Obstructive Sleep Apnea: What are the Components of Risk?

You are performing an annual visit evaluation for a 54-year-old sales manager. He has a history of hypertension and hyperlipidemia, both managed. He has no major complaints. He reports restful sleep and no daytime sleepiness. On examination his BMI is 37 and his blood pressure is 126/82 mm Hg.

You should consider him to be at high risk for obstructive sleep apnea (OSA) if which of the following also is present:

A. Hypothyroidism

B. Caucasian race

C. Smoking

D. Loud snoring

E. No additional conditions necessary; his risk of OSA is already elevated

See next page for answer and discussion.

 Answer: E. No additional conditions necessary; his risk of OSA is already elevated

Discussion

According to the STOP-BANG scoring model developed by Dr Frances Chung to evaluate the risk of OSA in patients scheduled for surgery, the combination of any 3 or more of the following factors imparts a high risk of OSA:

Snoring
   Do you snore loudly (louder that talking or loud enough to be heard through closed doors)?

Tired
   Do you often feel tired, fatigued, or sleepy during daytime?

Observed
   Has anyone observed you stop breathing during your sleep?

Blood Pressure
   Do you have or are you being treated for high blood pressure?

BMI
   BMI greater than 35 kg/m3

Age
   Age over 50 years?

Neck Circumference
   Neck circumference greater than 40 cm (15.75 in)?

Gender
   Gender male?

Scoring
High risk of OSA: “Yes” answer to 3 or more items

Low risk of OSA: “Yes” answer to fewer than 3 items

While snoring and smoking are associated with an increase in the risk of OSA, in the case of this patient, no additional factors are necessary to consider him high risk; his clinical characteristics already include 3 risk factors: male gender, BMI greater than 35, and a history of hypertension. Patients who are at high risk for OSA should be referred for polysomnography, to establish the diagnosis and the severity of the condition. Left untreated, OSA can increase the risk of various impairments, such as daytime hypersomnolence, cognitive impairment leading to occupational decrements, and accidents. It can also increase the risk of various medical and psychiatric morbidities, such as hypertension, cardiac arrhythmias, MI, CVA, and depression, among others.

The STOP-BANG inventory has a high sensitivity for severe OSA, but has a fairly low specificity. Its sensitivity diminishes with decreasing OSA severity values. In addition, it has not been validated in all patient populations. Therefore, although questionnaires may be useful screening tools, they cannot substitute for a thorough clinical evaluation, which includes a systematic review of symptoms and comorbidities associated with OSA, followed by a pertinent physical examination. The Berlin Questionnaire is a similar inventory that has received wider validation studies.