To Determine the Measurement Properties of the ACT in an African American Adolescent Population With Persistent Asthma
Condition: Asthma
MeSH terms: Asthma
Study type: Observational

Summary: 
      Purpose: To determine the measurement properties of the asthma control test (ACT) in a
      prospective clinical study in an African American adolescent population.
    

Detailed description: 
      African Americans have a higher rate of asthma (11.2%) compared to whites (7.7%), according
      to the Centers for Disease Control and Prevention, and this asthma is disproportionally not
      well-controlled. African Americans have higher mortality from and healthcare utilization for
      their asthma. Their asthma severity is more likely to be underestimated by their "main asthma
      provider". African-American adolescents are at particularly high risk of asthma-related
      morbidity and mortality.

      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 NAEPP
      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. Minorities see subspecialists less often than Caucasians (28.3% vs 41%, p=0.001), and
      this difference could not be explained by age, gender, health insurance, education,
      employment, patient preference, or frequency of respiratory symptoms. For primary care
      practices following these 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. 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. However, measurement properties of the ACT
      are lacking in the African American 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. Moreover, concerns have been raised as to the application of these cut-offs for
      different ethnic populations. Recent studies examining the ACT in pediatric adolescent
      populations have found higher optimal cut points to distinguish control classifications;
      these groups included both European cohorts as well as children of Mexican descent in
      Southern California. The ACT has not been validated in a more ethnically diverse population
      such as in African American adolescents.

      The measurement properties of validity, reliability, and responsiveness are critical to the
      usefulness of any questionnaire in both clinical and research settings. To date, we have been
      unable to identify a study that evaluated the measurement properties of the ACT in this
      at-risk minority population.

      Lung function measures are included in the rubric of assessing asthma control by the NAEPP.
      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 subspecialists 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. However, African
      Americans perceive asthma symptoms differently than Caucasians. They report less nighttime
      awakening and dyspnea, two symptoms that account for 20% of the ACT score, and children are
      less accurate describing their perceived asthma control. 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.

      Additionally, health literacy is often underestimated. In a review by Diette of approximately
      500 mostly African American patients who were asked to read asthma information, only 27% were
      able to read at a high school level, the level at which most health information and
      instructions are written. Patients with limited health literacy and chronic illness know less
      about how to manage their disease and have a higher likelihood of poorly controlled disease
      and health status compared to their counterparts with higher health literacy. Due to this,
      the IOM identifies health literacy as being fundamental to quality care and also considers it
      a priority in health-care quality and disease prevention. Because currently used
      questionnaires are often provided to patients at the time of intake at a clinic visit for
      self-administration, a high level of health literacy in this minority adolescent population
      is a dangerous assumption that must be considered when addressing the utilization of tools in
      the assessment of asthma control by primary care providers and subspecialists alike.

      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.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        80 African-American adolescents ages 12-18 with a physician diagnosis of persistent asthma.
        These adolescents are followed at the UNC Asthma Clinic seen by either pediatric
        pulmonologists or allergists.