Comparison 2. Active drain versus passive drain.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Mortality (30 days)	2	382	Risk Ratio (M‐H, Random, 95% CI)	1.23 [0.30, 5.06]
2.2 Intra‐abdominal infection	2	321	Risk Ratio (M‐H, Random, 95% CI)	0.87 [0.21, 3.66]
2.3 Wound infection	2	321	Risk Ratio (M‐H, Random, 95% CI)	0.92 [0.44, 1.90]
2.4 Morbidity	2	382	Risk Ratio (M‐H, Random, 95% CI)	0.97 [0.53, 1.77]
2.5 Length of hospital stay (days)	2	321	Mean Difference (IV, Random, 95% CI)	‐0.79 [‐2.63, 1.04]
2.6 Additional open procedures for postoperative complications	2	321	Risk Ratio (M‐H, Random, 95% CI)	0.44 [0.11, 1.83]