Table 2.

Univariate Correlation between Clinical Parameters, OSAS Severity Indices, and MSNA.

	apnea/hypopnea												hypoxia						MSNA
	apnea index			hypopnea index			apnea- hypopnea index			arousal index			3% oxygen desaturation index			% SpO2<90%			burst rate			burst incidence
	(events/hour)			(events/hour)			(events/hour)			(events/hour)			(events/hour)			(% of total sleep time)			(bursts/minute)			(bursts/100 heartbeats)
	r	p		r	p		r	p		r	p		r	p		r	p		r	p		r	p
age (year)	-0.193	0.098		0.011	0.925		-0.246	0.032		-0.066	0.572		-0.128	0.279		-0.305	0.008		0.037	0.785		0.244	0.065
body weight (kg)	0.397	0.001		-0.122	0.345		0.402	0.001		0.105	0.422		0.345	0.007		0.560	<0.001		0.121	0.403		-0.077	0.596
BMI (kg/m2)	0.436	<0.001		0.007	0.955		0.510	<0.001		-0.001	0.993		0.439	<0.001		0.653	<0.001		0.150	0.297		-0.028	0.849
waist circumference (cm)	0.450	<0.001		-0.018	0.890		0.514	<0.001		0.051	0.699		0.465	<0.001		0.610	<0.001		0.208	0.146		0.019	0.895
fat mass (kg)	0.445	<0.001		-0.001	0.995		0.516	<0.001		0.054	0.677		0.458	<0.001		0.600	<0.001		0.212	0.139		0.023	0.873
fat-free mass (kg)	0.320	0.011		-0.227	0.076		0.262	0.039		0.101	0.439		0.194	0.138		0.334	0.009		0.027	0.855		-0.154	0.286
apnea index (events/hour)				-0.468	<0.001		0.881	<0.001		0.050	0.672		0.852	<0.001		0.712	<0.001		0.294	0.025		0.239	0.071
hypopnea index (events/hour)	-0.468	<0.001					0.004	0.970		-0.007	0.954		-0.053	0.657		-0.142	0.227		0.182	0.170		0.089	0.504
apnea-hypopnea index (events/hour)	0.881	<0.001		0.004	0.970					0.053	0.653		0.919	<0.001		0.713	<0.001		0.419	0.001		0.310	0.018
arousal index (events/hour)	0.676	<0.001		-0.011	0.928		0.758	<0.001					0.708	<0.001		0.608	<0.001		0.333	0.011		0.172	0.201
3% oxygen desaturation index (events/hour)	0.852	<0.001		-0.053	0.657		0.919	<0.001		0.044	0.711					0.731	<0.001		0.460	<0.001		0.392	0.003
% SpO2<90% (% of total sleep time)	0.712	<0.001		-0.142	0.227		0.713	<0.001		-0.068	0.566		0.731	<0.001					0.380	0.004		0.261	0.050
burst rate (burstsr/minute)	0.294	0.025		0.182	0.170		0.419	0.001		-0.177	0.187		0.460	<0.001		0.380	0.004					0.789	<0.001
burst incidence (bursts/100 heartbeats)	0.239	0.071		0.089	0.504		0.310	0.018		-0.169	0.210		0.392	0.003		0.261	0.050		0.789	<0.001
systolic blood pressure (mmHg)	0.072	0.544		-0.014	0.909		0.074	0.533		-0.213	0.072		0.081	0.500		0.083	0.490		0.077	0.571		0.103	0.445
diastolic blood pressure (mmHg)	-0.071	0.552		0.095	0.425		-0.030	0.801		-0.264	0.025		-0.013	0.916		0.108	0.366		0.211	0.114		0.040	0.766
heart rate (beats/minute)	0.218	0.100		0.116	0.386		0.301	0.022		-0.045	0.741		0.251	0.062		0.292	0.027		0.633	<0.001		0.052	0.701
fasting plasma glucose (mg/dL)	-0.024	0.850		0.413	0.001		0.224	0.078		-0.178	0.166		0.122	0.348		0.146	0.256		0.246	0.100		0.188	0.211
HbA1c (%)	0.028	0.814		0.010	0.933		0.139	0.233		-0.014	0.910		-0.022	0.855		-0.103	0.384		0.020	0.886		0.005	0.970
HOMA-beta	0.016	0.892		-0.067	0.566		-0.015	0.898		0.002	0.990		0.041	0.728		0.375	0.001		0.253	0.105		0.117	0.461
insulinogenic index	0.088	0.517		0.195	0.150		0.197	0.146		0.023	0.866		0.163	0.234		0.340	0.010		0.168	0.292		0.063	0.697
HOMA-IR	0.048	0.725		0.143	0.289		0.125	0.356		-0.141	0.300		0.129	0.344		0.404	0.002		0.271	0.083		0.159	0.313
QUICKI	0.018	0.893		-0.050	0.712		-0.004	0.978		0.053	0.700		-0.008	0.952		-0.255	0.056		-0.095	0.551		-0.031	0.846
Matsuda index	0.304	0.023		-0.230	0.088		0.234	0.083		0.209	0.122		0.277	0.041		0.017	0.898		-0.177	0.268		-0.016	0.922
hepatic insulin resistance index	0.110	0.421		0.121	0.375		0.185	0.173		0.021	0.878		0.152	0.267		0.392	0.003		0.339	0.030		0.172	0.282

OSAS: obstructive sleep apnea syndrome, MSNA: muscle sympathetic nerve activity, HOMA-beta: homeostatic model assessment beta cell function, HOMA-IR: homeostasis model assessment of insulin resistance, QUICKI: quantitative insulin sensitivity check index