Assessing clinical and spirometric control and the intensity of the inflammatory process in asthma

To review the role of clinical assessment, quality of life assessment, spirometry, bronchial responsiveness test and inflammatory markers for asthma assessment.

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Clinical assessment aids with assessing asthma control and is widely recommended. However, patients may have airway inflammation and obstruction despite normal clinical findings. Spirometry quantifies the degree of airway obstruction and helps with diagnosis, while the bronchial responsiveness test may be indicated for when asthma is suspected but spirometry is normal. The results of assaying the inflammatory markers in exhaled breath condensate, induced sputum, bronchoalveolar lavage and bronchial biopsy specimens are abnormal in asthma patients, but these are complex techniques almost always restricted to research. Fractional exhaled nitric oxide (FeNO) is elevated in patients with asthma, is reproducible and noninvasive and reduces with treatment. Studies have investigated using FeNO to help with adjusting inhaled corticoid dosages, but the benefits are not clear.

A range of different methods are needed to accurately assess disease control, all with their advantages and limitations. Clinical and functional assessment is useful for diagnosing asthma, but is of limited use for precisely evaluating the intensity of the inflammatory process in the airways. More randomized and controlled studies with adequate statistical power should be carried out to investigate the true utility of noninvasive inflammatory markers, especially FeNO, for asthma management.