Table 1.

Demographics of investigated groups

	Subjects that underwent polysomnography
Parameter	OSAS group, n = 27	Severe OSAS subgroup, n = 11	CPAP-OSAS group, n= 22	Controls, n = 11
Male/Female	25/2	10/1	17/5	9/3
Smokers	15	0	15	6
Age [yrs]	53 ± 13	55 ± 15	58 ± 8	50 ± 10
BMI [kg/m2]	31.1 ± 5.1	32.1 ± 6.5	34.3 ± 7.3	28.8 ± 5.5
NC [cm]	42.6 ± 2.6	43.7 ± 2.9	43.7 ± 4.1	41.5 ± 2.0
ESS	11 ± 1	11 ± 5	15 ± 1*	9 ± 1
TST [h]	4.8 ± 1.2	4.7 ± 1.3	5.2 ± 1.6	5.3 ± 1.0
AHI [n/h]	31 ± 5	58 ± 18 †	9 ± 2*	2 ± 1*
ODI [n/h]	31 ± 5	55 ± 19 †	9 ± 3*	2 ± 1*
Mean SaO2 [%]	87 ± 1	84 ± 5 †	89 ± 1	91 ± 1*
Min SaO2 [%]	74 ± 3	68 ± 15 †	81 ± 2	88 ± 1*
TSaO2<88% [min]	55 ± 12	99 ± 74 †	12 ± 4*	2 ± 1*
Snoring [%TST]	29 ± 24	28 ± 24	10 ± 14*	20 ± 25

OSAS – patients with untreated OSAS; Severe OSAS – patients with AHI ≥ 30; CPAP-OSAS – patients with OSAS treated successfully at a first attempt with CPAP, controls – subjects without OSAS; BMI – body mass index; NC – neck circumference; ESS – Epworth sleepiness score; TST – total sleep time; AHI (apnea/hypopnea index) – the number of apneas and hypopneas per hour of sleep; ODI (oxygen desaturation index) – the number of desaturations ≥ 4% per hour of sleep; SaO₂-nocturnal oxygen saturation; T_SaO2 – duration of nocturnal oxygen saturation < 88%. Polysomnography data expressed as a mean ± SD. The daily cigarette consumption was 19 ± 12, 21 ± 13, and 17 ± 6 for current cigarette smokers in OSAS, CPAP-OSAS and control groups respectively. Blood for chemiluminescence measurement and other determinations was taken before and after polysomnographic controlled sleep.

* – p < 0.05 vs. OSAS group, † – p < 0.05 vs. CPAP-OSAS and controls groups.

Selected baseline characteristics of CPAP-OSAS patients before treatment initiation were: AHI 58 ± 29; ODI 56 ± 26; mean SaO₂ 82 ± 7 %, min SaO₂ 75 ± 9 %, and T_SaO2 < 88% 105 ± 90 min. of 5.2 ± 1.7 h TST.