Table 1: Asthma Severity Classification
| Classification | Symptoms | Lung Function |
|---|---|---|
| Step
1: Mild-Intermittent |
Daytime < 2 times per week Nighttime < 2 times per month Brief exacerbations Asymptomatic between exacerbations Intensity of exacerbations varies |
PEF
Variability < 20% FEV1 > 80% PEF > 80% |
| Step
2: Mild-Persistent |
Daytime > 2
times per week but < 1 time per day Nighttime > 2 times per month Exacerbations may affect activity |
PEF Variability
range of 20%-30% FEV1 > 80% PEF > 80% |
| Step
3: Moderate-Persistent |
Daytime symptoms
daily Nighttime symptoms > 1 time per week Exacerbations affect activity Exacerbations > 2 times per week Exacerbations last days Daily use of inhaled short-acting ß2-agonists |
PEF Variability
> 30% FEV1 > 60% but < 80% PEF > 60% but < 80% |
| Step
4: Severe-Persistent |
Daytime symptoms
continual Nighttime symptoms frequent Symptoms limit physical activity Exacerbations frequent |
PEF variability
> 30% FEV1 < 60% PEF < 60%
|
PEF = peak expiratory
flow, FEV1 = forced expiratory volume in 1 second
Adapted from National Asthma Education and Prevention Program. NIH.
1997;97-4051:iii-86.
Kelly HW, et al. Pharmacology: a Pathophysiologic Approach 5th
ed. New York: McGraw-Hill; 2002. p. 475-510