Although it has been assumed that airway inflammation airway remodelling have a cause and effect relationship, longitudinal evidence suggests remodelling is an independent parallel process, unresponsive to anti-inflammatory medication such as inhaled corticosteroids. Longitudinal follow-up of childhood asthma into adulthood suggest that in some asthma patients remodelling commences early in the disease process leading fixed airflow obstruction. These cohort studies from general populations in Australia and New Zealand have reproducibly shown that in children with persistent asthma symptoms, most deficits in lung function growth have already occurred by 6 to 9 years of age,   with a modest further effect of asthma on lung function thereafter. This is consistent with adult data, where a longitudinal study of more than 9000 subjects found that asthmatic non-smokers had reduced FEV1 at 19 years of age when compared with values in non-asthmatic non-smokers, and showed only minimal additional decrease thereafter.  This suggests that airway remodelling with irreversible airflow obstruction occurs early with persistent childhood asthma, but is a stable physiological phenotype thereafter. However, an accelerated decline in lung function has also been observed in chronic severe asthma, particularly in association with frequent and severe exacerbations.  
The life expectancy of the controlled asthmatic is similar to the general population.
Impact of inhaled corticosteroids (ICS)
ICS's provide clinical and laboratory improvement to the patient. If the steroids are discontinued, symptoms recur and pulmonary function studies return to the initial abnormality. Treatment with ICS's, although not disease modifying, provide an additional anti-inflammatory effect. In other words, the lung inflammation is reduced only while the patient is on the ICS and once stopped, the inflammatory process returns. When optimally controlled, asthma attacks decrease in frequency. Some patients will have no asthma attacks and others have continued attacks when exposed to precipitating agents.