VO2max & HRQoL in Children With Sickle Cell Disease
Condition: Sickle Cell; Children
MeSH terms: Anemia, Sickle Cell
Study type: Observational

Summary: 
      Sickle cell disease is the most common inherited genetic disorder, accounting for 300,000
      births worldwide per year. It is caused by an autosomal recessive mutation of the β-globin
      gene, responsible for an abnormal hemoglobin, the main protein in red blood cells,
      responsible for transporting oxygen from the lungs to the tissues. The abnormal hemoglobin,
      known as "Sickle" or S, deforms the red blood cell, causing chronic hemolytic anemia, organ
      damage (heart, spleen, etc.) and vaso-occlusive crises. Therapeutic progress and specialised
      patient follow-up have considerably improved the vital and functional prognosis of children
      and adolescents with sickle cell disease. Physical fitness, measured during a
      cardiorespiratory exercise test (CPET), is used to determine maximal oxygen uptake (VO2max).
      Patients with sickle cell disease have a multifactorial limitation of exercise tolerance,
      which may affect their physical fitness. Authors have shown that VO2max is impaired in
      children and adolescents with sickle cell disease, independently of their baseline hemoglobin
      level. Yet VO2max is a key determinant of health-related quality of life (HRQoL) in patients
      being monitored for a chronic disease. In the past, our team has contributed to the
      assessment of HRQoL in several groups of pediatric patients suffering from chronic disease
      (congenital heart disease, PAH). To date, the link between impaired physical fitness and
      HRQoL has not been demonstrated in sickle cell children. The pathophysiological determinants
      of reduced physical capacity and exercise tolerance in sickle cell patients have also not
      been fully elucidated. Studying these factors will enable us to propose appropriate treatment
      in the future, with the aim of improving physical fitness and HRQoL in children and
      adolescents with sickle cell disease.
    

Detailed description: 
      This prospective case-control study included sickle cell children and healthy controls from 6
      to 17 years old. Patients refuse the use of medical data will be excluded.

      After description of the study sample, we will first compare the VO2max Z-score between cases
      and controls. We will correlate the VO2max to PedsQL self- and proxy-related and Ricci and
      Gagnon scores (use of the coefficient of correlation rhô). Then we will compare others CPET
      parameters and will determine associated factors of VO2max with others resting data :
      hematological, respiratory, cardiologic, anthropometric, educational (use of the coefficient
      of correlation rhô, and multivariate linear regression model).
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Sickle cell children cohort consisted of children with a genetic diagnosis of sickle cell
        disease (HbS/S or HbS/C), followed at the Department of Pediatrics of Montpellier
        University Hospital, a tertiary care academic institution in southern France.

        Healthy children cohort consisted of children referred to a pediatric cardiologist for a
        nonsevere functional symptom related to exercise (murmur, palpitation, chest pain, and
        dyspnoea) or for a medical sports certificate. These children needed to have a completely
        normal check-up, including physical examination, ECG, and echocardiography. Children with
        any chronic disease, medical condition or medical treatment, and those requiring any
        further specialized medical consultation were not eligible.
      
Keywords: Cardiopulmonary exercise test; VO2max; Sickle cell disease; Child; Heath-related quality of life; Cardiopulmonary rehabilitation