Table 3

Summary of findings for the main comparisons: FeNO-based adult studies

Tailoring asthma treatment using FeNO vs clinical symptoms
Patient or population: adults with asthma
Setting: outpatient
Intervention: asthma treatment tailored on FeNO
Comparison: asthma treatment tailored on clinical symptoms
OutcomesAnticipated absolute effects* (95% CI)Relative effect
(95% CI)
Number of participants
(studies)
Quality of the evidence
(GRADE)
Comments
Risk with asthma treatment tailored on clinical symptoms†Risk with asthma treatment tailored on FeNO
No of participants who had ≥1 exacerbations over the study period
Follow-up: range 18 weeks to 52 weeks
25 per 10017 per 100
(13 to 22)
OR 0.60 (0.43 to 0.84)1005
(5 RCTs)
⊕⊕⊕⊝
Moderate1
No of exacerbations per 52 weeks (exacerbation rates)
Follow-up: mean 52 weeks
The control group ranged from 0.23 to 0.9 exacerbations per 52 weeksRate ratio 0.59 (0.45 to 0.77)842
(5 RCTs)
⊕⊕⊕⊝
Moderate1
ICS dose at final visit
Follow-up: range 18 weeks to 52 weeks
The mean ICS dose taken by the control group at final visit was
659 µg
The mean ICS dose taken in the FeNO groups was 17.01 lower (101.75 lower to 67.72 more) 577 µg582
(4 RCTs)
⊕⊕⊝⊝
Very low2 3
A random-effects sensitivity analysis gave a very imprecise result: MD −147.15 (95% CI −380.85 to 86.56)
  • GRADE Working Group grades of evidence:

  • High quality: We are very confident that the true effect lies close to that of the estimate of the effect.

  • Moderate quality: We are moderately confident in the effect estimate. The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.

  • Low quality: Our confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect .

  • Very low quality: We have very little confidence in the effect estimate. The true effect is likely to be substantially different from the estimate of effect .

  • *The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

  • †The control group risks were calculated as a mean of the scores or events in the control groups of the studies contributing to each analysis. We could not calculate a control risk for the number of exacerbations per 52 weeks because we did not have information for each arm of the studies, just ratios between them.

  • FeNO, fractional exhaled nitric oxide; ICS, inhaled corticosteroids; MD, mean difference; RCT, randomised controlled trial.