Association Between Obstructive Sleep Apnea and Reduced Mortality in Critically Ill Patients: A Propensity Score-Based Analysis

Figures & data

Table 1 Patient Baseline Demographic and Clinical Characteristics

Characteristic	Without OSA (N= 36,749)	With OSA (N= 1428)	P value
Baseline characteristics
Age(y)	65.82[52.34, 78.11]	63.04[53.54, 71.51]	<0.001
Man, n (%)	20,650(56.19)	959(67.16)	<0.001
Weight(kg)	77.30[65.20, 91.00]	104.00[86.60, 123.70]	<0.001
SAPS II	33.00[24.00, 42.00]	31.00[23.00, 39.00]	<0.001
SOFA score	3.00[2.00, 5.00]	4.00[2.00, 5.50]	0.191
Comorbidities
Hypertension, n (%)	15,875(43.20)	746(53.50)	<0.001
CAD, n (%)	10,385(28.26)	460(32.21)	0.001
COPD, n (%)	712(1.94)	64(4.48)	<0.001
Diabetes mellitus, n (%)	9227(25.11)	634(44.40)	<0.001
CKD, n (%)	4026(10.96)	279(19.54)	<0.001
Laboratory tests
Hemoglobin (g/dL)	10.80[9.50, 12.30]	11.10[9.60,12.70]	<0.001
WBC(K/ul)	10.80[7.90, 14.60]	10.50[7.70, 14.00]	0.031
Platelets(K/ul)	200.00[146.00, 266.00]	208.00[157.00, 269.00]	<0.001
Total bilirubin(mg/dl)	0.70[0.40, 1.40]	0.60[0.40, 1.10]	<0.001
Creatinine(mg/dl)	0.90[0.70, 1.30]	1.00[0.80, 1.40]	<0.001
Lactate (mmol/L)	1.80[1.20, 2.80]	1.60[1.10, 2.40]	<0.001
Clinical outcomes
28-day mortality, n (%)	4614(12.56)	84(5.88)	<0.001
90-day mortality, n (%)	6494(17.67)	127(8.89)	<0.001
ICU mortality, n (%)	2902(7.90)	46(3.22)	<0.001
In-hospital mortality, n (%)	4013(10.92)	71(4.97)	<0.001
Length of ICU stay (day)	2.11[1.20, 4.10]	2.08[1.22, 4.11]	0.694

Note: Continuous variables were expressed as median and interquartile range.

Abbreviations: OSA, obstructive sleep apnea; SAPSII, simplified acute physiology score II; SOFA, sequential organ failure assessment; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; CKD, chronic kidney disease; WBC, white blood cell; ICU, intensive care unit.

Figure 1 Flowchart of patient selection.

Table 2 Propensity Score-Matched Patients with and without OSA

Characteristic	Without OSA(N=402)	With OSA(N=402)	P value
Baseline characteristics
Age(y)	62.75[51.71, 72.36]	62.90[53.22, 70.93]	0.767
Man, n (%)	280(69.65)	273(67.91)	0.594
Weight(kg)	104.00[86.20, 127.30]	108.00[89.90, 127.00]	0.191
SAPS II	37.00[29.00, 47.00]	38.00[29.00, 48.00]	0.449
SOFA score	5.00[3.00, 8.00]	5.00[3.00, 8.00]	0.518
Comorbidities
Hypertension, n (%)	209(51.99)	196(48.76)	0.359
CAD, n (%)	130(32.34)	110(27.36)	0.123
COPD, n (%)	16(3.98)	17(4.23)	0.859
Diabetes mellitus, n (%)	212(52.74)	198(49.25)	0.323
CKD, n (%)	83(20.65)	85(21.14)	0.862
Laboratory tests
Hemoglobin (g/dL)	10.70[9.40, 12.20]	11.00[9.60, 12.60]	0.189
WBC(K/ul)	11.15[7.80, 15.40]	10.95[7.40, 15.60]	0.548
Platelets(K/ul)	203.50[143.00, 265.00]	198.00[148.00, 271.00]	0.520
Total bilirubin(mg/dl)	0.70[0.40, 1.10]	0.60[0.40, 1.20]	0.320
Creatinine(mg/dl)	1.15[0.80, 1.80]	1.10[0.80, 1.70]	0.276
Lactate (mmol/L)	1.60[1.20, 2.60]	1.60[1.10, 2.50]	0.116
Clinical outcomes
28-day mortality, n (%)	82(20.40)	47(11.69)	0.001
90-day mortality, n (%)	117(29.10)	62(15.42)	<0.001
ICU mortality, n (%)	67(16.67)	36(8.96)	0.001
In-hospital mortality, n (%)	80(19.90)	44(10.95)	<0.001
Length of ICU stay (day)	5.23[2.79, 11.10]	4.97[2.45, 10.54]	0.522

Note: Continuous variables were expressed as median and interquartile range.

Abbreviations: OSA, obstructive sleep apnea; SAPSII, simplified acute physiology score II; SOFA, sequential organ failure assessment; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; CKD, chronic kidney disease; WBC, white blood cell; ICU, intensive care unit.

Figure 2 Kaplan-Meier curve (and 95% confidence limits) depicts predicted overall survival between OSA and No OSA groups. (A) 28-day follow up; (B) 90-day follow up.