Continuous respiratory monitoring for sleep apnea screening by ambulatory hemodynamic monitor

Table 1 Demographics and clinical characteristics (mean ± SD)

Parameter	All (n = 85)	Negative SDB	Positive SDB
		(AHI < 5, n = 28)	(AHI≥5, n = 57)
Age (yr)	50.5 ± 12.4	47.2 ± 12.3	52.1 ± 12.2
Sex (% male)	83.50%	78.60%	91.60%
Weight (kg)	88.1 ± 18.9	82.1 ± 17.1	91.1 ± 19.2a
BMI (kg/m2)	28.9 ± 5.5	26.9 ± 4.8	29.9 ± 5.6a
History of hypertension (%)	34%	39%	21%
History of MI (%)	6%	11%	2%
History of CAD (%)	9%	18%	3%
AHI (events/h)	20.6 ± 27.8	1.5 ± 1.2	30.0 ± 29.8a
Obstructive apnea (n)	34.8 ± 89.3	0.9 ± 1.8	51.5 ± 105.3a
Central apnea (n)	5.7 ± 22.3	1.6 ± 4.8	7.7 ± 26.9a
Mean % SaO2 (%)	93.1 ± 2.7	93.9 ± 2.5	92.7 ± 2.7a
Oxygen desaturation index	12.5 ± 19.6	1.1 ± 1.2	17.5 ± 21.8a
Desaturation > 4% (n)	70.1 ± 120.3	6.2 ± 7.0	98.4 ± 135.7a
Apnea arousal (n)	31.6 ± 79.3	1.8 ± 4.9	46.2 ± 93.6a
Total arousals (n)	200.0 ± 137.8	166.1 ± 74.3	216.6 ± 158.0a
Awakening > 1 min (n)	17.4 ± 32.7	11.0 ± 17.2	20.6 ± 37.9
SDBSS	9.3 ± 15.3	1.4 ± 3.7	13.2 ± 17.2a

^aP < 0.05 vs negative SDB; AHI: Apnea/hypopnea index; MI: Myocardial infarction; CAD: Coronary artery disease; SDB: Sleep-disordered breathing; SDBSS: Sleep-disordered breathing severity score; BMI: Body mass index.

Table 2 Per minute sleep-disordered breathing results

		Expert
		Negative	Positive
Algorithm	Negative	9782	413
	Positive	398	1381

Table 3 Per minute sleep-disordered breathing algorithm performance statistics (%)

	Mean	95% CI
Accuracy	93.2	92.8-93.7
Sensitivity	77.0	75.0-78.9
Specificity	96.1	95.7-96.4
Positive predictive value	77.6	75.7-79.6
Negative predictive value	95.9	95.6-96.3

Table 4 Sleep-disordered breathing severity score performance statistics against apnea/hypopnea index ≥ 5 (%)

	Mean	95% CI
Accuracy	68.2	58.3-78.1
Sensitivity	57.9	45.0-69.8
Specificity	89.3	72.8-96.3
Positive predictive value	91.7	82.6-100
Negative predictive value	51.0	37.0-65.0

Table 5 Sleep-disordered breathing severity score performance statistics against mild, moderate and severe apnea/hypopnea index categories (%)

	Sensitivity	Specificity	Accuracy
	(95% CI)	(95% CI)	(95% CI)
Mild	57.9	89.3	68.2
5 ≤ AHI < 15	(45.0-69.8)	(72.8-96.3)	(58.3-78.1)
Moderate	74.3	86.0	81.2
15 ≤ AHI < 30	(57.9-85.8)	(73.8-93.0)	(72.9-89.5)
Severe	50.0	88.1	80.0
AHI ≥ 30	(29.0-71.0)	(78.2-93.8)	(71.5-88.5)

AHI: Apnea/hypopnea index.