ABSTRACT
The goals of asthma management are the accurate diagnosis and effective
control of symptoms, including nocturnal symptoms and exercise induced asthma, prevention of exacerbations, and the achievement of best pulmon-
ary function with minimal side effects (1). Whilst this is achieved in the
majority of patients, there remains a significant number who are misdiag-
nosed (2) or who suffer from troublesome symptoms and frequent exacer-
bations (3). The routine diagnosis and treatment of asthma in primary-
care and most secondary care settings involves evaluating variable airflow
obstruction with spirometry and peak flow measurement, and assessing
symptom control, but does not normally assess the two cardinal features of asthma: airway inflammation and airway hyper-responsiveness. The
question arises as to whether extending the goal of management to include
these features may lead to better outcomes. Current treatment guidelines
for asthma involve a concept of a stepwise increase in medication based
on symptom control and peak flow measurements (1). However, patients
who appear clinically well controlled on inhaled corticosteroids can still have evidence of airway inflammation and airway hyper-responsiveness
(4,5) and be vulnerable to exacerbations, airway remodeling and possibly
fixed airways obstruction (6,7). A treatment strategy based on an attempt
to return airway responsiveness towards normal has been shown to reduce
exacerbations and reduce sub-epithelial reticular basement thickening (8).
The development of feasible and valid non-invasive methods to assess air-
way inflammation has made it possible to examine whether assessment of
airway inflammation improves outcomes in patients with asthma. Assessment of airway inflammation may lead to more accurate diagnosis as well
as better identification of vulnerable patients who need more intensive
anti-inflammatory treatment. However, in order to be useful, the method
used to assess airway inflammation needs to be feasible in a clinical setting
and the results need to inform the physician about clinically important
aspects of the disease that cannot be discerned by a simpler method. In this
chapter, we discuss to what extent assessment of airway inflammation using
induced sputum fulfills these criteria.
