Title : Investigating outcome measures for physiotherapy trials of airway clearance in adults with cystic fibrosis ( CF ).
Gemma Stanford
Introduction : The best outcome measure ( OM ) for airway clearance ( AC ) in CF is unknown . Our NIHR funded RCT compares standard OMs ( sputum weight , FEV1 ) to new OMs ( electronic impedance tomography ( EIT ), lung clearance index ( LCI ), impulse oscillometry ( IOS )) to determine the most effective measure of AC . We describe our ongoing trial , present baseline characteristics and OM reproducibility .
Methods : Subjects complete OMs of LCI , IOS and FEV1 then are randomised to either supervised AC or rest for 30 minutes . LCI , IOS and FEV1 are repeated straight afterwards . EIT , oxygen saturations and sputum are collected during rest / AC period . At a subsequent visit the OMs are completed with the other intervention . The research team are blinded to sequence allocation . Primary endpoint is difference in change in OMs preand post- AC / rest . Target sample 64 , calculated with 80 % power and significance of 5 % for each OM .
Results : Recruitment to date ( after 36m ): 537 patients pre-screened , 2 enrolled , 50 completed ( 89 % of target to date ( TTD )). Completed subjects ’ demographics : 30male ; median age 48yrs ( IQR 17.5 ); 50 % F508del / F508del ; median FEV1 70 % pred ( IQR 42.5 ). Completed visits are 96 % of TTD , but scheduled visits are 201 % of TTD . Primary cause of cancellations is patient illness . Median visit length 209 minutes ( IQR 50.5 ). LCI has the longest duration ; ICCs of pre-intervention OMs are good between visits ( table ).
Conclusion : Completion of study visits is challenging , due to inclusion & exclusion criteria and requiring patient stability . Recruitment improved with enhanced communication and strategic overbooking . Trial closure due to the COVID-19 pandemic has inhibited completion of recruitment to date . The newer OMs of LCI , IOS and EIT are reproducible and feasible ; however , the long duration of LCI may inhibit future use in this cohort . We believe this RCT is the first to evaluate these OMs for use in CF AC trials .
Impact : Identification of a robust outcome measure for AC effect is paramount for future scientific research and for the application of personalized therapy not only for CF but for other chest diseases . Being able to assess effect of AC interventions will help to optimize management and reduce healthcare utilisation .
References :
Wilson LM , Morrison L , Robinson KA . Airway clearance techniques for cystic fibrosis : an overview of Cochrane systematic reviews . Cochrane Database of Systematic Reviews 2019 , Issue 1 . Art . No .: CD011231 . DOI : 10.1002 / 14651858 . CD011231 . pub2 .
Bradley JM , Moran FM , Elborn JS . Evidence for physical therapies ( airway clearance and physical training ) in cystic fibrosis : An overview of five Cochrane systematic reviews . Respiratory Medicine Volume 100 , Issue 2 , February 2006 , Pages 191-201
Stanford G , Davies JC , Usmani O , et al . Investigating outcome measures for assessing airway clearance techniques in adults with cystic fibrosis : protocol of a single-centre randomised controlled crossover trial . BMJ Open Respiratory Research 2020 ; 7 : e000694 . DOI : 10.1136 / bmjresp-2020-000694