Two in three older adults with type 1 diabetes screen positive for sleep apnoea

Design

cross-sectional questionnaire analysis within a long-running cohort study

Population

963 adults with type 1 diabetes, mean age 64, mean duration 43 years

Primary outcome

prevalence of raised sleep apnoea risk, poor sleep quality and daytime sleepiness

Effect

64% STOP-Bang 3 or more; 43% poor sleep quality; 15-20% higher odds of a sleep problem per 1% HbA1c

DCCT/EDIC asked 963 surviving participants with type 1 diabetes of a mean 43 years' duration, mean age 64, to complete validated sleep questionnaires. Twenty-nine per cent already had a diagnosis of obstructive sleep apnoea and 19% were using positive airway pressure.

Among the whole group, 64% scored at intermediate or high risk on STOP-Bang, 43% had poor sleep quality on the Pittsburgh index, and 10% reported at least mild daytime sleepiness. Each 1% absolute rise in current or mean HbA1c was associated with 15% to 20% higher odds of any sleep problem. After adjustment for age, sex, BMI and mean HbA1c, cardiovascular autonomic neuropathy was associated with higher odds of intermediate or high sleep apnoea risk, and albuminuria and severe hypoglycaemia with higher odds of poor sleep quality.

These are questionnaires, not sleep studies, and STOP-Bang is a screening instrument that overcalls. The gap worth noticing is the one between 64% screening positive and 29% carrying a diagnosis. In a long clinic focused on glucose, complications and devices, sleep is rarely asked about at all.

• Ask about snoring, witnessed apnoeas and morning headache at annual review in long-standing type 1 diabetes.
• STOP-Bang takes under a minute and needs no equipment; a score of 3 or more warrants discussion.
• Cardiovascular autonomic neuropathy on the record raises the prior for sleep apnoea.
• Unexplained poor sleep sits alongside albuminuria and severe hypoglycaemia in this cohort - review both.
• A positive screen means referral for a sleep study, not a presumptive diagnosis.

Why it matters

Sleep is not on most type 1 annual review templates, and this cohort suggests that is where a large share of undiagnosed apnoea is sitting.

Don't overread it

Questionnaire screening, cross-sectional - it cannot show that treating sleep apnoea improves glycaemia.

The statistics, in plain English

The 15-20% higher odds per 1% HbA1c is an association measured at one point in time, so it cannot say whether worse glucose disturbs sleep or disturbed sleep worsens glucose - both are plausible and the study design cannot separate them. STOP-Bang is deliberately tuned to miss few cases, which means a positive result is common and much less informative than a negative one.

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