Cardiopulmonary Fitness in Children With Asthma Versus Healthy Children
Condition: Asthmatic
MeSH terms: Asthma
Study type: Observational

Summary: 
      Asthma is the most common chronic disease in children worldwide. Asthma is characterised by a
      chronic inflammatory disorder of the airways,episodes of wheezing, breathlessness, chest
      tightness and coughing. There is a large variability of asthma prevalence between countries
      from 11 to 15% for children in developed countries.

      Asthma may limit the patient's ability to be physically active and can lead to a sedentary
      lifestyle and affect patients' quality of life. Indeed, long-term goal of asthma management
      as any chronic disease is to control symptoms in order to ensure a normal quality of life to
      children with asthma In 1980, the World Health Organization stated that functional capacity
      explorations best reflect the impact of a chronic disease on the quality of life. Indeed,
      cardiopulmonary exercise test (CPET) has become the "gold standard" in functional evaluation
      of cardiorespiratory diseases in adults gradually extended to children. Physical fitness is
      evaluated by maximal oxygen uptake "VO2 max" during a CPET. CPET also allows to determine
      possible limiting factors (cardiac limitation, ventilatory limitation, muscular
      deconditioning) responsible for a lower VO2max.

      There is actually contradictory evidence regarding the aerobic fitness levels of asthmatic
      children and it remains unclear whether significant differences exist between asthmatic
      children and their non-asthmatic counterparts. Few studies suggest ventilatory exercise
      limitations linked to the severity of bronchial obstruction whether others put in light the
      impact of muscular deconditioning in the asthmatic population.

      In this context, the investigators aimed to compare the cardiopulmonary fitness of children
      with asthma with that of age-adjusted and gender-adjusted controls. The investigators also
      intended to identify clinical characteristics associated with VO2max in this population.
    

Detailed description: 
      This retrospective study was carried out from November 2010 to September 2015 for control
      children (already published PMID: 29170358) : and January 2015 to December 2019 for asthmatic
      children.

      CPET were realised in 2 paediatric CPET laboratories (centre 1: Montpellier University
      Hospital, France; centre 2: Paediatric Cardiology and Rehabilitation Centre,
      Institut-Saint-Pierre, Palavas-Les-Flots, France).

      Children aged 5 to 18 years old were recruited in one of the 2 CPET laboratories.

      Two groups were identified: children with asthma and the control children.

        1. The asthma group consisted of children followed for asthma by any pediatrician or
           pulmonologist and referred to one of the 2 CPET laboratories. The following clinical
           data were collected : gender, weight, height, treatments to deduce treatment level (GINA
           step), associated pathologies, activity level, symptoms during exercice

        2. The control group consisted of children referred for a non-severe functional symptom
           linked to exercise (murmur, palpitation, or dyspnoea) or for a medical sports
           certificate. These children were classified in the control group only after a completely
           normal check-up, including physical examination, electrocardiogram, echocardiography,
           and spirometry. Children with any chronic disease, medical condition (cardiac,
           neurologic, respiratory, muscular, or renal), or medical treatment and those requiring
           any further specialized medical consultation were not eligible. The clinical data
           collected concerned gender, weight, height.

      CPET procedures in both centres were harmonized before the study started. Spirometry was
      systematically performed before the exercise test with a flow volume curve and measurement of
      forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the FEV1/FVC
      ratio (FEV1/FVC), with normalization to GLI 2012 Z scores. The same investigator coordinator
      manually calculated the VO2max and the ventilatory anaerobic threshold (VAT) using Beaver's
      method. VO2max and VAT values were normalized in a percentage of the predicted VO2max using
      normal values from Wasserman and Cooper. The investigators considered VO2max below 80% of
      predicted value as pathologic value and a VAT value below 55 % of predicted VO2max was in
      favor of muscular deconditioning.

      All informations from CPET were recorded : heart rate (HR), blood pressure (BP), estimated
      VO2/HR, VAT, breathing reserves (BR), respiratory rate (RR), VE/VCO2 slope, Tidal Volume (VT)
    

Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        Children aged 5 to 18 years old recruited in one of the 2 CPET laboratories after a regular
        paediatric cardiology outpatient visit.

        Cases : children with asthma Control : healthy children from a cohort already published
        (PMID: 29170358)
      
Keywords: Asthmatic children; VO2 max; Physical fitness; Peadiarics