Table 1.

Demographic and clinical characteristics of the patients with invasive and noninvasive skin and soft tissue infections caused by group A Streptococcus

Characteristic	No. of patients (%) witha:			Odds ratio (95% CI)b	P valueb
	SSTI (n = 73)	Invasive SSTI (n = 34)	Noninvasive SSTI (n = 39)
Demographic characteristics
Age (yr) (mean ± SD)	45.6 ± 24	58.5 ± 14.6	34.3 ± 25		<0.001
Male	57 (78.1)	26 (76.5)	31 (79.5)	0.84 (0.28–2.55)	0.756
Underlying illnesses
Diabetes mellitus	21 (28.8)	15 (44.1)	6 (15.4)	4.34 (1.44–13.07)c	0.007c
Hypertension	16 (21.9)	12 (35.3)	4 (10.3)	4.77 (1.37–16.67)d	0.01d
Congestive heart failure	4 (5.5)	3 (8.8)	1 (2.6)	3.68 (0.36–37.14)	0.333
Malignancy	4 (5.5)	3 (8.8)	1 (2.6)	3.68 (0.36–37.14)	0.333
Liver cirrhosis	2 (2.7)	1 (2.9)	1 (2.6)	1.15 (0.07–19.14)	0.999
Alcoholism	18 (24.7)	8 (23.5)	10 (25.6)	0.89 (0.31–2.6)	0.835
Clinical diagnoses
Cellulitis/wound infection	47 (64.4)	12 (35.3)	35 (89.7)	0.06 (0.02–0.22)	<0.001
Necrotizing fasciitis	19 (26)	19 (55.9)	0		<0.001
Deep abscess	2 (2.7)	2 (5.9)	0		0.213
Furuncle/carbuncle/pustule	4 (5.5)	0	4 (10.3)		0.118
Deep neck infection	1 (1.4)	1 (2.9)	0		0.466
Clinical manifestations
Shock	10 (13.7)	10 (29.4)	0		<0.001
Bacteremia	12 (16.4)	12 (35.3)	0		<0.001
Hospital-acquired infection	2 (2.7)	2 (5.9)	0		0.213
Intensive care unit admission	12 (16.4)	11 (32.4)	1 (2.6)	18.17 (2.2–150.14)	0.001
Hospitalization	55 (75.3)	34 (100)	21 (53.8)	2.62 (1.87–3.67)	<0.001
Surgical intervention	38 (52.1)	29 (85.3)	9 (23.1)	19.33 (5.79–64.61)	<0.001
Mortality	5 (6.8)	5 (14.7)	0		0.019

^aThe number of patients with skin and soft tissue infections (SSTIs) is given unless specified otherwise (i.e., age).

^bThe odds ratio (95% confidence interval [95% CI]) and P value for patients with invasive and noninvasive SSTIs are shown.

^cOR = 3.32 (95% CI, 1.05 to 10.51) and P = 0.042 by multivariate logistic regression analysis.

^dOR = 3.47 (95% CI, 0.93 to 12.87) and P = 0.063 by multivariate logistic regression analysis.