Bronchodilator Test is Useful for Assessing Asthma Control

Researchers have determined the benefits of the bronchodilator test in connection to forced expiratory volume in one second (FEV1) testing for assessing current clinical asthma control and future risk of asthma symptom exacerbation in patients with asthma.

The assessment of asthma has an important place in clinical treatment of asthma. In order to establish information about patients asthma control there are a common series of questionnaires (such as the American Thoracic Society’s Asthma Control Questionnaire (ACQ) and Asthma Control Test (ACT).

According to the study led by Marta Ferrer Galván, MD, and colleagues with the Medical-Surgical Unit for Respiratory Diseases at the Virgen Del Rocio University Hospital in Seville, Spain, these question-based instruments of determining asthma control do not always “correspond to the changes in endobronchial inflammation, bronchial hyper responsiveness or airway obstruction.”

Recent articles have argued for increased use of objective instruments for “evaluation of the degree of control of current asthma symptoms;” one commonly used tool for determining pulmonary function is the FEV1 test, which examines forced expiratory volume in one second. According to Galván, this tool is “an important part of the evaluation of future risk,” because it identifies “asthmatic exacerbations independent of the symptoms.”

The study’s purpose was two-fold, according to Galván: 1) to determine the “relationship of the degree of FEV1 reversibility with control according to the scoring of ACT, establishing a cutoff point of reversibility related to the non-control of asthma,” and 2) study the relationship of the established cutoff point to determination of future risk.

The study took place in an outpatient asthma center at the Virgen Del Rocio University Hospital and included a one-year long follow up study with visits every four months. The 407 study participants were older than 12-years-of-age, diagnosed with mild-to-severe asthma, non-smoking, and not currently treated with oral corticosteroids.

Clinical functional tests such as the FeNO (fractional Nitric Oxide), and forced spirometry with bronchodilation, the ACT questionnaire, and the allergen sensitization test (prick technique) was completed by each participant at the initial visit and four follow ups. Data collection and testing was performed in line with ATA and European Respiratory Society recommendations. Patients were given tests at baseline and post-bronchodilator, and the resulting data were then assessed.

Post-assessment, patients were classified as controlled, partially controlled, or non-controlled according to standards set by the Global Initiative for Asthma Management and Prevention (GINA 2006). Changes in asthma control were documented during each clinical visit to record worsening exacerbation, increase in symptoms, medical intervention, increased use of medication, and use of rescue inhalers.

The study found that ACT questionnaires alone could not objectively predict worsening asthma control in patients because the worsening symptoms were “hidden” by use of rescue inhalers and higher doses of corticosteroids. However, spirometric testing, and particularly post-bronchodilator FEV1 reversibility testing, revealed increased exacerbations in patients. Galván stated that “the persistence of a significant degree of bronchodilator response despite regular treatment” became a marker for decreased asthma control.

Resulting data confirmed, “Spirometric evaluation of the degree of reversibility would be a more objective evaluation parameter, which together with the classical evaluation of patient symptoms would help the clinician to take a better therapeutic control.” Galván suggested that post-bronchodilator FEV1 reversibility provides additional parameters for evaluating current clinical control of asthma in patients. An individual’s response to the bronchodilator test could, according to the study, help healthcare providers understand the response of the airway and “may be related to future risk parameters.”

The article “Is the Bronchodilator Test an Useful Tool to Measure Asthma Control?” appears in the May 2017 issue of Respiratory Medicine.

Related Coverage:

Children with “Hard-to-Control” Asthma Require Specific, Tailored Treatment

Patients with Severe Asthma Symptoms Require Improvements in Assessment and Diagnosis

Researchers Recommend Additional RV/TLC Testing for Patients with Longer Duration Asthma