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NCT Number: NCT05945355

Mechanistic Study of Inspiratory Training in Childhood Asthma (MICA)

This is single-center cross-sectional mechanistic study in lean and obese children with moderate-severe asthma, followed by a randomized, SHAM-controlled trial of Inspiratory Training (IT). The primary outcome is to describe the contributions of inspiratory muscle dysfunction (IMD) and Small Airway Dysfunction (SAD) to obesity-related versus non-obesity-related asthma. The study will involve training (IT) for 8 weeks at three intensity levels (SHAM, low and high). Target dose: 150 inspirations three times weekly. The population includes 6 to 17-year-old children with moderate to severe asthma and with a body mass index qualifying as normal habitus (BMI 5th to 84th CDC percentile) or obese habitus (≥95th percentile BMI and less than 170% of the 95th CDC percentile). Participants will be involved for 10 weeks. The investigators will use analysis of covariance (ANCOVA) to estimate and test the difference in mean values of baseline measures between obese and non-obese cohorts. Covariates will include age, sex (male/female), race/ethnicity, baseline asthma severity (NAEPP step 2 vs ≥3), and atopy status

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Key information

Conditions

Asthma in Children Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Pediatric Asthma Pediatric Obesity Signs and Symptoms

Age range

6 year–17 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Duke Health Center Creekstone, Durham, North Carolina, United States

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About this study

Cross-sectional analytic study of pulmonary mechanics comparing lean and obese children with asthma followed by a randomized, SHAM-controlled 3-arm intervention trial of inspiratory training on small airway dysfunction and inspiratory muscle function.

The central objective of the MICA (Mechanistic Study of Inspiratory Training in Childhood Asthma) study is to assess key respiratory mechanisms in 6-17 year olds with symptomatic asthma (with and without obesity) in response to IT. Our central hypothesis is that obesity promotes dyspnea and worse asthma control via inspiratory muscle fatigue/dysfunction (IMD) and small airway dysfunction (SAD), and that IT will improve inspiratory muscle function and small airway measures.

The sample size calculations and main analyses for the IT trial are designed as a traditional parallel arm intervention trial (any dose IT vs. SHAM control) with visits 1-2 serving as the baseline evaluation and the main IT endpoints being collected at the 8-week visit.

In depth phenotyping involving measures of respiratory mechanics and muscle functioning and a RCT involving inspiratory training will address these objectives.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 6-17 years of age
  • Documented clinician-diagnosed asthma
  • Currently requiring 2 or more controller prescriptions to treat disease (i.e. moderate to severe persistent disease)
  • Either obese (≥95th percentile BMI and less than 170% of the 95th CDC percentile) or have a normal BMI (BMI 5th to 84th CDC percentile)

Exclusion criteria

  • ACT (asthma control test) score <17
  • Ever intubated for asthma
  • FEV1 < 50% of predicted at enrollment
  • Currently pregnant
  • Legal guardian unable to consent in English or Spanish
  • Any major chronic illness that, in the opinion of the PI, would interfere with participation
  • Younger than 6 years of age

Treatment and study plan

Pro2 - Low Dose - 40% of participant's MIP

Device

Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that subjects achieve a pressure target that is 40% of their MIP (maximum inspiratory pressure).

Pro2 - High Dose - 75% of participant's MIP

Device

Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that subjects achieve a pressure target that is 75% of their MIP (maximum inspiratory pressure).

Pro2 - SHAM - 15% of participant's MIP

Device

Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that participants achieve a pressure target that is 15% of their MIP (maximum inspiratory pressure).

Primary outcomes

  1. Number of participants with inspiratory muscle dysfunction in obesity-related versus non-obesity-related asthma

    Time frame: 10 weeks

  2. Number of participants with small airway dysfunction in obesity-related versus non-obesity-related asthma

    Time frame: 10 weeks

Secondary outcomes

  1. Inspiratory muscle endurance (sustained maximal inspiratory pressure)

    Time frame: 10 weeks

Other outcomes

  1. Small airway dysfunction as measured by impulse oscillometry

    Time frame: 10 weeks

  2. Small airway dysfunction as measured by residual volume

    Time frame: 10 weeks

Study contacts

Contact information is provided by the study sponsor or research team.

Jason Lang, MD

CONTACT

[email protected]

9196843364

Sponsors and collaborators

Lead sponsor

Duke University

Other

Collaborators

  • National Institutes of Health (NIH)

Registry information

Acronym: MICA

Important dates

Study start
2024
Primary completion
2027
Study completion
2027
First posted
Jul 14, 2023
Registry last updated
Aug 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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