Indication of conservative treatment by antibiotics for uncomplicated and complicated acute appendicitis

Table 3 Univariate and multivariate analysis of risk factors for resistance to conservative treatment, n (%)

	Surgery group, n = 28	Conservative group, n = 242	Univariate analysis, P value	Multivariate analysis, P value	Hazard ration
Age
< 75	26 (10.7)	216 (89.3)	0.554
≥ 75	2 (7.1)	26 (92.9)
Sex
Female	12 (11.1)	96 (88.9)	0.744
Male	16 (9.9)	146 (90.1)
Past history of appendicitis
(-)	25 (11.6)	190 (88.4)	0.180
(+)	3 (5.5)	52 (94.5)
Rebound pain
(-)	9 (7.8)	106 (92.2)	0.238
(+)	19 (12.3)	136 (87.7)
Time to visit hospital (hour)
< 22	12 (8.1)	137 (81.9)	0.166
≥ 22	16 (13.2)	105 (86.8)
Body temperature (°C)
< 37.3	9 (5.6)	153 (94.4)	0.001	0.028	2.945
≥ 37.3	19 (17.6)	89 (82.4)
WBC count (/μL)
< 15160	16 (8.0)	185 (92.0)	0.027	0.138
≥ 15160	12 (17.4)	57 (82.6)
CRP (mg/dL)
< 4.6	14 (8.2)	157 (91.8)	0.122
≥ 4.6	14 (14.1)	85 (85.9)
Size of appendix (mm)
< 12	6 (5.0)	113 (95.0)	0.011	0.600
≥ 12	22 (14.6)	129 (85.4)
Stranding of the adjacent fat
(-)	1 (1.3)	79 (98.7)	0.001	0.162
(+)	27 (16.6)	163 (83.4)
Periappendiceal fluid
(-)	19 (8.4)	206 (91.6)	0.020	0.892
(+)	9 (20.0)	36 (80.0)
Air in appendix
(-)	22 (8.9)	224 (81.1)	0.014	0.164
(+)	6 (25.0)	18 (75.0)
Abscess
(-)	24 (9.4)	230 (80.6)	0.048	0.083
(+)	4 (25.0)	12 (75.0)
Appendicolith
(-)	9 (5.1)	167 (94.9)	< 0.001	0.008	3.746
(+)	19 (20.2)	75 (79.8)
Douglas sinus fluid
(-)	17 (7.7)	203 (92.3)	0.003	0.016	3.580
(+)	11 (22.0)	39 (78.0)
Antibiotics
Second-generation cephems	14 (7.3)	178 (92.7)	0.009	0.260
Broad-spectrum	14 (17.9)	64 (82.1)

CRP: C-reactive protein; WBC: White blood cell.