Table 1.

Description of the intervention

TIDieR category	Description of the CFHealthHub intervention
	CFHealthHub digital platform (website and smartphone application) that: (1) displays real-time objective adherence data from the nebulisers to the participant and care team, (2) provides behavioural change tools and content (comprises of six modules, see 1)) in a ‘My Toolkit’ area designed to increase motivation for adherence, to address capability and opportunity barriers and to build habits for taking treatments, and (3) includes an intervention manual, with procedures and worksheets for use by clinical interventionists in their interactions with participants. Behaviour change sessions where the content and behaviour change techniques within each of the six modules were delivered through the participant interactions with site’s interventionist.
Why	CFHealthHub aims to support adults with CF to increase adherence to nebuliser treatment using the COM-B framework and to build habits for treatment to enable maintenance.
Who	Interventionists were healthcare professionals employed for the trial (n=32), 18 of whom job shared (with clinical roles in the CF team) and 26 were existing members of the centre’s CF multidisciplinary team. There was the WTE of eight physiotherapists, three psychologists, six specialist CF nurses, one pharmacist and one dietitian; that is, one WTE interventionist per centre.
How and where	All intervention sessions were structured by a worksheet to guide delivery and delivered with a person-centred communication style. First intervention sessions were always face to face; review sessions were face to face or by telephone.
When and how much	Intervention participants had access to the digital platform and received tailored flexible support from the interventionist throughout the 12-month trial period. All intervention participants received a first and intermediate review visit, thereafter support was tailored according to response (figure 1; further details in online supplemental 1appendix A). Participants with baseline objectively measured effective adherence ≤80% underwent a normal pathway of six sessions (1× first intervention visit 40–60 min; 2× intermediate reviews 5–15 min; 2× reviews 30–45 min; 1× phase review 20–30 min) over 12 weeks, with phase reviews every 12 weeks thereafter, or every 6 weeks for participants with baseline adherence <25%. Participants with baseline objectively measured effective adherence >80% followed a ‘very high adherence’ pathway of three sessions (1× first intervention visit; 1× intermediate review; 1× phase review), with phase reviews every 12 weeks thereafter. Following these initial pathways, additional blocks of sessions were offered when: (1) a participant requested further support; (2) a participant’s adherence reduced by ≥20% in a 4-week period; or (3) a participant received intravenous antibiotics for an exacerbation.
Tailoring	Each session was tailored to an individual’s needs based on: their nebulised medication prescription; their necessity and concern beliefs (BMQ-Specific); and their discussions with interventionists about their motivation and specific capability and opportunity barriers to adherence. For example, the goal setting and review and treatment plan modules are used only for participants who are motivated to increase their treatment adherence and participants with very low motivation spend more time focusing on the my treatment module and on relationship building with the interventionist. While the entire content of the digital platform was available for participants to browse, tailored/personalised aspects were added to the ‘My Toolkit’ area. For example, content addressing particular participant concerns about treatment, and personal action and coping plans.
Modifications	There were no major changes to the delivery of the intervention through the study.
How well	Fidelity of intervention delivery was assessed throughout the study with two reviewers independently assessing a sample of audio-recording and worksheets from sessions (first intervention session, review, phase review) using a scoring sheet (further details in online supplemental appendix A).

BMQ-Specific, beliefs and medications questionnaire-specific; CF, cystic fibrosis; COM-B, capability opportunity motivation-behaviour; TIDieR, template for intervention description and replication; WTE, whole time equivalent.