Quality of life as an outcome measure in pulmonary diseases

Chronic obstructive pulmonary disease is a serious debilitating condition that is a major cause of death and disability in the modern world. There is no medical or surgical cure for chronic obstructive pulmonary disease and rehabilitation has become an accepted component of disease management and recommended in practice guidelines. Pulmonary rehabilitation programs are designed to restore patients to their highest level of functioning. Traditional physiological measures of lung function are of limited value in the evaluation of outcomes from rehabilitation and rarely capture the benefits of intervention. This review considers quality-of-life outcome measures. There are 2 major approaches to quality-of-life assessment: psychometric and decision theory. The psychometric approach is used to offer a profile summarizing different dimensions of quality of life. The decision theory approach attempts to weight the different dimensions of health in order to provide a single expression of health status. Measures can be classified as either generic or disease targeted. Generic measures can be used with any population, whereas disease-targeted measures are used for patients with a particular diagnosis. Finally, measures can be categorized by their probable uses. Most measures can be used to characterize populations and to study clinical change. However, only generic, decision theory-based measures can be used to evaluate cost-effectiveness. In this article, we review measures for chronic lung diseases in these different categories and identify those more suitable for particular purposes. We devote particular attention to methods designed for use in cost-effectiveness analysis.