Should asthma control be the guide for therapeutic decision‐making?

One of the challenges in studying asthma control is the lack of a gold standard definition. But acknowledging this limitation, Le Blanc et al. (1), in this month’s edition of Allergy, have taken a major step forward in validating a quantitative scoring system for asthma control. The Global Initiative for Asthma (GINA)(2) has defined control with seven parameters that are consistent with goals of therapy. Four of these measures are patient centric (minimal symptoms, minimal exacerbations, low use of rescue bronchodilator and no limitations to physical activity), one is a physiological measure (PEF variability), one a measure of resource utilization (ED visit) and one a safety concern (no significant adverse events from treatment). No measure of inflammation is included in the current GINA definition of control. Although these goals are specifically articulated, the accurate assessment of the patient centric measures of asthma disease control may be limited by the accuracy of patient reporting and of physician recording of information. GINA explicitly recommends the use of a structured questionnaire that can quantify patient symptoms over time. Rabe et al. (3) have demonstrated that the goals of asthma management are not being achieved. In their study, over 50% of patients reported symptoms during the past 4 weeks for one or more of the following: asthma symptoms during the day, night or with exercise. Further 32–49% of patients with self-reported symptoms of severe persistent asthma stated that their asthma was well or completely controlled. These findings were consistent throughout the world. The difficulty may be that patients do not perceive that the symptoms they are describing represent uncontrolled asthma and clinicians do not uniformly interpret and record these limitations illustrating the need for a structured reporting system. Several excellent validated survey tools have been developed to assess patient report of control (4–6), but there is no comprehensive measure of asthma control. Spirometry or peak expiratory flow rate have been traditional standards of successful treatment especially in clinical trials. They are frequently designated as the primary endpoint. Although measures of lung function correlate well with symptoms and beta agonist use in some clinical trials, in others these two outcomes are disparate (7, 8). As examples, there are many patients with asthma, especially children and young adults of all disease severities, with normal spirometry and active symptoms (9). Second, there are patients with abnormal lung function consistent with obstructive airflow without significant report of symptoms (8). It is essential for these patients who fail to report symptoms that measures of lung function are performed. Finally, there are patients with a past history of asthma but no active symptoms, no recent medication use, normal lung function and yet evidence of active airway inflammation (10). The selection of any single parameter reduces the sensitivity of determining asthma that is not well controlled and may reduce the likelihood of appropriate intervention. D. A. Stempel Infomed Northwest, Clyde Hill, WA; and University of Washington, School of Medicine, Seattle, WA, USA