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 | ||||||
| Outcomes | Anticipated 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 100 | 17 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 weeks | Rate 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 µg | – | 582 (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.