[Illness specific data collection on quality of life of patients with asthma and chronic obstructive bronchitis]

Abstract

Resource allocation in health care and rehabilitation has been increasingly influenced by medical outcome studies. In recent years, the importance of health-related quality of life (HRQOL) in the evaluation of medical care and intervention practice has been widely acknowledged. In particular for chronic diseases like asthma or COPD the multi-dimensional concept of quality of life (QOL) has adopted the role of an essential outcome parameter. Instruments used to measure QOL can be categorised as one of two types: a) generic instruments which assess overall QOL and b) disease-specific questionnaires which focus on specific aspects related to a particular disease. Over the last two decades more than 1,000 QOL-instruments have been developed, including nearly 20 disease-specific inventories for patients with chronical lung diseases. In clinical practice, both generic and specific questionnaires are used to assess quality of life in patients with asthma and COPD. Disease-specific QOL-instruments are considered to be more sensitive in establishing the specific restrictions related to asthma or COPD and in detecting possible improvements in QOL after treatment. To exemplify its properties, limitations, and special methodological issues, we chose two of the most widely used and well-validated disease-specific quality of life inventories: the "St. George Hospital Respiratory Questionnaire (SGRQ)" and the "Fragebogen zur Lebensqualität bei Asthma (FLA)". The FLA, representing the German revision of the "Living with Asthma Questionnaire (LAQ)" (Hyland et al., 1991), has been one of the first questionnaires available for measuring disease specific quality of life (QOL) in adults with asthma. The FLA contains 40 items in three dimensions ("physical symptoms", "functional status", "psychological distress"). The SGRQ (Jones et al., 1991) is a standardized questionnaire for measuring health related restrictions and quality of life in patients with chronical lung disease. In contrast to LAQ/FLA the SGRQ can be used both for patients with asthma and COPD. It includes 76 items, divided in three subscales ("symptoms", "activity", and "impacts") permitting to calculate different summary scores as well as a total score. Both questionnaires appear to be reliable, valid and efficient for the assessment of QOL in patients with asthma or COPD, and may facilitate decision making in the treatment process. On the other hand there are some unsolved methodological problems requiring further investigations and improvements in this research area.