Screening, Diagnostic and Outcome Tools for Asthma

Asthma is a chronic inflammatory disorder of the airways, affecting about 10% of children and 5 to 7% of the adult population. Improved asthma control will not only benefit the patient but will also result in reduced financial expenditure in asthma healthcare. This article summarises the tools that are available for assessing asthma and attempts to quantify the usefulness of each tool in assessing asthma in different clinical contexts, whether it be screening for asthmatics within a population, diagnosing asthma in an individual, influencing management or judging outcome. The overall role of the symptoms of asthma, lung function variables, bronchial hyperresponsiveness, atopy and biological markers of inflammation, as well as their application in various settings is summarised in tabulated form. Flow charts are presented proposing sequential testing in the screening and diagnostic procedures. Intervention and treatment strategies for the individual are subsequently considered. Prevention should be the start of the intervention, educating the patient to enhance disease knowledge and avoidance of environmental triggers ideally resulting in a change in behaviour, to which teaching programmes may contribute. Since the recognition that asthma is an inflammatory disorder resulting in variable and reversible airflow obstruction, inhaled corticosteroids have become the mainstay treatment, with inhaled bronchodilators to be prescribed on an as-needed basis. Recently the long-acting beta2-agonist bronchodilators have been shown to be especially effective in treating nocturnal symptoms and together with inhaled corticosteroids achieve better control of asthma. Considering the complex nature of the asthmatic inflammatory process, respiratory symptoms, lung function variables and biomarkers are presently used as complementary outcome measures; the frequency of assessment will depend on practical considerations.