Clinical Predictors of Mixed Apneas in Patients with Obstructive Sleep Apnea (OSA)

Figures & data

Table 1 Clinical Characteristics of Patients with Pure-OSA and Mixed-OSA

	Pure-OSA (n=344)	Mixed-OSA (n=169)	P value
Age (years)	47.8±12.3	49.2±10.6	0.212
Sex, male/female (male%)	269/75 (78.2)	160/9 (94.7)	< 0.001
BMI	28 (25.9, 30.5)	30 (27.7, 33)	< 0.001
Smoking (n, %)	144 (41.9)	91 (53.8)	< 0.05
Drinking (n, %)	188 (54.7)	104 (61.5)	< 0.001
Diabetes (n, %)	41 (11.9)	18 (10.6)	0.64
Hypertension (n, %)	153 (44.5)	97 (57.4)	< 0.01
Hyperlipidemia (n, %)	92 (26.7)	59 (34.9)	0.10
CHD (n, %)	31 (9)	22 (13)	0.185
CVD (n, %)	25 (7.3)	16 (9.5)	0.465
ESS	7 (4, 12)	14 (9, 18)	< 0.001

Abbreviations: BMI, body mass index; CHD, coronary heart diseases; CVD, cerebrovascular diseases; ESS, Epward sleepiness scale.

Table 2 Sleep Characteristics of OSA Patients with Pure-OSA and Mixed-OSA

	Pure-OSA (n=344)	Mixed-OSA (n=169)	P value
TST (min)	390.8 (335.5, 438.8)	428 (376, 475)	< 0.001
SE (%)	87.8 (78.4, 92.2)	90.3 (87, 93.5)	< 0.001
SLT (min)	6 (3, 13.6)	5 (2.4, 9)	0.001
RSLT (min)	84.3 (67.5, 122.6)	87.5 (65, 123)	0.792
N1%	21 (14.3, 29.5)	41.6 (31, 52)	< 0.001
N2%	43.8±9.7	37.7±10.8	< 0.001
N3%	11.15 (5.2, 16.6)	0 (0, 3.2)	< 0.001
REM%	19.25 (15, 23.6)	18 (14.4, 22)	0.071
ArI	32 (19.7, 53.6)	68.6 (60, 79.3)	< 0.001
AHI	33.6 (15.5, 55.9)	70 (61.2, 81.4)	< 0.001
15>AHI≥5 (n, %)	76 (22.1)	0 (0)	< 0.001
30>AHI≥15 (n, %)	80 (23.3)	1 (0.6)	< 0.001
AHI≥30 (n, %)	188 (54.7)	168 (99.4)	< 0.001
MSO2	94.3 (92.8, 95.3)	91 (87.7, 93.1)	< 0.001
LSO2	82 (75, 87)	67 (59, 74)	< 0.001

Abbreviations: TST, total sleep time; SE, sleep efficiency; SLT, sleep latency; RSLT, REM sleep latency; NREM, non-rapid eye movement sleep; N1, NREM sleep stage 1; N2, NREM sleep stage 2; N3, NREM sleep stage 3; REM, rapid eye movement sleep; ArI, arousal index; AHI, apnea-hypopnea index; MSO₂, mean oxygen saturation; LSO₂, lowest oxygen saturation.

Table 3 Multivariate Logistic Regression Analysis of Factors Associated with Mixed-OSA

	OR	95% CI	P value
Sex (male)	0.263	(0.11, 0.626)	0.003
BMI	1.099	(1.079, 1.164)	0.003
ESS	1.071	(1.027, 1.117)	0.001
AHI	1.046	(1.032, 1.060)	0.000
LSO2	0.958	(0.936, 0.981)	0.000

Abbreviations: BMI, body mass index; ESS, Epworth sleeping scale; AHI, apnea-hypopnea index; LSO₂, lowest oxygen saturation.

Table 4 Cut-off Value of AHI for Predicting Mixed-OSA with Different MAI Criteria

MAI Criteria	Cut-off Value	Sensitivity	Specificity	AUC	P value
MAI > 0	47	0.752	0.652	0.731	< 0.001
MAI ≥ 5	47	0.952	0.652	0.822	< 0.001
MAI > 30% AI	48	0.809	0.438	0.628	< 0.001

Abbreviations: MAI, mixed sleep apnea index; AHI, apnea-hypopnea index; AUC, area under curve.

Table 5 Cut-off Value of LSO₂ for Predicting Mixed-OSA with Different MAI Criteria

MAI Criteria	Cut-off Value	Sensitivity	Specificity	AUC	P value
MAI > 0	77	0.652	0.675	0.696	< 0.001
MAI ≥ 5	77	0.822	0.675	0.792	< 0.001
MAI > 30% AI	73	0.642	0.643	0.636	< 0.001

Abbreviations: MAI, mixed sleep apnea index; LSO₂, lowest oxygen saturation; AUC, area under curve.

Figure 1 ROC curves of the cut-off value for AHI and LSO2 to predict mixed-OSA. (A, C, E) ROC curves of the cut-off values for AHI to predict mixed-OSA with different criteria to define mixed-OSA, which were MAI ≥ 5 (A), MAI > 0 (C), and MAI > 30% AI (E), respectively. (B, D, F) ROC curves of the cut-off values for LSO₂ to predict mixed-OSA with different criteria to define mixed-OSA, which were MAI ≥ 5 (B), MAI > 0 (D), and MAI > 30% AI (F), respectively.