ABSTRACT
This book deals with the importance of dyspnea as a symptom of disease
(and as a major cause of disability and handicap) as well as the measurement of dyspnea, including its worsening or improvement This chapter will
identify and address issues as they relate to clinical trials. Most often, the
measurement of dyspnea in clinical trials is in the context of evaluating ther-
apeutic intervention for chronic dyspnea. These studies most often involve
large numbers of patients (100-1000), large numbers of investigating cen-
ters (50-100), several countries (up to 20), and comparison to controls such
as usual care (i.e., placebo added to stable standard medication) which allow
true assessment of a drug effect on dyspnea. Drug development trials often consist of two replicate trials of similar or identical design in order to insure
substantial evidence of clinical effectiveness.
