Summary of findings 1. Cough augmentation therapy compared with an alternative cough augmentation technique or combination of techniques for people with neuromuscular diseases.

Cough augmentation compared with an alternative cough augmentation technique or combination technique
Patient or population: participants with chronic neuromuscular diseases Settings: – Intervention: cough augmentation Comparison: alternative cough augmentation technique
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Alternative cough augmentation technique	Cough augmentation
Number of unscheduled hospital admissions for 'maintenance therapy'	Not reported
Duration of hospital stay (days) for 'rescue' therapy	Not reported
PCF Follow‐up: < 1 day ('rescue' and 'maintenance' therapy)	8 RCTs (198 participants) studied various cough augmentation techniques or combinations of techniques. Reported that MI‐E, mechanical exsufflation, MAC, mechanical insufflation, manual and mechanical breathstacking, glossopharyngeal breathing, mechanical insufflation + MI‐E, MAC + MI‐E, and MAC + breathstacking may increase PCF above unassisted cough. 2 cross‐over RCTs (26 participants) reported no change in PCF with MAC compared to unassisted cough. 1 cross‐over RCT reported no difference in PCF with mechanical insufflation compared to unassisted cough (22 participants). Repeated measures data were reported and could not be meta‐analysed.		—	198 (8 RCTs (7 cross‐over, 1 parallel group)	⊕⊝⊝⊝ Verylowa	Cough augmentation may improve PCF compared to unassisted cough, but the certainty of evidence was very low. See Table 2 for details.
Any adverse events Follow‐up: < 1 day or 1–2 days ('rescue and maintenance therapy)	4 cross‐over RCTs (64 participants) compared various cough augmentation techniques or combinations of techniques (including mechanical insufflation, mechanical exsufflation, MI‐E, MAC, MAC + manual breathstacking, MI‐E + MAC, MAC + manual breathstacking, MAC + mechanical insufflation). 0 trials reported serious adverse events. 3 trials reported no adverse events occurred. In most trials it was unclear whether adverse effects were systematically investigated. 1 cross‐over RCT (8 participants) reported fatigue as an adverse event, measured on a 10‐point ordinal VAS. Fatigue was reported to increase from baseline in the MAC + M‐IE group, with no change in the MAC group. No data were provided for the control group or the separate periods of cross‐over. The mean postintervention fatigue score for both periods of the cross‐over trial was 5.1 (SD 2.6).		—	64 (4 cross‐over RCTs)	⊕⊝⊝⊝ Verylowb	We are unable to draw a conclusion as the certainty of evidence is very low. See Table 3; Table 4 for details.
Quality of life for 'maintenance' therapy	No study measured or reported quality of life.
Participant preference or satisfaction for 'rescue' and 'maintenance' therapy	No study measured or reported participant preference or satisfaction.
*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% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; MAC: manually assisted cough; MI‐E: mechanical insufflation‐exsufflation; PCF: peak cough flow; RCT: randomised controlled trial; RR: risk ratio; SD: standard deviation; VAS: visual analogue scale.
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.

^aDowngraded three levels – twice for study limitations – all studies were at high risk of bias in at least one domain and unclear in several. Data were based on repeated (dependent) measurements from seven cross‐over and one parallel‐group RCTs. We also downgraded the evidence for imprecision – all studies had a small sample size, wide CI, or both. The outcome was measured less than one day after the intervention, rather than in the medium and long term as specified.
^bDowngraded three levels – twice for study limitations – all studies were at high risk of bias in at least one domain and unclear in several. Data were based on repeated (dependent) measurements from seven cross‐over and one parallel‐group RCTs. We also downgraded the evidence for imprecision – all studies had a small sample size.