Prevalence and Predictors of Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease Undergoing Inpatient Pulmonary Rehabilitation

Figures & data

Figure 1. Flow chart of the study. COPD: chronic obstructive pulmonary disease; AECOPD: acute exacerbations of chronic obstructive pulmonary disease; AHI: apnea-hypopnea index; CPAP: continuous positive airway pressure, NIV: noninvasive ventilation.

Table 1. Demographic, anthropometric, physiological, clinical characteristics of patients.

	OSA	Non-OSA
Variable	AHI≥ 15 ev/h (n = 190)	AHI <15 ev/h (n = 232)	p value
Antropometric/clinical
Age (years)	69 ± 9	72 ± 8	.0001
Males (n, %)	144 (76%)	166 (72%)	.3
BMI (Kg/m^2)	31 ± 7	26 ± 5	.0001
ESS	6.2 ± 4.4	4.1 ± 3.1	.0001
LTOT (n, %)	22 (11%)	54 (23%)	.0001
Comorbidities
Cardiovascular comorbidities (n, %)	56 (29%)	65 (28%)	.8
Arythmias (n, %)	23 (12%)	23 (10%)	.46
Frequent exacerbators (n, %)	66 (35%)	123 (65%)	.0001
Arterial blood gases
PaO2 (mmHg)	66.1 ± 9.2	66.4 ± 10.2	.59
PaCO2 (mmHg)	41.2 ± 7.1	41.7 ± 7.2	.38
Functional tests
FEV1/FVC (%)	53.1 ± 11.1	43.3 ± 12.2	.0001
FEV1 (L)	1.5 ± 0.6	1.1 ± 0.4	.0001
FEV1 (%pred)	58.3 ± 21.2	44.2 ± 18.1	.0001
TLC (L)	5.2 ± 1.2	5.1 ± 1.4	.44
TLC (%pred)	83.1 ± 18.2	85.3 ± 20.1	.21
PSG
SpO2 mean (%)	90.7 ± 4.3	92.6 ± 3.1	.0001
ODI (ev/h)	33.4 ± 21.2	6.7 ± 10.1	.0001
T90 (%)	29.4 ± 34.8	16.3 ± 26.4	.0001

PaO₂: arterial oxygen tension; PaCO₂: arterial carbon dioxide tension; FEV1: forced expiratory volume at 1 second; FVC: forced vital capacity; TLC = total lung capacity, SpO₂=pulse oximetry oxygen saturation; T90 = percentage of sleep time with SpO₂ <90%.

Table 2. Baseline characteristics of patients discharged with CPAP or NIV.

Variable	CPAP (n  =  29)	NIV (n  =  9)	p value
Antropometric/clinical
Age (years)	68 ± 8	71 ± 7	.17
BMI (kg/m^2)	33 ± 8	28 ± 8	.007
ESS	6.9 ± 4.3	6.1 ± 4.8	.43
Arterial blood gases
PaO2 (mmHg)	66.7 ± 9.7	63.8 ± 10.5	.16
PaCO2 (mmHg)	40.3 ± 6.1	52.5 ± 8.7	.0001
Functional tests
FEV1/FVC (%)	55.1 ± 10.2	44.2 ± 13.6	.0004
FEV1 (L)	1.6 ± 0.6	0.9 ± 0.5	.0001
FEV1 (%pred)	63.1 ± 19.3	33.2 ± 15.1	.0001
PSG
AHI (ev/h)	42.1 ± 20.2	24.2 ± 25.2	.0017
Mean SpO2 (%)	90.7 ± 4.1	89.5 ± 6.1	.31
ODI (ev/h)	36.4 ± 21.1	22.2 ± 25.3	.0017
T90 (%)	32.2 ± 35.3	34.1 ± 36.2	.68

PaO₂ = arterial oxygen tension; PaCO₂ = arterial carbon dioxide tension; FEV₁ = forced expiratory volume at 1 second, FVC  =  forced vital capacity; SpO₂ = pulse oximetry oxygen saturation; T90  =  percentage of sleep time with SpO₂ <90%.