Background  
The relationship between excessive daytime sleepiness (EDS) and glycemic control in people with type 2 diabetes (T2D) had been reported. However, the relationships of EDS with blood pressure and lipid control, as well as overall attainment of treatment targets remain unclear.

Aim   
To examine the association between EDS and treatment targets attainment in T2D.

 Method  
This was a cross-sectional analysis of people with T2D enrolled in the Hong Kong Diabetes Register (HKDR). EDS was defined as a score >10 based on the Epworth Sleepiness Scale (ESS). Insomnia and anxiety/depression states were assessed using the Insomnia Severity Index (ISI) and the EQ-5D questionnaires respectively. Sleep habits including habitual snoring were assessed by a validated sleep questionnaire. Treatment targets attainment was defined as (1) glycated haemoglobin (HbA1c) < 7% (2) blood pressure < 140/90 mmHg, and (3) low density lipoprotein cholesterol (LDL-C) < 2.6 mmol/L.

Results  
Between 6th July 2010 and 27th May 2015, a total of 3637 T2D from HKDR were included in the present analysis. Among them, 19.8% had EDS. Using multivariate logistic regression analysis, EDS was associated with failure of attainment of all three treatment targets [Odds Ratio (OR) = 1.53 (95% confidence interval, CI=1.20, 1.95), p < 0.001] and LDL-C target [OR= 1.22 (95% CI= 1.02, 1.46), p = 0.033] after adjustment for age, gender, body mass index (BMI), T2D duration, insomnia and anxiety/depression status, use of anti-diabetic agents,anti-hypertensives, lipid regulating drugs and aspirin. For subgroup analysis of T2D with obesity (BMI > 25kg/m2), there were associations between EDS and failure to attain all three treatment targets [OR = 1.77 (95% CI=1.29, 2.43), p < 0.001], HbA1c target [OR = 1.32 (95% CI=1.05, 1.66), p = 0.018] and LDL-C target [OR = 1.29 (95% CI=1.03, 1.62), p = 0.029]. In contrast, there was no significant association between EDS and treatment targets in non-obese T2D. After further adjustment for habitual snoring, the association between EDS and failure to attain all three treatment targets [OR = 1.68 (95% CI= 1.21, 2.34), p = 0.002] and HbA1c target [OR = 1.28 (95% CI= 1.00, 1.63), p = 0.046] remained significant in obese T2D, while that with LDL-C target attainment was attenuated [OR = 1.25 (95% CI= 0.98, 1.59), p = 0.069].

 Discussion  
EDS is independently associated with failure of achieving glycemic and lipid targets, as well as a composite of all three treatment targets in obese individuals with T2D. Prospective studies are required to elucidate the causal relationship between EDS and metabolic control in obese T2D.



Excessive Daytime Sleepiness Is Associated with Failure of Treatment Targets Attainment in Type 2 Diabetes