Sleep-Disordered Breathing Is Associated with Metabolic Syndrome in Outpatients with Diabetes Mellitus Type 2

Table 4

Previous studies examining the association between SDB and MS.

	Study design and participants	Patients with pathological glucose tolerance	Definition and assessment of SDB	Main results
Neumann et al. (2019)	228 SDB patients, 451 controls; 61% men	100% (all participants had proven DM2)	SDB: ; ApneaLink	(i) In patients with DM2, MS as well as its criteria hypertension and visceral obesity was significantly more frequent in the case of more severe SDB
Bonsignore et al. [5]	529 OSA patients; 80% men	17% (DM2)	SDB: ; PSG	(i) The prevalence of MS increased with OSA severity; (ii) Obesity and OSA led to metabolic abnormalities with different patterns between the two sexes; (iii) Metabolic score increased with the HOMA index
Lin et al. [39]	113 OSA patients, 45 controls; 82% men; only nonobese subjects included; no difference in BMI among groups	18% (hyperglycaemia)	SDB: ; PSG	(i) Patients with OSA had significantly higher systolic blood pressure and triglyceride levels; (ii) Dyslipidaemia, hypertension, and at least two of the NCEP criteria were significantly more frequent in the OSA group; (iii) AHI was independently associated with increased triglycerides and insulin resistance (assessed with HOMA) in linear regression
Nieto et al. [41]	253 OSA patients, 293 controls; 56% men	Not given	Mild SDB: AHI 5-14.9, moderate to severe SDB: AHI ≥15 or CPAP PSG	(i) Logistic regression adjusted for age, sex, autonomic and neuroendocrine parameters, and BMI showed an association of MS with mild and moderate/severe SDB
Kono et al. [40]	42 OSA patients, 52 controls matched for age, BMI, and visceral fat accumulation; 100% men; only nonobese subjects included	5% (DM2)	SDB: ; PSG	(i) No significant differences in serum levels of triglycerides, HDL, and diastolic BP; (ii) Prevalence of hyperglycaemia, dyslipidaemia, and hypertension was significantly higher in the OSA group; (iii) Patients with OSA had more often at least two of the criteria hypertension, hyperglycaemia, and dyslipidaemia, independent of visceral fat obesity
Parish et al. [34]	146 OSA patients, 82 controls; 59% men	30% (hyperglycaemia)	SDB: and ≥10; PSG	(i) MS was more often present in patients with OSA; (ii) Prevalence of hypertension was significantly higher in the OSA group; (iii) No significant differences in hyperglycaemia and dyslipidaemia; (iv) Prevalence of MS increased with severity of OSA
Gruber et al. [36]	38 OSA patients, 41 controls; percentage of men not given; MS is defined according to IDF	Not given	Minimal patient contact sleep diagnosis system (VISI-3, Stowood Scientific Instruments Ltd. (SSI), Oxford);	(i) The prevalence of MS was higher in the OSA group; (ii) Logistic regression adjusted for age, BMI, and smoking showed an independent association of OSA and MS; (iii) OSA was independently associated with the levels of triglycerides and glucose as well as the Epworth score values, whereas insulin resistance (assessed with HOMA) was not significant
Lam et al. [37]	95 OSA patients, 160 controls; 59% men	7% (DM2)	SDB: ; PSG	(i) Patients with OSA were five times more likely to have MS; (ii) OSA was independently associated with MS and some of its components; (iii) Prevalence of MS increased with OSA severity
Sasanabe et al. [38]	819 OSA patients, 89 controls; 86% men	22% (hyperglycaemia)	SDB: ; PSG	(i) MS was significantly more frequent in patients with OSA; (ii) The risk of MS was associated with the severity of OSA; (iii) Hypertension, dyslipidaemia, and visceral obesity were more common in patients with OSA
Coughlin et al. [35]	61 OSA patients, 43 controls; 100% men	Not given	SDB:; PSG	(i) Patients with OSA had a greater waist circumference and higher systolic and diastolic blood pressure, were more insulin-resistant (assessed with HOMA), and had lower HDL and a higher prevalence of MS; (ii) Patients with OSA were 9.1 times more likely to have MS

DM2: diabetes mellitus type 2; AHI: apnea-hypopnea index; PSG: polysomnography; OSA: obstructive sleep apnea; MS: metabolic syndrome; BP: blood pressure; BMI: body mass index; IDF: International Diabetes Federation; HDL: high-density lipoprotein; HOMA: Homeostasis Model Assessment; CPAP: continuous positive airway pressure.