Fat Embolism Syndrome and in-Hospital Mortality Rates According to Patient Age: A Large Nationwide Retrospective Study

Figures & data

Table 1 Demographic and Clinical Variables of the Study Population Stratified by Age Groups

Variable	Subgroup	Overall (n=451)	Age <40 (n=253)	Age 40–64 (n=96)	Age ≥65 (n=102)	p-value
Male (%)		302 (67.0%)	187 (74.2%)	67 (70.5%)	48 (47.1%)	<0.001
Race (%)	White	328 (72.7%)	163 (66.3%)	76 (84.4%)	89 (91.8%)	<0.001
	Black	50 (11.1%)	36 (14.6%)	9 (10.0%)	5 (5.2%)
	Hispanic	36 (8.0%)	32 (13.0%)	4 (4.4%)	0 (0.0%)
	Other	19 (4.2%)	15 (6.1%)	1 (1.1%)	3 (3.1%)
Comorbid Illnesses (%)	Alcoholism	20 (4.4%)	14 (5.5%)	4 (4.2%)	2 (2.0%)	0.33
	Bleeding disorder	30 (6.7%)	13 (5.1%)	4 (4.2%)	13 (12.7%)	0.018
	Cerebrovascular accident	20 (4.4%)	7 (2.8%)	5 (5.2%)	8 (7.8%)	0.10
	Chronic Obstructive Pulmonary DIsease	41 (9.1%)	18 (7.1%)	9 (9.4%)	14 (13.7%)	0.15
	Chronic Renal Failure	5 (1.1%)	0 (0.0%)	4 (4.2%)	1 (1.0%)	0.004
	Liver Cirrhosis	2 (0.4%)	1 (0.4%)	1 (1.0%)	0 (0.0%)	0.54
	Congestive Heart Failure	23 (5.1%)	1 (0.4%)	8 (8.3%)	14 (13.7%)	<0.001
	Smoker	45 (10.0%)	26 (10.3%)	15 (15.6%)	4 (3.9%)	0.022
	Cancer with current chemotherapy	1 (0.2%)	0 (0.0%)	1 (1.0%)	0 (0.0%)	0.16
	Dementia	3 (0.7%)	0 (0.0%)	0 (0.0%)	3 (2.9%)	0.006
	Dependent Status	10 (2.2%)	4 (1.6%)	1 (1.0%)	5 (4.9%)	0.11
	Hypertension	87 (19.3%)	5 (2.0%)	33 (34.4%)	49 (48.0%)	<0.001
	Steroid user	3 (0.7%)	1 (0.4%)	1 (1.0%)	1 (1.0%)	0.73
Insurance (%)		367 (81.4%)	201 (83.4%)	74 (89.2%)	92 (98.9%)	<0.001
Acute Respiratory Distress Syndrome (%)		40 (8.9%)	29 (11.5%)	7 (7.3%)	4 (3.9%)	0.064

Note: % as percentage, bold text are statistically significant p values.

Abbreviation: n, total numbers.

Figure 1 Patient selection and age stratification.

Abbreviations: NTDB, National Trauma Databank; ICD-9, International Classification of Diseases, Ninth Edition.

Table 2 Outcome Variables of the Study Population Stratified by Age Groups

Variable	Overall (n=451)	Age <40 (n=253)	Age 40–64 (n=96)	Age ≥65 (n=102)	p-value
In-hospital mortality (%)	53 (11.8%)	21 (8.3%)	14 (14.6%)	18 (17.6%)	0.029
Hospital discharge non home (%)	309 (68.5%)	180 (71.1%)	57 (59.4%)	72 (70.6%)	0.094
Length of stay (%)	13.2 (0.6)	13.2 (0.7)	15.1 (1.6)	12.1 (0.9)	<0.001
Require ICU stay (%)	344 (76.3%)	203 (80.1%)	79 (82.2%)	62 (61.2%)	<0.001
Require ventilation use (%)	273 (60.6%)	150 (59.2%)	65 (67.9%)	58 (57.1%)	<0.001

Note: % as percentage, bold text are statistically significant p values.

Abbreviation: n, total numbers.

Table 3 Injury Mechanism, Severity, and Type of the Study Population Stratified by Age Groups

Variable	Subgroup	Overall	Age <40	Age 40–64	Age ≥65	p-value
		(n=451)	(n=253)	(n=96)	(n=102)
Mechanism of Injury	Stab	2 (0.4%)	1 (0.4%)	1 (1.1%)	0 (0.0%)	<0.001
	Falls	129 (28.6%)	20 (8.0%)	29 (30.9%)	80 (79.2%)
	GSW	10 (2.2%)	8 (3.2%)	1 (1.1%)	1 (1.0%)
	MVA	246 (54.5%)	180 (71.7%)	48 (51.1%)	18 (17.8%)
	Pedestrian	4 (0.9%)	2 (0.8%)	2 (2.1%)	0 (0.0%)
	Struck-by	15 (3.3%)	12 (4.8%)	3 (3.2%)	0 (0.0%)
	Other	40 (8.9%)	28 (11.2%)	10 (10.6%)	2 (2.0%)
ISS	1 to 8	46 (10.2%)	29 (11.5%)	10 (10.5%)	7 (6.9%)	<0.001
	9 to 15	255 (56.5%)	126 (49.8%)	48 (50.5%)	81 (79.4%)
	16 to 24	84 (18.6%)	57 (22.5%)	19 (20.0%)	8 (7.8%)
	25 to 75	65 (14.4%)	41 (16.2%)	18 (18.9%)	6 (5.9%)
GCS	3	24 (5.3%)	18 (7.5%)	5 (5.8%)	1 (1.2%)	0.058
	4 to 5	5 (1.1%)	5 (2.1%)	0 (0.0%)	0 (0.0%)
	6 to 8	8 (1.8%)	6 (2.5%)	2 (2.3%)	0 (0.0%)
	9 to 12	10 (2.2%)	6 (2.5%)	4 (4.7%)	0 (0.0%)
	13 to 15	364 (80.7%)	205 (85.4%)	75 (87.2%)	84 (98.8%)
Injury type	Blunt	426 (94.5%)	239 (95.2%)	88 (93.6%)	99 (98.0%)	0.19
	Penetrating	12 (2.7%)	9 (3.6%)	2 (2.1%)	1 (1.0%)
	Others	8 (1.8%)	3 (1.2%)	4 (4.3%)	1 (1.0%)

Note: % as percentage, bold text are statistically significant p values.

Abbreviation: n, total numbers.

Table 4 Fracture Location and Numbers Among Fat Embolism Syndrome Patients Stratified by Age Groups in the National Trauma Databank

	Overall (n=451)	Age <40 (n=253)	Age 40–64 (n=96)	Age ≥65 (n=102)	p-value
Spinal Fracture	84 (18.6%)	50 (19.8%)	24 (25.0%)	10 (9.8%)	0.018
Rib Fracture	94 (20.8%)	49 (19.4%)	36 (37.5%)	9 (8.8%)	<0.001
Pelvic Fracture	90 (20.0%)	52 (20.6%)	23 (24.0%)	15 (14.7%)	0.25
Clavicle Fracture	20 (4.4%)	12 (4.7%)	7 (7.3%)	1 (1.0%)	0.092
Scapula Fracture	13 (2.9%)	9 (3.6%)	3 (3.1%)	1 (1.0%)	0.42
Humerus Fracture	32 (7.1%)	17 (6.7%)	8 (8.3%)	7 (6.9%)	0.87
Radioulnar Fracture	61 (13.5%)	39 (15.4%)	16 (16.7%)	6 (5.9%)	0.035
Carpal Bone Fracture	28 (6.2%)	19 (7.5%)	7 (7.3%)	2 (2.0%)	0.13
Hip Fracture (Femoral Neck)	321 (71.2%)	26 (10.3%)	17 (17.7%)	66 (64.7%)	<0.001
Other Femoral Fracture	234 (51.9%)	168 (66.4%)	45 (46.9%)	21 (20.6%)	<0.001
Patella Fracture	26 (5.8%)	19 (7.5%)	5 (5.2%)	2 (2.0%)	0.12
Tibiofibular Fracture	134 (29.7%)	100 (39.5%)	26 (27.1%)	8 (7.8%)	<0.001
Ankle Fracture	39 (8.6%)	26 (10.3%)	9 (9.4%)	4 (3.9%)	0.15
Foot Fracture	35 (7.8%)	24 (9.5%)	10 (10.4%)	1 (1.0%)	0.014
Unspecified	2 (0.4%)	1 (0.4%)	0 (0.0%)	1 (1.0%)	0.57
Fracture site numbers					<0.001
No Fracture	11 (2.4%)	6 (2.4%)	4 (4.2%)	1 (1.0%)
One Fracture site	191 (42.4%)	88 (34.8%)	35 (36.5%)	68 (66.7%)
Two Fracture sites	83 (18.4%)	49 (19.4%)	14 (14.6%)	20 (19.6%)
Three Fracture sites	70 (15.5%)	48 (19.0%)	15 (15.6%)	7 (6.9%)
More than three fracture sites	96 (24.5%)	62 (24.5%)	28 (29.2%)	6 (5.9%)

Note: % as percentage, bold text are statistically significant p values.

Abbreviation: n, total numbers.

Table 5 Odds Ratios for in Hospital Mortality, Hospital Non-Home Discharge, and Coefficients for Length of Stay, ICU Days and Ventilation Days, with Stratified Age Groups as Predictor, Among Fat Embolism Syndrome Patients. Covariates Included Were Sex, Race, Insurance Status, ISS, Mechanism of Injury, Emergency Department GCS Score, Comorbidities, Type of Fracture, Type of Procedure, Hospital Teaching Status and Hospital Bed Count

	Age <40 (n=253); Age 40–64 (n=96); Age ≥65 (n=102)
	Unadjusted OR (95% CI)	p-value	*Adjusted OR (95% CI)	p-value
In Hospital Mortality
<40	Ref		Ref
40–64	1.89 (0.92,3.88)	0.085	7.09 (1.74,28.84)	0.006
>65	2.37 (1.20,4.66)	0.013	24.16 (3.73, 156.59)	0.001
Total Length of Stay
<40	Ref		Ref
40–64	1.94 (−0.94,4.82)	0.186	2.29 (−1.53,6.12)	0.239
>65	−1.05 (−3.87,1.77)	0.463	3.50 (−1.46,8.45)	0.166
Total ICU Length of Days
<40	Ref		Ref
40–64	1.31 (−0.90,3.52)	0.244	1.02 (−1.90,3.93)	0.492
>65	−1.65 (−3.79,0.49)	0.13	0.79 (−2.94,4.54)	0.675
Total Ventilation Days
<40	Ref		Ref
40–64	0.27 (−1.67,2.20)	0.79	−0.25 (−2.88,2.37)	0.85
>65	−1.44 (−3.33,0.45)	0.13	−0.25 (−3.55,3.05)	0.88
Hospital non-home discharge
<40	Ref		Ref
40–64	0.59 (0.36,0.97)	0.036	0.42 (0.19,0.93)	0.032
>65	0.97 (0.59,1.61)	0.917	0.56 (0.20,1.61)	0.283

Notes: *Adjusted by sex, race, insurance status, ISS, mechanism of injury, emergency department GCS score, comorbidities, type of fracture, type of procedure. % as percentage, bold text are statistically significant p values.

Abbreviations: n, total numbers; Ref, reference.

Table 6 Femoral Neck Fractures Compared to Other Femoral Fractures in Patients 65 and Older Who Developed FES

Age ≥65 n=102 (Total)	Femoral Neck Fracture (n=66, 64.7%)	Other Femoral Fracture (n=21, 20.6%)
In Hospital Mortality	12 (18%)	3 (14%)
Total Length of Stay	9.77 (7.94, 11.61)	16.29 (10.50, 22.07)
Total ICU Length of Days	2.97 (1.30, 4.64)	7.2 (3.55, 10.85)
Total Ventilation Days	1.94 (0.35, 3.53)	5.06 (1.53, 8.58)
Hospital non-home Discharge	42 (64%)	16 (76%)

Note: % as percentage.

Abbreviation: n, total numbers.