Introduction: We aimed to evaluate the longitudinal relationships, both at between–and within–person levels, that adherence to inhaled corticosteroids–based maintenance treatment and inhalation technique present with symptom control, exacerbations, and health – quality of life (HRQoL) in children and adolescents with asthma. Methods: Participants (6–14 years old) from the ARCA (Asthma Research in Children and Adolescents) cohort – a prospective, multicenter, observational study (NCT04480242) – were followed for a period from 6 months to 5 years, via computer–assisted telephone interviews and a smartphone application. The Medication Intake Survey–Asthma (MIS–A) was administered to assess the implementation stage of adherence; and the Inhalation Technique Questionnaire (InTeQ) to assess the five key steps when using an inhaler. Symptoms control was measured with the Asthma Control Questionnaire (ACQ), and HRQL with the EQ–5D and the PROMIS–Pediatric Asthma Impact Scale (PROMIS–PAIS). Multilevel longitudinal mixed models were constructed separately with symptom control, exacerbation occurrence, EQ–5D, and PROMIS–PAIS as dependent variables. Results: Of 360 participants enrolled, 303 (1203 interviews) were included in the symptom control and exacerbation analyses, 265 (732) in the EQ–5D, and 215 (619) in the PROMIS–PAIS. Around 60% of participants were male and most underwent maintenance treatment with inhaled corticosteroids plus long–acting β–agonists in a fixed dose (68–74%). Within–person variability was 83.6% for asthma control, 98.6% for exacerbations, 36.4% for EQ-5D and 49.1% for PROMIS-PAIS. At within–person level, patients with higher adherence had better symptom control (p=0.002) and HRQoL over time (p=0.016). Patients with better inhalation technique reported worse HRQoL simultaneously (p=0.012), but better HRQoL in future assessments (p=0.012). Frequency of reliever use was associated with symptom control (p<0.001), exacerbation occurrence (p<0.001), and HRQoL (p=0.042); and boys were more likely to present better symptom control and HRQoL than girls. Conclusion: Our results confirm longitudinal associations at within–person level of the two indicators of quality use of inhalers: for adherence to maintenance treatment with symptom control and HRQoL, and for inhalation technique with HRQoL. Although treatment adherence showed to be excellent, a third part of participants reported a suboptimal inhalation technique, highlighting the need of actions for improving asthma management of pediatric population.

The authors have declared no competing interest.

https://classic.clinicaltrials.gov/ct2/show/NCT04480242?term=NCT04480242&draw=2&rank=1

Financial support for this study was provided through grants by the Instituto de Salud Carlos III FEDER: Fondo Europeo de Desarrollo Regional (PI15/00449) and Generalitat de Catalunya (AGAUR2021 SGR 00624, 2017 SGR 452). The following researchers have worked on this manuscript while funded by grants: CLB (University of Costa Rica OAICE-85-2019) and KM (ISCIII FI16/00071).

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The studies involving humans were approved by Ethics committee of clinical research of the Parc de Salut Mar (n 2015/62/12l) and of participant centers, following national and international guidelines (code of ethics, Helsinki Declaration), as well as legislation on data confidentiality (Spanish Organic Law 3/2018 of December 5 on the Protection of Personal Data and the Guarantee of Digital Rights). The studies were conducted in accordance with the local legislation and institutional requirements.

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