Timing of surgical operation for patients with intra-abdominal infection: A systematic review and meta-analysis

Table 1 Characteristics of included studies

Ref.	Design	Sample size, n	Age in year	Sex, male/female	Start of time calculation	Primary end-point(s)	Follow-up time
Elramah et al[24]	RC	523	61	-	Admission time	Mortality rate; Cure rate	9 year
Giraudo et al[23]	RC	746	28.8	343/380	Admission time	Complications rate; Mortality rate	6 year
Lee et al[25]	RC	1076	35.2 ± 17.1	612/464	Time of symptom onset	Cure rate; Complications rate	3 year
Maroju et al[28]	PC	114	28.3	86/28	Time of symptom onset	Length of hospital stay	1 year
Kim et al[29]	RC	192	33.6 ± 19.5	99/93	Time of symptom onset	Complications rate; Length of hospital stay	1 year
Saar et al[30]	PC	270	35.4 ± 14.8	136/130	Time of symptom onset	Cure rate	1 year
Rause et al[22]	RC	197	68	51%/49%	Admission time	Mortality rate	8 year
Azuhata et al[26]	PC	154	66.5 ± 13.9	88/66	Admission time	Survival rate	4 year
Wen and Tang[27]	RC	101	56.26 ± 15.7	65/36	Admission time	Mortality rate; Length of hospital stay	3.5 year

PC: Prospective cohort; RC: Randomized controlled.

Table 2 Results of quality assessment using the Newcastle-Ottawa Scale for case-control studies

Ref.	Selection				Comparability	Exposure			Quality score
	Adequate definition of cases	Representativeness of the cases	Selection of controls	Definition of controls	Comparability of cases and controls on the basis of the design or analysis	Ascertainment of exposure	Same method of ascertainment for cases and controls	Non-Response rate
Elramah et al[24]	1	1	-	1	1	1	1	1	7
Giraudo et al[23]	1	1	-	1	1	1	1	1	7
Lee et al[25]	1	1	-	1	1	1	1	1	7
Maroju et al[28]	1	1	-	1	1	1	1	1	7
Kim et al[29]	1	1	-	1	1	1	1	1	7
Saar et al[30]	1	1	-	-	2	1	1	1	7
Rause et al[22]	1	1	-	-	1	1	1	1	6
Azuhata et al[26]	1	1	-	1	2	1	1	1	8
Wen and Tang[27]	1	1	-	1	2	1	1	1	8

¹Indicates that the inclusion study met the relevant criteria and represents a score of 1.

²Indicates that the inclusion study met the relevant criteria and represents a score of 2.