Health-Related Quality of Life in COPD and Asthma - Discriminative and evaluative aspects

Sammanfattning: Background - The effects of intervention can be evaluated in different ways, and objective measurements of changes in lung function are commonly used as the outcome measure. Patient-reported outcome (PRO) is an umbrella term used for all patient-based assessments. One important PRO is health-related quality of life (HRQL), which may be used as an evaluative or discriminative measure. Objectives - To examine COPD subjects' completion of self-administered questionnaires. To study the evaluative effects with HRQL assessments after pulmonary interventions in COPD and asthma. Finally, to explore the discriminative possibility of using HRQL with regard to its relationship to other clinical indices and to disease severity in both COPD and asthma. Results - Most COPD subjects find it easy to complete questionnaires; however, the correlation of age with difficulty in completing questionnaires needs to be considered. Furthermore, it was shown that assessments of HRQL may be useful for evaluative purposes in COPD and asthma, although in COPD longer studies will be needed. The discriminative possibility of using HRQL data in COPD and asthma was shown. Symptoms correlated with HRQL, whereas between lung function and HRQL the relationship was weaker. HRQL seems to deteriorate with disease severity in COPD and asthma, as measured by lung function, or with age. However, great individual variation was noticed. Conclusions - The completion of up to five PRO questionnaires was well accepted by subjects with COPD. HRQL questionnaires might be used for evaluative purposes. HRQL questionnaires appear to have a possibility to be used for discriminative purposes in COPD and asthma, and for comparison of these diseases; however, this needs to be further explored. In homogeneous populations, used in evaluative studies, assessment of HRQL is valuable. In heterogeneous populations, a great variation in HRQL is likely to be seen and therefore there may be a chance to show a relationship between HRQL and lung function measures. However, within severity stages there is a great individual variation.