How do I determine if a patient has obstructive sleep apnea?

How to Determine if a Patient Has Obstructive Sleep Apnea

Diagnose OSA through a two-step process: first perform a comprehensive sleep evaluation including specific clinical features, then confirm with objective testing using either polysomnography (PSG) or home sleep apnea testing (HSAT) in appropriate patients. 1, 2

Step 1: Clinical Screening and Evaluation

Initial Screening Questions

Ask every patient during routine health visits about:

• Snoring (loud enough to be heard through a closed door) - this is the most sensitive screening measure 1, 2
• Witnessed apneas during sleep 1, 2
• Nocturnal choking or gasping episodes 1, 2
• Excessive daytime sleepiness not explained by other factors 1, 2

Comprehensive Sleep History (if screening positive)

Obtain detailed information about:

• Total sleep duration, quality, and timing 2
• Sleep fragmentation or maintenance insomnia 1
• Nocturia 1
• Morning headaches 1
• Decreased concentration and memory 1
• Assess sleepiness severity using the Epworth Sleepiness Scale, though recognize this has limited diagnostic utility (sensitivity 0.27-0.72, specificity 0.50-0.76) 1

Physical Examination Findings

Measure and document:

• Body mass index (obesity is a major risk factor) 1, 2
• Neck circumference (>17 inches in men, >16 inches in women suggests increased risk) 1
• Craniofacial abnormalities affecting the airway 1
• Anatomical nasal obstruction 1
• Tonsillar hypertrophy (tonsils nearly touching or touching in the midline) 1
• Evaluate respiratory, cardiovascular, and neurologic systems 1, 2

High-Risk Populations Requiring Evaluation

Screen aggressively for OSA in patients with:

• Obesity 1, 2
• Hypertension (especially treatment-refractory) 1, 2
• Congestive heart failure 1, 2
• Atrial fibrillation 1
• Type 2 diabetes 1, 2
• Stroke 1, 2
• Patients being evaluated for bariatric surgery 1
• High-risk driving populations (commercial truck drivers) 1

Step 2: Objective Diagnostic Testing

When to Use PSG (In-Laboratory Polysomnography)

PSG is mandatory for: 2

• Patients with significant cardiorespiratory disease
• Potential respiratory muscle weakness
• Awake hypoventilation or suspected sleep-related hypoventilation
• Severe insomnia
• Symptoms suggesting other sleep disorders (periodic limb movements, parasomnias, narcolepsy)

When HSAT (Home Sleep Apnea Testing) is Appropriate

HSAT can be used for: 2

• Uncomplicated patients with suspected moderate-to-severe OSA
• Patients without significant comorbidities
• When using a technically adequate device

Important caveat: HSAT is not appropriate for patients with the conditions listed above requiring PSG 2

Diagnostic Criteria for OSA

OSA is diagnosed when either: 2

• ≥5 obstructive respiratory events per hour (apneas, hypopneas, or respiratory effort-related arousals) PLUS symptoms (daytime sleepiness, snoring, witnessed apneas, or awakenings with gasping/choking)
• OR ≥15 obstructive respiratory events per hour even without symptoms (due to increased cardiovascular disease risk)

Severity Classification

Use the sleep laboratory's overall assessment when available, but if only AHI is reported: 1

• None: AHI 0-5
• Mild OSA: AHI 6-20
• Moderate OSA: AHI 21-40
• Severe OSA: AHI >40

Clinical Prediction Tools: Limited Diagnostic Value

STOP-BANG Questionnaire

• Has high sensitivity but low specificity (sensitivity 0.93, specificity 0.36) 1
• Useful for screening to rule out OSA but produces too many false positives to confirm diagnosis 1
• Should not be used alone to diagnose individual patients 1

Berlin Questionnaire

• Produces a large number of false negatives, limiting its utility for diagnosis 1
• Can be used for initial risk stratification but requires objective testing for confirmation 1

Epworth Sleepiness Scale

• Has poor diagnostic performance with high false negative rates 1
• Should not be relied upon to rule out OSA 1

Critical Pitfalls to Avoid

Do not rely on absence of daytime sleepiness to rule out OSA - many patients with severe OSA do not report sleepiness 2

Self-reported symptoms alone are never sufficient for diagnosis - objective testing with PSG or HSAT is always required 2

Clinical questionnaires and prediction rules cannot replace objective testing - while they have reasonable sensitivity, their specificity is too low to confirm or exclude OSA diagnosis 1

Do not skip the comprehensive sleep evaluation before testing - diagnostic testing should always be performed in conjunction with thorough clinical assessment and adequate follow-up under supervision of a board-certified sleep medicine physician 1