Classification of Asthma Severity*
Components of Severity | Intermittent | Mild Persistent | Moderate Persistent | Severe Persistent |
|---|---|---|---|---|
Symptoms and risk measures | All ages: ≤ 2 days/week | All ages: > 2 days/week, not daily | All ages: Daily | All ages: Throughout the day |
Nighttime awakenings | Adults and children ≥ 5 years: ≤ 2 times/month Children 0–4 years: 0 | Adults and children ≥ 5 years: 3–4 times/month Children 0–4 years: 1–2 times/month | Adults and children ≥ 5 years: > 1 time/week but not nightly Children 0–4 years: 3–4 times/month | Adults and children ≥ 5 years: Often 7 times/week Children 0–4 years: > 1 time/week |
SABA rescue inhaler use for symptoms (not to prevent EIB) | ≤ 2 days/week | Adults and children ≥ 5 years: > 2 days/week but not daily Children 0–4 years: > 2 days/week but not daily | Daily | Several times per day |
Interference with normal activity | None | Minor limitation | Some limitation | Extreme limitation |
FEV1 | Adults and children ≥ 5 years: > 80% Children 0–4 years: Not applicable | Adults and children ≥ 5 years: > 80% Children 0–4 years: Not applicable | Adults and children ≥ 5 years: 60–80% Children 0–4 years: Not applicable | Adults and children ≥ 5 years: < 60% Children 0–4 years: Not applicable |
FEV1/FVC | Adults and children ≥ 12 years: Normal† Children 5–11 years: > 85% Children 0–4 years: Not applicable | Adults and children ≥ 12 years: Normal† Children 5–11 years: > 80% Children 0–4 years: Not applicable | Adults and children ≥ 12 years: Reduced 5%† Children 5–11 years: 75–80% Children 0–4 years: Not applicable | Adults and children ≥ 12 years: Reduced > 5%† Children 5–11 years: < 75% Children 0–4 years: Not applicable |
Risk of an asthma exacerbations requiring oral corticosteroid bursts‡ | 0–1/year | Adults and children ≥ 5 years: ≥ 2/year Children 0–4 years: ≥ 2 in 6 months or wheezing ≥ 4 times/year lasting > 1 day AND risk factors for persistent asthma | More frequent and intense events indicate greater severity | More frequent and intense events indicate greater severity |
* Severity is categorized based on degree of impairment and risk of exacerbations requiring oral corticosteroids. Impairment is assessed over the previous 2–4 weeks, and risk is assessed over the past year. Severity is best classified at the first visit before a controller therapy is initiated (not SABA or systemic corticosteroid bursts for symptoms or exacerbations). | ||||
† Evidence for airflow obstruction is based on an FEV1/FVC ratio less than expected normal values by age group. Normal FEV1/FVC ratios by age group: 8–19 years = 85%; 20–39 years = 80%; 40–59 years = 75%; 60–80 years = 70%. | ||||
‡ At present, there are inadequate data to correlate frequencies of exacerbations with different levels of asthma severity. In general, more frequent and intense exacerbations (eg, requiring urgent, unscheduled care, hospitalization, or intensive care unit admission) indicate greater underlying disease severity. For treatment purposes, patients with ≥ 2 exacerbations may be considered to have persistent asthma. | ||||
EIB = exercise-induced bronchospasm; FEV1 = forced expiratory volume in 1 second; FVC = forced vital capacity; ICS = inhaled corticosteroid; SABA = short-acting beta-2 agonist. | ||||
Adapted from National Heart, Lung, and Blood Institute: Expert Panel Report 3: Guidelines for the diagnosis and management of asthma—full report 2007. August 28, 2007. Available at http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm. | ||||