Data from: Global assessment of the impact of type 2 diabetes on sleep through specific questionnaires. A case-control study

Type 2 diabetes (T2D) is an independent risk factor for sleep breathing
disorders. However, it is unknown whether T2D affects daily somnolence and
quality of sleep independently of the impairment of polysomnographic
parameters. Material and Methods: A case-control study including 413
patients with T2D and 413 non-diabetic subjects, matched by age, gender,
BMI, and waist and neck circumferences. A polysomnography was performed
and daytime sleepiness was evaluated using the Epworth Sleepiness Scale
(ESS). In addition, 135 subjects with T2D and 45 controls matched by the
same previous parameters were also evaluated through the Pittsburgh Sleep
Quality Index (PSQI) to calculate sleep quality. Results: Daytime
sleepiness was higher in T2D than in control subjects (p=0.003), with
23.9% of subjects presenting an excessive daytime sleepiness
(ESS>10). Patients with fasting plasma glucose (FPG ?13.1 mmol/l)
were identified as the group with a higher risk associated with an
ESS>10 (OR 3.9, 95% CI 1.8-7.9, p=0.0003). A stepwise regression
analyses showed that the presence of T2D, baseline glucose levels and
gender but not polysomnographic parameters (i.e apnea-hyoapnea index or
sleeping time spent with oxigen saturation lower than 90%) independently
predicted the ESS score. In addition, subjects with T2D showed higher
sleep disturbances [PSQI: 7.0 (1.0-18.0) vs. 4 (0.0-12.0),
p<0.001]. Conclusion: The presence of T2D and high levels of FPG
are independent risk factors for daytime sleepiness and adversely affect
sleep quality. Prospective studies addressed to demonstrate whether
glycemia optimization could improve the sleep quality in T2D patients seem
warranted.