What are the diagnostic criteria for Obstructive Sleep Apnea (OSA)?

Diagnostic Criteria for Obstructive Sleep Apnea (OSA)

The diagnosis of OSA requires both clinical symptoms AND polysomnographic evidence of ≥5 respiratory events per hour of sleep, with appropriate testing determined by patient risk factors and comorbidities. 1

Clinical Criteria

The clinical diagnosis requires:

1. Primary Symptom:

   • Excessive daytime sleepiness not better explained by other factors 1, 2

2. OR at least two of the following symptoms:

   • Choking or gasping during sleep
   • Recurrent awakenings from sleep
   • Unrefreshing sleep
   • Daytime fatigue
   • Impaired concentration 2

Polysomnographic Criteria

The objective diagnosis requires:

• ≥5 obstructive respiratory events per hour of sleep 1, 2
• Respiratory events defined as:
  • Apnea: Complete absence of airflow for ≥10 seconds with continued respiratory effort
  • Hypopnea: Reduction in airflow of ≥30% for ≥10 seconds associated with either:
    • ≥3% oxygen desaturation OR
    • An electroencephalographic arousal 1

Severity Classification

OSA severity is classified by the Apnea-Hypopnea Index (AHI):

• Mild: 5-15 events per hour
• Moderate: 15-30 events per hour
• Severe: ≥30 events per hour 1

Diagnostic Testing Algorithm

1. Initial Assessment for OSA Risk:

   • Evaluate for excessive daytime sleepiness AND at least two of:
     • Habitual loud snoring
     • Witnessed apnea or gasping/choking
     • Diagnosed hypertension 3

2. Testing Selection:

   A. Home Sleep Apnea Testing (HSAT) is appropriate when:

   • Patient has increased risk of moderate to severe OSA
   • Patient has no significant comorbidities
   • Device must include minimum of:
     • Nasal pressure
     • Chest and abdominal respiratory inductance plethysmography
     • Oximetry 3, 1

   B. In-laboratory Polysomnography (PSG) is required when:

   • Patient has significant cardiopulmonary disease
   • Potential respiratory muscle weakness due to neuromuscular condition
   • History of stroke
   • Chronic opioid medication use
   • Severe insomnia
   • Symptoms of other significant sleep disorders
   • Environmental or personal factors that preclude adequate HSAT
   • Previous HSAT was negative, inconclusive, or technically inadequate 3, 1

3. Technical Requirements:

   • HSAT requires minimum 4 hours of technically adequate oximetry and flow data 3
   • PSG monitors EEG, EOG, EMG, airflow, respiratory effort, oxygen saturation, and ECG 1

Important Considerations

• Clinical tools, questionnaires, and prediction algorithms alone should NOT be used to diagnose OSA in the absence of PSG or HSAT 3

• The correlation between AHI and daytime symptoms is often weak, with significant interindividual variability in symptom presentation 2

• Prevalence of OSA (AHI ≥5/hr) is approximately 17% in women and 34% in men, though many are asymptomatic 4

• OSA is associated with 2-3 fold increased risk of cardiovascular and metabolic disease, making accurate diagnosis crucial 4

• In non-obese patients (BMI <30), specific anatomical factors like craniofacial abnormalities and retrognathia may be more significant contributors to OSA 5

• Follow-up should occur early after diagnosis and treatment initiation to ensure adherence 1