Tactics for clinical trials of therapy in patients with chronic asthma

Asthma can be conceptualized as a disease system ranging from the molecular to the social level. It is important to monitor both subjective and objective indices appropriate to different parts of the system. Objective indices alone are not enough. It is also important to distinguish disability from symptom severity or frequency and pulmonary impairment. The personality of the patient or the duration of follow-up can profoundly affect the perceived outcome of a particular treatment. It is important in controlled trials, and also in clinical practice, to take these factors into account.