Investigating outcome measures for physiotherapy trials of airway clearance in adults with cystic fibrosis
File(s)
Full thesis
Author(s)
Stanford, Gemma
Type
Thesis
Abstract
Background
Airway clearance techniques (ACTs) are integral to cystic fibrosis (CF) management. However, there’s no recognised best outcome measure (OM) to assess ACT efficacy and no previous RCTs specifically investigating clinimetric properties of potential OMs (systematic review PROSPERO no.CRD42020206033). Therefore, this RCT assessed clinimetric properties of spirometry, sputum weight, multiple breath washout (MBW), impulse oscillometry (IOS) and electrical impedance tomography (EIT), to determine the most appropriate short-term OM for ACTs.
Methods
Adults with CF were randomised to either a 30-minute session of supervised ACT or rest, completing MBW, IOS and spirometry pre-and post. EIT and sputum were collected during rest/ACT. At a subsequent visit OMs were completed with the other intervention. Primary endpoint was net difference in change in OMs pre-and post-ACT/rest. Secondary endpoints included other physiological parameters. Target sample size was 64, allowing subgroup analysis stratified by FEV1 percent predicted (pp) (ppFEV1 >60% & 60%). Clinimetrics and participant preference were assessed.
Results
68 participants completed: 42male; mean age 41yrs (SD:14.2); mean ppFEV1 64.5% (SD:23.9). Sputum weight differed significantly after ACT v. rest, mean net difference of change 5.71g (95% CI:4.21, 7.21) (p<0.001). No other significant differences for primary OMs. No clinically significant changes for secondary endpoints. Subgroup analysis showed no additional differences. All OMs showed good reliability (ICC 0.91-0.99), validity measures were lower. MBW ranked lowest for patient preference.
Conclusions
For adults with CF, spirometry, MBW, IOS and EIT are not suitable OMs to assess single ACT session efficacy. While sputum weight changed significantly, it’s limited in use to sputum producers. OM sensitivity didn’t change with subgroup stratification. All primary OMs showed good reliability but limited validity for ACT efficacy. MBW acceptability was low, probably linked to long duration. Further trials are needed to identify sensitive OMs for short and long-term ACT assessment for the whole adult CF cohort.
Airway clearance techniques (ACTs) are integral to cystic fibrosis (CF) management. However, there’s no recognised best outcome measure (OM) to assess ACT efficacy and no previous RCTs specifically investigating clinimetric properties of potential OMs (systematic review PROSPERO no.CRD42020206033). Therefore, this RCT assessed clinimetric properties of spirometry, sputum weight, multiple breath washout (MBW), impulse oscillometry (IOS) and electrical impedance tomography (EIT), to determine the most appropriate short-term OM for ACTs.
Methods
Adults with CF were randomised to either a 30-minute session of supervised ACT or rest, completing MBW, IOS and spirometry pre-and post. EIT and sputum were collected during rest/ACT. At a subsequent visit OMs were completed with the other intervention. Primary endpoint was net difference in change in OMs pre-and post-ACT/rest. Secondary endpoints included other physiological parameters. Target sample size was 64, allowing subgroup analysis stratified by FEV1 percent predicted (pp) (ppFEV1 >60% & 60%). Clinimetrics and participant preference were assessed.
Results
68 participants completed: 42male; mean age 41yrs (SD:14.2); mean ppFEV1 64.5% (SD:23.9). Sputum weight differed significantly after ACT v. rest, mean net difference of change 5.71g (95% CI:4.21, 7.21) (p<0.001). No other significant differences for primary OMs. No clinically significant changes for secondary endpoints. Subgroup analysis showed no additional differences. All OMs showed good reliability (ICC 0.91-0.99), validity measures were lower. MBW ranked lowest for patient preference.
Conclusions
For adults with CF, spirometry, MBW, IOS and EIT are not suitable OMs to assess single ACT session efficacy. While sputum weight changed significantly, it’s limited in use to sputum producers. OM sensitivity didn’t change with subgroup stratification. All primary OMs showed good reliability but limited validity for ACT efficacy. MBW acceptability was low, probably linked to long duration. Further trials are needed to identify sensitive OMs for short and long-term ACT assessment for the whole adult CF cohort.
Version
Open Access
Date Issued
2023-03-01
Date Awarded
28/03/2024
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Simmonds, Nicholas
Davies, Jane
Bilton, Diana
Jones, Mandy
Sponsor
National Institute of Health and Care Research
Grant Number
CDRF-2014-05-055
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)