Summary of findings for the main comparison. Tailoring asthma treatment using FeNO versus clinical symptoms.
| Tailoring asthma treatment using FeNO versus 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) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with asthma treatment tailored on clinical symptoms** | Risk with asthma treatment tailored on FeNO | |||||
| Number of participants who had ≥ 1 exacerbations over 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 | ‐ |
| Number 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 mcg | The mean ICS dose taken in the FeNO groups was 17.01 lower (101.75 lower to 67.72 more) 577 mcg | ‐ | 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) |
| *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. CI: confidence interval; FeNO: fractional exhaled nitric oxide; ICS: inhaled corticosteroids; MD: mean difference; OR: odds ratio; RCT: randomised controlled trial | ||||||
| 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 | ||||||
1Two studies, Honkoop 2014 and Syk 2013, carrying 36% of the analysis weight, were at high risk of performance and detection bias due to lack of blinding. There were several uncertainties across studies, particularly with regard to the control of selection bias (one downgrade for risk of bias). 2Final inhaled corticosteroid doses were quite varied, with one study having particularly high doses (360 to 1282 in the control groups and 423 to 740 in the FeNO groups). There was substantial statistical heterogeneity in the analysis (I2 = 82%; P = 0.0007). A random‐effects sensitivity analysis changed the result substantially to MD ‐147.15 (95% CI ‐380.85 to 86.56) (one downgrade for heterogeneity, one downgrade for imprecision). 3One study carrying 51% of the analysis weight, Syk 2013, was open labelled, which may have introduced bias (one downgrade for risk of bias).