Comparison 1. Subcutaneous omalizumab + steroid versus placebo + steroid (stable steroid).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Number of participants with at least one exacerbation (ICS and OCS users)	10	3261	Odds Ratio (M‐H, Fixed, 95% CI)	0.55 [0.46, 0.65]
1.1 Moderate to severe	7	2889	Odds Ratio (M‐H, Fixed, 95% CI)	0.50 [0.42, 0.60]
1.2 Severe (ICS)	2	277	Odds Ratio (M‐H, Fixed, 95% CI)	1.00 [0.50, 1.99]
1.3 Severe (ICS and OCS)	1	95	Odds Ratio (M‐H, Fixed, 95% CI)	1.65 [0.66, 4.13]
2 Exacerbations requiring oral steroids	3		Rate Ratio (Fixed, 95% CI)	Subtotals only
2.1 Moderate to severe asthma (ICS + mixed treatments)	2		Rate Ratio (Fixed, 95% CI)	0.52 [0.37, 0.73]
2.2 Severe asthma (ICS + LABA)	1		Rate Ratio (Fixed, 95% CI)	0.66 [0.45, 0.97]
2.3 Severe asthma (ICS + LABA + other treatment)	1		Rate Ratio (Fixed, 95% CI)	0.72 [0.53, 0.98]
2.4 Severe asthma (ICS and OCS)	1		Rate Ratio (Fixed, 95% CI)	0.95 [0.63, 1.43]
3 Hospitalisations	4	1824	Odds Ratio (M‐H, Fixed, 95% CI)	0.16 [0.06, 0.42]
3.1 Moderate to severe asthma	4	1824	Odds Ratio (M‐H, Fixed, 95% CI)	0.16 [0.06, 0.42]
3.2 Severe asthma	0	0	Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
4 Mortality	9	4245	Odds Ratio (M‐H, Fixed, 95% CI)	0.19 [0.02, 1.67]
4.1 Moderate to severe asthma	7	3124	Odds Ratio (M‐H, Fixed, 95% CI)	0.32 [0.01, 7.85]
4.2 Severe asthma	2	1121	Odds Ratio (M‐H, Fixed, 95% CI)	0.14 [0.01, 2.73]
5 Peak expiratory flow rate (am)	4	1651	Mean Difference (IV, Fixed, 95% CI)	3.56 [‐5.05, 12.18]
5.1 Moderate to severe asthma	3	1405	Mean Difference (IV, Fixed, 95% CI)	4.93 [‐4.11, 13.97]
5.2 Severe asthma	1	246	Mean Difference (IV, Fixed, 95% CI)	‐9.90 [‐38.27, 18.47]
6 Change in am PEF	2		Mean Difference (Fixed, 95% CI)	Totals not selected
6.1 Moderate to severe asthma	1		Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
6.2 Severe asthma	1		Mean Difference (Fixed, 95% CI)	0.0 [0.0, 0.0]
7 FEV1 (mL)	2	1071	Mean Difference (IV, Fixed, 95% CI)	68.31 [‐23.45, 160.07]
7.1 Moderate to severe	2	1071	Mean Difference (IV, Fixed, 95% CI)	68.31 [‐23.45, 160.07]
7.2 Severe	0	0	Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
8 Change in FEV1 (mL)	5	1463	Mean Difference (Fixed, 95% CI)	56.39 [16.82, 95.96]
8.1 Moderate to severe asthma	2	732	Mean Difference (Fixed, 95% CI)	67.29 [23.75, 110.83]
8.2 Severe asthma	3	731	Mean Difference (Fixed, 95% CI)	4.68 [‐90.16, 99.52]
9 Change in FEV1 predicted	4	1498	Mean Difference (Fixed, 95% CI)	2.15 [1.01, 3.30]
9.1 Moderate to severe asthma	3	1079	Mean Difference (Fixed, 95% CI)	2.01 [0.76, 3.27]
9.2 Severe asthma	1	419	Mean Difference (Fixed, 95% CI)	2.8 [0.10, 5.50]
10 Symptom scores	10		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
10.1 Moderate to severe asthma	6		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
10.2 Severe asthma	4		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
11 Mean change in Wasserfallen asthma score	1		Symptoms (Fixed, 95% CI)	Totals not selected
11.1 Moderate to severe asthma	1		Symptoms (Fixed, 95% CI)	0.0 [0.0, 0.0]
12 Quality of life—change from baseline in AQLQ scores	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
12.1 Moderate to severe asthma	0		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
12.2 Severe asthma	1		Mean Difference (IV, Fixed, 95% CI)	0.0 [0.0, 0.0]
13 Global evaluation rated good to excellent	4	1136	Odds Ratio (M‐H, Fixed, 95% CI)	2.12 [1.67, 2.68]
13.1 Moderate to severe asthma	1	405	Odds Ratio (M‐H, Fixed, 95% CI)	3.32 [2.19, 5.05]
13.2 Severe asthma	3	731	Odds Ratio (M‐H, Fixed, 95% CI)	1.69 [1.26, 2.26]
14 Rescue medication	9		Mean Difference (Fixed, 95% CI)	Subtotals only
14.1 Moderate to severe asthma	4		Mean Difference (Fixed, 95% CI)	‐0.58 [‐0.84, ‐0.31]
14.2 Severe asthma (ICS)	4		Mean Difference (Fixed, 95% CI)	‐0.30 [‐0.49, ‐0.10]
14.3 Severe asthma (ICS and OCS)	1		Mean Difference (Fixed, 95% CI)	‐0.4 [‐4.81, 4.01]
15 Adverse event—any	14	5167	Odds Ratio (M‐H, Fixed, 95% CI)	0.92 [0.81, 1.06]
15.1 Moderate to severe asthma	8	3246	Odds Ratio (M‐H, Fixed, 95% CI)	0.91 [0.76, 1.09]
15.2 Severe asthma	6	1921	Odds Ratio (M‐H, Fixed, 95% CI)	0.94 [0.76, 1.16]
16 Adverse event—serious	15	5713	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.57, 0.91]
16.1 Moderate to severe asthma	9	3792	Odds Ratio (M‐H, Fixed, 95% CI)	0.68 [0.48, 0.95]
16.2 Severe asthma	6	1921	Odds Ratio (M‐H, Fixed, 95% CI)	0.77 [0.56, 1.05]
17 Injection site reactions	9	3577	Odds Ratio (M‐H, Fixed, 95% CI)	1.72 [1.33, 2.24]
17.1 Moderate to severe asthma	6	2001	Odds Ratio (M‐H, Fixed, 95% CI)	1.79 [1.31, 2.43]
17.2 Severe asthma	3	1576	Odds Ratio (M‐H, Fixed, 95% CI)	1.57 [0.96, 2.57]