Table 1—

Common usage of the terms“severity” and “control” in asthma, indicating both the overlapping and the distinguishing features

CharacteristicCommon usage of the terms
SymptomsThe intensity of respiratory distress when asthma symptoms/episodes/attacks occurThe frequency with which symptoms, episodes and attacks occur over time
ExacerbationsThe speed of onset (rapidity), degree of disability, and advent of respiratory failureFrequency of exacerbations of any severity
MedicationAmount of treatment required to maintain best symptom control and lung functionFrequency with which additional therapy is required, especially SABA use and courses of steroid tablets
Lung functionThe degree of loss of lung functionThe variability of change in lung function which occurs over a short to medium time frame
Airway hyperresponsivenessThe level of response to challenge agents e.g. methacholine, exerciseThe frequency with which actual challenge situations, such as exercise, result in acute episodes of asthma
Airway inflammationThe degree of inflammation present when untreatedThe degree of inflammation present while on treatment
  • SABA: short-acting β2-agonist.