Comparison 1. Interventions versus placebo or no prophylaxis.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Clinically important upper GI bleeding	30	3132	Risk Ratio (M‐H, Fixed, 95% CI)	0.47 [0.39, 0.57]
1.1 H2 receptor antagonists vs placebo or no prophylaxis	24	1844	Risk Ratio (M‐H, Fixed, 95% CI)	0.46 [0.37, 0.59]
1.2 Proton pump inhibitors vs placebo or no prophylaxis	3	159	Risk Ratio (M‐H, Fixed, 95% CI)	0.57 [0.13, 2.59]
1.3 Prostagladin analogues vs placebo or no prophylaxis	1	58	Risk Ratio (M‐H, Fixed, 95% CI)	1.0 [0.22, 4.55]
1.4 Anticholinergics vs placebo or no prophylaxis	2	103	Risk Ratio (M‐H, Fixed, 95% CI)	0.87 [0.30, 2.49]
1.5 Antacids vs placebo or no prophylaxis	7	515	Risk Ratio (M‐H, Fixed, 95% CI)	0.39 [0.23, 0.63]
1.6 Sucralfate vs placebo or no prophylaxis	7	453	Risk Ratio (M‐H, Fixed, 95% CI)	0.47 [0.25, 0.87]
2 Nosocomial pneumonia	9	1331	Risk Ratio (M‐H, Fixed, 95% CI)	1.15 [0.90, 1.48]
2.1 H2 receptor antagonists vs placebo or no prophylaxis	8	788	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.77, 1.46]
2.2 Proton pump inhibitors vs placebo or no prophylaxis	2	149	Risk Ratio (M‐H, Fixed, 95% CI)	1.13 [0.59, 2.17]
2.3 Anticholinergics vs placebo or no prophylaxis	1	72	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.43, 2.59]
2.4 Sucralfate vs placebo or no prophylaxis	4	322	Risk Ratio (M‐H, Fixed, 95% CI)	1.59 [0.84, 3.01]
3 All‐cause mortality in ICU	19	2159	Risk Ratio (M‐H, Fixed, 95% CI)	1.10 [0.90, 1.34]
3.1 H2 receptor antagonists vs placebo or no prophylaxis	14	1209	Risk Ratio (M‐H, Fixed, 95% CI)	1.16 [0.89, 1.53]
3.2 Proton pump inhibitors vs placebo or no prophylaxis	3	180	Risk Ratio (M‐H, Fixed, 95% CI)	1.05 [0.46, 2.38]
3.3 Prostagladin analogues vs placebo or no prophylaxis	1	58	Risk Ratio (M‐H, Fixed, 95% CI)	1.14 [0.48, 2.74]
3.4 Anticholinergics vs placebo or no prophylaxis	2	103	Risk Ratio (M‐H, Fixed, 95% CI)	1.22 [0.59, 2.56]
3.5 Antacids vs placebo or no prophylaxis	2	250	Risk Ratio (M‐H, Fixed, 95% CI)	1.02 [0.58, 1.79]
3.6 Sucralfate vs placebo or no prophylaxis	5	359	Risk Ratio (M‐H, Fixed, 95% CI)	0.93 [0.58, 1.51]
4 All‐cause mortality in hospital	5	857	Risk Ratio (M‐H, Fixed, 95% CI)	1.15 [0.85, 1.55]
4.1 H2 receptor antagonists vs placebo or no prophylaxis	4	387	Risk Ratio (M‐H, Fixed, 95% CI)	1.14 [0.71, 1.83]
4.2 Proton pump inhibitors vs placebo or no prophylaxis	1	100	Risk Ratio (M‐H, Fixed, 95% CI)	1.17 [0.42, 3.22]
4.3 Antacids vs placebo or no prophylaxis	1	126	Risk Ratio (M‐H, Fixed, 95% CI)	1.44 [0.79, 2.64]
4.4 Sucralfate vs placebo or no prophylaxis	2	244	Risk Ratio (M‐H, Fixed, 95% CI)	0.94 [0.53, 1.68]
5 Duration of ICU stay	2	447	Mean Difference (IV, Fixed, 95% CI)	0.24 [‐1.13, 1.61]
5.1 H2 receptor antagonists vs placebo or no prophylaxis	2	152	Mean Difference (IV, Fixed, 95% CI)	0.73 [‐1.64, 3.09]
5.2 Proton pump inhibitors vs placebo or no prophylaxis	2	149	Mean Difference (IV, Fixed, 95% CI)	0.01 [‐2.33, 2.35]
5.3 Sucralfate vs placebo or no prophylaxis	2	146	Mean Difference (IV, Fixed, 95% CI)	‐0.01 [‐2.40, 2.38]
6 Duration of intubation	2	447	Mean Difference (IV, Fixed, 95% CI)	0.87 [‐0.58, 2.31]
6.1 H2 receptor antagonists vs placebo or no prophylaxis	2	152	Mean Difference (IV, Fixed, 95% CI)	0.78 [‐1.72, 3.29]
6.2 Proton pump inhibitors vs placebo or no prophylaxis	2	149	Mean Difference (IV, Fixed, 95% CI)	0.36 [‐2.18, 2.90]
6.3 Sucralfate vs placebo or no prophylaxis	2	146	Mean Difference (IV, Fixed, 95% CI)	1.43 [‐1.04, 3.89]
7 Number of participants requiring blood transfusions	9	981	Risk Ratio (M‐H, Fixed, 95% CI)	0.63 [0.41, 0.97]
7.1 H2 receptor antagonists vs placebo or no prophylaxis	7	605	Risk Ratio (M‐H, Fixed, 95% CI)	0.57 [0.35, 0.94]
7.2 Antacids vs placebo or no prophylaxis	2	226	Risk Ratio (M‐H, Fixed, 95% CI)	0.94 [0.30, 2.96]
7.3 Sucralfate vs placebo or no prophylaxis	1	150	Risk Ratio (M‐H, Fixed, 95% CI)	0.75 [0.13, 4.34]
8 Units of blood transfused	2	309	Mean Difference (IV, Random, 95% CI)	0.09 [‐0.99, 1.17]
8.1 H2 receptor antagonists vs placebo or no prophylaxis	2	159	Mean Difference (IV, Random, 95% CI)	‐1.73 [‐6.37, 2.90]
8.2 Sucralfate vs placebo or no prophylaxis	1	150	Mean Difference (IV, Random, 95% CI)	0.80 [0.25, 1.35]