Summary of findings for the main comparison. Heated, humidified air compared to control for treating the common cold.
| Heated, humidified air compared to control for treating the common cold | ||||||
| Patient or population: People with the common cold Setting: Clinics, university communities, general practice Intervention: Heated, humidified air administered using a RhinoTherm device Comparison: Ambient air heated to 20 °C to 30 °C at various flow rates | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with control | Risk with rhinothermy | |||||
| Reduction in the clinical severity of the common cold (measured by decrease in the symptom score index) | Study population |
Fixed‐effect model OR 0.30 (0.16 to 0.56) Random‐effects model OR 0.22 (0.03 to 1.95) |
149 (2 RCTs) | ⊕⊕⊝⊝ LOW 1 2 | The significance of the effect is uncertain because use of the fixed‐effect model produces a different result than use of the random‐effects model. | |
| 681 per 1000 |
Fixed‐effect model 390 per 1000 (254 to 544) Random‐effects model 319 per 1000 (60 to 806) |
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| Number of participants with the subjective response: therapy did not help | Study population | OR 0.58 (0.28 to 1.18) | 124 (2 RCTs) | ⊕⊕⊝⊝ LOW 3 4 | We downgraded the evidence for risk of bias and imprecision. | |
| 524 per 1000 | 389 per 1000 (235 to 565) | |||||
| Number of participants with positive nasal wash cultures | Study population | OR 0.47 (0.04 to 5.19) | 20 (1 RCT) | ⊕⊕⊝⊝ LOW 5 6 | We downgraded the evidence for risk of bias and imprecision. | |
| 900 per 1000 | 809 per 1000 (265 to 979) | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; 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. | ||||||
1Ophir 1987 had high attrition rates; Tyrrell 1989b did not perform allocation concealment. 2Downgraded for inconsistency. 3Forstall 1994 and Macknin 1990 did not clearly describe randomisation and allocation concealment methods. 4Downgraded one point for imprecision. 5Hendley 1994 did not clearly state randomisation and allocation methods. Downgraded one point. 6Downgraded one point for imprecision.