. 2021 Nov 4;13:1967–1984. doi: 10.2147/NSS.S331389

Table 2.

Baseline and Follow-Up Characteristics of Subjects with Different Baseline OSA Status and Subtypes (N = 234)

Characteristics	Normal (OAHI<1/h) N = 95	PS N= 47	OSA (OAHI ≥1/h) N = 92			P value^e
Characteristics	Normal (OAHI<1/h) N = 95	PS N= 47	REM-OSA N = 58	Non REM-OSA N = 34	P value^d	P value^e
Male sex, n (%)	49 (51.6)	27 (57.4)	42 (72.4)	22 (64.7)	0.438	0.073
Follow-up length, years	10.4 ± 1.0	10.7 ± 0.9	10.3 ± 1.1	10.2 ± 1.2	0.580	0.123
Age, years
Baseline	9.9 ± 1.8	9.3 ± 1.8	10.0 ± 1.9	9.6 ± 1.7	0.241	0.139
Follow-up	20.3 ± 2.0	20.0 ± 1.9	20.4 ± 2.0	19.8 ± 1.9	0.167	0.419
BMI z score, median (IQR)
Baseline	0.30 (−0.30–1.04)	0.52 (−0.21–1.16)	0.71 (−0.11–1.55)	0.77 (0.12–1.57)	0.713	0.067
Follow-up	0.33 (−0.92–1.00)	0.20 (−0.31–0.88)	0.47 (−0.32–0.93)	0.27 (−0.01–1.17)	0.783	0.557
Overweight/obese, n (%)
Baseline	24 (25.3)	13 (27.7)	21 (36.2)	14 (41.2)	0.636	0.251
Follow-up	31 (32.6)	14 (29.8)	19 (32.8)	12 (35.3)	0.804	0.964
Tonsils ≥ grade 2, n (%)
Baseline	33 (34.7)	23 (48.9)	28 (48.3)	22 (64.7)	0.148	0.030
Follow-up	11 (11.6)	9 (19.1)	12 (20.7)	4 (11.8)	0.276	0.353
Adenoid ≥ grade 2, n (%)
Baseline	29 (30.5)	14 (29.8)	19 (32.8)	14 (41.2)	0.489	0.751
Follow-up	NA	NA	NA	NA
Allergic rhinitis, n (%)
Baseline	82 (86.3)	42 (89.4)	52 (89.7)	29 (85.3)	0.534	0.194
Follow-up	67 (70.5)	31 (66.0)	45 (77.6)	25 (73.5)	0.354	0.573
Habitual snoring^&, n (%)
Baseline	0 (0)	47 (100)	19 (32.8)	11 (32.4)	0.968	<0.001
Follow-up	12 (12.6)	16 (34.0)	16 (27.6)	7 (20.6)	0.454	0.019
Mouth breathing^&, n (%)
Baseline	26 (27.4)	20 (42.6)	19 (32.8)	6 (17.6)	0.116	0.091
Follow-up	16 (16.8)	17 (36.2)	21 (36.2)	6 (17.6)	0.052	0.010
ESS score
Baseline	6.0 ± 4.1	7.1 ± 3.8	6.3 ± 4.3	7.0 ± 4.1	0.409	0.399
Follow-up	7.1 ± 4.1	7.7 ± 3.9	7.5 ± 4.3	6.7 ± 4.8	0.413	0.672
REM sleep duration, minutes
Baseline	105.8 ± 26.4	103.5 ± 24.2	106.1 ± 21.9	96.0 ± 24.8	0.045	0.214
Follow-up	120.2 ± 32.7	114.5 ± 33.9	111.5 ± 35.4	104.6 ± 38.7	0.389	0.126
NREM sleep duration, minutes
Baseline	377.9 ± 38.1	374.3 ± 37.5	387.8 ± 29.5	378.4 ± 42.3	0.211	0.251
Follow-up	380.2 ± 50.1	383.8 ± 59.9	377.9 ± 35.4	377.8 ± 65.4	0.989	0.953
OAHI, events/h, median (IQR)
Baseline	0.12 (0.00–0.39)^a	0.22 (0.00–0.50)^a	2.41 (1.38–4.57)^b	2.01 (1.14–3.82)^b	0.261	<0.001
Follow-up	0.60 (0.00–3.80)^a	1.40 (0.47–5.30)^b	2.05 (0.33–7.42)^b	1.80 (0.48–5.85)^b	0.624	0.013
OAHI_REM, events/h, median (IQR)
Baseline	0.00 (0.00–0.69)^a	0.00 (0.00–1.09)^a	7.85 (5.38–14.15)^b	1.07 (0.35–2.90)^c	<0.001	<0.001
Follow-up	1.28 (0.00–6.00)^a	3.08 (0.59–10.75)^a	8.12 (1.40–24.84)^b	3.36 (0.00–14.11)^a,b	0.089	0.003
OAHI_NREM, events/h, median (IQR)
Baseline	0.00 (0.00–0.29)^a	0.00 (0.00–0.30)^a	0.64 (0.40–1.65)^b	2.12 (1.34–3.55)^c	<0.001	<0.001
Follow-up	0.52 (0.13–2.10)^a	0.84 (0.25–3.14)^a	1.51 (0.48–4.21)^b	1.85 (0.57–3.94)^b	0.993	0.014
ODI, events/h, median (IQR)
Baseline	0.12 (0.00–0.29)^a	0.13 (0.00–0.45)^a	0.53 (0.20–1.50)^b	0.86 (0.48–1.42)^b	0.151	<0.001
Follow-up	1.26 (0.30–3.80)^a	0.86 (0.20–3.63)^a	2.16 (0.85–5.28)^b	2.70 (0.82–9.30)^b	0.411	0.022
ArI, events/h, median (IQR)
Baseline	5.63 (4.51–7.66)^a	6.08 (4.76–7.82)^a	7.08 (5.58–8.63)^b	8.24 (6.32–10.71)^b	0.054	<0.001
Follow-up	11.59 (8.99–15.64)	12.17 (9.25–15.99)	12.20 (9.58–16.53)	13.02 (10.06–16.45)	0.824	0.654
SpO2 nadir, %
Baseline	92.9 ± 2.6^a	93.1 ± 1.7^a	91.3 ± 2.8^b	90.4 ± 2.6^b	0.133	<0.001
Follow-up	92.6 ± 2.7	93.1 ± 3.4	91.6 ± 3.3	91.7 ± 2.5	0.845	0.051
SpO2 nadir in REM, %
Baseline	93.6 ± 2.6^a	93.8 ± 1.5^a	91.5 ± 2.8^b	91.9 ± 2.1^b	0.412	<0.001
Follow-up	93.4 ± 2.8	93.8 ± 3.6	92.4 ± 3.2	93.1 ± 2.6	0.276	0.080
SpO2 nadir in NREM, %
Baseline	93.8 ± 1.9^a	93.7 ± 1.9^a,b	92.8 ± 1.9^b	90.8 ± 2.7^c	<0.001	<0.001
Follow-up	93.3 ± 2.2^a	93.7 ± 1.9^a	92.8 ± 2.6^a,b	92.1 ± 2.3^b	0.198	0.011
Daytime SBP, mmHg
Baseline*	111.5 ± 9.6	112.0 ± 7.8	112.8 ± 8.8	114.1 ± 6.5	0.533	0.635
Follow-up	114.4 ± 9.5	115.0 ± 10.2	116.2 ± 9.6	117.4 ± 9.3	0.553	0.415
Daytime DBP, mmHg
Baseline*	71.1 ± 5.6	72.9 ± 5.7	71.7 ± 5.5	73.4 ± 5.1	0.245	0.259
Follow-up	72.4 ± 6.0	73.3 ± 6.6	72.6 ± 6.3	73.0 ± 6.3	0.780	0.876
Nighttime SBP, mmHg
Baseline*	99.4 ± 10.3	97.8 ± 6.3	103.1 ± 9.3	100.7 ± 7.3	0.293	0.089
Follow-up	102.7 ± 8.7	103.8 ± 8.9	105.2 ± 10.0	104.8 ± 8.3	0.865	0.366
Nighttime DBP, mmHg
Baseline*	59.1 ± 6.2	58.2 ± 4.8	59.9 ± 6.2	59.4 ± 5.3	0.760	0.698
Follow-up	61.9 ± 6.1	62.9 ± 6.7	62.1 ± 7.1	62.0 ± 5.0	0.914	0.815
Nocturnal SBP dipping,%
Baseline*	10.8 ± 5.0^a	12.5 ± 5.0^a	8.4 ± 6.5^b	11.7 ± 5.1^a	0.046	0.016
Follow-up	10.1 ± 4.9	9.6 ± 6.1	9.2 ± 6.1	10.6 ± 4.8	0.267	0.627
Nocturnal DBP dipping,%
Baseline*	16.8 ± 6.6	19.8 ± 7.4	16.4 ± 6.5	19.0 ± 5.1	0.114	0.087
Follow-up	14.5 ± 6.4	14.0 ± 7.1	14.4 ± 7.3	14.8 ± 6.1	0.799	0.954
Any hypertension
Baseline*	14 (20.9)	3 (10.3)	10 (26.3)	5 (21.7)	0.687	0.447
Follow-up	11 (11.6)	10 (21.3)	12 (20.7)	5 (14.7)	0.452	0.347

Notes: Data presented as mean ± standard deviation unless otherwise specified. P value^d represents the comparisons between REM-OSA and non REM-OSA. P value^e represents the comparisons among all groups by one-way ANOVA, Kruskal–Wallis 1-way ANOVA and Chi-Square for parametric, non-parametric and categorical variables respectively. ^a,b,c Cells in each row with different superscripts represent statistically significant differences in group means or medians (p<0.05). *Data were available from 67 normal, 29 PS, 38 REM-OSA and 23 non REM-OSA subjects. ^&Habitual snoring and mouth-breathing ≥ 3 nights per week.

Abbreviations: OSA, obstructive sleep apnea; PS, primary snoring; h, hour; OAHI, obstructive apnea–hypopnea index; REM, rapid-eye-movement; NREM, non-rapid-eye-movement; BMI, body mass index; ESS, Epworth Sleepiness Scale; ODI, oxygen desaturation index; ArI, arousal index; SpO2, oxygen saturation; OAHI_REM, OAHI in REM sleep; OAHI_NREM, OAHI in NREM sleep; DBP, diastolic blood pressure; SBP, systolic blood pressure.