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Biomedical subjects

Alan Tennant

Publications and source records attributed to Alan Tennant.

26 records · Page 2Linked to original sources

Development of the BD-QoL: a quality of life measure specific to Behçet's disease.

OBJECTIVE: Current outcome measures for patients with Behçet's disease (BD) are impairment-focused and do not necessarily take account of the wider impact of the condition on the individual's lifestyle. Our aim was to develop a disease-specific measure of quality of life (QoL) for BD. METHODS: The content of the BD-QoL was derived from qualitative interviews with patients using a "needs-based" approach to identify items. A postal survey was used to test the scaling properties, reliability, internal consistency, and validity of the new questionnaire using Rasch analysis. A second postal survey was used to assess test-retest reliability and internal consistency and to provide further evidence of the validity of the questionnaire. RESULTS: Main themes emerging from the qualitative interviews included relationships, emotions, limitations in day to day activities, and self-image. From these themes 71 statements were chosen as potential items for the BD-QoL. After analysis, 30 items of the BD-QoL emerged free of item bias for age and sex. Fit to the Rasch model was excellent. In the second postal survey test-retest reliability of the 30 item BD-QoL was 0.84. CONCLUSION: The BD-QoL provides the clinician with a simple, reliable, and valid tool for assessing the influence of interventions for BD and for evaluating models of service delivery. It is well accepted by patients, and has excellent scaling and psychometric properties. The BD-QoL complements information obtained through BD-specific disease activity scales.

Adult↗

Development of a work instability scale for rheumatoid arthritis.

OBJECTIVES: To explore the concept of work instability (WI), a state in which the consequences of a mismatch between an individual's functional abilities and the demands of his or her job could threaten continuing employment if not resolved, in people with rheumatoid arthritis (RA). To develop the Work Instability Scale (WIS). METHODS: WI in people with RA was explored through qualitative interviews, which were then used to generate items for the WIS. RESULTS: Through Rasch analysis and validation against a gold standard of expert vocational assessment, a short 23-item, self administered, RA WIS was developed. CONCLUSION: The WIS can be scored in 3 bands indicating low, medium, and high risk of work disability.

Adult↗

Disability in young adults following major trauma: 5 year follow up of survivors.

BACKGROUND: Injuries are a major cause of mortality and morbidity in young people. Despite this, the long-term consequences for young survivors of severe injury are relatively unexplored. METHODS: Population based cohort study involving 5 year post injury structured interview of all cases of major trauma (Injury Severity Score > 15) identified retrospectively for 12 month period (1988 to 1989) within former Yorkshire Health Authority area of the United Kingdom. RESULTS: 125 individuals aged 11-24 years at time of injury were identified. Of these, 109 (87%) were interviewed. Only 20% (95% CI 14-29%) of those interviewed reported no disability. Mean Office of Population Census and Surveys (OPCS) disability score of the remainder was 7.5 (median 5.8, range 0.5 to 19.4). The most commonly encountered areas of disability were behaviour (54%, 95% CI 45-63%), intellectual functioning (39%, 95% CI 31-49%) and locomotion (29%, 95% CI 22-39%). Many respondents reported that their daily lives were adversely affected by their health problems for example, causing problems with work, 54% (95% CI 45-63%), or looking after the home, 28% (95% CI 21-38%). Higher OPCS scores were usually but not always associated with greater impact on daily activities. The burden of caring responsibilities fell largely on informal carers. 51% (95% CI 42-61%) of those interviewed would have liked additional help to cope with their injury and disability. CONCLUSION: The study has revealed significant disability amongst a cohort of young people 5 years post severe injury. Whilst many of these young people were coping well with the consequences of their injuries, others reported continuing problems with the activities of daily life. The factors underpinning the young people's differing experiences and social outcome should be explored.

Adaptation, Psychological↗

Adaptation and validation of the Turkish version of the Rheumatoid Arthritis Quality of Life Scale.

OBJECTIVE: The aim of this study was to adapt the Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire for use in Turkey and to test its reliability and validity. METHODS: The translation process included the recent guidelines for cross-cultural adaptation. Reliability of the Turkish RAQoL was assessed by internal consistency and test-retest reliability, internal construct validity by Rasch analysis, and external construct validity by associations with impairments, disability, and general health status. Cross-cultural validity was tested through analysis of differential item functioning (DIF) by comparison with data from the UK version of the RAQoL. RESULTS: Reliability of the adapted version was good, with high internal consistency (Cronbach's alpha 0.95 and 0.96 at times 1 and 2, respectively) and test-retest reliability (Spearman's rho 0.874). Internal construct validity was confirmed by excellent fit to the Rasch model (mean item fit 0.236, SD 1.113) and external construct validity by expected associations. The DIF for culture was found in four items. CONCLUSIONS: Adaptation of the RAQoL for use in Turkey was successful. The instrument can be used in both national and international studies for cross-cultural comparison with the UK, as long as adjustments are made for the few items displaying DIF for culture.

Aged↗

A randomised controlled trial to determine the effect of intensity of therapy upon length of stay in a neurological rehabilitation setting.

A randomised single-blind controlled trial was designed to determine whether intensity of therapy (physiotherapy and occupational therapy) shortened length of stay for patients in a rehabilitation unit. Patients were under 65, primarily with stroke, but also with other conditions such as traumatic brain injury, and multiple sclerosis. The experimental group were timetabled to receive 67% more therapy in any given week, than the control group. After controlling for confounders and case mix (as expressed by type of therapy required) patients in the experimental group showed a significant 14-day reduction in length of stay (<0.01). Concurrently average length of stay was increased for both groups by 16 days due to delays in discharge.

Adult↗

Measuring disability in ankylosing spondylitis: comparison of bath ankylosing spondylitis functional index with revised Leeds Disability Questionnaire.

OBJECTIVE: Disability has been identified as a core outcome measure in ankylosing spondylitis (AS). The Dougados Functional Index (DFI) and the Bath Ankylosing Spondylitis Functional Index (BASFI) have been selected as core measures of function in this disease. However, neither of these instruments has undergone rigorous psychometric testing. METHODS: The psychometric properties of 2 measures of disability, the BASFI and the revised Leeds Disability Questionnaire (RLDQ), were compared in a cohort of 208 outpatients with AS. Rasch analysis was used to examine the properties of each measure and to compare them on a common scale. Test-retest was assessed in a cohort of 149 subjects who completed each instrument twice over an interval of 2 weeks. RESULTS: Both instruments gave an even spread of scores across the study group, but BASFI responses were positively skewed and RLDQ responses negatively skewed. There was a highly significant difference between perceived severity groups for both instruments (Kruskal-Wallis chi-squared: RLDQ, 75.1; BASFI, 80.4; both p < 0.0001). Both instruments gave acceptable test-retest scores (RLDQ ICC = 0.95, 95% CI 0.93-0.97; BASFI ICC = 0.94, 95% CI 0.92-0.96). Both instruments were found to be unidimensional according to the Rasch model, but the BASFI had more items displaying differential item functioning. Category disordering was apparent with the BASFI but not the RLDQ. However, both instruments displayed disordered item thresholds. Neither instrument can be used as an interval measure. Both measures had "towers" of thresholds whereby several thresholds were marking the same point on the underlying disability construct. This was particularly notable in the case of the BASFI. CONCLUSION: Both the BASFI and RLDQ provide a unidimensional measure of function in AS that is in accord with patient perception of disease severity. Neither instrument can be used as an interval measure. Changing the way that the instruments are scored, for example by collapsing categories, may improve their performance.

Activities of Daily Living↗

Application of Rasch analysis in the development and application of quality of life instruments.

This paper discusses recent advances that have been made in the field of psychometrics, specifically, the application of Rasch analysis to the instrument development process. It emphasizes the importance of assessing the fundamental scaling properties of an instrument prior to consideration of traditional psychometric indicators. The paper introduces Rasch analysis and shows how it has been applied in the development of needs-based measures in order to ensure that they provide unidimensional measurement. By ensuring that scales are based on the same measurement model and that they fit the Rasch model it is possible for QoL scores to be compared across diseases by means of cocalibration and item banking.

Health Services Needs and Demand↗