To Determine the Validity of the ACT in an Adolescent Population With Persistent Asthma
Condition: Asthma
MeSH terms: Asthma
Study type: Observational

Summary: 
      To determine the measurement profiles of the asthma control test (ACT) in an adolescent
      population with persistent asthma.
    

Detailed description: 
      Asthma is the most common chronic illness of childhood, and adolescents represent a group
      that is typically difficult to engage in self-management strategies. Adolescent asthmatics
      tend to have poor perception of symptoms and experience a higher rate of asthma deaths
      compared to younger children. Studies have shown that perceived severity of asthma symptoms
      is related to self-management in adolescents, who were less likely to receive appropriate
      treatment for asthma exacerbation's. This poor perception of asthma control is likely one
      cause of the disproportionate asthma mortality rates seen in adolescent patients.

      Because asthma control is now the focus of asthma care, assessment of control is the critical
      step in appropriate management. The two domains of asthma control, impairment and risk,
      evaluate the role asthma plays in a patient's quality of life and functional capacity on an
      ongoing basis and the risk their asthma presents for future adverse events. Although the
      National Asthma Education and Prevention Program guidelines contain a rubric for asthma
      control based on these domains, thus representing the "gold standard" for asthma care, their
      utilization may be time-consuming and cumbersome to implement in primary care offices, and
      primary care providers may be unfamiliar with their use. For primary care practices following
      adolescent patients, it remains imperative that the tools being used to gauge asthma control
      be evaluated and validated in this at-risk population.

      At this time, there are approximately 17 questionnaires available for use in the assessment
      of asthma control, although most are not well validated. Of these, the most widely validated
      and most commonly used instrument is the Asthma Control Test (ACT). The ACT is a
      self-administered questionnaire intended to assess the impairment domain over the past four
      weeks and is completed by patients starting at age 12 years. The ACT has five questions with
      an overall best score of 25. For primarily adult Caucasian populations, the ACT has been
      found to be a valid, reliable, and responsive instrument of asthma control, and cut-offs for
      controlled and not well controlled asthma (< 19) as well as minimal clinically important
      (MIC) differences (3 points) have been identified. The measurement properties of validity,
      reliability, and responsiveness are critical to the usefulness of any questionnaire in both
      clinical and research settings. However, measurement properties of the ACT are lacking in the
      adolescent asthma population.The landmark validation study for the ACT by Schatz et al was
      comprised of a large sample size of over 300 patients that showed that a cut-off score of 19
      as distinguishing well-controlled versus not well-controlled asthmatics. However, the mean
      age was 35 for that study population, and concerns have been raised as to whether this
      cut-off is appropriate for adolescents in general. Recent studies examining use of the ACT in
      Caucasian and Hispanic adolescent populations have found higher optimal cut points to
      distinguish control classifications.

      Lung function measures are included in the rubric of assessing asthma control by the NAEPP
      (National Asthma Education and Prevention Program). Per these recommendations, spirometry
      should be available to physicians caring for asthma patients and used with initiation of
      treatment, change in asthma control, and every one to two years. While sub-specialists often
      have access to spirometry, office-based spirometry is time-consuming, requires technical
      ability and staff training, equipment maintenance and calibration, and is not always
      available or feasible for use in primary care physician offices. Because spirometry may be of
      limited accessibility to primary care providers, questionnaires are quickly taking a leading
      role in asthma management. Studies of adolescent asthmatics reveal poor perception of asthma
      control leading to under-reporting of asthma symptoms and thus under-treatment of
      exacerbation's. This type of under-reporting reflects a false level of asthma control when
      queried by the ACT and leads to inappropriate medical management when spirometry is not
      utilized.

      As exploratory endpoints, we will obtain fractional exhaled nitric oxide (FeNO) measurements
      shortly after spirometry is performed. Elevated FeNO indicates eosinophilic airway
      inflammation and assists in assigning the correct asthma phenotype, which can have
      implications for asthma management. We will also obtain nasal epithelial lining fluid (ELF)
      for collection of nasal cytokines and chemokines. This information is useful for expanding
      our current understanding of the inflammatory mediators involved in asthma-associated airway
      inflammation.
    

Intervention name(s): Validation of Asthma Control Questionnaire
Intervention type(s): Other
Intervention description(s): This is an observational study so there is no planned intervention.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children ages 12-18 with a physician diagnosis of persistent asthma living in a defined
        geographical area