Two in three older adults with long-standing type 1 diabetes screen at risk of sleep apnoea

Design

Cross-sectional analysis within a long-term cohort, validated questionnaires

Population

963 adults with type 1 diabetes, mean age 64, mean duration 43 years (DCCT/EDIC)

Primary outcome

Prevalence of OSA risk (STOP-Bang ≥3), poor sleep quality and daytime sleepiness

Effect

OSA risk 64%, poor sleep 43%, sleepiness 10%; each 1% HbA1c rise linked to 15–20% higher odds of a sleep problem

Investigators from the DCCT/EDIC cohort gave validated sleep questionnaires to 963 participants with type 1 diabetes, mean age 64 and mean diabetes duration 43 years. They used STOP-Bang for apnoea risk, the Pittsburgh index for sleep quality and the Epworth scale for daytime sleepiness.

29% already had a diagnosis of obstructive sleep apnoea and 19% were using a positive airway pressure device. A further screen put 64% at intermediate or high risk. Poor sleep quality was reported by 43%. Each 1% higher HbA1c was associated with 15–20% higher odds of any sleep problem, and cardiovascular autonomic neuropathy was associated with apnoea risk after adjustment for BMI and glycaemia.

Sleep apnoea is usually thought of as a type 2 diabetes and obesity problem. This cohort suggests it is common in older people with type 1 as well, and is linked to autonomic neuropathy rather than weight alone. It is cross-sectional and questionnaire-based, so it cannot say that better glucose control would improve sleep, or which way the association runs. It is a reason to ask, not a reason to change treatment.

• Ask older patients with long-standing type 1 diabetes about snoring, witnessed apnoeas and daytime sleepiness at the annual review.
• STOP-Bang takes under a minute and was the screening tool used here; a score of 3 or more is intermediate or high risk.
• Consider sleep assessment particularly where there is cardiovascular autonomic neuropathy, which was associated with higher apnoea risk.
• Poor sleep was linked to albuminuria and severe hypoglycaemia; ask about nocturnal hypos when a patient reports broken sleep.
• A normal BMI does not rule out sleep apnoea in this group.

Why it matters

Sleep apnoea is usually screened for in type 2 diabetes and obesity; this suggests the type 1 clinic is missing it.

Don't overread it

A STOP-Bang score is a risk screen, not a diagnosis, and the HbA1c link is an association rather than a cause.

The statistics, in plain English

'15–20% higher odds per 1% HbA1c' means the chance of reporting a sleep problem rises steadily with glucose, but this is a snapshot taken at one time. People who sleep badly may have higher HbA1c because of the poor sleep, rather than the other way round.

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