Revisiting the disabilities of the arm, shoulder and hand (DASH) and QuickDASH in rheumatoid arthritis.

BACKGROUND: Limitations in upper limb functioning are common in Musculoskeletal disorders and the Disabilities of the Arm, Shoulder and Hand scale (DASH) has gained widespread use in this context. However, various concerns have been raised about its construct validity and so this study seeks to examine this and other psychometric aspects of both the DASH and QuickDASH from a modern test theory perspective. METHODS: Participants in the study were eligible if they had a confirmed diagnosis of Rheumatoid Arthritis (RA). They were mailed a questionnaire booklet which included the DASH. Construct validity was examined by fit to the Rasch measurement model. The degree of precision of both the DASH and QuickDASH were considered through their Standard Error of Measurement (SEM). RESULTS: Three hundred and thirty-seven subjects with confirmed RA took part, with a mean age of 62.0 years (SD12.1); 73.6% (n = 252) were female. The median standardized score on the DASH was 33 (IQR 17.5-55.0). Significant misfit of the DASH and QuickDASH was observed but, after accommodating local dependency among items in a two-testlet solution, satisfactory fit was obtained, supporting the unidimensionality of the total sets and the sufficiency of the raw (ordinal or standardized) scores. CONCLUSION: Having accommodated local response dependency in the DASH and QuickDASH item sets, their total scores are shown to be valid, given they satisfy the Rasch model assumptions. The Rasch transformation should be used whenever all items are used to calculate a change score, or to apply parametric statistics within an RA population. SIGNIFICANCE AND INNOVATIONS: Most previous modern psychometric analyses of both the DASH and QuickDASH have failed to fully address the effect of a breach of the local independence assumption upon construct validity. Accommodating this problem by creating 'super items' or testlets, removes this effect and shows that both versions of the scale are valid and unidimensional, as applied with a bi-factor equivalent solution to an RA population. The Standard Error of Measurement of a scale can be biased by failing to take into account the local dependency in the data which inflates reliability and thus making the SEM appear better (i.e. smaller) than the true value without bias.

Life stories of people with rheumatoid arthritis who retired early: how gender and other contextual factors shaped their everyday activities, including paid work.

OBJECTIVE: The aim of the present study was to explore how contextual factors affect the everyday activities of women and men with rheumatoid arthritis (RA), as evident in their life stories. METHODS: Fifteen people with RA, who had retired early due to the disease, were interviewed up to three times, according to a narrative biographic interview style. The life stories of the participants, which were reconstructed from the biographical data and from the transcribed 'told story' were analysed from the perspective of contextual factors, including personal and environmental factors. The rigour and accuracy of the analysis were enhanced by reflexivity and peer-review of the results. RESULTS: The life stories of the participants in this study reflected how contextual factors (such as gender, the healthcare system, the support of families and social and cultural values) shaped their everyday activities. In a society such as in Austria, which is based on traditional patriarchal values, men were presented with difficulties in developing a non-paid-work-related role. For women, if paid work had to be given up, they were more likely to engage in alternative challenging activities which enabled them to develop reflective skills, which in turn contributed to a positive and enriching perspective on their life stories. Health professionals may thus use some of the women's strategies to help men. CONCLUSION: Interventions by health professionals in people with RA may benefit from an approach sensitive to personal and environmental factors.

Patient perspective of hand osteoarthritis in relation to concepts covered by instruments measuring functioning: a qualitative European multicentre study.

OBJECTIVE: To explore whether the concepts important to patients with hand osteoarthritis (OA) are covered by the most commonly used instruments measuring functioning. METHOD: A qualitative multicentre study using a focus group technique was performed in five European countries: Austria, The Netherlands, Norway, Sweden and the United Kingdom. The qualitative data analysis followed a modified form of "meaning condensation" and used the International Classification of Functioning, Disability and Health (ICF) as a theoretical framework. Finally, the concepts from the focus groups were compared with the content of the most commonly used instruments which had been identified in an earlier theoretical analysis. RESULTS: Fifty-six people (51 women, mean (SD) age 62.7 (7.9) years) with hand OA participated in this study in two focus groups per centre. 63 concepts were extracted from the focus groups. Twenty-one (33%) of the 63 concepts were covered by at least one instrument. Psychological consequences, different qualities of pain, aesthetic changes and leisure activities are important concepts from the focus groups which were not covered by the instruments. The qualitative analysis revealed detailed descriptions of pain-concerning sensations, levels and a certain relation to activity, none of which were fully represented in the instruments routinely used. CONCLUSION: It was possible to combine the concepts of the focus groups from each centre into a common qualitative analysis. The concepts important to people with hand OA are not fully represented in the most commonly used instruments.