The goal of this clinical trial is to compare REBUILD-SM (a purpose-built smartphone app and self-management package) with standard care in people with interstitial lung disease (ILD). The main question it aims to answer is:

• Does REBUILD-SM improve health-related quality of life, symptoms, anxiety, self-efficacy and physical activity for people with ILD?

Participants in the intervention group will work through the self-management package with support from a healthcare professional via phone or Zoom. They will also enter deidentified health data into the RE-BUILD smartphone app to track their progress over time. Participants in the control group will use a reduced functionality version of the smartphone app only.

Researchers will compare both groups to see if there is any difference in health-related quality of life, symptoms, anxiety, self-efficacy and level of physical activity.

This study compares REBUILD-SM with standard care in people with ILD. REBUILD-SM comprises a purpose-built smartphone app that allows subjects to enter and track health data over time and an integrated self-management package.

Participants will enter their respiratory diagnosis, medications and side effects, weight, lung function test results, oxygen saturation level and supplemental oxygen usage into the smartphone app. They will also complete questionnaires at specific timepoints using the app. Participants will input most of this data at the beginning of the trial and update it when it changes, for example, after obtaining a new lung function result, starting a new medication, or getting a new side effect from an existing medication. Entering data into the app is expected to take around 30 minutes at the start of the trial, and about 20 minutes at 12, 26 and 52 weeks when completing the questionnaires. Updating data is expected to take about 5-10 minutes and will only happen when there is a change, for example, once per week, although it may not be this frequent.

The app will not provide any recommendations on the health data participants enter - it is simply for recording purposes. To ensure data collection is as complete as possible, electronic reminders will be sent to participants when questionnaires are not completed at the specified timepoints and will alert the study team if the participant fails to complete the questionnaires after the reminder. This will prompt a phone call from a member of the study team to encourage the participant to complete the endpoints. App analytics will be used in the data analysis phase (after the trial is over) to understand how participants have engaged with the app.

Participants in the intervention group will be asked to log into and use the self-management website or view the content via the REBUILD app with support from the study team. The self-management content includes 13 modules and has been designed in collaboration with people with ILD to help increase their ability to self-manage their chronic disease.

During the intervention period, participants will receive four phone calls from a health professional involved in the management of people with ILD to help them set health-related goals and identify appropriate modules from the website to help achieve these goals. These four phone calls are expected to take about 15-30 minutes each.

Each module provides information regarding the topic and provides access to relevant websites, fact sheets, booklets, videos and webinars as well as other external resources. Participants will have direct access to these external resources from within the package through hyperlinks embedded in the title of each resource. Participants are expected to work through their selected modules at their own pace - there is no specific amount of time they are required to allocate to the intervention, and they can utilize as many or as few of the resources as they like.

Inclusion Criteria:

• Diagnosis of fibrotic ILD
• In possession of a smartphone/tablet and an email address
• Able to understand written and spoken English
• Adequate digital literacy to complete requirements of trial
• On stable ILD treatment for 30 days prior to enrolment

Exclusion Criteria:

• Not in possession of a smartphone/tablet
• Insufficient digital literacy to complete requirements of trial
• Unable to communicate in written/spoken English
• Not on stable ILD treatment for 30 days prior to enrolment
• Acute exacerbation within 30 days prior to enrolment
• Participating in pulmonary rehab at enrolment or during 12-week intervention period
• Unable to provide informed consent

Deidentified data will be placed in a secure repository for future analysis.

The data will be available at the end of the trial (approx. April 2028).

Requires ethical approval

Due to the nature of the intervention, blinding will not be possible for participants and care providers (i.e. healthcare professionals making phone calls to participants). Where practicable, members of the investigative team will be blinded. Outcome assessors will also be blinded.