Scolaris Content Display Scolaris Content Display

Study flow diagram.
Figures and Tables -
Figure 1

Study flow diagram.

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Figures and Tables -
Figure 2

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Figures and Tables -
Figure 3

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

Trial sequential analysis of drain use versus no drain use for intra‐peritoneal abscess. Analysis was performed with an event rate of 10.7% (Pc) in the control group, a risk ratio reduction of 20%, alpha 5%, beta 20%, and observed diversity 63%. The cumulative Z‐curve did not cross the trial sequential boundaries (inward sloping etched lines). The results showed that the observed diversity‐adjusted required information size was 2,570 participants, corresponding to 20.3% of the total sample size in the included trials. Accordingly, the meta‐analysis did not support or refute an intervention effect as data were too few.
Figures and Tables -
Figure 4

Trial sequential analysis of drain use versus no drain use for intra‐peritoneal abscess. Analysis was performed with an event rate of 10.7% (Pc) in the control group, a risk ratio reduction of 20%, alpha 5%, beta 20%, and observed diversity 63%. The cumulative Z‐curve did not cross the trial sequential boundaries (inward sloping etched lines). The results showed that the observed diversity‐adjusted required information size was 2,570 participants, corresponding to 20.3% of the total sample size in the included trials. Accordingly, the meta‐analysis did not support or refute an intervention effect as data were too few.

Comparison 1 Drain use versus no drain use, Outcome 1 Intra‐peritoneal abscess.
Figures and Tables -
Analysis 1.1

Comparison 1 Drain use versus no drain use, Outcome 1 Intra‐peritoneal abscess.

Comparison 1 Drain use versus no drain use, Outcome 2 Wound infection.
Figures and Tables -
Analysis 1.2

Comparison 1 Drain use versus no drain use, Outcome 2 Wound infection.

Comparison 1 Drain use versus no drain use, Outcome 3 Morbidity.
Figures and Tables -
Analysis 1.3

Comparison 1 Drain use versus no drain use, Outcome 3 Morbidity.

Comparison 1 Drain use versus no drain use, Outcome 4 Mortality.
Figures and Tables -
Analysis 1.4

Comparison 1 Drain use versus no drain use, Outcome 4 Mortality.

Comparison 1 Drain use versus no drain use, Outcome 5 Hospital stay.
Figures and Tables -
Analysis 1.5

Comparison 1 Drain use versus no drain use, Outcome 5 Hospital stay.

Comparison 2 Drain use versus no drain use (sensitivity analyses by excluding quasi‐randomised trials), Outcome 1 Intra‐peritoneal abscess.
Figures and Tables -
Analysis 2.1

Comparison 2 Drain use versus no drain use (sensitivity analyses by excluding quasi‐randomised trials), Outcome 1 Intra‐peritoneal abscess.

Summary of findings for the main comparison. Drainage compared to no drainage for complicated appendicitis

Abdominal drainage to prevent intra‐peritoneal abscess after open appendectomy for complicated appendicitis

Patient or population: people undergoing emergency open appendectomy for complicated appendicitis
Setting: hospital
Intervention: drainage
Comparison: no drainage

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Risk with no drain use

Risk with drain use

Intra‐peritoneal abscess

Follow‐up: 14 days

107 per 1000

131 per 1000
(50 to 342)

RR 1.23
(0.47 to 3.21)

453
(5 studies)

⊕⊝⊝⊝
Very lowa,b,c

Wound infection

Follow‐up: 30 days

254 per 1000

511 per 1000
(224 to 1000)

RR 2.01
(0.88 to 4.56)

478
(5 studies)

⊕⊝⊝⊝
Very lowa,b,c

Morbidity

Follow‐up: 30 days

67 per 1000

445 per 1000
(142 to 1000)

RR 6.67
(2.13 to 20.87)

90
(1 study)

⊕⊝⊝⊝
Very lowa,c

Mortality

Follow‐up: 30 days month

6 per 1000

27 per 1000
(7 to 101)

Peto OR 4.88
(1.18 to 20.09)

363
(4 studies)

⊕⊕⊕⊝
Moderatec

Hospital stay (days)

The mean hospital stay in the control groups was 4.60 days

The mean hospital stay in the intervention groups was
2.17 days higher
(1.76 days to 2.58 days higher)

MD 2.17 days higher
(1.76 higher to 2.58 higher)

298
(3 studies)

⊕⊝⊝⊝
Very lowa,d

Hospital cost

Not reported

Pain

Not reported

Quality of life

Not reported

*The basis for the assumed risk is the mean comparison group proportion in the studies. The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: confidence interval; Peto OR: Peto odds ratio; RR: risk ratio

GRADE Working Group grades of evidence
High quality: We are very confident that the true effect lies close to that of the estimate of the effect
Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different
Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect
Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

a Downgraded two levels for very serious risk of bias.

b Downgraded one level for severe inconsistency (substantial heterogeneity as indicated by the I2 statistic).

c Downgraded one level for serious imprecision. For abscess, morbidity and infection, the confidence interval includes appreciable benefit and harm, and the sample size is small. For mortality, there are few events (8 deaths in total)

d Downgraded one level for serious imprecision (small sample size).

Figures and Tables -
Summary of findings for the main comparison. Drainage compared to no drainage for complicated appendicitis
Comparison 1. Drain use versus no drain use

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Intra‐peritoneal abscess Show forest plot

5

453

Risk Ratio (M‐H, Random, 95% CI)

1.23 [0.47, 3.21]

2 Wound infection Show forest plot

5

478

Risk Ratio (M‐H, Random, 95% CI)

2.01 [0.88, 4.56]

3 Morbidity Show forest plot

1

90

Risk Ratio (M‐H, Random, 95% CI)

6.67 [2.13, 20.87]

4 Mortality Show forest plot

4

363

Peto Odds Ratio (Peto, Fixed, 95% CI)

4.88 [1.18, 20.09]

5 Hospital stay Show forest plot

3

298

Mean Difference (IV, Random, 95% CI)

2.17 [1.76, 2.58]

Figures and Tables -
Comparison 1. Drain use versus no drain use
Comparison 2. Drain use versus no drain use (sensitivity analyses by excluding quasi‐randomised trials)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Intra‐peritoneal abscess Show forest plot

3

316

Risk Ratio (M‐H, Random, 95% CI)

0.76 [0.28, 2.02]

Figures and Tables -
Comparison 2. Drain use versus no drain use (sensitivity analyses by excluding quasi‐randomised trials)