The bedrock of asthma management is the attainment and maintenance of optimal asthma control. Numerous studies have confirmed the inadequacy of asthma control in the U.S. Therefore, periodic appraisal and monitoring of asthma control using validated tools that can be used routinely in a clinical practice setting is paramount.
Knowledge of the properties, applications and relative value of the instruments described in a new AAP clinical report can help clinicians integrate standardized measures into ambulatory practice for delivery of high-quality, customized care.
The report, Clinical Tools to Assess Asthma Control in Children, from the Section on Allergy and Immunology and Section on Pediatric Pulmonology and Sleep Medicine, is available at http://dx.doi.org/10.1542/peds.2016-3438 and will be published in the January issue of Pediatrics.
Using the tools
Asthma control exhibits short- and long-term variability. Health care providers need to be cognizant that a judicious combination of subjective (patient reported) and objective (physiologic and inflammatory) measures may need to be utilized. To date, no unequivocal benchmark of asthma control accurately encapsulates both patient-reported domains of impairment and risk and objective measures of lung function.
Subjective measures of asthma control include detailed history taking, use of composite asthma control scores and quality-of-life measures.
The first step is a meticulous history exploring patient-centered outcomes (such as the limitations on the child's daily activities, adherence to therapy and factors that may complicate care). Some of these elements can be captured using patient-reported composite asthma control scores. These attempt to transcribe the multidimensional nature of asthma control into a single numerical value that enables comparison of asthma control across encounters.
Commonly used composite tools are the Asthma Control Test (ACT), the Childhood Asthma Control Test (C-ACT) and the Asthma Control Questionnaire (ACQ). In addition, the Test for Respiratory and Asthma Control in Kids (TRACK) can be used in children younger than 5 years of age. These instruments have comparable content and measure asthma disease activity over one to four weeks, though none of them has been validated to assess an acute exacerbation. A range of asthma-related quality-of-life measures are available, but they are time-intensive, limiting their use in practice.
Currently available objective measures of asthma control include assessment of lung function, evaluation of airway hyperresponsiveness and biomarkers.
A bedside test of lung function traditionally used in the management of acute exacerbations is the peak expiratory flow (PEF) measurement because it is easier to perform than a spirometric maneuver and is available as a small, portable and inexpensive device. However, many concerns regarding PEF have been voiced, such as the high variability in results and adherence to PEF monitoring, and the fact that there is no benefit over symptom monitoring; hence, the test no longer is recommended.
Measurement of spirometric indices of lung function, such as the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio, is an integral part of the assessment of asthma severity, control and response to treatment. Spirometric measures are highly reproducible within testing sessions in approximately 75% of children older than 5 to 6 years. However, airflow limitation may be mild or absent, particularly in children, and if the spirometry result is normal, it does not rule out asthma.
Bronchodilator reversibility testing assesses temporal variability of airflow obstruction and the response to treatment. Although not specific, it is useful for confirming the diagnosis of asthma and assessing asthma control. Increased bronchodilator reversibility correlates with increased asthma severity; it is diminished in patients with well-controlled asthma and in those with airway remodeling. Annual assessment of pre-bronchodilator and post-bronchodilator FEV1 might help identify children at risk for developing progressive decline in airflow. Impulse oscillometry, available at only a few centers, assesses airflow resistance and bronchodilator response in younger children.
Airway hyperresponsiveness (AHR) may be assessed by bronchial provocation tests performed with agents such as methacholine or stimuli such as physical exercise. In general, evidence does not support the routine assessment of AHR in the clinical management of asthma control.
The utility of noninvasive biomarkers in routine clinical practice for monitoring inflammation in children with asthma is undefined, apart from exhaled nitric oxide measurements. Sputum eosinophilia, exhaled breath condensates and urinary leukotrienes are used as tools primarily in research studies.
Measurement of the fractional concentration of nitric oxide in exhaled air (FENO) serves as an indirect noninvasive marker of airway inflammation. It is available as a reproducible, easy-to-perform, standardized test that is feasible to measure in ambulatory clinical settings and has no risk to patients. The value of additional FENO monitoring in children whose asthma is appropriately managed using guideline-based strategies is unproven, and reimbursement for this test varies by location. Nevertheless, some asthma specialists use FENO as an adjunct ambulatory clinical tool for measuring airway inflammation and serial monitoring asthma control in individual patients with difficult-to-control asthma.
Summary
Suggested measures that can be used in routine ambulatory monitoring of asthma control in clinical practice include detailed history-taking with a complete environmental and social history; use of validated asthma composite scores; and pre-bronchodilator and post-bronchodilator spirometry at the initial consultation. Clinicians should offer asthma education and training regarding home management using symptom-based or objective action strategies.
At subsequent visits, monitoring of symptom scores, FEV1 and FENO (if performed and found elevated at initial visit) may be done. Education regarding asthma triggers, review of inhaler techniques, assessment and reinforcement of adherence, and treatment of comorbidities can be provided. The need for assessment by a pediatric allergist or pulmonologist can be considered when faced with challenges in attaining optimal asthma control.
Dr. Dinakar is a lead author of the clinical report and member of the AAP Section on Allergy and Immunology Executive Committee.
