Predictive factors for recurrent acute appendicitis after conservative treatment

Figures & data

Figure 1. Study flow chart demonstrating defined cohort of patients with conservatively treated acute appendicitis.

Table 1. Characteristics of study cohort at index admission.

Variables	Study cohort (n = 379)
Age (years)
18–≤ 40	112 (29.6)
41–≤ 60	130 (34.3)
> 60	137 (36.1)
Gender
female	187 (49.3)
BMI^a (kg/m^2)
18–< 25	164 (47.1)
25–< 30	98 (28.2)
≥ 30	86 (24.7)
CRP (mg/L)	159 (95–240)
WBC (×10^9/L)	13.4 (11–16.6)
CCI
0	288 (76)
1	45 (11.9)
2	20 (5.3)
3	10 (2.6)
4	5 (1.3)
5	2 (0.5)
6	8 (2.1)
7	1 (0.3)
Hypertension	77 (20.3)
Previous abdominal surgery	81 (21.4)
Abscess	196 (51.7)
Appendicolith^b	53 (16.2)
Appendix external diameter^c (mm)
> 10	154 (49.8)
Antibiotic therapy (days)	13 (12.4–13.5)
Length of stay (days)	4 (2–6)
Recurrence	78 (20.6)
Time to recurrence (months)	6.5 (1–17.8)
Type of follow-up
No follow-up	115 (30.3)
Clinical/lab	57 (15)
Colonoscopy	130 (34.3)
Radiology	35 (9.2)
Radiology and Colonoscopy	42 (11.1)
Appendectomy during follow-up	68 (17.9)
Study follow-up time (months)	68 (45–98)

BMI: body mass index; CRP: C-reactive protein; WBC: white blood cell; CCI: Charlson Comorbidity Index; CT: computed tomography; US: ultrasound; MR: magnetic resonance; mm: millimeter.

Categorical data presented as number (column percentage), continuous parametric data as mean (95% CI) and continuous non-parametric data as median (Q1–Q3) in italics.

^an = 348,^bn = 327,^cn = 309.

Figure 2. Kaplan–Meier curve representing time to recurrence one year after conservatively treated acute appendicitis.

Figure 3. Receiver operating characteristic (ROC) curve representing the predictive ability of the multivariable logistic regression model.

Table 2. Univariable and multivariable logistic regression for prediction of recurrent acute appendicitis.

Variables	Recurrence (n = 78)	Without recurrence (n = 301)	Univariable		Multivariable
			OR (95% CI)	p-value	OR (95% CI)	p-value
Age (years)
18–≤ 40	17 (21.8)	95 (31.6)
41–≤ 60	30 (38.5)	100 (33.2)	1.68 (0.87–3.24)	.124	1.63 (0.79-3.34)	.184
> 60	31 (39.7)	106 (35.2)	1.63 (0.85–3.14)	.140	1.51 (0.74-3.07)	.259
Gender
female	39 (50)	148 (49.2)	1.03 (0.63–1.7)	.896	1.09 (0.63-1.89)	.763
BMI^a (kg/m^2)
18–< 25	35 (46.1)	129 (47.4)
25–< 30	29 (38.2)	69 (25.4)	1.55 (0.87–2.75)	.134
≥ 30	12 (15.4)	74 (27.2)	0.60 (0.29–1.22)	.158
CRP (mg/L)	134 (72–233)	163 (100–241)	1.0 (0.99–1.0)	.941
CCI
0	61 (78.2)	227 (75.4)
1–2	10 (12.9)	55 (18.3)	0.68 (0.33–1.4)	.296
≥ 3	7 (9)	19 (6.2)	1.37 (0.55–3.41)	.497
Previous abdominal surgery	18 (23.1)	238 (79.1)	1.13 (0.63–2.06)	.680
Abscess	48 (61.5)	148 (49.2)	1.65 (0.99–2.75)	.053	2.05 (1.18–3.56)	.011
Appendicolith^b	14 (18.9)	39 (15.4)	1.28 (0.65–2.51)	.473
Appendix external diameter^c (mm)
> 10	48 (66.7)	106 (44.7)	2.47 (1.42–4.3)	.001	2.4 (1.37–4.21)	.002
Length of stay (days)	4 (2–6)	4 (2–6)	0.98 (0.91–1.05)	.565

OR: odds ratio; CI: confidence interval; BMI: body mass index; CRP: C-reactive protein; CCI: Charlson Comorbidity Index; mm: millimeter.

Categorical data presented as number (column percentage), continuous parametric data as mean (95% CI) and continuous non-parametric data as median (Q1–Q3) in italics. Univariable and multivariable logistic regression analysis adjusted for age, gender, abscess formation and external appendix diameter, presented in OR (95% CI) and p-value.

^an = 348, ^bn = 327, ^cn = 309.