Table 2

Characteristics of trials that have used F_ENO to guide treatment in children with asthma

First author [ref.]	Primary outcome(s)	Mean age^# years	Participants	Atopy as inclusion criterion?	FEV₁ <80% pred also used in treatment algorithm?	F_ENO cut-off(s) used ppb	What did the trial find? (F_ENO treatment compared to standard care)
Fritsch [21]	FEV₁	11.5	47	Yes	Yes	20	Higher midexpiratory flow, higher dose of ICS
Peirsman [22]	Symptom-free days	11	99	Yes	Yes	20	Reduced exacerbations, increased LTRA and ICS dose No difference in primary outcome
Petsky [23]	Exacerbations	10	63	No	No	10 for nonatopic, 12 with one PSPT, 20 for >1 PSPT	Reduced exacerbation, increased ICS dose
Pijnenburg [24]	Cumulative ICS dose	12	84	No	No	30	Reduced F_ENO and bronchial hyperresponsiveness No increase in ICS dose
Pike [25]	ICS dose and exacerbation frequency	11	90	No	No	≤15 and ≥25	No differences in outcomes
Szefler [26]	Days with asthma symptoms	14	546	Yes	Yes	20, 30 and 40	Reduced exacerbations, increased ICS dose No difference in primary outcome.
Verini [27]	Exacerbations, symptom score, treatment	12	64	No	No	12	Reduced exacerbations, improved symptom score, less asthma treatment
Voorend-van Bergen [28]	Proportion of symptom-free days	10	181^¶	Yes	No	20 and 50	Increased asthma control but not the primary outcome

PSPT: positive skin-prick test; LTRA: leukotriene receptor antagonist. ^#: where mean age is given for children in separate arms of trial, an approximate overall mean age is given; ^¶: not including 91 randomised to a web-based intervention.