Using humanistic health outcomes data in asthma.

One of the aims of treatment of asthma is to improve patient well-being, which incorporates the concept of patients' perceptions of how they feel and their ability to function in their everyday life [health-related quality of life (HR-QOL)]. The weak association between conventional measures of clinical status in asthma and asthma-specific quality of life means that quality of life must be measured directly--it cannot be inferred from clinical measures. HR-QOL is measured using instruments which elicit information from patients about the impact of the disease and its treatment on both their physical and emotional functioning. Such instruments may be generic (used for all diseases) or specific to a particular group of patients, function or disease. Disease-specific quality-of-life questionnaires are useful in clinical trials and practice because they are more responsive to small but clinically important changes than generic instruments. Generic instruments provide an estimate of the patients' burden of illness that can be compared with the burden experienced by patients with other medical conditions. Consequently, HR-QOL should be included as an outcome measure in all assessments of asthma.