Inhaled corticosteroids and asthma prevention.

摘要

In today's Lancet, Clare Murray and colleagues1 report a trial that tested the hypothesis that inhaled corticosteroids, when administered to symptomatic preschool children, can change the natural course of asthma. There was no difference between drug and placebo. Two other similar trials (PEAK and PAC), which failed to show a difference, were recently published.It is useful first to define what is meant by the natural course of asthma. There ought to be a first period during which there is no clinical evidence of the disease, and during this phase factors that determine inception are at work. At inception, which could be identified with the first manifestations of the disease, two scenarios are possible: either the physiological and anatomical features, congenital or acquired, that underlie the subsequent chronic expression of the disease are already present (course A-C, figure), or they are not (B-D), and develop concomitantly with the transition between initial phase and full-blown chronic illness. Remission (B-E) is also possible and is common in young children, the so-called transient wheezers.