Currently submitted to: JMIR Research Protocols
Date Submitted: May 17, 2020
Open Peer Review Period: May 17, 2020 - Jul 12, 2020
(currently open for review)
Lung function variability in children and adolescents (LUV study): protocol for a prospective, non-randomized, clinical trial
Background Variability analysis of peak expiratory flow (PEF) and forced expiratory volume at 1 s (FEV1) has been used in research to predict exacerbations in adult individuals with asthma. However, there is a paucity of data regarding PEF and FEV1 variability in healthy or asthmatic children and adolescents. The objective of the present study is the assessment of PEF and FEV1 variability in: a) healthy children and adolescents, to define the normal daily fluctuation of PEF and FEV1 and the parameters that may influence it, and b) children and adolescents with asthma, to explore the differences from healthy subjects and reveal any specific variability changes prior to exacerbation. Methods The study will include 100 healthy children and adolescents aged 6 to 18 years (assessment of normal PEF and FEV1 variability) and 100 children and adolescents of the same age with diagnosed asthma (assessment of PEF and FEV1 variability in asthmatics). PEF and FEV1 measurements will be performed using an ultra-portable spirometer (MIR Spirobank Smart) capable to smartphone connection. Measurements will be performed twice a day between 07:00-09:00 and 19:00-21:00 hours and will be dispatched via email to a central database for a period of 3 months. PEF and FEV1 variability will be assessed by detrended fluctuation and sample entropy analysis, aiming to define the normal pattern (healthy controls) and to detect and quantify any deviations (asthmatics). The anticipated duration of the study is 24 months. Discussion Healthy children and adolescents may present normal short- and long-term fluctuations in lung function; the pattern of this variability may be influenced by age, sex and environmental conditions. Significant lung function variability may also be present in children and adolescents with asthma, but the patterns may differ from those observed in healthy children and adolescents. Such data would improve our understanding regarding the chronobiology of asthma and permit the development of integrated tools for assessing the level of control and risk of future exacerbations. Trial registration ClinicalTrials.gov, NCT04163146. Registered on 14 November 2019
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