is likely because the t-test and linear regression are robust to the violations of assumptions that HRQoL data are likely to cause (i.e. non-Normality). While particular to our datasets, these findings are likely to generalise to other HRQoL outcomes, which have discrete, bounded and skewed distributions. Future research with other HRQoL outcome measures, interventions and populations, is required to confirm this conclusion.

Project description:BackgroundRheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily affects joints with some extraarticular involvement. If inappropriately treated, it usually results in persistent joint pain, irreversible deformities, and functional disability, leading to poor quality of life. Our objective was to evaluate health-related quality of life (HRQoL) and related factors in patients with RA.MethodsFour hundred sixty-four patients from the Rheumatoid Arthritis registries of Siriraj and Phramongkutklao teaching hospitals were enrolled. Sociodemographic, clinical and laboratory data related to disease activity, and functional status were collected. HRQoL was assessed using the Thai version of EuroQol five dimensional questionnaire (EQ-5D) and EQ global health visual analogue scale (EQ VAS). Univariate and multivariate analyses were employed to identify factors related to HRQoL.ResultsEighty-five percent were female with a mean age ± SD of 59.15 ± 11.43 years and a mean disease duration ± SD of 11.53 ± 8.3 years. The mean educational level ± SD was 9.42 ± 5.21 years. Almost half were unemployed or retired (47%). They had moderate disease activity (mean cumulative DAS28 ± SD, 3.5 ± 0.8) and mild functional impairment (mean HAQ ± SD, 0.70 ± 0.68). The mean EQ-5D ± SD (0-1) was 0.87 ± 0.13 and mean EQ VAS ± SD (0-10) was 7.94 ± 1.7. Based on the EQ-5D domain, 49% reported that they had no problem with mobility, 83% had no difficulties with self-care, 65% had no difficulties with usual activity, 30% had no pain or discomfort, and 61% had no depression or anxiety. The relationship between problems of each dimension in EQ-5D significantly increased according to severity of RA assessed by the Disease Activity Score (DAS) 28 and Health Assessment Questionnaire (HAQ) (p < 0.01). In multivariate analyses, high cumulative disease activity, functional disability, depression, and anxiety were negatively associated with EQ-5D (adjusted R 2 0.38, p < 0.001) and EQ VAS (adjusted R 2 0.19, p < 0.001).ConclusionDisease severity and psychological disturbance have a negative impact on quality of life in patients with RA. These factors should be considered in management of RA patients to improve the standard of care.

Dataset Information

Performance of the Dutch SF-36 version 2 as a measure of health-related quality of life in patients with rheumatoid arthritis.

Background

Methods

Results

Conclusion

Publications

Performance of the Dutch SF-36 version 2 as a measure of health-related quality of life in patients with rheumatoid arthritis.

Similar Datasets

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