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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Quality of life research 6 (1997), S. 0-0 
    ISSN: 1573-2649
    Keywords: Anticipated effect size ; ; Hospital Anxiety and Depression Scale (HADS) ; quality of life ; randomized trials ; sample size ; small cell lung cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper describes the methods appropriate for calculating sample sizes for clinical trials assessing quality of life (QOL). An example from a randomized trial of patients with small cell lung cancer completing the Hospital Anxiety and Depression Scale (HADS) is used for illustration. Sample size estimates calculated assuming that the data are either of the Normal form or binary are compared to estimates derived using an ordered categorical approach. In our example, since the data are very skewed, the Normal and binary approaches are shown to be unsatisfactory: binary methods may lead to substantial over estimates of sample size and Normal methods take no account of the asymmetric nature of the distribution. When summarizing normative data for QOL scores the frequency distributions should always be given so that one can assess if non-parametric methods should be used for sample size calculations and analysis. Further work is needed to discover what changes in QOL scores represent clinical importance for health technology interventions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    ISSN: 1573-2649
    Keywords: Quality of life ; randomized trials ; symptoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The assessment of physical symptoms is a key com-ponent of quality of life studies in palliative care, but is often hampered by missing data from patient-completed questionnaires. In two large multicentre randomized trials of palliative treatment conducted by the Medical Research Council Lung Cancer Working Party, involving over 700 patients, patients completed Rotterdam Symptom Checklists and doctors reported on eleven of the same physical symptoms at each assessment, using the same 4-point severity scale. Ratings by doctors and patients were compared with respect to compliance, severity, and outcomes for the respective trials. Doctors provided more data than patients: 66% vs. 52%in the first 6 months in one trial, 68% vs. 61% in the other. Comparisons of over 33,000 symptom assessments showed 78% complete agreement between doctor and patient, 18% disagreement by one, 4% two, and 1% three grades (complete disagreement). There was no change in levels of agreement over time, but increasing disagreement with increasing symptom severity, and a consistent bias towards doctors underestimating severity. Nevertheless, the two methods of data collection resulted in similar between-treatment conclusions. Therefore, in randomized trials the doctors' assessments of key physical symptoms may be sufficient for the between-treatment comparison. However, the fact that doctors underestimate symptom severity 15% of the time has important implications for palliative interventions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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