How is asthma categorized and what are the corresponding treatment options?

Asthma Categorization and Treatment Options

Asthma should be classified based on both impairment and risk domains, with severity categorized as intermittent, mild persistent, moderate persistent, or severe persistent to guide initial treatment decisions, while subsequent management should focus on the level of control. 1

Classification of Asthma Severity

Asthma severity is determined by assessing two key domains:

1. Impairment Domain

The impairment domain evaluates the frequency and intensity of symptoms and functional limitations:

• Intermittent Asthma

  • Symptoms ≤2 days/week
  • Nighttime awakenings ≤2 times/month
  • SABA use for symptom control ≤2 days/week
  • No interference with normal activity
  • FEV₁ >80% predicted
  • Normal FEV₁/FVC ratio 1

• Mild Persistent Asthma

  • Symptoms >2 days/week but not daily
  • Nighttime awakenings 3-4 times/month
  • SABA use >2 days/week but not daily
  • Minor limitation of normal activity
  • FEV₁ >80% predicted
  • Normal FEV₁/FVC ratio 1

• Moderate Persistent Asthma

  • Daily symptoms
  • Nighttime awakenings >1/week but not nightly
  • Daily SABA use
  • Some limitation of normal activity
  • FEV₁ >60% but <80% predicted
  • FEV₁/FVC reduced by 5% 1

• Severe Persistent Asthma

  • Symptoms throughout the day
  • Nighttime awakenings often 7 times/week
  • SABA use several times per day
  • Extreme limitation of normal activity
  • FEV₁ <60% predicted
  • FEV₁/FVC reduced >5% 1

2. Risk Domain

The risk domain assesses the likelihood of future exacerbations:

• Frequency of exacerbations requiring oral systemic corticosteroids
• Patients with ≥2 exacerbations requiring oral corticosteroids in the past year should be considered as having persistent asthma, regardless of impairment level 1, 2

Treatment Approach Based on Severity Classification

Treatment follows a stepwise approach based on severity classification:

Step 1: Intermittent Asthma

• Short-acting beta-agonist (SABA) as needed for symptoms 1, 2

Step 2: Mild Persistent Asthma

• Low-dose inhaled corticosteroid (ICS) as preferred controller
• Alternative: Leukotriene receptor antagonist or theophylline 1

Step 3: Moderate Persistent Asthma

• Low-dose ICS plus long-acting beta-agonist (LABA)
• Alternative: Medium-dose ICS or low-dose ICS plus leukotriene receptor antagonist or theophylline 1, 3

Step 4: Moderate-to-Severe Persistent Asthma

• Medium-dose ICS plus LABA
• Alternative: Medium-dose ICS plus leukotriene receptor antagonist or theophylline 1

Step 5: Severe Persistent Asthma

• High-dose ICS plus LABA
• Consider omalizumab for patients with allergies 1

Step 6: Very Severe Persistent Asthma

• High-dose ICS plus LABA plus oral corticosteroid
• Consider omalizumab for patients with allergies 1

Monitoring Asthma Control

After initial treatment based on severity, ongoing management should focus on assessing control at all subsequent visits:

Control Assessment Categories

• Well Controlled

  • Symptoms ≤2 days/week
  • Nighttime awakenings ≤2 times/month
  • SABA use ≤2 days/week
  • No interference with normal activity
  • FEV₁ or PEF ≥80% predicted/personal best 1, 2

• Not Well Controlled

  • Symptoms >2 days/week
  • Nighttime awakenings 1-3 times/week
  • SABA use >2 days/week
  • Some limitation of normal activity
  • FEV₁ or PEF 60-80% predicted/personal best 1, 2

• Very Poorly Controlled

  • Symptoms throughout the day
  • Nighttime awakenings ≥4 times/week
  • SABA use several times per day
  • Extreme limitation of normal activity
  • FEV₁ or PEF <60% predicted/personal best 1, 2

Validated Assessment Tools

Several validated questionnaires can help assess asthma control:

• Asthma Control Test (ACT)
• Asthma Control Questionnaire (ACQ)
• Asthma Therapy Assessment Questionnaire (ATAQ) 1

Treatment Adjustments Based on Control

• If asthma is well controlled for at least 3 months, consider stepping down therapy
• If asthma is not well controlled, step up therapy (first check adherence, inhaler technique, environmental control, and comorbid conditions)
• If asthma is very poorly controlled, consider short course of oral corticosteroids and step up to next treatment level 1, 3

Important Clinical Considerations

• Inhaled corticosteroids are the most effective single controller medication for improving asthma control in both children and adults 1
• Combination therapy with ICS and LABA provides better control than increasing ICS dose alone in moderate-to-severe persistent asthma 3
• All patients should have a written action plan detailing medications and environmental control strategies 1
• Risk factors for asthma-related mortality include previous ICU admission, ≥2 hospitalizations or ≥3 ED visits in the past year, and poor perception of symptom severity 2

By properly categorizing asthma severity and regularly assessing control, clinicians can optimize treatment to reduce morbidity, mortality, and improve quality of life for patients with asthma.