Sex differences in serious outcomes among critically ill adults following endotracheal intubation

Table 1 Emergency department intubation characteristics between males and females, n (%)/median (interquartile range)

Characteristics	Total 1021	Sex distribution		OR (95%CI)	P value
		Female 387	Male 634
Age (years), mean ± SD	52.2 ± 17.5	52.2 ± 17.8	52.1 ± 17.3		0.986
Age groups
< 45 years	336 (32.9)	126 (32.6)	210 (33.1)	1.026 (0.784-1.343)	0.852
≥ 45 years	685 (67.1)	261 (67.4)	424 (66.9)
Shifts
Night (10 PM-08 AM)	427 (41.8)	181 (46.8)	246 (38.8)	0.722 (0.559-0.943)	0.012
Morning to evening (08 AM-10 PM)	594 (58.2)	206 (53.2)	388 (61.2)
Pre intubation vitals
Systolic blood pressure (mmHg)	130 (153-110)	128 (150-110)	130 (155-110)		0.311
Diastolic blood pressure (mmHg)	77 (90-62)	75 (89-60)	78 (90-63)		0.133
Heart rate	106 (122-88)	108 (126-90)	106 (120-86)		0.260
Oxygen saturations (%)	94 (98-81)	95 (98-81)	94 (98-80)		0.614
Respiratory rate	25 (32-20)	25 (32-20)	25 (32-20)		0.692
Reasons for intubation
Coma	39 (3.8)	12 (3.1)	27 (4.3)	0.719 (0.360-1.437)	0.349
Hypoxia	119 (11.7)	47 (12.1)	72 (11.4)	1.075 (0.727-1.590)	0.703
Metabolic acidosis	136 (13.3)	52 (13.4)	84 (13.2)	1.016 (0.701-1.474)	0.932
Anticipated decline	147 (14.4)	55 (14.2)	92 (14.5)	0.979 (0.682-1.404)	0.895
Respiratory distress	395 (38.8)	171 (44.2)	224 (35.4)	1.442 (1.114-1.867)	0.005
Polytrauma	24 (2.4)	4 (1)	20 (3.2)	0.320 (0.109-0.944)	0.03
Isolated trauma (trauma to one body region, not gunshot wound)	32 (3.1)	5 (1.3)	27 (4.3)	0.294 (0.112-0.771)	0.008
Gunshot injury	10 (1)	3 (0.8)	7 (1.1)	0.700 (0.180-2.722)	0.605
Others	29 (2.8)	11 (2.8)	18 (2.8)	1.004 (0.469-2.149)	0.998
Shock index
< 0.9	587 (57.5)	196 (50.6)	391 (61.7)	1.568 (1.214-2.025)	< 0.001
≥ 0.9	434 (42.5)	191 (49.4)	243 (38.3)
pH
≥ 7.3	444 (43.5)	220 (32.8)	224 (63.8)	1.298 (1.004-1.677)	< 0.001
< 7.3	577 (56.5)	450 (67.2)	127 (36.2)
HEAVEN criteria
Hypoxemia	414 (40.5)	158 (40.8)	256 (40.4)	1.019 (0.788-1.318)	0.887
Extremes of size	22 (2.2)	8 (2.1)	14 (2.2)	0.935 (0.389-2.249)	0.880
Anatomic abnormalities	35 (3.4)	0 (0)	35 (5.5)	0.095 (0.023-0.397)	< 0.001
Aspiration (vomit/blood/fluid)	219 (21.4)	119 (30.7)	100 (15.8)	2.371 (1.750-3.212)	< 0.001
Exsanguination	60 (5.9)	14 (3.6)	46 (7.3)	0.480 (0.260-0.885)	0.016
Neck mobility issues	17 (1.7)	7 (1.8)	10 (1.6)	1.149 (0.434-3.045)	0.779

OR: Odds ratio; CI: Confidence interval; AM: Ante meridiem; PM: Post meridiem.

Table 2 Sex differences in outcome of patients requiring endotracheal intubation, n (%)

Characteristics	Total 1021	Sex distribution		OR (95%CI)	P value
		Female 387	Male 634
Cardiac arrest	195 (19.1)	77 (19.9)	118 (18.6)	1.086 (0.789-1.496)	0.612
Post intubation hypotension (SBP < 100 mmHg)	379 (37.1)	154 (39.8)	225 (35.5)	1.201 (0.925-1.559)	0.167
Desaturation (< 92%)	131 (12.8)	46 (11.9)	85 (13.4)	0.871 (0.594-1.278)	0.481
Death in emergency (within 1 hour after intubation)	7 (0.7)	3 (0.8)	4 (0.6)	1.232 (0.274-5.533)	0.786
Death in hospital	398 (39.1)	135 (35)	263 (41.5)	0.756 (0.682-0.982)	0.036
Discharge	492 (48.3)	198 (51.3)	294 (46.4)	1.21 (0.941-1.561)	0.137
Serious outcomes	702 (68.8)	271 (70)	431 (68)	1.10 (0.837-1.447)	0.494

OR: Odds ratio; CI: Confidence interval; SBP: Systolic blood pressure.

Table 3 Univariate and multivariate logistic regression analysis for predicting serious outcomes among males following endotracheal intubation

Parameters	Univariate		Multivariate-initial level		Multivariate-final level
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
Age ≥ 45 years	2.06 (1.46-2.92)	< 0.001	1.82 (1.14-2.91)	0.012	1.8 (1.15-2.8)	0.009
Shift duty (morning-evening)	1.68 (1.2-2.36)	0.003	1.49 (0.97-2.29)	0.071	1.52 (1.12-2.33)	0.048
Altered mental status	1.07 (0.75-1.52)	0.704
Coma (GCS ≤ 6)	1.26 (0.57-2.81)	0.569
Fever	2.06 (1.29-3.29)	0.003	1.21 (0.68-2.18)	0.515
Drowsiness (< 15)	2.78 (1.86-4.18)	< 0.001	1.74 (1.03-2.94)	0.037	1.72 (1.05-2.81)	0.03
Shortness of breath	1.55 (1.1-2.18)	0.013	1.07 (0.64-1.77)	0.801
Seizures	0.46 (0.25-0.85)	0.014	0.97 (0.43-2.18)	0.941
Vomiting/blood/fluid	1.7 (1.03-2.8)	0.037	1.06 (0.55-2.03)	0.865	1.65 (1.07-2.56)	0.024
Hypoxia	4.35 (2.42-7.81)	< 0.001	3.78 (1.88-7.6)	< 0.001	3.96 (1.97-7.92)	< 0.001
Metabolic acidosis	2.19 (1.24-3.88)	0.007	1.48 (0.74-2.95)	0.268
Anticipated decline	1.97 (1.16-3.37)	0.013	2.09 (1.07-4.08)	0.031	2.05 (1.05-3.99)	0.034
Respiratory distress	1.51 (1.05-2.16)	0.025	1.29 (0.8-2.09)	0.294
Polytrauma	0.7 (0.28-1.73)	0.433
Isolated trauma	0.57 (0.26-1.25)	0.162
Gunshot	0.45 (0.13-1.57)	0.210
Shock index ≥ 0.9	3.18 (2.37-4.27)	< 0.001	2.81 (1.72-4.58)	< 0.001	2.81 (1.74-4.55)	< 0.001
pH group ≤ 7.3	1.92 (1.47-2.509)	< 0.001	2.52 (1.62-3.9)	< 0.001	2.55 (1.65-3.93)	< 0.001

OR: Odds ratio; CI: Confidence interval; GCS: Glasgow Coma Scale.

Table 4 Univariate and multivariate logistic regression analysis for predicting serious outcomes among females following endotracheal intubation

Parameters	Univariate		Multivariate
	OR (95%CI)	P value	OR (95%CI)	P value
Age ≥ 45 years	1.2 (0.76-1.89)	0.444
Shift duty (morning-evening)	1.33 (0.86-2.05)	0.202
Altered mental status	1.08 (0.7-1.68)	0.726
Coma	0.42 (0.13-1.32)	0.135
Fever	1.37 (0.78-2.39)	0.277
Drowsiness	1.39 (0.88-2.19)	0.155
Shortness of breath	1.55 (1.1-2.18)	0.013	0.73 (0.44-1.21)	0.225
Seizures	0.48 (0.21-1.11)	0.086
Vomiting/blood/fluid	2.38 (1.41-4.03)	0.001
Trauma	1.15 (0.3-4.4)	0.843
Hypoxia	6.63 (2.79-15.75)	< 0.001	3.78 (1.88-7.6)	< 0.001
Metabolic acidosis	1.5 (0.76-2.98)	0.246
Anticipated decline	0.94 (0.51-1.75)	0.845
Respiratory distress	1.99 (1.22-3.23)	0.006	2.01 (1.09-3.69)	0.024
Polytrauma	0.42 (0.06-3.05)	0.394
Isolated trauma	0.64 (0.11-3.87)	0.625
Gun shot injury	0.86 (0.08-9.52)	0.899
Shock index ≥ 0.9	2.97 (1.87-4.71)	< 0.001	3.24 (1.87-5.61)	< 0.001
pH group ≤ 7.3	1.64 (1.05-2.55)	0.029	2.17 (1.25-3.75)	0.006

OR: Odds ratio; CI: Confidence interval.

Table 5 Adjustment of sex differences in outcome of patients requiring endotracheal intubation through propensity score

Outcome	Total	Sex distribution		P value
		Male	Female
Total	774	387	387	-
Outcome
Cardiac arrest	147 (19)	70 (18.1)	77 (19.9)	0.009
Hypotension (SBP < 100 mmHg)	304 (39.3)	150 (38.8)	154 (39.8)	< 0.001
Oxygen saturation (> 92%)	92 (11.9)	46 (11.9)	46 (11.9)	0.012
Death in emergency	7 (0.9)	4 (1)	3 (0.8)	0.292
Death in hospital	271 (35)	136 (35.1)	135 (34.9)	< 0.001
Discharge	396 (51.2)	198 (51.2)	198 (51.2)	< 0.001
Serious outcome	532 (68.7)	261 (67.4)	271 (70)	< 0.001

SBP: Systolic blood pressure.