Abstract: Searches retrieved 35 references to 21 individual studies, of which seven (n = 208) were eligible for inclusion. One study was of parallel design with the remaining six being cross-over in design; participant numbers ranged from 17 to 75. The total study duration varied between four days and two years. The age of participants ranged between seven and 63 years with a wide range of disease severity reported. Six studies enrolled participants who were clinically stable, whilst participants in one study had been hospitalised with an infective exacerbation. All studies compared autogenic drainage to one (or more) other recognised airway clearance technique. Exercise is commonly used as an alternative therapy by people with cystic fibrosis; however, there were no studies identified comparing exercise with autogenic drainage. The quality of the evidence was generally low or very low. The main reasons for downgrading the level of evidence were the frequent use of a cross-over design, outcome reporting bias and the inability to blind participants. The review's primary outcome, forced expiratory volume in one second, was the most common outcome measured and was reported by all seven studies; only three studies reported on quality of life (also a primary outcome of the review). One study reported on adverse events and described a decrease in oxygen saturation levels whilst performing active cycle of breathing techniques, but not with autogenic drainage. Six of the seven included studies measured forced vital capacity and three of the studies used mid peak expiratory flow (per cent predicted) as an outcome. Six studies reported sputum weight. Less commonly used outcomes included oxygen saturation levels, personal preference, hospital admissions or intravenous antibiotics. There were no statistically significant differences found between any of the techniques used with respect to the outcomes measured except when autogenic drainage was described as being the preferred technique of the participants in one study over postural drainage and percussion. Autogenic drainage is a challenging technique that requires commitment from the individual. As such, this intervention merits systematic review to ensure its effectiveness for people with cystic fibrosis. From the studies assessed, autogenic drainage was not found to be superior to any other form of airway clearance technique. Larger studies are required to better evaluate autogenic drainage in comparison to other airway clearance techniques in view of the relatively small number of participants in this review and the complex study designs. The studies recruited a range of participants and were not powered to assess non-inferiority. The varied length and design of the studies made the analysis of pooled data challenging.

Plain-language summary: We searched the literature for studies comparing at least two sessions of autogenic drainage with other breathing techniques and devices which help to clear the lungs of mucus. We included seven studies in the review involving 208 people with cystic fibrosis, aged between seven and 63 years of age. People were selected for one physiotherapy treatment or the other randomly. The number of people in the studies ranged from 17 to 75, and had a wide range of disease severity. The studies lasted from four days to two years in total. We did not find any clear evidence that autogenic drainage was better than the other techniques for lung function or quality of life in either the short-term or long-term studies. This was also true for our other outcome measures such as hospital admissions, additional antibiotic treatment, exercise tolerance and oxygen saturation, but in one study autogenic drainage was the preferred technique compared to postural drainage and percussion. Exercise was identified as a comparator for airway clearance by the authors of this review but no included studies used it in this way, even though it is often used as an alternative therapy by people with cystic fibrosis. Overall, the quality of the evidence from the studies was judged to be mainly low or very low. The main problems for this being the small numbers of participants in each study, the unclear reporting of results in the studies and the study design used. In one study, which was classed as having a high risk of bias due to incomplete results, those taking part had to change physiotherapy technique halfway through the study and there were many who dropped out and did not comply with the postural drainage and percussion treatment arm. Five of the seven studies used research staff to assess results who did not know which technique each person was using and this improved the quality of the evidence and reduced any bias.