Prognostic bases of asthma. Natural history?

Different causes of asthma have been established. The most common cause is conditioned to a genetic predisposition towards atopy (atopic asthma), although other factors can also give rise to bronchial inflammation, such as over-exposure to environmental irritants (occupational asthma), altered arachidonic acid metabolism (aspirin-induced asthma) and also exercise - in which different thermal and osmotic mechanisms are known to intervene. The prognosis of these different variants of asthma depends on the severity of the condition; patient age at onset of the disease; patient age at the time of diagnosis; the treatment provided; and adherence to therapy. The concept of "natural history" refers to the spontaneous evolution or course of the disease process in the absence of pathogenic or etiological treatment, with the provision of only symptomatic treatment. In order to gain increased certainty regarding the course of these patients, the study groups must present similar baseline characteristics in terms of the start and severity of the condition; the start of treatment; compliance; and the clinical and functional control findings.