Obstructive sleep apnea means the upper airway repeatedly narrows or closes during sleep. The National Heart, Lung, and Blood Institute describes the blockage as reducing or completely stopping airflow, many times a night. Each event fragments sleep and triggers a surge of sympathetic activity. The metabolic consequences follow from that pattern: worse insulin sensitivity, higher overnight glucose, higher blood pressure, and daytime tiredness that quietly removes physical activity from the week.

Who should be screened

The American Academy of Sleep Medicine lists excess weight, large neck size, male sex and middle age as the main risk factors, and states that risk is higher at a body mass index of 25 or above. Snoring matters most when it is followed by silent pauses and then choking or gasping. Morning headache, memory complaints, waking to urinate repeatedly and erectile dysfunction belong on the same list. The STOP-Bang questionnaire packages these into eight yes or no questions.

Letter	Question
S	Do you snore loudly, loud enough to be heard through a closed door?
T	Are you often tired or sleepy during the day?
O	Has anyone observed you stop breathing, choke or gasp in your sleep?
P	Are you being treated for high blood pressure?
B	Is your body mass index above 35?
A	Are you older than 50?
N	Is your neck circumference above 40 cm?
G	Are you male?

What the screening numbers mean

A 2015 systematic review and meta-analysis in PLoS One pooled 17 studies and 9,206 patients. In sleep clinic populations, a STOP-Bang score of 3 or more detected 90 percent of any sleep apnea, 94 percent of moderate to severe disease and 96 percent of severe disease. Those are sensitivities, which is the point of a screening tool: it is built to miss very little and to over-call a great deal. A high score means test, not diagnose.

What treatment changes and what it does not

The 2017 American Academy of Sleep Medicine guideline recommends polysomnography or an adequate home sleep apnea test for diagnosis, and reserves in-laboratory study for people with heart or lung disease, neuromuscular disease or opioid use. Continuous positive airway pressure is the frontline treatment for most patients, with oral appliances for mild to moderate disease and positional therapy for some. Treating apnea improves sleep quality, daytime alertness and blood pressure. It is not a weight loss treatment, and expecting the scale to move because of it leads to people abandoning the machine.

If two or more of the STOP-Bang questions are a yes and you also have insulin resistance, prediabetes, resistant hypertension or overnight glucose that rises for no dietary reason, ask directly for a sleep study rather than another diet change. Bring a two week note of bedtime, wake time and what your partner hears.

Severity is graded by the apnea-hypopnea index: 5 to 14.9 events per hour is mild, 15 to 29.9 moderate, 30 or more severe, with symptoms or comorbidity required at the lower end. The 2017 AASM guideline is explicit that clinical tools, questionnaires and prediction algorithms should not be used to diagnose obstructive sleep apnea in the absence of polysomnography or home testing, and that a negative or technically inadequate home study in a symptomatic patient should be followed by in-laboratory polysomnography. Home testing underestimates the index because it divides events by recording time rather than measured sleep time. Screen every patient with type 2 diabetes and obesity, resistant hypertension, atrial fibrillation, nocturia or unexplained overnight hyperglycemia on continuous glucose monitoring. Untreated apnea also blunts adherence to everything else in a metabolic plan.

Could sleep apnea be behind my metabolic problems?

Who should be screened

What the screening numbers mean

What treatment changes and what it does not

Sources

Who should be screened

What the screening numbers mean

What treatment changes and what it does not

Sources

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