Impact of non-apnea sleep disorders on diabetic control and metabolic outcome - A population-based cohort study

There has been a growing recognition that obstructive sleep apnea (OSA) could increase the propensity for type 2 diabetes the metabolic syndrome. However, studies concerning about the impact of non-apnea sleep disorders (NSD) on diabetes control and metabolic outcomes are relatively scarce. Our aim is to investigate the impact of non-apnea sleep disorders (NSD) on diabetic control and associated metabolic outcomes in patients with type 2 diabetes.

The data were obtained from two nationwide population-based databases for a period 2007 to 2012. A total 66,992 patients with type 2 diabetes were enrolled and divided into two cohorts based on comorbidity with or without a NSD diagnosis, and were followed up four years. The primary outcomes were to compare rate of change in HbA1c and associated metabolic outcomes during follow-up visits between patients with or without NSD. The secondary outcome is to examine whether NSD were associated with poor glycemic control of the last clinical records while controlling for the baseline HbA1c value.

Of the 66,992 patients with type 2 diabetes, 14.82% had comorbidity with a NSD. HbA1C decreases were significantly lower by 0.04% in the NSD group (P < 0.05), and triglyceride (TG) decreases remained significantly lower by 2.53% in the NSD group (P < 0.05). Furthermore, patients in the NSD group had an 8% higher risk of poor glycemic control (HbA1C >9) (OR = 1.08; 95%CI, 1.01-1.16).

Our findings indicated patients with type 2 diabetes comorbid with NSD had a slower improvement in HbA1c compared with the comparison cohort. It may because there may exist potential floor effect given those with NSD having significantly lower HbA1c values at baseline. On the other hand, the poor diabetic control among those with NSD may be also affected by other confounders such as medical treatment or interventions. Nevertheless, given the rapidly increasing prevalence of metabolic diseases and subsequent complications, the results may highlight the importance of sleep in the clinical management of type 2 diabetes.