Differentiating Lower Extremity Necrotizing Soft Tissue Infection from Severe Cellulitis by Laboratory Parameters and Relevant History Points

Figures & data

Table 1 Laboratory Values from NF and Control Group are Compared Using a Mann–Whitney U-Test

Continue Variables	NF Group (n=60)		Control Group (n=60)		P-value
	(Mean±SD)	Range	(Mean±SD)	Range
m-LRINEC score	25.1 ± 9.8	(10–50)	12 ± 6.9	(8–35)	–
Age	49.1 ± 13.2	(23–90)	46.2 ± 13.8	(21–88)	0.17
HCRP (mg/dL)	110.5 ± 76.3	(28–306)	65.8 ± 20.5	(15–104)	0.06
WBC (x10^4 /uL)	21.2 ± 9.4	(6.8–51)	15.2 ± 6.3	(3.7–25.6)	0.02*
Blood glucose(mg/dL)	214.8 ± 149.6	(83–968)	172.9 ± 122.7	(64–985)	0.59
Sodium (mEq/L)	134.5 ± 7.1	(115–152)	134.6 ± 5.6	(118–158)	0.44
Lactate (mg/dL)	18.3 ± 10.5	(12–109)	8.6 ± 7.1	(9–36)	< 0.01*
INR	1.3 ± 0.4	(0.7–3.6)	1.1 ± 0.2	(0.8–1.5)	0.19
ESR	53.1 ± 28.5	(14–109)	61.9 ± 28.6	(8–102)	0.84
Hemoglobin	12.2 ± 2.5	(4.8–16.6)	11.4 ± 2.8	(7.6–16.8)	0.63
Tmax	37.7 ± 0.9	(36.5–39.4)	37.5 ± 0.8	(36.2–39.7)	0.43
Time to presentation (days)	6.5 ± 4.2	(0–13)	5.2 ± 3.6	(0–16)	0.74

Note: *P < 0.05.

Abbreviations: HCRP, high sensitive C reactive protein; WBC, white blood cell count; INR, international normalized ratio; ESR, erythrocyte sedimentation rate; Tmax, maximal temperature at ED; SD, standard deviation.

Table 2 Vital Signs from NF and Control Group are Compared Using a Mann–Whitney U-Test

Continue Variables	NF Group (n=60)		Control Group (n=60)		P-value
	(Mean±SD)	Range	(Mean±SD)	Range
HRmax	111.5 ± 19.6	(72–150)	103.5 ± 18.5	(66–140)	0.06
RRmax	23.0 ± 5.9	(10–39)	22.1 ± 12.8	(18–35)	0.25
SBPmax	130.2 ± 20.3	(104–198)	150.8 ± 12.5	(118–194)	0.02*
DBPmax	85.7 ± 14.4	(46–117)	84.4 ± 13.6	(54–113)	0.78
MAPmax	103.5 ± 14.9	(76–129)	107.0 ± 13.7	(81–136)	0.27
SBPmin	110.3 ± 17.1	(70–148)	112.5 ± 18.6	(64–152)	0.56
DBPmin	67.5 ± 12.3	(44–86)	65.8 ± 12.2	(36–94)	0.97
MAPmin	82.1 ± 13.5	(58–112)	82.5 ± 13.2	(56–110)	0.73
dSBP	26.8 ± 19.1	(0–75)	35.9 ± 14.5	(4–95)	0.04*
dMAP	21.4 ± 14.7	(0–69)	24.4 ± 11.2	(3–45)	0.22
PPmax	53.4 ± 19.2	(18–88)	63.7 ± 14.6	(40–86)	< 0.01*
PPmin	43.8 ± 11.2	(21–74)	44.6 ± 14.3	(17–69)	0.83

Note: *P < 0.05.

Abbreviations: HRmax, maximum heart rate in ED; RRmax, maximum respiratory rate in ED; SBPmax, maximum systolic blood pressure in ED; DBPmax, maximum diastolic blood pressure in ED; MAPmax, maximum mean arterial pressure in ED; SBPmin, minimum systolic blood pressure in ED; DBPmin, minimum diastolic blood pressure in ED; MAPmin, minimum mean arterial pressure in ED; dSBP, delta systolic pressure; dMAP, delta mean arterial pressure; PPmax, maximum pulse pressure; PPmin, minimum pulse pressure.

Table 3 Categorical Variables from NF and Control Group are Compared Using a Chi-Squared Test

Categorical Variables	NF Group (n=60)		Control Group (n=60)			p-value
	(n)	%	(n)	%	χ2
Gender					6.65	0.01
Male	42	70.0%	37	61.7%
Female	18	30.0%	23	38.3%
Laterality					0.06	0.81
Left	25	41.7%	24	40.0%
Right	35	58.3%	36	60.0%
Homeless					11.32	< 0.01
Yes	10	16.7%	2	3.3%
No	50	83.3%	58	96.7%
IV substance use					15.05	< 0.01
Yes	12	20.0%	3	5.0%
No	48	80.0%	57	95.0%
Subjective fever					16.62	< 0.01
Yes	30	50.0%	16	26.7%
No	30	50.0%	44	73.3%
Objective fever					3.44	0.07
Yes	23	38.3%	26	43.3%
No	37	61.7%	34	56.7%

Note: Patients with an “objective fever” have a temperature > 37.5 degrees Celsius.

Table 4 Binary Logistic Regression Displays All Significant Statistically Variables

							95% CI for Exp(B)
Factor	B	S.E	Wald	df	Sig.	Exp(B)	Lower	Upper
Gender	2.71	1.15	5.69	1.00	0.016	15.47	1.63	98.95
Subjective fever	2.61	0.87	9.12	1.00	0.003	13.74	0.014	0.478
IV substance user	2.63	0.82	10.38	1.00	0.001	13.98	2.95	58.41
Lactate	1.54	0.58	7.34	1.00	0.006	4.970	1.52	13.85
Constant	−2.28	1.27	3.22	1.00	0.078	0.152	–	–