What a STOP-Bang Score Means, From the Eight Questions to the 3 and 5 Cutoffs

STOP-Bang was published in 2008 by Frances Chung and colleagues in Anesthesiology as a quick preoperative screen for undiagnosed obstructive sleep apnea, a condition in which the airway repeatedly narrows or closes during sleep. A total score of 3 or more is the classic cutoff for flagging possible sleep apnea, and the 2016 revision in Chest reserves “high risk” for 5 or more. It estimates risk. It does not diagnose anything.

The eight STOP-Bang items and how they score

The name is an acronym, and each yes scores one point, for a total of 0 to 8.

1. Snoring: do you snore loudly?
2. Tired: do you often feel tired, fatigued or sleepy during the day?
3. Observed apnea: has anyone seen you stop breathing during sleep?
4. Pressure: do you have high blood pressure?
5. BMI: is your body mass index above 35 kg/m²?
6. Age: are you older than 50?
7. Neck circumference: is your neck larger than 40 cm (about 16 inches)?
8. Gender: are you male?

Neck size is where versions disagree. The American Thoracic Society’s questionnaire page states it as 16 inches or more, other forms say 40 cm, and those are not quite the same number. Check which form your clinician uses.

Validation: high sensitivity, modest specificity

Chung et al., 2008, Anesthesiology, started with the four-item STOP (snoring, tiredness, observed apnea, pressure). In 2,467 patients given the questionnaire, 211 also had an overnight sleep study: 34 in a pilot group and 177 in a validation group. STOP alone had sensitivity of 65.6, 74.3 and 79.5 percent for apnea defined as AHI above 5, 15 and 30. Adding BMI, age, neck circumference and gender raised those to 83.6, 92.9 and 100 percent. AHI is the apnea-hypopnea index, the number of breathing pauses and shallow breaths per hour of sleep, and it is the number a sleep test produces.

The later numbers matter more. Nagappa et al., 2015, PLoS ONE, pooled 17 studies and 9,206 patients. At a cutoff of 3 in sleep clinic patients, sensitivity was 90, 94 and 96 percent and specificity 49, 34 and 25 percent for AHI of at least 5, 15 and 30. In surgical patients, sensitivity was 84, 91 and 96 percent and specificity 43, 32 and 29 percent.

Score bands: 0 to 2, 3 to 4, and 5 to 8

As reported by Chung, Abdullah and Liao, 2016, Chest, a score of 3 or more detects moderate-to-severe apnea (AHI above 15) with 93 percent sensitivity and severe apnea (AHI above 30) with 100 percent. Their bands:

• 0 to 2: low risk for moderate-to-severe apnea.
• 3 to 4: intermediate. Extra criteria are needed, for example a STOP score of 2 or more plus BMI above 35.
• 5 to 8: high risk. As reported in Chung et al., 2016, the probability of moderate-to-severe apnea rises from about 18 percent at the bottom of the scale to about 60 percent at 7 to 8.

Probability of severe apnea at each score

Nagappa et al., 2015, give the probability of severe apnea by score. In sleep clinic patients it is 25 percent at 3, 35 percent at 4, 45 percent at 5, 55 percent at 6 and 75 percent at 7 or 8. In surgical patients it is 15, 25, 35, 45 and 65 percent.

That is the trade a screening tool makes. A low cutoff catches almost everyone who has the condition, which suits a screen, and sends many people without it to testing, which is the cost. A score of 5 is a stronger signal than 3, but still a probability. Even in a sleep clinic, 45 percent for severe apnea at a score of 5 means roughly half do not have it.

What STOP-Bang cannot do

It cannot diagnose, rank severity for one person, or rule out apnea. It cannot see anything that is not on the list: two people with identical scores can have very different nights. It was validated mostly in sleep clinic and surgical populations, which differ from a general crowd. Diagnosis comes from a clinician and a sleep test, either overnight polysomnography in a lab or a home sleep apnea test, with the result expressed as an AHI.

Waking up tired and when to see a clinician

Waking tired has many causes, and apnea is one of them. A tired morning does not by itself mean a sleep study. But a score of 3 or higher, or a persistent pattern of unrefreshing sleep despite enough time in bed, is a reasonable thing to bring to a doctor, who decides whether testing is warranted. Bring the filled-in answers and anything a bed partner has noticed.

For the morning side of this: snoozing through several alarms, or feeling that no alarm is early enough to compensate for how you feel, is usually read as a discipline problem, and sometimes it is a symptom. The post on other reasons you stay tired after eight hours lists causes to rule out, and the Epworth sleepiness questionnaire is what a clinician may use alongside STOP-Bang.