Comparison 1. Asthma treatment tailored on FeNO versus clinical symptoms.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Number of participants who had ≥ 1 exacerbations over study period	5	1005	Odds Ratio (Fixed, 95% CI)	0.60 [0.43, 0.84]
2 Number of exacerbations per 52 weeks (exacerbation rates)	5	842	Rate Ratio (Fixed, 95% CI)	0.59 [0.45, 0.77]
3 Severe exacerbations requiring oral corticosteroids	3	495	Odds Ratio (M‐H, Random, 95% CI)	0.86 [0.50, 1.48]
4 Severe exacerbations requiring hospitalisation	3	488	Odds Ratio (M‐H, Fixed, 95% CI)	0.14 [0.01, 2.67]
5 FEV1% pred at final visit	4	802	Mean Difference (Fixed, 95% CI)	0.11 [‐1.15, 1.37]
6 FeNO level at final visit	5	668	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.00 [‐0.16, 0.15]
7 Symptom score as per Asthma Control Test	4	707	Mean Difference (IV, Fixed, 95% CI)	‐0.08 [‐0.18, 0.01]
8 Symptom score as per AQLQ	2		Mean Difference (Fixed, 95% CI)	0.00 [‐0.10, 0.10]
9 ICS dose at final visit (microgram per day)	4	582	Mean Difference (IV, Random, 95% CI)	‐147.15 [‐380.85, 86.56]
10 Subgroup (control guideline use): Number of participants who had ≥ 1 exacerbations over study period	5		Odds Ratio (Fixed, 95% CI)	0.60 [0.43, 0.84]
10.1 Guideline control	2		Odds Ratio (Fixed, 95% CI)	0.87 [0.47, 1.61]
10.2 Other control	3		Odds Ratio (Fixed, 95% CI)	0.51 [0.34, 0.76]
11 Subgroup (control guideline use): Number of exacerbations per 52 weeks (exacerbation rates)	5		Rate Ratio (Fixed, 95% CI)	0.59 [0.45, 0.77]
11.1 Guideline control	3		Rate Ratio (Fixed, 95% CI)	0.76 [0.48, 1.19]
11.2 Other control	2		Rate Ratio (Fixed, 95% CI)	0.51 [0.37, 0.71]