Table 1

Classification of asthma severity

SeverityDay time symptomsNight time symptomsPeak flow
The presence of any of the features of severity is sufficient to place a patient in that category. Patients in any category can have severe exacerbations.2
Mild intermittentLess than once per weekLess than twice per month≥80% predicted, variability <20%
Mild persistentBetween once per week and once dailyMore than twice per month≥80% predicted, variability 20%–30%
Moderate persistentDaily, attacks affect activityMore than once weekly60%–80% predicted, variability >30%
Severe persistentContinuous, limited activityFrequent≤60% predicted, variability >30%