Summary of findings for the main comparison.

Oscillating devices compared with positive expiratory pressure (PEP) for cystic fibrosis

Oscillating devices compared with positive expiratory pressure (PEP) for cystic fibrosis
Patient or population: adults and children with cystic fibrosis Settings: outpatients and hospitalised patients Intervention: oscillating devices Comparison: positive expiratory pressure (PEP)
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	PEP	Oscillating devices1
FEV₁: % predicted Follow‐up: less than 1 week to 1 year	There were no statistically significant differences between oscillating devices and PEP in terms of FEV₁ % predicted post‐intervention or change from baseline at any time point.		NA	510 (15 studies)	⊕⊝⊝⊝ very low3,4
FEF25‐75 : % predicted Follow‐up: less than 1 week to 1 year	There were no statistically significant differences between oscillating devices and PEP in terms of FEF25‐75 % predicted post‐intervention or change from baseline at any time point.		NA	355 (9 studies)	⊕⊝⊝⊝ very low3,4
FVC Follow‐up: less than 1 week to 1 year	There were no statistically significant differences between oscillating devices and PEP in terms of FVC post‐intervention or change from baseline at any time point.		NA	362 (9 studies)	⊕⊝⊝⊝ very low3,4
Sputum: volume (mL) Follow‐up: up to 1 week	The mean sputum volume in the PEP group was 8.5 mL.	The mean sputum volume in the oscillating device group was 1.8 mL lower (6.6 mL lower to 3.0 mL higher).	NA	23 (1 study)	⊕⊕⊝⊝ low4,5	A second study recruiting 30 participants reported that there was an increase in sputum volume when HFCWO was compared to participants' usual ACT; however, it was not clear exactly what interventions were included in the usual ACT treatment arm.
Sputum: weight (dry or wet) (g) Follow‐up: up to 2 weeks	3 out of 4 studies reported no statistically significant difference between oscillating devices and PEP in terms of sputum weight (g). 1 study reported that a significantly greater weight of sputum was yielded using PEP compared to HFCWO.		NA	104 (4 studies)	⊕⊕⊝⊝ low4,6
Frequency of exacerbations2 Follow‐up: up to one year	2 out of 4 studies reported no statistically significant difference between oscillating devices and PEP. 2 out of 4 studies reported that significantly more hospitalizations or participants requiring antibiotics in the oscillating devices groups compared to the PEP groups.		NA	219 (4 studies)	⊕⊕⊝⊝ low4,6
Participant‐reported satisfaction with treatment intervention Follow‐up: less than 1 week to 1 year	Some differences were reported between treatment groups in single domains of satisfaction questionnaires or measurement scales (in favour of or against oscillating devices). Overall across the 7 studies, no consistent differences were reported in terms of satisfaction of any treatment intervention.		NA	242 (7 studies)	⊕⊝⊝⊝ very low3,4,7
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (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). ACT: airway clearance technique; CI: confidence interval; FEF25‐75 : mid‐expiratory flow; FEV₁: forced expiratory volume at one second;FVC: forced vital capacity; HFCWO: high frequency chest wall oscillation;IPV: intrapulmonary percussive ventilation; NA: not applicable; PEP: positive expiratory pressure.
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

1. The oscillating devices included in the trials under this comparison were HFCWO, flutter, IPV, acapella and cornet.

2. Frequency of exacerbations were measured as defined by Rosenfeld as a consequence of the treatment intervention (Rosenfeld 2001).

3. Downgraded twice due to serious risk of bias; many judgements of high risk of bias across the included studies due to reasons such as inadequate allocation concealment, lack of blinding of participants, clinicians and outcome assessors, incomplete outcome data and selective reporting (see Risk of bias in included studies for further information).

4. Downgraded once due to imprecision: many included studies had very small sample sizes, short treatment durations and employed cross‐over designs. As results were not presented from paired analyses for these studies, we treated the cross‐over trials as if they were parallel trials which is a conservative approach as it does not take into account within‐patient correlation. Sensitivity analyses indicates that results were robust to this approach.

5. Downgraded once due to unclear risk of bias; the study was published as an abstract only and very limited information was available regarding the study design.

6. Downgraded once due to risk of bias; judgements of high risk of bias across some of the included studies due to reasons such as inadequate allocation concealment, lack of blinding of participants clinicians and outcome assessors, incomplete outcome data and selective reporting (see Risk of bias in included studies for further information).

7. Downgraded once due to applicability; three of the studies reported anecdotal findings in terms of participant satisfaction or preference for a treatment arm without numerical results to support these findings.