Design, Development and Evaluation of a Digital Health Assistant for Paediatric Asthma

This cohort study is designed to track over a period of six consecutive months lung function parameters, lung inflammation, asthma symptoms and burden, medication adherence, and passively recorded nocturnal asthma symptoms and markers related to sleep quality. The study is comprised of two phases:

In Phase I (months 1-3), Digital Health Assistant (DHA) 's core functionality will be deployed, i.e., active collection of daily lung function, and fortnightly administration of the Asthma Control Questionnaire (ACQ), together with passive monitoring of controller asthma medication use and nocturnal physiological metrics (respiratory rate, SpO₂, heart rate, cough frequency) via inhaler sensor, smartwatch and bedside microphone. Moreover, Digital Health Assistant will act as an engagement/adherence enhancing patient coach, providing behavioral economics informed reminders and incentives, and educational materials on asthma and asthma treatment. This phase will enable to determine the effect of these core features of the Digital Health Assistant on asthma control.

In Phase II (months 3-6), the platform will be augmented with lung-function-fluctuations analysis-informed therapeutic recommendations, allowing to quantify the incremental benefit of targeted decision support beyond the gamified DHA alone.

In addition, an embedded qualitative study will be conducted to evaluate acceptability of and engagement with the DHA. This will include in-depth interviews (IDIs) with adolescents and focus group discussions (FGDs) with adolescents and healthcare providers.

• Phase I (months 1-3): DHA core functionality (Other): Active collection of daily lung function, and fortnightly administration of the Asthma Control Questionnaire (ACQ), together with passive monitoring of controller asthma medication use and nocturnal physiological metrics (respiratory rate, SpO₂, heart rate, cough frequency) via inhaler sensor, smartwatch and bedside microphone. Moreover, ALEX will act as an engagement/adherence enhancing patient coach, providing behavioral economics informed reminders and incentives, and educational materials on asthma and asthma treatment. This phase will enable to determine the effect of these core features of the DHA on asthma control.
• Phase II (months 3-6): platform augmentation (Other): Platform augmentation with lung-function-fluctuations analysis-informed therapeutic recommendations, allowing to quantify the incremental benefit of targeted decision support beyond the gamified DHA alone.
• Embedded qualitative study (Other): An embedded qualitative study will be conducted to evaluate acceptability of and engagement with the DHA. This will include in-depth interviews (IDIs) with adolescents and focus group discussions (FGDs) with adolescents and healthcare providers.

Primary outcomes

• Change in the asthma control questionnaire (ACQ) score [After 3 months relative to baseline (= Visit 2)]: The Asthma Control Questionnaire (ACQ) measures asthma control over the past week, with scores ranging from 0 (well-controlled) to 6 (extremely poorly controlled).

Secondary outcomes

• Change in the asthma control questionnaire (ACQ) score [At Visit 2 (3 months after baseline), at Visit 3 (4.5 months after baseline),at Visit 4 (6 months after baseline)]: The Asthma Control Questionnaire (ACQ) measures asthma control over the past week, with scores ranging from 0 (well-controlled) to 6 (extremely poorly controlled).
• Change in adherence to preventive inhaled corticosteroids [At 1.5 months, 3 months, 4.5 months and 6 months after baseline]: Adherence is defined as the proportion of preventer doses taken relative to the number of doses prescribed for a given time window.
• Number of days off school [From Baseline to Visit 4 (6 months after baseline)]: Proportion of days off school for any reason with respect to the total number of available official school days since last visit (as reported by the patient and/or their parents/caregivers).
• Number of unplanned attendances to general practitioner/emergency department for asthma [From Baseline to Visit 4 (6 months after baseline)]: Number of unplanned attendances to general practitioner/emergency department for asthma. since last visit (as reported by the patient and/or their parents/caregivers).
• Number of days of reliever (fast acting β-agonists) use [From Baseline to Visit 4 (6 months after baseline)]: Number of days of reliever (fast acting β-agonists) use since last visit (as reported by the patient and/or their parents/caregivers).
• Number of participants with one or more asthma exacerbations [From Baseline to Visit 4 (6 months after baseline)]: Number of participants with one or more asthma exacerbations (as reported by the treating physician).
• Absence from work the patient (as reported by the parents/caregivers). [From Baseline to Visit 4 (6 months after baseline)]: Whether or not parents or caregivers were absent from work for one or more days since last visit due to health issues concerning the patient (as reported by the parents/caregivers).
• Correlation between nocturnal breathing and nocturnal cough frequency measured passively using the smartphone and the smartwatch [From Baseline to Visit 4 (6 months after baseline)]: Correlation between nocturnal breathing and nocturnal cough frequency measured passively using the smartphone and the smartwatch

Sex: All, ages: 10 Years to 19 Years

Observational study population:

Inclusion Criteria:

* Written informed assent or consent, and parental/caregivers consent, depending on age.
* Age 10 to 19 years.
* Sufficient understanding of the Romanian language.
* Digital literacy, including the parents/caregivers, as assessed by the treating physician and/or by the recruiting healthcare provider using a multiple-choice questionnaire administered to the patient and their parents after a brief introduction to the functionalities of the Alex app.
* Confirmed asthma, i.e., history of recurrent wheeze, at least one spirometry in the three years prior to inclusion showing reversible obstruction (increase in forced expiratory volume at one second (FEV1) of ≥12% and/or ≥200ml) and/or a positive airway challenge test142.
* Participants need to be under treatment with regular prescribed asthma drugs, including inhaled corticosteroids, Long-acting β adrenoceptor agonists (LABA), and/or leukotriene receptor antagonists at recruitment, with no change in their medication in the last month.

Exclusion Criteria:

* Inability to perform adequate lung function measurements due to physical and/or intellectual disability.
* Acute asthma exacerbation requiring systemic corticosteroids within four weeks prior to recruitment.
* Not willing to use smartphones.
* Underlying chronic respiratory disease other than asthma (cystic fibrosis, primary ciliary dyskinesia).
* Acute lower respiratory tract infections (e.g., pneumonia, bronchitis) diagnosed by physician within past 4 to 6 weeks. For tuberculosis, see next exclusion criterion.
* Active tuberculosis as per Quantiferon test.
* Other causes of nocturnal cough such as postnasal drip, and vocal cord dysfunction.
* Active smoking as per urinary Cotinin test.
* Substance abuse as per urinary drug test.

Qualitative study population:

Inclusion criteria:

* Enrolled in the observational study
* Have had access to the DHA for at least 6 weeks
* Provide informed assent (and parental/guardian consent where applicable) or consent, according to age
* Able to participate in interviews or group discussions in Romanian

Exclusion criteria:

* Significant cognitive or communication difficulties that would limit participation in interviews or group discussions
* Withdrawn from the observational study prior to data collection for qualitative work

• Edgar Delgado-Eckert, Prof. Dr. med., Principal investigator, University Children's Hospital at University of Basel, Basel, Switzerland
• Torsten Schmitz Cherdron, Principal investigator, Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland
• Filipe Da Conceicao Barata, Principal investigator, Center for Digital Health Interventions at ETH Zurich, Zurich, Switzerland